Module 10 -- Lobes of the Brain:
Frederick Robert Carrick, DC, PhD, DACAN, DABCN, DACAN, DAAPM, FACCN,
Distinguished Post Graduate Professor of Clinical Neurology, Logan College.
Module 10 of the Diplomate in Neurology Program emphasizes the stereotactic relationships
of the lobes of the human brain to function. The breadth of information in this knowledge
area module is specific to the anatomy and physiology of the lobes of the brain and the
specific functional relationships of specific brain areas to general and specific plastic human
expression. The depth of information in this knowledge area will be specific to clinical
applications utilizing non pharmaceutical and non surgical methodology. Clinical techniques
specific to the application of the knowledge area will be introduced.
The following references have been utilized by Prof. Carrick in his preparation of his lecture
on the Lobes of the Brain. The abstracts of these references are the reading requirements for
this module. Due to the changing state of knowledge in the field of brain there are no text
required readings or references for this module that represent the current level of knowledge
represented in these references.
 
1. Abdullaev, Y. G.; Posner, M. I. Event-related brain potential imaging of semantic
encoding during processing single words. Neuroimage. 1998 Jan; 7(1): 1-13; ISSN:
1053-8119.
UNITED-STATES. Functional brain imaging studies with positron emission
tomography (PET) have identified blood flow changes in widely separated areas
of brain during the performance of word processing tasks. In the present study we
have utilized event-related brain potentials (ERPs) to investigate the temporal
relationships among cortical areas previously identified by PET to be
differentially activated when performing semantic tasks with visual words. ERPs
revealed task-related differences over the central and left inferior frontal regions
around 170 and 220 ms, respectively, over a left occipital region around 200 ms,
over a large left parietotemporal region around 600 ms, and finally over the right
temporal lobe around 800 ms after the word presentation. Analysis of
topographic maps and dipole sources as well as PET data allowed relating frontal
midline positivity around 170 ms to the anterior cingulate activation, and left
inferior frontal positivity around 220 ms to the PET activation of the left inferior
prefrontal cortex. The left parieto-temporal positivity around 600 ms seems to
reflect the activity of Wernicke's area. The right anterior temporal negativity
beginning around 800 ms and peaking around 1100 ms may reflect the activity of
the right insula. The left occipital negativity around 200 ms is likely to reflect
activation of a visual word-form area in the left occipital lobe. These results
provide the time course for parts of the circuitry involved in semantic processing
of words and also demonstrate how combining the spatial localization of PET
with the temporal resolution of ERPs helps to understand the brain mechanisms
involved in human cognition.
2. Abounader, R.; Hamel, E. Associations between neuropeptide Y nerve terminals and
intraparenchymal microvessels in rat and human cerebral cortex. J-Comp-Neurol.
1997 Nov 24; 388(3): 444-53; ISSN: 0021-9967.
UNITED-STATES. Neuropeptide Y (NPY) can influence local brain perfusion,
possibly via direct relationships with the microvascular bed. To evaluate this
possibility, the authors quantitatively analyzed by light and electron microscopy
the morphological associations between immunostained NPY neuronal elements
and intraparenchymal microvessels in the rat and human cerebral cortex. At the
light microscopic level in the rat frontoparietal cortex, about 16% of NPY neurons
and large proximal processes as well as a subset of nerve terminals not affected by
double sympathectomy were associated with penetrating arterioles and local
microvessels. In human temporal cortex, a dense network of NPY nerve fibers was
observed, many of which approached and/or contacted intracortical vessels. At
the ultrastructural level, 14% of NPY axonal varicosities in the rat cerebral cortex
were considered perivascular and associated with capillaries (approximately 70%)
or microarterioles (approximately 30%). They were particularly enriched in the
immediate vicinity (< 0.25 micron) of the microvessels, where the perivascular
astrocytic leaflets represented a frequent target. In human cerebral cortex, NPY
varicosities were observed in proximity to microvessels corresponding primarily
to capillaries. Perivascular NPY varicosities never established synaptic junctions
with vascular or astroglial elements. The results show that central NPY nerve
terminals associate with microvessels and perivascular astroglial cells in the rat
and human cerebral cortex. Thus, NPY released from these nerves could possibly
influence (via a parasynaptic mode of action) vascular and/or astrocytic functions
depending on the distribution of NPY receptors in these cellular compartments.
These results provide morphological support for the effects of NPY on brain
perfusion and homeostasis.. 0.
3. Alden, J. D.; Harrison, D. W.; Snyder, K. A.; Everhart, D. E. Age differences in
intention to left and right hemispace using a dichotic listening paradigm.
Neuropsychiatry-Neuropsychol-Behav-Neurol. 1997 Oct; 10(4): 239-42; ISSN:
0894-878X.
UNITED-STATES. This study assessed the influence of age (younger women
and elderly women living in communities) on cerebral laterality using dichotic
listening. Previous research has purported to show a relative right cerebral decline
with age. To date, however, research on the right hemiaging hypothesis has
provided mixed findings. It is possible that these mixed findings are caused by use
of simple versus complex dichotic listening tasks. As a test of this hypothesis,
older women were expected to have a heightened right ear advantage (REA) for
phonemic speech sounds and greater difficulty switching intention to the left ear
when instructed to focus to either the left or the right ear. No age difference was
found using the traditional presentation of concurrent phonemes. However, the
right hemiaging hypothesis was supported on the intentional task, in which older
women were less able to switch intention to the left but not to the right ear.
Implications for right hemiaging are discussed.
4. Alexander, M. J.; DeSalles, A. A.; Tomiyasu, U. Multiple radiation-induced
intracranial lesions after treatment for pituitary adenoma. Case report. J-
Neurosurg. 1998 Jan; 88(1): 111-5; ISSN: 0022-3085.
UNITED-STATES. This 53-year-old man presented with a syncopal episode 31
years after undergoing craniotomy and external-beam radiation for a pituitary
macroadenoma. A gadolinium-enhanced magnetic resonance (MR) image of the
brain demonstrated a 2.5-cm enhancing mass in the right caudate region that had
not been seen on previous studies. A stereotactically guided biopsy procedure
was performed to obtain specimens from the mass, which were consistent with
ependymoma. The MR image also revealed two additional lesions that appeared
to be within the radiation fields: a right temporal meningioma and a left frontal
cavernous malformation. A review of the literature found three previous reports in
which ependymomas presented after radiation therapy.
5. Alonso, S. J.; Navarro, E.; Santana, C.; Rodriguez, M. Motor lateralization, behavioral
despair and dopaminergic brain asymmetry after prenatal stress. Pharmacol-
Biochem-Behav. 1997 Oct; 58(2): 443-8; ISSN: 0091-3057.
UNITED-STATES. This paper presents data suggesting a relationship between
rat behavioral despair in the Porsolt test and motor lateralization in the T-maze
test. In addition, experimental evidence suggests a functional coupling among
dopaminergic systems, behavioral despair and motor lateralization. In the first
experiment, female, not male, rats with a high level of behavioral despair showed a
low level of behavioral lateralization. The inverse relationship was found in female
offspring of mothers stressed during gestation. In comparison with unstressed-
mother rats, the female offspring of stressed mothers showed an increase of
dopamine (DA) and a decrease of dihydroxyphenylacetic acid (DOPAC) and
Homovanillic (HVA) levels and of DOPAC:DA and HVA:DA indexes in the n.
accumbens of the right side of the brain. No significant differences were found in
the n. accumbens of the left brain. Taken together, the present data provide
evidence of a relation between behavioral despair and motor lateralization,
suggesting that the biological dopaminergic inervation of n. accumbens could be
the basis for this functional coupling. Because the stress of gestant mothers
modified these biochemical and behavioral variables, the present study also
suggests that lateralization of behavior and emotion during adulthood can be
modified by prenatal variables.. 51-61-6.
6. Amunts, K.; Schlaug, G.; Schleicher, A.; Steinmetz, H.; Dabringhaus, A.; Roland, P.
E.; Zilles, K. Asymmetry in the human motor cortex and handedness.
Neuroimage. 1996 Dec; 4(3 Pt 1): 216-22; ISSN: 1053-8119.
UNITED-STATES. Handedness is one of the most obvious functional
asymmetries, but its relation to an anatomical asymmetry of the hand
representation area in the motor cortex has not been demonstrated. This would be
a crucial test for the hypothesis of structure-function correlation in cortical motor
organization. Using magnetic resonance morphometry, we show for the first time
that the depth of the central sulcus is related to handedness. In right-handers, the
left central sulcus is deeper than the right, and vice versa in left-handers.
Macrostructural asymmetry is complemented by a microstructural left-larger-
than-right asymmetry in neuropil volume (i.e., tissue compartment containing
dendrites, axons, and synapses) in Brodmann's area 4. These asymmetries suggest
that hand preference is associated with increased connectivity (demonstrated by
an increased neuropil compartment in left area 4) and an increased intrasulcal
surface of the precentral gyrus in the dominant hemisphere.
7. Amunts, K.; Schmidt Passos, F.; Schleicher, A.; Zilles, K. Postnatal development of
interhemispheric asymmetry in the cytoarchitecture of human area 4. Anat-
Embryol-Berl. 1997 Nov; 196(5): 393-402; ISSN: 0340-2061.
GERMANY. The postnatal development of interhemispheric asymmetry was
analyzed in the primary motor cortex (area 4) of 20 human brains with
quantitative cytoarchitectonic techniques. The volume fraction of cortical tissue
occupied by cell bodies (grey level index) was determined by automated image
analysis. In children as well as in adults, the volume fraction of cell bodies
averaged over all cortical layers was greater on the right than on the left. Thus, the
space between cell bodies, i.e. the volume fraction of neuropil containing axons,
dendrites and synapses, was greater in the left than in the right primary motor
cortex. At the level of single layers, however, interhemispheric asymmetry of the
neuropil volume fraction differed between age groups. The supragranular layers
were significantly less asymmetrical in children than in adults, whereas the
infragranular layers showed a similar degree of asymmetry in both age groups.
Thus, the postnatal development of the architectonic asymmetry in the supra-
and infragranular layers of area 4 follows the same sequence of maturation as
found during neuronal migration, i.e. an inside-to-outside gradient. Comparing the
layer-specific developmental pattern with available functional data, it was found
that the structural maturation of interhemispheric asymmetry in the supragranular
layers correlates with the development of hand preference.
8. Andersson, J. L. How to estimate global activity independent of changes in local
activity. Neuroimage. 1997 Nov; 6(4): 237-44; ISSN: 1053-8119.
UNITED-STATES. A method is suggested to ensure independence between the
estimated global flow and changes in local flow in PET activation studies. Global
flow is estimated as the average of all intracerebral voxels, except those that
exhibit a consistent change in flow as a consequence of the experimental design.
This is achieved by performing an initial analysis, using all intracerebral voxels for
estimation of global flow, in which an F-map depicting task related changes is
produced. A second analysis is performed, now excluding all voxels with a P <
0.05 in the F-map when evaluating global flow, thereby ensuring independence
from areas changing in a task-dependent manner. The feasibility of the method is
demonstrated on phantom data, showing that the distribution is skewed in
nonactivated areas when including the activated areas in the calculation of global
flow. By excluding these areas the distribution is translated toward zero and
becomes consistent with the null-hypothesis. Furthermore, the usefulness of the
suggested scheme is demonstrated on human data. Scans performed while subjects
watched a movie featuring snakes were contrasted to scans performed while
watching white noise, producing highly significant activations of the visual
system. When using the traditional way of estimating global flow, deactivations
were observed in very large portions of the frontal, parietal, and temporal lobes.
When using the method suggested in the present paper these disappeared, which
would be more consistent with the expected effects of stimulation. The method
was used in conjunction with both ratio and ANCOVA adjustment with very
similar results. Copyright 1997 Academic Press.
9. Andreasen, N. C.; O'Leary, D. S.; Cizadlo, T.; Arndt, S.; Rezai, K.; Watkins, G. L.;
Ponto, L. L.; Hichwa, R. D. II. PET studies of memory: novel versus practiced
free recall of word lists. Neuroimage. 1995 Dec; 2(4): 296-305; ISSN: 1053-8119.
UNITED-STATES. Positron emission tomography (PET) with the tracer
H215O was used to measure regional cerebral blood flow in 13 healthy volunteers
while they engaged in free recall of 15-item word lists from the Rey Auditory
Verbal Learning task. The study was designed so that recall of well-practiced
versus novel material could be compared. One week before the PET study,
subjects were trained to perfect recall of List A, while they were exposed to list B
only 60 s prior to PET data acquisition. As in the companion study of free recall
of complex narratives, we observed that practice tended to decrease the size of
activations in regions involved in the memory component of the task; we also
observed that the novel recall task produced greater activation in left frontal
regions, probably due to active encoding. A commonality of other regions
observed in this pair of studies, as well as other studies of memory in the
literature, suggests that the human brain may contain a distributed multinodal
general memory system. Nodes on this network include the frontal, parietal, and
temporal cortices, the thalamus, the anterior and posterior cingulate, the
precuneus, and the cerebellum. There appears to be a commonality of components
across tasks (e.g., retrieval, encoding) that is independent of content, as well as
differentiation of some components that may be content-specific or tasks-
specific. In addition, these results support a significant role for the cerebellum in
cognitive functions such as memory.
10. Annoni, J. M.; Pegna, A. J. Random motor generation in a finger tapping task:
influence of spatial contingency and of cortical and subcortical hemispheric brain
lesions. J-Neurol-Neurosurg-Psychiatry. 1997 Nov; 63(5): 654-9; ISSN: 0022-
3050.
ENGLAND. OBJECTIVE: To test the hypothesis that, during random motor
generation, the spatial contingencies inherent to the task would induce additional
preferences in normal subjects, shifting their performances farther from
randomness. By contrast, perceptual or executive dysfunction could alter these
task related biases in patients with brain damage. METHODS: Two groups of
patients, with right and left focal brain lesions, as well as 25 right handed subjects
matched for age and handedness were asked to execute a random choice motor
task--namely, to generate a random series of 180 button presses from a set of 10
keys placed vertically in front of them. RESULTS: In the control group, as in the
left brain lesion group, motor generation was subject to deviations from theoretical
expected randomness, similar to those when numbers are generated mentally, as
immediate repetitions (successive presses on the same key) are avoided. However,
the distribution of button presses was also contingent on the topographic
disposition of the keys: the central keys were chosen more often than those
placed at extreme positions. Small distances were favoured, particularly with the
left hand. These patterns were influenced by implicit strategies and task related
contingencies. By contrast, right brain lesion patients with frontal involvement
tended to show a more square distribution of key presses--that is, the number of
key presses tended to be more equally distributed. The strategies were also altered
by brain lesions: the number of immediate repetitions was more frequent when the
lesion involved the right frontal areas yielding a random generation nearer to
expected theoretical randomness. The frequency of adjacent key presses was
increased by right anterior and left posterior cortical as well as by right subcortical
lesions, but decreased by left subcortical lesions. CONCLUSIONS: Depending on
the side of the lesion and the degree of cortical-subcortical involvement, the
deficits take on a different aspect and direct repetions and adjacent key presses
have different patterns of alterations. Motor random generation is therefore a
complex task which seems to necessitate the participation of numerous cerebral
structures, among which those situated in the right frontal, left posterior, and
subcortical regions have a predominant role.
11. Aouda, A.; Hayashi, F.; Fukuda, Y.; Masuda, Y. An in vitro brainstem-heart
preparation of the neonatal rat with intact right vagus nerve. Jpn-J-Physiol. 1997
Oct; 47(5): 443-8; ISSN: 0021-521X.
JAPAN. An in vitro brainstem preparation of the neonatal rat with intact right
vagal (X) innervation of the right atrium, and intact medullary roots of the left X
and glossopharyngeal (IX) nerves for stimulation was developed. The preparation
was continuously superfused with artificial CSF at 25 degrees C. The electrical
activity of the right atrium was recorded to determine the heart rate. Applications
of atropine or propranolol to the superfusate did not alter the heart rate. Electrical
stimulation (0.5 ms pulse, 20 Hz) of the left IX and X afferents elicited a
reduction in the heart rate from 70.3 +/- 13.2 to 50.6 +/- 13.2 beats/min (mean +/-
SD, p < 0.05), which was abolished after division of the right X or application of
atropine to the superfusing solution. A similar reflex bradycardia was seen in a
preparation with intact left vagal-right atrium innervation during right IX and X
afferent stimulation. Cervical spinal cord transection affected neither the baseline
heart rate nor the magnitude of the reflex bradycardia. Longitudinal sectioning of
the medulla oblongata in the mid-line down to the level of the posterior inferior
cerebellar artery abolished the heart rate response. After bilateral cervical
vagotomies, electrical stimulation (0.5 ms pulse, 20 Hz, up to 100 microA) of the
ventrolateral medulla oblongata, lateral funiculus at C2 or intermediate nucleus of
the spinal cord at Th1-4 did not affect the heart rate. These results indicate that
the functions in the lower brainstem are preserved in this preparation, at least in
regard to the generation of reflex bradycardia. The results also suggest that the
laterality of cardiac vagal innervation and sympathetic innervation will develop
during the postnatal period. This preparation may be useful for the study of the
central neuronal network controlling the heart rate.. 0; 0; 51-55-8; 525-66-6.
12. Arndt, S.; Cizadlo, T.; O'Leary, D.; Gold, S.; Andreasen, N. C. Normalizing counts
and cerebral blood flow intensity in functional imaging studies of the human brain.
Neuroimage. 1996 Jun; 3(3 Pt 1): 175-84; ISSN: 1053-8119.
UNITED-STATES. Image intensity normalization is frequently applied to
eliminate or adjust for subject or injection global blood flow (gCBF) and other
sources of nuisance variation. Normalization has several other positive effects on
the analysis of PET images. However, the choice of an intensity normalization
technique affects the statistical and psychometric properties of the image data.
We compared three normalization procedures, the ratio approach (regional
(r)CBF/gCBF), histogram equalization, and ANCOVA, on both PET count and
flow data sets. The ratio method presents the proportional increase of regions, the
histogram equalization method offers the relative ranking of intensities over the
image, and the ANCOVA method provides statistical deviations from an expected
linear model of regional values from the subject's gCBF. The original study used
33 normal subjects in a standard subtraction paradigm. The normalization
methods were evaluated on their ability to remove extraneous error variation,
induce homogeneity of intersubject variation, and remove unwanted dependencies.
In general, the normalization modified the subtraction image more than the
individual condition images. All three methods worked well at removing the
dependency of rCBF on gCBF in count and flow images. For count data, the three
methods also reduced the amount of error variation equally well, improving the
signal to noise ratio. For flow data, the histogram equalization and ratio methods
worked best at reducing statistical error. All three methods dramatically stabilized
the variance over the image.
13. Arrowsmith, J. E.; Robertshaw, H. J.; Boyd, J. D. Nasotracheal intubation in the
presence of frontobasal skull fracture. Can-J-Anaesth. 1998 Jan; 45(1): 71-5;
ISSN: 0832-610X.
CANADA. PURPOSE: To present a case of maxillofacial trauma and basal skull
fracture (BSF) in whom nasotracheal intubation (NTI) was successfully used,
without complication, to facilitate surgical fixation. To present alternative
methods of airway management in this situation and to review the evidence
supporting the notion that NTI is contraindicated in the presence of basal skull
fracture. CLINICAL FEATURES: A 17-yr-old man was referred for surgical
fixation of bilateral mandibular fractures. Cranial computed tomography revealed
intracranial air and blood in all four sinuses and distortion of the nasal passage on
the right. There was no cerebral injury and the left nasal passage appeared patent.
In order to facilitate intraoperative intermaxillary fixation fibreoptic NTI was
undertaken in preference to tracheostomy. The patient made an uneventful
recovery without evidence of meningitis or direct cerebral injury. CONCLUSION:
In selected patients NTI may be performed in the presence of BSF. Available
evidence suggests that BSF-should not be regarded as an absolute contraindication
to NTI.
14. Asano, K.; Sekiya, T.; Shimamura, N.; Tanaka, M.; Takemura, A.; Suzuki, S.; Kubo,
O. [A case of giant cell-rich gliosarcoma]. No-To-Shinkei. 1997 Oct; 49(10): 938-
44; ISSN: 0006-8969.
JAPAN. We report a case of gliosarcoma with numerous giant cells resembling
ganglion cells and having clear nucleoli. A 75-year woman was admitted to our
hospital suffering from progressive left hemiparesis and ambulatory disturbance
of one week's duration. CT and MRI studies showed ring enhancement on a clear
margin mass in the right parieto-occipital lobe. The mass was totally removed
macroscopically. Her left hemiparesis had improved and self walk came to be
possible. But the tumor was regrowthed during next two months and she died for
three months and a week. The gross and microscopic appearances of the tumors
showed the double structure. The surface of the tumor was well enhanced and
consisted of soft, gray, and easily bleeding tissue. The central core, however, was
poorly enhanced and consisted of hard, yellow, non-bleeding tissue.
Macroscopically, the central area included numerous giant ganglion-like cells
which were negative for GFAP but positive for EMA in the cytoplasm. These
giant cells had abundant collagen fibers and were surrounded by such fibers.
Microscopic findings of the surrounding area included numerous spindle shaped
cells which were positive for GFAP and vimentin. The origins of giant cells or
tumor tissues have long been discussed, but no consensus has yet been obtained.
Therefore, we speculated as to the origin in our patient based on
immunohistochemical study and the findings of electronmicroscopy. We
concluded, in sharp contrast to the old theory of one origin, epithelial tissue of a
hamartomatous nature existed initially, followed by the growth of malignant tissue
of a reactive astrocytic tumor with a sarcomatous component.. 80529-93-7.
15. Badan, M.; Caramazza, A. Haptic processing by the left hemisphere in a split-brain
patient. Neuropsychologia. 1997 Sep; 35(9): 1275-87; ISSN: 0028-3932.
ENGLAND. We report the case of a patient who suffered an ischemic accident
resulting in damage to the anterior part of the corpus callosum and to the white
matter in the posterior right hemisphere. Recognition of two-dimensional haptic
stimuli explored with the right hand was severely impaired. The deficit was not
specific to the type of stimuli, since letters, digits and geometrical shapes were
not correctly recognized. Poor performance was not due to a specific mode of
haptic exploration, since deficits were also observed without active manipulation
of the stimuli. In contrast, the patient correctly named visual letters presented in
the right visual hemifield (left hemisphere), and recognized three-dimensional
common objects palpated with the right hand. Comparable results were observed
in a surgical split-brain patient tested as a control. We conclude that (i) the
construction of spatial representations of haptic stimuli, such as two-dimensional
stimuli or three-dimensional block letters, cannot be fully realized in the intact left
hemisphere, this ability requiring the contribution of both hemispheres, and (ii)
tests for correct naming of common objects do not provide sufficient evidence to
establish the integrity of the system involved in the identification of haptic
information processed by the right hand of split-brain patients.
16. Bandettini, P. A.; Wong, E. C. A hypercapnia-based normalization method for
improved spatial localization of human brain activation with fMRI. NMR-
Biomed. 1997 Jun; 10(4-5): 197-203; ISSN: 0952-3480.
ENGLAND. An issue in blood oxygenation level dependent contrast-based
functional MRI is the accurate interpretation of the activation-induced signal
changes. Hemodynamic factors other than activation-induced changes in blood
oxygenation are known to contribute to the signal change magnitudes and
dynamics, and therefore need to be accounted for or removed. In this paper, a
general method for removal of effects other than activation-induced blood
oxygenation changes from fMRI brain activation maps by the use of hypercapnic
stress normalization is introduced. First, the effects of resting blood volume
distribution across voxels on activation-induced BOLD-based fMRI signal
changes are shown to be significant. Second, the effects of hypercapnia and
hypoxia on resting and activation-induced signal changes are demonstrated. These
results suggest that global hemodynamic stresses may be useful for non-invasive
mapping of blood volume. Third, the normalization technique is demonstrated..
124-38-9; 7782-44-7.
17. Bandettini, P. A.; Wong, E. C. A hypercapnia-based normalization method for
improved spatial localization of human brain activation with fMRI. NMR-
Biomed. 1997 Jun; 10(4-5): 197-203; ISSN: 0952-3480.
ENGLAND. An issue in blood oxygenation level dependent contrast-based
functional MRI is the accurate interpretation of the activation-induced signal
changes. Hemodynamic factors other than activation-induced changes in blood
oxygenation are known to contribute to the signal change magnitudes and
dynamics, and therefore need to be accounted for or removed. In this paper, a
general method for removal of effects other than activation-induced blood
oxygenation changes from fMRI brain activation maps by the use of hypercapnic
stress normalization is introduced. First, the effects of resting blood volume
distribution across voxels on activation-induced BOLD-based fMRI signal
changes are shown to be significant. Second, the effects of hypercapnia and
hypoxia on resting and activation-induced signal changes are demonstrated. These
results suggest that global hemodynamic stresses may be useful for non-invasive
mapping of blood volume. Third, the normalization technique is demonstrated..
124-38-9; 7782-44-7.
18. Bandinelli, G.; Cencetti, S.; Buccheri, A. M.; Lagi, A. Noninvasive assessment of
posterior cerebral artery stenosis inducing hemiplegia. Ann-Ital-Med-Int. 1997
Jan; 12(1): 31-4; ISSN: 0393-9394.
ITALY. Posterior cerebral artery infarction usually causes hemianopsia and,
occasionally, symptoms referred to infarction in the territory of the middle
cerebral artery. We describe a case of cerebral infarction of the posterior cerebral
artery territory that mimicked middle cerebral artery occlusion. A patient with
infarction of the right surface and deep territories of the posterior cerebral artery
presented with left hemiplegia and left homonymous hemianopsia. Brain
computed tomography and magnetic resonance investigation disclosed a
hypodense lesion in the occipital right lobe and the medial and inferior part of the
right temporal lobe. Transcranial Doppler studies disclosed an abnormally
increased blood flow velocity in the proximal posterior cerebral artery and a sharp
reduction in distal flow velocity. This case underscores the utility of noninvasive
techniques to diagnose posterior artery stenosis: they were not only more
economical than angiography but also spared the patient discomfort and risk.
19. Barbas, H.; Rempel Clower, N. Cortical structure predicts the pattern of
corticocortical connections. Cereb-Cortex. 1997 Oct; 7(7): 635-46; ISSN: 1047-
3211.
UNITED-STATES. Cortical areas are linked through pathways which originate
and terminate in specific layers. The factors underlying which layers are involved
in specific connections are not well understood. Here we tested whether cortical
structure can predict the pattern as well as the relative distribution of projection
neurons and axonal terminals in cortical layers, studied with retrograde and
anterograde tracers. We used the prefrontal cortices in the rhesus monkey as a
model system because their laminar organization varies systematically, ranging
from areas that have only three identifiable layers, to those that have six layers.
We rated each prefrontal area based on the number and definition of its cortical
layers (level 1, lowest; level 5, highest). The structural model accurately predicted
the laminar pattern of connections in approximately 80% of the cases. Thus,
projection neurons from a higher-level cortex originated mostly in the upper layers
and their axons terminated predominantly in the deep layers (4-6) of a lower-level
cortex. Conversely, most projection neurons from a lower-level area originated in
the deep layers and their axons terminated predominantly in the upper layers (1-
3) of a higher-level area. In addition, the structural model accurately predicted that
the proportion of projection neurons or axonal terminals in the upper to the deep
layers would vary as a function of the number of levels between the connected
cortices. The power of this structural model lies in its potential to predict
patterns of connections in the human cortex, where invasive procedures are
precluded.. 0.
20. Baumgartner, R.; Scarth, G.; Teichtmeister, C.; Somorjai, R.; Moser, E. Fuzzy
clustering of gradient-echo functional MRI in the human visual cortex. Part I:
reproducibility. J-Magn-Reson-Imaging. 1997 Nov; 7(6): 1094-101; ISSN: 1053-
1807.
UNITED-STATES. Reproducibility of human functional MRI (fMRI) studies is
essential for clinical and neuroresearch applications of this new human brain
mapping method. Based on a recently presented study on reproducibility of
gradient-echo fMRI in the human visual cortex (Moser et al. Magn Reson Imaging
1996; 14:567-579), comparing the performance of three different threshold
strategies for correlation analysis, we demonstrate that (a) fuzzy clustering is a
robust, model-independent method to extract functional information in time and
space; (b) intertrial reproducibility of cortical activation is significantly improved
by the capability of fuzzy clustering to separate signal contributions from larger
vessels, running perpendicular to the slice orientation, from activation apparently
close to the primary visual cortex; and (c) for repeated single subject studies, SDs
of <20% for signal enhancement in approximately 80% of the studies and SDs of
<30% for activated area size in approximately 65% of the studies are obtained.
This, however, depends also on signal-to-noise ratio, (motion) artifacts, and
subject cooperation.
21. Bechara, A.; Damasio, H.; Tranel, D.; Anderson, S. W. Dissociation Of working
memory from decision making within the human prefrontal cortex. J-Neurosci.
1998 Jan 1; 18(1): 428-37; ISSN: 0270-6474.
UNITED-STATES. We tested the hypothesis that cognitive functions related to
working memory (assessed with delay tasks) are distinct from those related to
decision making (assessed with a gambling task), and that working memory and
decision making depend in part on separate anatomical substrates. Normal
controls (n = 21), subjects with lesions in the ventromedial (VM) (n = 9) or
dorsolateral/high mesial (DL/M) prefrontal cortices (n = 10), performed on (1)
modified delay tasks that assess working memory and (2) a gambling task
designed to measure decision making. VM subjects with more anterior lesions (n =
4) performed defectively on the gambling but not the delay task. VM subjects
with more posterior lesions (n = 5) were impaired on both tasks. Right DL/M
subjects were impaired on the delay task but not the gambling task. Left DL/M
subjects were not impaired on either task. The findings reveal a cognitive and
anatomic double dissociation between deficits in decision making (anterior VM)
and working memory (right DL/M). This presents the first direct evidence of such
effects in humans using the lesion method and underscores the special importance
of the VM prefrontal region in decision making, independent of a direct role in
working memory.
22. Bernardi, L.; Hayoz, D.; Wenzel, R.; Passino, C.; Calciati, A.; Weber, R.; Noll, G.
Synchronous and baroceptor-sensitive oscillations in skin microcirculation:
evidence for central autonomic control. Am-J-Physiol. 1997 Oct; 273(4 Pt 2):
H1867-78; ISSN: 0002-9513.
UNITED-STATES. To determine whether skin blood flow is local or takes part
in general regulatory mechanisms, we recorded laser-Doppler flowmetry (LDF;
left and right index fingers), blood pressure, muscle sympathetic nerve activity
(MSNA), R-R interval, and respiration in 10 healthy volunteers and 3 subjects
after sympathectomy. We evaluated 1) the synchronism of LDF fluctuations in
two index fingers, 2) the relationship with autonomically mediated fluctuations in
other signals, and 3) the LDF ability to respond to arterial baroreflex stimulation
(by neck suction at frequencies from 0.02 to 0.20 Hz), using spectral analysis
(autoregressive uni- and bivariate, time-variant algorithms). Synchronous LDF
fluctuations were observed in the index fingers of healthy subjects but not in
sympathectomized patients. LDF fluctuations were coherent with those obtained
for blood pressure, MSNA, and R-R interval. LDF fluctuations were leading
blood pressure in the low-frequency (LF; 0.1 Hz) band and lagging in the
respiratory, high-frequency (HF; approximately 0.25 Hz) band, suggesting
passive "downstream" transmission only for HF and "upstream" transmission for
LF from the microvessels. LDF fluctuations were responsive to sinusoidal neck
suction up to 0.1 Hz, indicating response to sympathetic modulation. Skin blood
flow thus reflects modifications determined by autonomic activity, detectable by
frequency analysis of spontaneous fluctuations.
23. Berthoz, A. Parietal and hippocampal contribution to topokinetic and topographic
memory. Philos-Trans-R-Soc-Lond-B-Biol-Sci. 1997 Oct 29; 352(1360): 1437-48;
ISSN: 0962-8436.
ENGLAND. This paper reviews the involvement of the parietal cortex and the
hippocampus in three kinds of spatial memory tasks which all require a memory
of a previously experienced movement in space. The first task compared, by
means of positron emission tomography (PET) scan techniques, the production,
in darkness, of self-paced saccades (SAC) with the reproduction, in darkness, of a
previously learned sequence of saccades to visual targets (SEQ). The results show
that a bilateral increase of activity was seen in the depth of the intraparietal sulcus
and the medial superior parietal cortex (superior parietal gyrus and precuneus)
together with the frontal sulcus but only in the SEQ task, which involved memory
of the previously seen targets and possibly also motor memory. The second task
is the vestibular memory contingent task, which requires that the subject makes,
in darkness, a saccade to the remembered position of a visual target after a
passively imposed whole-body rotation. Deficits in this task, which involves
vestibular memory, were found predominantly in patients with focal vascular
lesions in the parieto-insular (vestibular) cortex, the supplementary motor area-
supplementary eye field area, and the prefrontal cortex. The third task requires
mental navigation from the memory of a previously learned route in a real
environment (the city of Orsay in France). A PET scan study has revealed that
when subjects were asked to remember visual landmarks there was a bilateral
activation of the middle hippocampal regions, left inferior temporal gyrus, left
hippocampal regions, precentral gyrus and posterior cingulate gyrus. If the
subjects were asked to remember the route, and their movements along this route,
bilateral activation of the dorsolateral cortex, posterior hippocampal areas,
posterior cingulate gyrus, supplementary motor areas, right middle hippocampal
areas, left precuneus, middle occipital gyrus, fusiform gyrus and lateral premotor
area was found. Subtraction between the two conditions reduced the activated
areas to the left hippocampus, precuneus and insula. These data suggest that the
hippocampus and parietal cortex are both involved in the dynamic aspects of
spatial memory, for which the name 'topokinetic memory' is proposed. These
dynamic aspects could both overlap and be different from those involved in the
cartographic and static aspects of 'topographic' memory.
24. Bevan, R. D.; Vijayakumaran, E.; Gentry, A.; Wellman, T.; Bevan, J. A. Intrinsic tone
of cerebral artery segments of human infants between 23 weeks of gestation and
term. Pediatr-Res. 1998 Jan; 43(1): 20-7; ISSN: 0031-3998.
UNITED-STATES. Segments of basilar and middle cerebral arteries of eight
human preterm and early postnatal infants have been examined using the
resistance artery myograph technique for wire-mounted segments and the
pressure perfusion arteriograph. Myograph-mounted segments spontaneously
developed tone of varying duration and time course. Perfused segments showed
maintained tone levels of approximately 40% of maximum possible constriction
when the intraluminal pressure was 60 mm Hg. This level is not different from
that found in adult human pial arteries of similar lumen diameter. Indomethacin
(10[-5] M) either initiated tone increase or potentiated existing tone in the
isometrically mounted segments. After washout of vasoconstrictors
norepinephrine (10[-6] M) and angiotensin II (10[-8] M), indomethacin caused a
pronounced, long lasting increase in basal tone. Spontaneous tone was reversed by
acetylcholine (10[-6] M), isoproterenol (10[-8] to 10[-5] M), histamine (10[-8] to
10[-5] M), and papaverine (10[-5] M). Low levels of tone were increased and
higher levels decreased by intraluminal flow. The pressure/diameter curves of
these vessels were of similar shape as those of the equivalent size in the adult. It
is concluded that intrinsic tone is a prominent feature of these large cerebral
arteries, and it is modified by an endogenous indomethacin-sensitive process.
25. Bishop, K. M.; Wahlsten, D. Sex differences in the human corpus callosum: myth or
reality? Neurosci-Biobehav-Rev. 1997 Sep; 21(5): 581-601; ISSN: 0149-7634.
UNITED-STATES. It has been claimed that the human corpus callosum shows
sex differences, and in particular that the splenium (the posterior portion) is larger
in women than in men. Data collected before 1910 from cadavers indicate that, on
average, males have larger brains than females and that the average size of their
corpus callosum is larger. A meta-analysis of 49 studies published since 1980
reveals no significant sex difference in the size or shape of the splenium of the
corpus callosum, whether or not an appropriate adjustment is made for brain size
using analysis of covariance or linear regression. It is argued that a simple ratio of
corpus callosum size to whole brain size is not an appropriate way to analyse the
data and can create a false impression of a sex difference in the corpus callosum.
The recent studies, most of which used magnetic resonance imaging (MRI),
confirm the earlier findings of larger average brain size and overall corpus callosum
size for males. The widespread belief that women have a larger splenium than men
and consequently think differently is untenable. Causes of and means to avoid
such a false impression in future research are discussed.
26. Biswal, B. B.; Van Kylen, J.; Hyde, J. S. Simultaneous assessment of flow and BOLD
signals in resting-state functional connectivity maps [see comments]. NMR-
Biomed. 1997 Jun; 10(4-5): 165-70; ISSN: 0952-3480.
Note: Comment in: NMR Biomed 1997 Jun-Aug;10(4-5):157-9.
ENGLAND. We have recently demonstrated using functional magnetic resonance
imaging the presence of synchronous low-frequency fluctuations of signal
intensities from the resting human brain that have a high degree of temporal
correlation (p < 0.0001) both within and across the sensorimotor cortex. A
statistically significant overlap between the resting-state functional connectivity
map and the task-activation map due to bilateral finger tapping was obtained.
Similar results have been obtained in the auditory and visual cortex. Because the
pulse sequence used for collecting data was sensitive to blood flow and blood
oxygenation, these low-frequency fluctuations of signal intensity may have arisen
from variations of both. The objective of this study was simultaneously to
determine the contribution of the blood oxygenation level signal and the flow
signal to physiological fluctuations in the resting brain using the flow-sensitive
alternating inversion recovery pulse sequence. In all subjects, the functional
connectivity maps obtained from BOLD had a greater coincidence with task-
activation maps than the corresponding functional connectivity maps obtained
from blood-flow signals at the same level of statistical significance. Results of this
study suggest that while variations in blood flow might contribute to functional
connectivity maps, BOLD signals play a dominant role in the mechanism that
gives rise to functional connectivity in the resting human brain.. 7782-44-7.
27. Biver, F.; Wikler, D.; Lotstra, F.; Damhaut, P.; Goldman, S.; Mendlewicz, J.
Serotonin 5-HT2 receptor imaging in major depression: focal changes in orbito-
insular cortex. Br-J-Psychiatry. 1997 Nov; 171: 444-8; ISSN: 0007-1250.
ENGLAND. BACKGROUND: Serotonin receptors may play an important role
in the pathophysiology of affective disorders. We studied type-2 serotonin (5-
HT2) receptors in the brain of patients with major depression. METHOD: Using
positron emission tomography (PET) and the selective radioligand
[18F]altanserin, we investigated 5-HT2 receptor distribution in eight drug-free
unipolar depressed patients and 22 healthy subjects. Data were analysed using
Statistical Parametric Mapping 95. RESULTS: In depressed patients,
[18F]altanserin uptake was significantly reduced in a region of the right
hemisphere including the posterolateral orbitofrontal cortex and the anterior
insular cortex. A trend to similar changes was found in the left hemisphere. No
correlation was found between the uptake and the Hamilton rating scale score.
CONCLUSIONS: Pathophysiology of depression may involve changes in 5-HT2
receptor in brain regions selectively implicated in mood regulation.. 0; 0; 74050-
98-9; 76330-71-7.
28. Blin, J.; Ivanoiu, A.; Coppens, A.; De Volder, A.; Labar, D.; Michel, C.; Laterre, E. C.
Cholinergic neurotransmission has different effects on cerebral glucose
consumption and blood flow in young normals, aged normals, and Alzheimer's
disease patients. Neuroimage. 1997 Nov; 6(4): 335-43; ISSN: 1053-8119.
UNITED-STATES. Cerebral blood flow (CBF) and glucose consumption (GC)
are both tracers of brain metabolic activity used to image the human brain in vivo.
To know if both tracers reacted in the same manner when brain cholinergic
neurotransmission was activated, CBF and GC were measured in young normals
(YN), aged normals (AN), and Alzheimer's Disease patients (AD) using positron
emission tomography (PET), H2 15O, and 18F-FDG. Each subject was studied
twice, under placebo and physostigmine, in randomized order and blind fashion
using the maximal tolerated dose of physostigmine individually determined. Under
physostigmine CBF increased significantly (P = 0.0007) in posterior regions of
the cerebral cortex and in the subcortical structures. Inversely, GC was decreased
significantly in most regions. The largest decrease was seen in the prefrontal
region of the cerebral cortex (P < 0.0001). Significant regional decreases were
registered in all three groups of subjects, but were larger in AD than in controls.
Looking at the absolute values of prefrontal cortex metabolism we found no
correlation (r = 0.04) between the responses of CBF and GC. After normalization
of the regional values for the mean we found a significant positive correlation
between the responses of CBF and GC (r = 0.71, P < 0.0001). These findings
suggest two components in the CBF response to physostigmine: one metabolic,
depressive, and regional which follows the GC response; and one vascular, larger,
diffuse, and opposite in direction to the metabolic component. These results have
implications for the interpretation of CBF values as tracer of brain metabolic
activity when brain cholinergic neurotransmission is manipulated. Copyright 1997
Academic Press.. 0; 63503-12-8.
29. Bohning, D. E.; Pecheny, A. P.; Epstein, C. M.; Speer, A. M.; Vincent, D. J.;
Dannels, W.; George, M. S. Mapping transcranial magnetic stimulation (TMS)
fields in vivo with MRI. Neuroreport. 1997 Jul 28; 8(11): 2535-8; ISSN: 0959-
4965.
ENGLAND. Transcranial magnetic stimulation (TMS) is a non-invasive
technique for investigating brain function that uses pulsed magnetic fields created
by special coils to induce localized neuronal depolarization. Despite the
technique's expanding application, the exact magnetic field produced by TMS
coils have never been directly measured in human subjects. Using a standard 1.5T
MR scanner and TMS coils constructed from non magnetic materials, we have
obtained 3D maps of the magnetic field created by TMS coils in human
volunteers. Further, we mapped the combined field of two coils and demonstrated
that combinations of coils might be used to focus the magnetic field to achieve
improved stimulation patterns and, perhaps, reach areas out of reach of single
coils.
30. Bol, P.; Scheirs, J.; Spanjaard, L. Meningitis and the evolution of dominance of
righthandedness. Cortex. 1997 Dec; 33(4): 723-32; ISSN: 0010-9452.
ITALY. In bacterial meningitis, forced deviation of the head and/or the eyes
towards either the left or the right side reflects an ipsilateral focal inflammation of
the brain. Also, the symptom of forced deviation is associated with a high fatality
and sequelae rate. In this study it was observed that, among 2124 Dutch patients
with bacterial meningitis, forced deviation was significantly more often to the right
than to the left. Because the right hemisphere is dominant for motor functions in
natural lefthanders, it was concluded that bacterial meningitis might have been a
selection mechanism favouring the evolution of a dominance of righthandedness.
31. Bona, E.; Johansson, B. B.; Hagberg, H. Sensorimotor function and neuropathology
five to six weeks after hypoxia-ischemia in seven-day-old rats. Pediatr-Res. 1997
Nov; 42(5): 678-83; ISSN: 0031-3998.
UNITED-STATES. Various therapeutic interventions after hypoxia-ischemia
(HI) have been shown to reduce brain injury in the short-term perspective, but it
remains uncertain whether such findings are accompanied by long-term functional
and structural improvements. HI was induced in 7-d-old rats as follows. The left
carotid artery was ligated, and the rat was exposed to 100 min of hypoxia (7.70%
oxygen in nitrogen). At postnatal d 42 the rats were assessed using four
sensorimotor tests. The results were correlated with the extent of brain damage
expressed as volume of deficit of the left hemisphere as percent of the right
hemisphere. In the grip-traction test, the time to falling was 2.2 times shorter in
the HI animals compared with controls (p < 0.01). Asymmetries of limb-placing
and foot-faults (p < 0.001) were detected in HI animals, and the motor function
was abnormal in the postural reflex test (p < 0.001). We found a moderate
correspondence between functional and neuropathologic outcome (r = 0.842, p <
0.001). A set of four easily performed sensorimotor tests is presented for the
long-term evaluation of neurologic function in the 7-d-old rat model of HI.
32. Bookheimer, S. Y. Functional MRI applications in clinical epilepsy. Neuroimage.
1996 Dec; 4(3 Pt 3): S139-46; ISSN: 1053-8119.
UNITED-STATES. Functional MRI holds great promise as a diagnostic tool in
presurgical evaluation of patients with epilepsy. Recent research has used fMRI
for localization of the seizure focus by tracking interictal spikes and by observing
blood flow changes during seizure onset. Localization of the language-dominant
hemisphere with fMRI has been well-validated in normal volunteers and left-
hemisphere-dominant epilepsy patients, but is less developed for patients with
mixed- or right-hemisphere language dominance. Intrahemispheric mapping of
sensory and motor functions with fMRI is fairly well established, and progress is
being made in mapping higher-level cognitive functions, particularly language.
Little research has convincingly demonstrated hippocampal function in the normal
brain during memory processing, and applications of memory mapping in
epilepsy are still lacking. While the clinical use of fMRI in epilepsy needs
substantially more study, this is nonetheless a very promising technique that may
dramatically change the presurgical diagnostic regimen for these patients.
33. Borch, K.; Greisen, G. Blood flow distribution in the normal human preterm brain.
Pediatr-Res. 1998 Jan; 43(1): 28-33; ISSN: 0031-3998.
UNITED-STATES. Disturbances in cerebral blood flow (CBF) are a major factor
in the etiology and pathogenesis of cerebral damage in the neonate. As most
animals are more mature at birth than man, extrapolation from animal studies to
the human is questionable. Therefore, we have measured regional CBF (rCBF) in
preterm infants. rCBF flow was measured in 12 normotensive and normoxic
preterm infants [mean birth weight 915 g (range 550 to 2680 g), mean gestational
age 27.7 wk (25 to 32 wk)]. All infants had a normal cerebral ultrasound
examination. rCBF was measured using a mobile brain dedicated fast-rotating four-
head multidetector system specially designed for neonatal studies. The tracer was
99mTc-labeled D,L-hexamethylpropylenamine oxime in a dose of 4 Mbq/kg.
rCBF of the subcortical white matter was 0.53 (0.48-0.58) of the global CBF.
After correction for scattered radiation, the estimate of rCBF to the white matter
was reduced to 0.39 (0.36-0.42). The flow to the basal ganglia was 2.33 (2.08-
2.59) times the global CBF. After correction for partial volume effect, the cortical
flow was higher than the flow to the basal ganglia and highest in the
frontotemporal cortex (motor cortex). The flow to the cerebellum was of the same
magnitude as the flow to the basal ganglia, but with a significantly higher variation.
rCBF in 12 preterm infants showed a flow distribution similar to flow in other
newborn mammals. The gray-white matter contrast, however, was greater. This
new information, combined with existing data showing low global CBF, suggests
that blood flow to the white matter in the preterm human neonate is extremely
low.
34. Bowden, D. M.; Martin, R. F. NeuroNames Brain Hierarchy. Neuroimage. 1995 Mar;
2(1): 63-83; ISSN: 1053-8119.
UNITED-STATES. The NeuroNames Brain Hierarchy is a structured system of
neuroanatomical terminology that provides a comprehensive representation of
virtually all human and nonhuman primate brain structures that are identifiable
either grossly or in Niss1-stained histological sections. This system was devised
for computer applications to address deficiencies in the brain terminology
presented in Nomina Anatomica. English terms are listed for 783 structures in
nine levels of hierarchical ranking. Abbreviations are provided for all superficial
and primary volumetric structures. The substructures that constitute the total
volume of every superstructure are identified. Superficial features of the brain are
clearly distinguished from internal, volumetric brain structures. Structures found
solely in either humans or macaques are identified. The purpose of the
NeuroNames Brain Hierarchy is to bring greater standardization to the
neuroanatomical terminology used by scientific investigators, clinicians, and
students. This effort is consistent with the goals of the Unified Medical Language
System program of the National Library of Medicine. It is hoped that the
systematic construction of the NeuroNames Brain Hierarchy will facilitate use of
the most widely accepted definitions of classical neuroanatomy in quantitative
computerized neuroimaging applications. It should provide an accurate structural
framework against which to reference the many other kinds of neuroanatomical
information that are acquired by modern imaging, mapping, and histological
labeling techniques.
35. Bowler, J. V.; Wade, J. P.; Jones, B. E.; Nijran, K. S.; Steiner, T. J. Natural history of
the spontaneous reperfusion of human cerebral infarcts as assessed by 99mTc
HMPAO SPECT. J-Neurol-Neurosurg-Psychiatry. 1998 Jan; 64(1): 90-7; ISSN:
0022-3050.
ENGLAND. OBJECTIVE: Little is known about the effect of spontaneous
reperfusion of human cerebral infarcts. Single photon emission computerised
tomography (SPECT) data were analysed from a study using 99Tc(m) HMPAO
(99Tc(m) hexamethylpropyleneamine oxime) in human cerebral infarction for the
frequency of reperfusion and to see if it affected infarct size, oedema,
haemorrhagic transformation, or functional outcome. METHODS: Fifty
sequential cases of ischaemic stroke were studied with 124 99Tc(m) HMPAO
SPECT at around one day, one week, and three months after stroke along with
detailed clinical and functional assessments. RESULTS: Visually apparent
reperfusion occurred in 14 of 50 patients (28%) with a mean delay of 5.8 days
and reperfusion was seen in seven others in whom it was identified on the basis of
changes in perfusion deficit volume. It occurred in 13 of 23 embolic events but
only in three of 23 other events. In only two cases did spontaneous reperfusion
occur early enough to preserve tissue or function. Reperfusion did not otherwise
reduce infarct size, or improve clinical or functional outcome, and was not
associated with oedema but an association with haemorrhagic transformation was
suggested. Reperfusion significantly decreased the apparent perfusion defect as
measured by SPECT one week from the ictus, but was mostly non-nutritional and
transient. The mean volume of tissue preserved by nutritional reperfusion was 10
cm3, but this was unequally distributed between cases. Late washout of 99Tc(m)
HMPAO from areas of hyperaemic reperfusion may be a good prognostic marker
but is a rare phenomenon and too insensitive to be of general applicability.
CONCLUSIONS: Spontaneous reperfusion after cerebral infarction occurs in 42%
of cases within the first week but is associated with clinical improvement in only
2%. It has few adverse consequences although it may be associated with
haemorrhagic transformation.. 0; 0.
36. Braga, J.; Boesch, C. Further data about venous channels in South African Plio-
Pleistocene hominids. J-Hum-Evol. 1997 Oct; 33(4): 423-47; ISSN: 0047-2484.
ENGLAND. Original data about venous channels in South African Plio-
Pleistocene hominids are discussed. To assess possible changes in blood volume
flow of fossil hominids, we test whether dimensions of three extracranial venous
foramina were different between Australopithecus africanus and Australopithecus
(Paranthropus) robustus. Moreover, providing further data about the small
sample of South African Plio-Pleistocene hominids, we also attempt to re-analyse
the incidence of divided hypoglossal canals and four emissary foramina in a very
large sample of extant African apes representing all ages, species and subspecies,
in A. africanus and in "robust australopithecines". Up to now, only very poor
data on extracranial dimensions of venous foramina were available for fossil
hominids. However, this topic provides interesting information about the
modifications of volume flow during human evolution. Assuming that in fossil
hominids, as in humans, dimensions of condylar and mastoid foramina, as well as
those of jugular foramina, depended on volume flow through them, we conclude,
first, that volume flow through internal jugular veins was comparable in South
African australopithecines, extant chimpanzees and humans, and second, that, in
comparison with the extant less-encephalized chimpanzees (presumably reflecting
the ancestral condition), volume flow was higher through condylar veins in A. (P.)
robustus. This increase was responsible for a significantly greater amount of blood
drainage from the brain (and consequently an increased arterial blood supply). We
support the view that encephalization was the prevailing functional explanation
for volume flow increase through condylar veins in A. (P.) robustus, in
comparison with its ancestor with its presumably more ape-like degree of
encephalization. Considering the incidence of emissary canals and foramina,
significant differences between A. africanus, "robust australopithecines" and all
the extant African ape species, were tested statistically. Concerning the condylar
canal, we did not find differences between "robust australopithecines" and extant
African apes. Concerning the incidence of divided hypoglossal canals, mastoid
canals, parietal and occipital foramina, no difference was found between extant
African apes, A. africanus and "robust australopithecines". High frequencies of
either condylar or mastoid canals cannot be regarded as a "pongid condition".
Moreover, we did not find convincing data to support the hypothesis that
mastoid emissary veins (partly representing a putative "radiator" for cooling the
brain) were selected in A. africanus, in comparison with "robust
australopithecines".
37. Braun, A. R.; Balkin, T. J.; Wesensten, N. J.; Gwadry, F.; Carson, R. E.; Varga, M.;
Baldwin, P.; Belenky, G.; Herscovitch, P. Dissociated pattern of activity in visual
cortices and their projections during human rapid eye movement sleep. Science.
1998 Jan 2; 279(5347): 91-5; ISSN: 0036-8075.
UNITED-STATES. Positron emission tomography was used to measure cerebral
activity and to evaluate regional interrelationships within visual cortices and their
projections during rapid eye movement (REM) sleep in human subjects. REM
sleep was associated with selective activation of extrastriate visual cortices,
particularly within the ventral processing stream, and an unexpected attenuation
of activity in the primary visual cortex; increases in regional cerebral blood flow in
extrastriate areas were significantly correlated with decreases in the striate cortex.
Extrastriate activity was also associated with concomitant activation of limbic and
paralimbic regions, but with a marked reduction of activity in frontal association
areas including lateral orbital and dorsolateral prefrontal cortices. This pattern
suggests a model for brain mechanisms subserving REM sleep where visual
association cortices and their paralimbic projections may operate as a closed
system dissociated from the regions at either end of the visual hierarchy that
mediate interactions with the external world.
38. Breier, J. I.; Plenger, P. M.; Castillo, R.; Fuchs, K.; Wheless, J. W.; Thomas, A. B.;
Brookshire, B. L.; Willmore, L. J.; Papanicolaou, A. Effects of temporal lobe
epilepsy on spatial and figural aspects of memory for a complex geometric figure.
J-Int-Neuropsychol-Soc. 1996 Nov; 2(6): 535-40; ISSN: 1355-6177.
ENGLAND. The preoperative delayed memory performance on the Rey-
Osterrieth Complex Figure (Lezak, 1983) of 54 patients with complex partial
seizures of temporal lobe origin was analyzed using 3 different indices. One index
(composite) was derived using a common scoring method that included both
spatial and figural aspects of memory in its score. The other two indices were
derived emphasizing either spatial or figural aspects of memory for the elements
of the figure separately. All 3 indices distinguished between individuals with right-
sided (RTLE) and left-sided (LTLE) seizure onset. However, spatial memory was
significantly lower than figural memory in individuals with RTLE as compared to
those with LTLE. Both the spatial and figural memory indices were significantly
lower in the presence of magnetic resonance imaging (MRI) evidence for
hippocampal sclerosis in individuals with RTLE. Results suggest that while both
the spatial and figural aspects of nonverbal memory are sensitive to right
hippocampal dysfunction, figural memory may be less vulnerable to the effects of
RTLE.
39. Brinkley, J. F.; Bradley, S. W.; Sundsten, J. W.; Rosse, C. The digital anatomist
information system and its use in the generation and delivery of Web-based
anatomy atlases. Comput-Biomed-Res. 1997 Dec; 30(6): 472-503; ISSN: 0010-
4809.
UNITED-STATES. Advances in network and imaging technology, coupled with
the availability of 3-D datasets such as the Visible Human, provide a unique
opportunity for developing information systems in anatomy that can deliver
relevant knowledge directly to the clinician, researcher or educator. A software
framework is described for developing such a system within a distributed
architecture that includes spatial and symbolic anatomy information resources,
Web and custom servers, and authoring and end-user client programs. The
authoring tools have been used to create 3-D atlases of the brain, knee and thorax
that are used both locally and throughout the world. For the one and a half year
period from June 1995-January 1997, the on-line atlases were accessed by over
33,000 sites from 94 countries, with an average of over 4000 "hits" per day, and
25,000 hits per day during peak exam periods. The atlases have been linked to by
over 500 sites, and have received at least six unsolicited awards by outside rating
institutions. The flexibility of the software framework has allowed the
information system to evolve with advances in technology and representation
methods. Possible new features include knowledge-based image retrieval and
tutoring, dynamic generation of 3-D scenes, and eventually, real-time virtual
reality navigation through the body. Such features, when coupled with other on-
line biomedical information resources, should lead to interesting new ways for
managing and accessing structural information in medicine. Copyright 1997
Academic Press.
40. Buchner, H.; Gobbele, R.; Wagner, M.; Fuchs, M.; Waberski, T. D.; Beckmann, R.
Fast visual evoked potential input into human area V5. Neuroreport. 1997 Jul 28;
8(11): 2419-22; ISSN: 0959-4965.
ENGLAND. Studies of the human visual cortex have demonstrated that an area
for motion processing (V5) is located in the lateral occipito-temporal cortex. To
study the timing of arrival of signals in V5 we recorded multi-channel visual
evoked potentials (VEPs) to checkerboard stimuli. We then applied dipole source
analysis which was computed on a grand average of 10 subjects, and on five
individual subjects, respectively. We demonstrate an early VEP component with
onset before 30 ms and with a peak around 45 ms, located in the vicinity of V5.
This early component was independent of a second activity, which started around
50 ms and peaked around 70 ms, and was located within the striate cortex (V1).
These results provide further evidence for a very fast input to V5 before
activation of V1.
41. Buchsbaum, M. S.; Trestman, R. L.; Hazlett, E.; Siegel, BV Jr; Schaefer, C. H.; Luu
Hsia, C.; Tang, C.; Herrera, S.; Solimando, A. C.; Losonczy, M.; Serby, M.;
Silverman, J.; Siever, L. J. Regional cerebral blood flow during the Wisconsin Card
Sort Test in schizotypal personality disorder. Schizophr-Res. 1997 Oct 17; 27(1):
21-8; ISSN: 0920-9964.
NETHERLANDS. Regional cerebral blood flow (rCBF) was measured by single
photon emission computed tomography in 10 patients with schizotypal
personality disorder (SPD) and nine age- and sex-matched normal volunteers.
Subjects performed both the Wisconsin Card Sort Test (WCST) and a control
task, the Symbol Matching Test (SMT). Four-way analyses of variance were
performed to assess relative rCBF of the prefrontal cortex and of the medial
temporal region. Normal volunteers showed more marked activation in the
precentral gyrus, while SPD patients showed greater activation in the middle
frontal gyrus. Relative flow in the left prefrontal cortex was correlated with better
WCST performance in normal volunteers. SPD patients, however, showed no
such correlations in the left prefrontal cortex, but demonstrated correlations of
good and bad performance with CBF in the right middle and inferior frontal gyrus,
respectively. Thus, at least some SPD patients demonstrate abnormal patterns of
prefrontal activation, perhaps as a compensation for dysfunction in other regions.
42. Buchsbaum, M. S.; Yang, S.; Hazlett, E.; Siegel, BV Jr; Germans, M.; Haznedar, M.;
O'Flaithbheartaigh, S.; Wei, T.; Silverman, J.; Siever, L. J. Ventricular volume and
asymmetry in schizotypal personality disorder and schizophrenia assessed with
magnetic resonance imaging. Schizophr-Res. 1997 Oct 17; 27(1): 45-53; ISSN:
0920-9964.
NETHERLANDS. Magnetic resonance imaging (MRI) was performed in 12
patients with schizotypal personality disorder (SPD), 11 patients with chronic
schizophrenia, and 23 age- and sex-matched normal volunteers. MRI slices were
acquired in the axial plane at 1.2-mm intervals, and the ventricles were traced on
every other slice. The lateral ventricular system was divided into the anterior
horn, temporal horn, and dorsal lateral ventricle. Schizophrenic patients had larger
left anterior and temporal horns than the normal volunteers. Size of the left
anterior and temporal horn in SPD patients was intermediate between those of
normal volunteers and schizophrenic patients and differed significantly from
schizophrenic patients. The left-minus-right difference was larger in schizophrenic
patients than in normal volunteers or SPD patients. Thus, in their structural brain
characteristics, as well as in their clinical symptomatology, SPD patients
evidence, in attenuated form, abnormalities resembling those found in full-fledged
schizophrenia. The findings suggest that decreased left hemispheric volume, in
frontal and temporal regions, may characterize both psychotic and non-psychotic
disorders of the schizophrenia spectrum.
43. Buckner, R. L.; Koutstaal, W. Functional neuroimaging studies of encoding, priming,
and explicit memory retrieval. Proc-Natl-Acad-Sci-U-S-A. 1998 Feb 3; 95(3):
891-8; ISSN: 0027-8424.
UNITED-STATES. Human functional neuroimaging techniques provide a
powerful means of linking neural level descriptions of brain function and
cognition. The exploration of the functional anatomy underlying human memory
comprises a prime example. Three highly reliable findings linking memory-related
cognitive processes to brain activity are discussed. First, priming is accompanied
by reductions in the amount of neural activation relative to naive or unprimed task
performance. These reductions can be shown to be both anatomically and
functionally specific and are found for both perceptual and conceptual task
components. Second, verbal encoding, allowing subsequent conscious retrieval, is
associated with activation of higher order brain regions including areas within the
left inferior and dorsal prefrontal cortex. These areas also are activated by working
memory and effortful word generation tasks, suggesting that these tasks, often
discussed as separable, might rely on interdependent processes. Finally, explicit
(intentional) retrieval shares much of the same functional anatomy as the encoding
and word generation tasks but is associated with the recruitment of additional
brain areas, including the anterior prefrontal cortex (right > left). These findings
illustrate how neuroimaging techniques can be used to study memory processes
and can both complement and extend data derived through other means. More
recently developed methods, such as event-related functional MRI, will continue
this progress and may provide additional new directions for research.
44. Buckner, R. L.; Koutstaal, W. Functional neuroimaging studies of encoding, priming,
and explicit memory retrieval. Proc-Natl-Acad-Sci-U-S-A. 1998 Feb 3; 95(3):
891-8; ISSN: 0027-8424.
UNITED-STATES. Human functional neuroimaging techniques provide a
powerful means of linking neural level descriptions of brain function and
cognition. The exploration of the functional anatomy underlying human memory
comprises a prime example. Three highly reliable findings linking memory-related
cognitive processes to brain activity are discussed. First, priming is accompanied
by reductions in the amount of neural activation relative to naive or unprimed task
performance. These reductions can be shown to be both anatomically and
functionally specific and are found for both perceptual and conceptual task
components. Second, verbal encoding, allowing subsequent conscious retrieval, is
associated with activation of higher order brain regions including areas within the
left inferior and dorsal prefrontal cortex. These areas also are activated by working
memory and effortful word generation tasks, suggesting that these tasks, often
discussed as separable, might rely on interdependent processes. Finally, explicit
(intentional) retrieval shares much of the same functional anatomy as the encoding
and word generation tasks but is associated with the recruitment of additional
brain areas, including the anterior prefrontal cortex (right > left). These findings
illustrate how neuroimaging techniques can be used to study memory processes
and can both complement and extend data derived through other means. More
recently developed methods, such as event-related functional MRI, will continue
this progress and may provide additional new directions for research.
45. Buklina, S. B. [Clinico-neuropsychological syndromes involving the human gyrus
cinguli]. Kliniko-neiropsikhologicheskie sindromy porazheniia poiasnoi izviliny
cheloveka. Zh-Nevrol-Psikhiatr-Im-S-S-Korsakova. 1997; 97(10): 11-6.
RUSSIA. There was performed clinical and neurophysiological observation of 41
patients with arteriovenous malformations (AVM) of gyrus cinguli. Disorders of
memory appeared to be the main manifestations before the operation in 38
patients, moreover they had the features of Korsakov's syndrome in 5 patients.
Autonomic and epileptic-like fits weren't quite characteristic. Memory
impairment was observed in 23 from 38 patients after operation, however there
weren't found any qualitatively new disorders. The first appearance of Korsakov's
syndrome after operation was found in 3 patients. The degree of the increase of
memory impairment correlated with the degree of the destruction of the gyrus
cinguli as well as with the massivity of AVM passing into corpus callosum.
Qualitative analysis of amnestic syndromes revealed that practically all the
patients had the alteration of the selectivity of the memory traces, inability to
keep in mind the meaning of the tale. It was accompanied by an absence of
criticism toward patients' own defects. Similar signs of disorders had close
resemblance with amnestic defects of the patients with frontal damages. That
testified the significance of both damages of frontal lobes and their connections in
formation of clinical pattern in human.
46. Bullitt, E.; Liu, A.; Pizer, S. M. Three-dimensional reconstruction of curves from
pairs of projection views in the presence of error. I. Algorithms. Med-Phys. 1997
Nov; 24(11): 1671-8; ISSN: 0094-2405.
UNITED-STATES. We have previously described an approach to 3D
intracerebral vascular reconstruction that uses an MRA as a reconstruction base.
Additional vessels seen only by angiography are added by segmenting 2D curves
from projection angiograms and reconstructing these curves into 3D, building
upon the MRA. Intracerebral vascular reconstruction is difficult for at least two
reasons. First, 2D curves must be associated on projection images even when the
human eye cannot do so. Second, 3D curves must be reconstructed in the presence
of errors such as misregistration, image distortion, and misdefinition of 2D curves.
This paper is the first of two that address the specific issue of reconstruction of a
3D curve from a given pair of 2D curves in the presence of error. The method
explicitly separates what can and cannot be determined from a pair of projection
views. It is also capable of recognizing interruptions produced by viewplane
errors, of continuing reconstruction beyond such interruptions, and of localizing
and estimating the magnitude of the interruptions. These measurements can also
be used to estimate the lengths of regional disparities between a pair of 2D curves,
leading to a quantitative estimate of the capacity of a pair of 2D curves to
combine to create a 3D object (match value). Match values can be used, in turn, as
part of the strategy for automatically associating pairs of 2D curves. This paper
provides methods for reconstructing a given pair of 2D curves into 3D in the
presence of error and for calculating match values. Error analysis is given in the
companion report.
47. Bullmore, E. T.; Rabe Hesketh, S.; Morris, R. G.; Williams, S. C.; Gregory, L.; Gray,
J. A.; Brammer, M. J. Functional magnetic resonance image analysis of a large-
scale neurocognitive network. Neuroimage. 1996 Aug; 4(1): 16-33; ISSN: 1053-
8119.
UNITED-STATES. Many "higher-order" mental functions are subserved by
large-scale neurocognitive networks comprising several spatially distributed and
functionally specialized brain regions. We here report statistical and graphical
methods of functional magnetic resonance imaging data analysis which can be used
to elucidate the functional relationships (i.e., connectivity and distance) between
elements of a neurocognitive network in a single subject. Data were acquired from
a normal right-handed volunteer during periodic performance of a task which
demanded visual and semantic processing of words and subvocalization of a
decision about the meaning of each word. Major regional foci of activation were
identified (by sinusoidal regression modeling and spatiotemporal randomization
tests) in left extrastriate cortex, angular gyrus, supramarginal gyrus, superior and
middle temporal gyri, lateral premotor cortex, and Broca's area. Principal
component (PC) analysis was initially undertaken by singular value
decomposition (SVD) of the "raw" time series observed at 170 activated voxels.
This revealed a large functional distance (negative connectivity) between visual
processing systems and all other brain regions in the space of the first PC. SVD of
a matrix of fitted time series, and a matrix of six sinusoidal regression parameters
estimated at each activated voxel, were developed as less noisy (more informative)
alternatives to SVD of the "raw" data. Canonical variate analysis of denoised data
was then used to clarify functional relationships between the major regional foci.
Visual input analysis systems (extrastriate cortex and angular gyrus) were
colocalized in the space of the first canonical variate (CV) and significantly
separated from all other brain regions. Semantic analysis systems (supramarginal
and temporal gyri) were colocalized and significantly separated in the space of the
second CV from the subvocal output system (Broca's area). These results are
provisionally interpreted in terms of underlying hemodynamic events and
cognitive psychological theory.
48. Burgund, E. D.; Marsolek, C. J. Letter-case-specific priming in the right cerebral
hemisphere with a form-specific perceptual identification task. Brain-Cogn. 1997
Nov; 35(2): 239-58; ISSN: 0278-2626.
UNITED-STATES. In a form-specific perceptual identification task, subjects
identify and write letter strings in the same letter case as they appear on a
computer display. Letter-case-specific repetition priming was observed in this
task when test items were presented directly to the right hemisphere, but not
when they were presented directly to the left hemisphere, similar to results in
previous word-stem completion experiments. This pattern of results was not
obtained in a standard perceptual identification task. Results indicate that a
specific visual-form subsystem, but not an abstract visual-form subsystem,
operates more effectively in the right hemisphere than in the left, and task
demands greatly affect which subsystems are recruited in different priming tests.
Copyright 1997 Academic Press.
49. Bussey, T. J.; Everitt, B. J.; Robbins, T. W. Dissociable effects of cingulate and
medial frontal cortex lesions on stimulus-reward learning using a novel Pavlovian
autoshaping procedure for the rat: implications for the neurobiology of emotion.
Behav-Neurosci. 1997 Oct; 111(5): 908-19; ISSN: 0735-7044.
UNITED-STATES. The effects of quinolinic acid-induced lesions of the anterior
cingulate, posterior cingulate, and medial frontal cortices on stimulus-reward
learning were investigated with a novel Pavlovian autoshaping procedure in an
apparatus allowing the automated presentation of computer-graphic stimuli to
rats (T. J. Bussey, J. L. Muir, & T. W. Robbins, 1994). White vertical rectangles
were presented on the left or the right of a computer screen. One of these
conditioned stimuli (the CS+) was always followed by the presentation of a
sucrose pellet; the other, the CS-, was never followed by reward. With training,
rats came to approach the CS+ more often than the CS-. Anterior cingulate cortex-
lesioned rats failed to demonstrate normal discriminated approach, making
significantly more approaches to the CS- than did sham-operated controls. Medial
frontal cortex-lesioned rats acquired the task normally but had longer overall
approach latencies. Posterior cingulate cortex lesions did not affect acquisition.
50. Cabeza, R.; McIntosh, A. R.; Tulving, E.; Nyberg, L.; Grady, C. L. Age-related
differences in effective neural connectivity during encoding and recall.
Neuroreport. 1997 Nov 10; 8(16): 3479-83; ISSN: 0959-4965.
ENGLAND. Age-related differences in brain activity may reflect local neural
changes in the regions involved or they may reflect a more global transformation
of brain function. To investigate this issue, we applied structural equation
modeling to the results of a positron emission tomography (PET) study in which
young and old adults encoded and recalled word pairs. In the young group there
was a shift from positive interactions involving the left prefrontal cortex during
encoding to positive interactions involving the right prefrontal cortex during recall,
whereas in the old group frontal interactions were mixed during encoding and
bilaterally positive during recall. The present results suggest that age-related
changes in neural activation are partly due to age-related changes in effective
connectivity in the neural network underlying the task.
51. Caldwell, F. T.; Graves, D. B.; Wallace, B. H. Studies on the mechanism of fever after
intravenous administration of endotoxin. J-Trauma. 1998 Feb; 44(2): 304-12;
ISSN: 0022-5282.
UNITED-STATES. BACKGROUND: The sequential events in fever production
after intravenous administration of lipopolysaccharide (LPS) remain unsettled and
controversial. Vessels of the organum vasculosum laminae terminalis (OVLT) lack
the tight junctions of the blood-brain barrier and allow substances of high
molecular weight to enter the interstitium but not the neuropil. The present
studies investigate the hypothesis that the OVLT is needed for fever production
after intravenous administration of LPS in the rat. METHODS: Electrolytic
lesions were produced in the OVLT of rats. After recovery, left carotid and right
atrial catheters were inserted, and 24 hours later calorimetry was performed.
Blood was drawn for baseline assay for cytokines and LPS after which LPS was
given intravenously, with studies continued for 5 hours, and additional blood
samples were drawn at 90 and 300 minutes. RESULTS: The maximal increment in
rectal temperature for the sham lesion LPS group (1.25 +/- 0.44 degrees C) was
significantly greater than for the sham-saline (-0.05 +/- 0.46 degrees C) and the
lesion-LPS groups (0.35 +/- 0.45 degrees C) for minutes 120 to 300. Ninety
minutes after LPS administration, serum levels of interleukin (IL)-6, tumor
necrosis factor-alpha, and LPS were significantly elevated (p < 0.0001) above
baseline for the sham-LPS and lesion-LPS groups. IL-1beta serum levels remained
below detection levels. CONCLUSION: Large lesions of the OVLT prevent
and/or attenuate fever due to LPS even though tumor necrosis factor-alpha and IL-
6 are greatly increased in serum. IL-1beta does not seem to be an endogenous
humoral mediator in this model.. 0; 0; 0; 0.
52. Campbell, A.; Villavicencio, A. T.; Yeghiayan, S. K.; Balikian, R.; Baldessarini, R. J.
Mapping of locomotor behavioral arousal induced by microinjections of dopamine
within nucleus accumbens septi of rat forebrain. Brain-Res. 1997 Oct 10; 771(1):
55-62; ISSN: 0006-8993.
NETHERLANDS. Dopamine (DA) at ca. ED50 (16 microg) or saline was
stereotaxically microinjected unilaterally 2 h after pretreatment with an MAO
inhibitor into left or right nucleus accumbens septi of 697 freely moving rats
(1394 injections) to define subregions involved in DA-induced behavioral arousal
throughout the anatomical extent of the accumbens. Locomotion was quantified
electronically and behavioral responses were assigned to histologically verified
injection sites; postural or stereotyped behaviors characteristic of DA injections
in caudate-putamen did not occur. Screening with 60 injections across mid-
accumbens (2.2-3.2 mm rostral to bregma) indicated that locomotion was elicited
non-homogeneously, and was particularly intense dorsomedially. Sites yielding
intense arousal and their inactive surround were mapped along the rostrocaudal
axis (1.4-4.2 mm anterior to bregma) in coronal sections. Responses to DA
showed lateral symmetry and were similar across rostrocaudal levels, with intense
responses in dorsomedial accumbens along its border with the caudate-putamen.
This functional localization does not coincide closely with reported distributions
of DA or its receptors, nor with histologically or histochemically defined core-
shell regions of this limbic structure. Nucleus accumbens in rat brain thus appears
to be organized functionally into distinct subregions differing markedly in ability
to produce locomotor hyperactivity in response to exogenous DA.. 51-61-6.
53. Camuscu, H.; Dujovny, M.; Abd, el Bary T.; Beristain, X.; Vinas, F. C.
Microanatomy of the perforators of the anterior communicating artery complex.
Neurol-Res. 1997 Dec; 19(6): 577-87; ISSN: 0161-6412.
ENGLAND. We describe the microanatomy of the perforating arteries arising
from the anterior communicating artery complex (5 mm distal of the anterior
cerebral artery, the anterior communicating artery, and 5 mm proximal of the distal
anterior cerebral artery). Thirteen unfixed human brains were used in this study.
The origin and number of perforators are described, as is the site of brain
penetration, and results are correlated with previous studies. The hemodynamics
of blood flow in relation to the formation of an anterior communicating artery
aneurysm and different surgical approaches are mentioned. The
neuropsychological outcome after aneurysm clipping with regards to the pattern
of blood supply from the anterior cerebral artery complex is also discussed.
54. Camuscu, H.; Dujovny, M.; Abd, el Bary T.; Beristain, X.; Vinas, F. C.
Microanatomy of the perforators of the anterior communicating artery complex.
Neurol-Res. 1997 Dec; 19(6): 577-87; ISSN: 0161-6412.
ENGLAND. We describe the microanatomy of the perforating arteries arising
from the anterior communicating artery complex (5 mm distal of the anterior
cerebral artery, the anterior communicating artery, and 5 mm proximal of the distal
anterior cerebral artery). Thirteen unfixed human brains were used in this study.
The origin and number of perforators are described, as is the site of brain
penetration, and results are correlated with previous studies. The hemodynamics
of blood flow in relation to the formation of an anterior communicating artery
aneurysm and different surgical approaches are mentioned. The
neuropsychological outcome after aneurysm clipping with regards to the pattern
of blood supply from the anterior cerebral artery complex is also discussed.
55. Carlsson, G. Memory for words and drawings in children with hemiplegic cerebral
palsy. Scand-J-Psychol. 1997 Dec; 38(4): 265-73; ISSN: 0036-5564.
ENGLAND. A list-learning paradigm was used to study learning and memory of
verbal and figurative material in children with right versus left-sided hemiplegic
cerebral palsy. Thirty-one children with right (n = 18), or left (n = 13) congenital
hemiplegia were compared with normal controls (n = 19). All children had normal
intelligence (IQ > 80), and were attending standard schools. The inclusion criteria
for the two hemiplegic groups were; no epilepsy, no hearing or visual
impairments, and a mild to moderate hemiparesis. The aim of this study was to
explore material-specific (words and drawings) differences in the acquisition, recall
and serial position effects in children with an early unilateral brain lesion. The left-
hemisphere impaired (i.e. right hemiplegia) group showed impaired acquisition for
drawings, as compared with the normal controls. There was also a material-
specific difference in the serial position effect for all three groups. Learning of
words followed the primacy principle, whereas the learning of drawings followed
the recency principle. There were no group-differences in delayed-recall (i.e. long-
term memory) for either words or drawings. The results are discussed in terms of
acquisition and retention of verbal and figurative materials in relation to lesion side
and size.
56. Chang, J.; Jozwiak, R.; Wang, B.; Ng, T.; Ge, Y. C.; Bolton, W.; Dwyer, D. E.;
Randle, C.; Osborn, R.; Cunningham, A. L.; Saksena, N. K. Unique HIV type 1
V3 region sequences derived from six different regions of brain: region-specific
evolution within host-determined quasispecies. AIDS-Res-Hum-Retroviruses.
1998 Jan 1; 14(1): 25-30; ISSN: 0889-2229.
UNITED-STATES. HIV type 1 viral quasispecies were amplified by polymerase
chain reaction (PCR) in the hypervariable V3 region of gp120 from six different
regions of the brain (right and left frontal; right and left parietal; and right and left
occipital) and from the peripheral blood mononuclear cells (PBMCs) of a patient
who died of AIDS dementia complex (ADC). Cloning and sequencing of the entire
V3 region suggested the presence of genetically unique sequences in different
regions of the brain. In contrast, the blood-derived viral quasispecies carried
homogeneous sequences that were characterized by a single octapeptide crest
motif (HLGPGSAF), a motif important in viral fusion. The brain-derived viral
strains showed extensive sequence heterogeneity and the presence of seven
different octapeptide and four different tetrapeptide crest motifs (HIGPGRAF,
RIGPGRAF, HIGPGSAI, HLGPGSAF, HIGPESAI, HLGPESAI, and
YLRPGSAF). In addition, the brain-derived strains were also characterized by
variable net V3 loop charge and hydrophilicity, along with distinct amino acid
changes specific to different brain regions. Together, the sequence and
phylogenetic analyses are unique in identifying the complexity of a viral
quasispecies and its independent regional evolution within the brain compartment.
Uniquely divergent viral strains were identified in the frontal regions and their
presence was further supported by the presence of multinucleated giant cells
(characteristic of HIV encephalopathy) predominantly in the left and right frontal
regions. In summary, these analyses suggest that genetically different populations
of HIV-1 may be present in different brain compartments and confirm that
specific neurotropic variants may exist.. 0; 0; 0.
57. Chatterjee, A.; Yapundich, R.; Mennemeier, M.; Mountz, J. M.; Inampudi, C.; Pan,
J. W.; Mitchell, G. W. Thalamic thought disorder: on being "a bit addled". Cortex.
1997 Sep; 33(3): 419-40; ISSN: 0010-9452.
ITALY. Humans can generate and maintain relatively coherent trains of thought
in natural discourse. The neural mediation of this ability and the phenomenology
of its breakdown are not well understood. We report a case of a woman with
paramedian thalamic strokes involving the mammillothalamic tract, intralaminar
nuclei, parts of the dorsomedial and ventral lateral nuclei bilaterally. She presented
with a dense amnesia and confusion typical of the syndrome of bilateral
paramedian thalamic infarcts. Her Tc-99m HMPAO brain SPECT scan showed
decreased thalamic and basal ganglia blood flow. General diminution of cerebral
blood flow and areas of further diminution in the right frontal, left temporal and
left temporoparietal regions were also observed. Although her amnesia was
characteristic of diencephalic amnesia, her most striking clinical feature was a
bizarre, disconnected and at times incoherent speech output. Analysis of her
speech revealed relatively preserved lexical and morpho-syntactic linguistic
production. By contrast, analysis of the macrostructure of her discourse revealed
frequent unpredictable topic shifts that were completely unconstrained by
contextual factors. Many of her shifts were intrusions from previous topics. We
interpret her severely disordered speech output as representing the surface
manifestations of a thought disorder (rather than as a language disorder per se)
characterized by an inability to maintain and appropriately shift themes that
normally guide discourse. Median and intralaminar thalamic nuclei appear to be
critical for the neurophysiologic regulation of thalamocortical and striatocortical
circuits, which in turn may be critical for the functional regulation of contextually
appropriate transitions of thought.
58. Chen, Bee CH; Frostig, R. D. Variability and interhemispheric asymmetry of single-
whisker functional representations in rat barrel cortex. J-Neurophysiol. 1996 Aug;
76(2): 884-94; ISSN: 0022-3077.
UNITED-STATES. 1. The rat whisker-to-barrel system was used to investigate
the variability and interhemispheric asymmetry in the functional organization of
primary somatosensory cortex as assessed with intrinsic signal optical imaging.
The areal extent of whisker D1 functional representation was determined for both
the left and right barrel cortex of each of 10 adult male rats. The average size of
whisker D1 functional representation and the amount of variability away from
this average across animals were determined. In addition, interhemispheric
asymmetry was addressed at both the population level and the individual level.
The degree of side preference for thigmotactic scanning (typical whisker-related
rodent behavior) was determined for each rat in an attempt to find a behavioral
correlate for the degree of interhemispheric asymmetry in the size of whisker D1
functional representation. 2. The average areal extent of whisker D1 functional
representation (defined as area at half-height) was large (1.95 +/- 0.14 mm2, mean
+/- SE, N = 10 rats), suggesting that stimulation of a single whisker evokes
activity over a large cortical area that includes other whisker representations. 3.
The average size of whisker D1 functional representation was not significantly
different between the left (1.86 +/- 0.21 mm2) and right (2.04 +/- 0.15 mm2)
hemispheric side, suggesting that interhemispheric functional asymmetry of barrel
cortex is not systematic toward a specific hemispheric side at the population
level. 4. The degree of variability in the size of whisker D1 functional
representation from the left hemisphere ranged between 54.6% smaller than to
50.6% larger than the left average areal extent. A large degree of variability was
also observed for the right D1 representation, 37.6% smaller than to 34.9% larger
than the right average areal extent. Thus it appears that a large variability in the
size of unmanipulated single-whisker functional representations exists across
animals from the same species and is not exclusive to a particular hemispheric
side. 5. In 5 of 10 rats, the size of whisker D1 functional representation between
the two hemispheres differed by > or = 25% within an individual animal. Of these
five rats, four had a larger representation in their right hemisphere. The degree and
direction of behavioral asymmetry was not linearly correlated with the
interhemispheric asymmetry in the size of D1 functional representation (r =
0.494). 6. The large size of a single-whisker functional representation as defined
with intrinsic signal optical imaging is discussed with respect to previous
anatomic and 2-deoxyglucose autoradiography studies, whereas the large
variability in this size across animals is discussed with respect to the individuality
of each animal. In addition, the results of the present study have implications for
projects that plan to investigate relative changes in the size of single-whisker
functional representations.
59. Chen, R.; Cohen, L. G.; Hallett, M. Role of the ipsilateral motor cortex in voluntary
movement. Can-J-Neurol-Sci. 1997 Nov; 24(4): 284-91; ISSN: 0317-1671.
CANADA. The ipsilateral primary motor cortex (M1) plays a role in voluntary
movement. In our studies, we used repetitive transcranial magnetic stimulation
(rTMS) to study the effects of transient disruption of the ipsilateral M1 on the
performance of finger sequences in right-handed normal subjects. Stimulation of
the M1 ipsilateral to the movement induced timing errors in both simple and
complex sequences performed with either hand, but with complex sequences, the
effects were more pronounced with the left-sided stimulation. Recent studies in
both animals and humans have confirmed the traditional view that ipsilateral
projections from M1 to the upper limb are mainly directed to truncal and
proximal muscles, with little evidence for direct connections to distal muscles. The
ipsilateral motor pathway appears to be an important mechanism for functional
recovery after focal brain injury during infancy, but its role in functional recovery
for older children and adults has not yet been clearly demonstrated. There is
increasing evidence from studies using different methodologies such as rTMS,
functional imaging and movement-related cortical potentials, that M1 is involved
in ipsilateral hand movements, with greater involvement in more complex tasks
and the left hemisphere playing a greater role than the right.
60. Chen, W.; Kato, T.; Zhu, X. H.; Strupp, J.; Ogawa, S.; Ugurbil, K. Mapping of lateral
geniculate nucleus activation during visual stimulation in human brain using fMRI.
Magn-Reson-Med. 1998 Jan; 39(1): 89-96; ISSN: 0740-3194.
UNITED-STATES. Functional magnetic resonance imaging has been successfully
used to map the activation in the lateral geniculate nucleus (LGN) in both
hemispheres as well as the primary visual cortex (V1) during a checkerboard visual
stimulation. The average blood oxygenation level dependent (BOLD) change in
LGN was less than that in V1. However, the BOLD temporal responses were
similar between LGN and V1. The activation in the pulvinar nucleus during visual
perception was also detected, and its activated location could be separated from
LGN in 3D images. The LGN activation between intersubject and intrasubject
multiple trials was compared. The results demonstrate that fMRI can reliably and
robustly detect small subcortical nucleus activation in the human brain.
61. Cho, S.; Jones, D.; Reddick, W. E.; Ogg, R. J.; Steen, R. G. Establishing norms for
age-related changes in proton T1 of human brain tissue in vivo. Magn-Reson-
Imaging. 1997; 15(10): 1133-43; ISSN: 0730-725X.
UNITED-STATES. The goal of this study was to determine the expected normal
range of variation in spin-lattice relaxation time (T1) of brain tissue in vivo, as a
function of age. A previously validated precise and accurate inversion recovery
method was used to map T1 transversely, at the level of the basal ganglia, in a
study population of 115 healthy subjects (ages 4 to 72; 57 male and 58 female).
Least-squares regression analysis shows that T1 varied as a function of age in
pulvinar nucleus (R2 = 56%), anterior thalamus (R2 = 51%), caudate (R2 = 50%),
frontal white matter (R2 = 47%), optic radiation (R2 = 39%), putamen (R2 =
36%), genu (R2 = 22%), occipital white matter (R2 = 20%) (all p < 0.0001), and
cortical gray matter (R2 = 53%) (p < 0.001). There were no significant differences
in T1 between men and women. T1 declines throughout adolescence and early
adulthood, to achieve a minimum value in the fourth to sixth decade of life, then
T1 begins to increase. Quantitative magnetic resonance imaging provides evidence
that brain tissue continues to change throughout the lifespan among healthy
subjects with no neurologic deficits. Age-related changes follow a strikingly
different schedule in different brain tissues; white matter tracts tend to reach a
minimum T1 value, and to increase again, sooner than do gray matter tracts. Such
normative data may prove useful for the early detection of brain pathology in
patients.. 0.
62. Chokron, S.; Bartolomeo, P. Patterns of dissociation between left hemineglect and
deviation of the egocentric reference. Neuropsychologia. 1997 Nov; 35(11): 1503-
8; ISSN: 0028-3932.
ENGLAND. Sixteen control subjects and six right brain-damaged patients with
left hemiparesis (three showing signs of left unilateral neglect, three with no signs
of neglect) performed a straight-ahead pointing task with their right hand while
blindfolded. The aim was to test the hypothesis that the egocentric reference
shows significant ipsilesional deviation in left neglect patients. We found no
correlation between the position of the egocentric reference and the presence of
neglect signs. Neglect patients, like non-neglect patients, showed leftward,
rightward or no significant deviation when pointing straight ahead. Results are
discussed with reference to egocentric hypotheses of neglect and experimental
remission of neglect.
63. Clarisse, J.; Soto Ares, G.; Pertuzon, B.; Ayachi, M.; Francke, J. P. [Identification of
the central sulcus using the scanner and MRI]. Reperage du sillon central en
scanner et en IRM. J-Neuroradiol. 1997 Oct; 24(3): 187-204; ISSN: 0150-9861.
FRANCE. Methods to directly and indirectly identify the central sulcus are
presented. In the axial plan, direct method is remarkable but obviously requires
good visualization of the sulci in the central region. Sulci are readily visible in 90%
of the cases on CT scans and in 50% of the cases on MRI. The method can also
be applied when tumoral development erases the cerebral sulci by direct lecture of
the controlateral rolandic region and right-left transfer. Within the precision limits
of the method, it can be considered that the central sulci are symmetrical. The
main signs are: the relative morphologies of the superior frontal sulcus and the
precentral sulcus, the hook-shaped aspect of the middle part of the central sulcus,
the internal end of the central sulcus projection anteriorly to the pars marginalis,
the bifid nature of the internal end of the posterior central sulcus contouring the
pars marginalis, and the lesser thickness of the posterior central gyrus compared
with the precentral gyrus. The indirect method is less precise and is used when
the direct method is unsuccessful. The central sulcus is identified on the sagittal
images and, using the lateral view of the skull as a reference image, the topographic
information is transferred to the axial images.
64. Cohen, H. L.; Porjesz, B.; Begleiter, H.; Wang, W. Neurophysiological correlates of
response production and inhibition in alcoholics. Alcohol-Clin-Exp-Res. 1997
Nov; 21(8): 1398-406; ISSN: 0145-6008.
UNITED-STATES. Scalp recordings of the P300 component of the event-related
potential were made from a group of medication-free, chronic male alcoholics and
a control group, participating in a visual Go/No Go reaction time paradigm.
Subjects were presented with large and small forms of the letters T and V. The
large forms (Go stimuli) required a button press with either the left or right hand,
whereas the small forms (NO Go stimuli) required response inhibition. Recordings
were made from 31 electrodes that, for statistical analyses, were grouped into five
regions: frontal, central, parietal, occipital, and temporal. The results indicated
that, in each of the five regions, both Go and NO Go response amplitudes were
larger in the controls than in the alcoholics. No group differences in latency were
observed in any region. Surface energy (Wang et al., Brain Topogr. 6:193-202,
1994) magnitudes paralleled P300 amplitudes and in the controls, compared with
the alcoholics, were larger during both Go and No Go trials. Our findings suggest
that abstinent, chronic alcoholics differ electro-physiologically from control
individuals. These differences are manifested as widespread reductions in P300
amplitudes during the performance of a simple information processing paradigm.
The reduced amplitudes may reflect a deficiency in an inhibitory mechanism
proposed to underlie P300 generation.
65. Cohen, J. E.; Garrote, M. Central neurocytoma with symptomatic paraventricular
cyst: case report. Neurol-Res. 1998 Jan; 20(1): 89-92; ISSN: 0161-6412.
ENGLAND. This is the first report of the occurrence of a central neurocytoma
and a symptomatic paraventricular cyst; this entity may have particular surgical
implications. A 37-year-old male was admitted with a four month history of
dizziness and gait instability. He subsequently developed increasing weakness of
his left arm and leg. An unenhanced computed tomography scan revealed a
hyperdense mass in the right lateral ventricle with a paraventricular cystic lesion
in the frontoparietal white matter. MR images showed the origin and extent of the
lesion more completely. A frontoparietal craniotomy with a transfrontal
transcystic approach allowed resection of the tumor. Intraventricular tumors
continue to present a major challenge for neurosurgeons because of their depth and
the important surrounding structures. We report the use of a well-known
neurosurgical strategy, the transcystic approach, for gross removal of a
neurocytoma located in the ventricles.
66. Cole, D. J.; Nary, J. C.; Reynolds, L. W.; Patel, P. M.; Drummond, J. C.
Experimental subarachnoid hemorrhage in rats: effect of intravenous alpha-alpha
diaspirin crosslinked hemoglobin on hypoperfusion and neuronal death.
Anesthesiology. 1997 Dec; 87(6): 1486-93; ISSN: 0003-3022.
UNITED-STATES. BACKGROUND: Hemodilution with diaspirin crosslinked
hemoglobin (DCLHb) ameliorates occlusive cerebral ischemia. However,
subarachnoid hemoglobin has been implicated as a cause of cerebral
hypoperfusion. The effect of intravenous DCLHb on cerebral perfusion and
neuronal death after experimental subarachnoid hemorrhage was evaluated.
METHODS: Rats (n = 48) were anesthetized with isoflurane and subarachnoid
hemorrhage was induced by injecting 0.3 ml of autologous blood into the cistema
magna. Each animal received one of the following regimens: Control, no hematocrit
manipulation; DCLHb, hematocrit concentration decreased to 30% with DCLHb;
or Alb, hematocrit concentration decreased to 30% with human serum albumin.
The experiments had two parts, A and B. In part A, after 20 min, cerebral blood
flow (CBF) was assessed with 14C-iodoantipyrine autoradiography. In part B,
after 96 h, in separate animals, the number of dead neurons was determined in
predetermined coronal sections by hematoxylin and eosin staining. RESULTS:
Cerebral blood flow was greater for the DCLHb group than for the control group;
and CBF was greater for the Alb group than the other two groups (P < 0.05). In
one section, CBF was 45.5 +/- 10.9 ml x 100 g(-1) x min(-1) (mean +/- SD) for the
control group, 95.3 +/- 16.6 ml x 100 g(-1) x min(-1) for the DCLHb group, and
138.1 +/- 18.7 ml x 100 g(-1) x min(-1) for the Alb group. The number of dead
neurons was less in the Alb group (611 +/- 84) than in the control group (1,097
+/- 211), and was less in the DCLHb group (305 +/- 38) than in the other two
groups (P < 0.05). CONCLUSIONS: These data support a hypothesis that
hemodilution decreases hypoperfusion and neuronal death after subarachnoid
hemorrhage. The data do not support the notion that intravascular molecular
hemoglobin has an adverse effect on brain injury after subarachnoid hemorrhage..
0; 0; 50-78-2.
67. Colon, G. P.; Quint, D. J.; Dickinson, L. D.; Brunberg, J. A.; Jamerson, K. A.; Hoff,
J. T.; Ross, D. A. Magnetic resonance evaluation of ventrolateral medullary
compression in essential hypertension. J-Neurosurg. 1998 Feb; 88(2): 226-31;
ISSN: 0022-3085.
UNITED-STATES. OBJECT: The authors designed a blinded prospective study
comparing patients with essential hypertension to patients without hypertension
in which magnetic resonance (MR) imaging was used to evaluate the role of lateral
medullary compression by adjacent vascular structures as a cause of neurogenic
hypertension. METHODS: Patients with documented essential hypertension
were recruited to undergo thin-slice axial brainstem MR imaging evaluation.
Nonhypertensive (control) patients scheduled to undergo MR imaging for other
reasons also underwent thin-slice MR imaging to form a basis for comparison.
Magnetic resonance images obtained in patients from the hypertensive (30
patients) and the control (45 patients) groups were then compared by four
independent reviewers (two neuroradiologists and two neurosurgeons) who were
blinded to the patients' diagnosis and hypertensive status. Images were reviewed
with regard to left versus right vertebral artery (VA) dominance, compression of
the medulla on the left and/or right side, and brainstem rotation. Medullary
compression was graded as either vessel contact without associated brainstem
deformity or vessel contact with associated brainstem deformity.
CONCLUSIONS: There was a tendency toward left VA dominance in the
hypertensive group compared with the control group, although a significant
difference was shown by only one of the four reviewers. There were no
differences in brainstem compression or rotation between the hypertensive and
nonhypertensive groups. These results are contrary to those of recently published
studies in which MR imaging and/or MR angiography revealed lateral brainstem
vascular compression in hypertensive patients but not in nonhypertensive
(control) patients. Reasons for this discrepancy are discussed. On the basis of
their own experience and that of others, the authors believe that neurogenic
hypertension does exist. However, thin-slice MR imaging may not be a reliable
method for detecting neurovascularly induced essential hypertension and the
prevalence of neurovascular compression as the source of hypertension may be
overestimated when using current imaging techniques.
68. Cornford, E. M.; Hyman, S.; Cornford, M. E.; Landaw, E. M.; Delgado Escueta, A.
V. Interictal seizure resections show two configurations of endothelial Glut1
glucose transporter in the human blood-brain barrier. J-Cereb-Blood-Flow-Metab.
1998 Jan; 18(1): 26-42; ISSN: 0271-678X.
UNITED-STATES. Immunogold electron microscopy was used to analyze and
quantify the Glut1 glucose transporter in brain tissue from five patients
undergoing surgery for treatment of seizures. Samples were prepared from two
different regions of each resection: (1) the most actively spiking epileptogenic site,
and (2) the least actively spiking region, as indicated by intraoperative EEG
monitoring. Two configurations of endothelial cell Glut1 were observed. About
one half of the capillary profiles examined displayed abundant Glut1
immunoreactivity on both luminal and abluminal endothelial membranes. In the
remainder of the profiles, reduced Glut1 labeling was seen, but adjacent
erythrocyte membranes remained highly Glut1 immunoreactive, suggesting that
reduced endothelial Glut1 reactivity was not attributable to method artifacts.
Immunogold studies using antisera to human glial fibrillary acidic protein and
human serum albumin demonstrated increased quantities of these two epitopes in
the extravascular regions in which more EEG spiking activity had been
demonstrated. These observations were consistent with the hypotheses that
capillary integrity was more compromised, and gliosis was quantitatively
increased, in the more actively spiking region of the resection. Altered glucose
transporter activity in the blood-brain barrier was characterized by a bimodal
Glut1 distribution in which the smaller (type B) endothelial cells displayed low
Glut1 immunoreactivity, whereas adjacent (and even contiguous) larger (type A)
endothelial cells showed 5- to 10-fold greater expression of membrane Glut1
transporter protein. Because this transporter facilitates glucose entry to the brain,
small pericapillary volumes of brain tissue may have quite different
concentrations of glucose. We hypothesize that in complex partial seizures and
other forms of brain insult, an alteration of blood-brain barrier Glut1 glucose
transporter activity is indicated by the appearance of these two subpopulations
of endothelial cells. In comparison with previous studies of human brain
capillaries in hemangioblastoma and brain injury, endothelial Glut1 density was
apparently reduced (interictally) in affected temporal lobes of patients with
complex partial seizures.. 0; 0; 50-99-7.
69. Courtney, S. M.; Petit, L.; Maisog, J. M.; Ungerleider, L. G.; Haxby, J. V. An area
specialized for spatial working memory in human frontal cortex. Science. 1998
Feb 27; 279(5355): 1347-51; ISSN: 0036-8075.
UNITED-STATES. Working memory is the process of maintaining an active
representation of information so that it is available for use. In monkeys, a
prefrontal cortical region important for spatial working memory lies in and around
the principal sulcus, but in humans the location, and even the existence, of a region
for spatial working memory is in dispute. By using functional magnetic resonance
imaging in humans, an area in the superior frontal sulcus was identified that is
specialized for spatial working memory. This area is located more superiorly and
posteriorly in the human than in the monkey brain, which may explain why it was
not recognized previously.
70. Covenas, R.; de Leon, M.; Narvaez, J. A.; Aguirre, J. A.; Tramu, G.; Gonzalez Baron,
S. ACTH/CLIP immunoreactivity in the cat brain stem. Peptides. 1997; 18(7):
965-70; ISSN: 0196-9781.
UNITED-STATES. The distribution of adrenocorticotropin
hormone/corticotropin-like intermediate lobe peptide was studied in the cat brain
stem, using an indirect immunoperoxidase technique. No immunoreactive cell
bodies were observed. However, a high density of immunoreactive fibers was
found in the periaqueductal gray, the dorsal nucleus of the raphe, the locus
coeruleus, and the marginal nucleus of the brachium conjunctivum. A moderate
density was found in the central linear nucleus, the central tegmental field, the
Kolliker-Fuse nucleus, the inferior central nucleus, and the postpyramidal nucleus
of the raphe. A low density was found in the superior and inferior colliculi, the
interpeduncular nucleus, the nucleus sagulum, the superior central nucleus, the
cuneiform nucleus, the accessory dorsal tegmental nucleus, the nucleus of the
solitary tract, the dorsal motor nucleus of the vagus, and the paralemniscal,
magnocellular, gigantocellular, and lateral tegmental fields. Moreover, single
immunoreactive fibers were observed in numerous nuclei of the cat brain stem. In
comparison with previous studies carried out in the same region of the cat, as well
as the rat and the human, our results point to a more widespread distribution of
adrenocorticotropin hormone/corticotropin-like intermediate lobe peptide
immunoreactive structures in the cat brain stem. This widespread distribution
indicates that the peptide might be involved in several physiological functions of
the cat brain stem.. 0; 53917-42-3; 9002-60-2.
71. Cox, R. W.; Hyde, J. S. Software tools for analysis and visualization of fMRI data.
NMR-Biomed. 1997 Jun; 10(4-5): 171-8; ISSN: 0952-3480.
ENGLAND. The tools needed for analysis and visualization of three-dimensional
human brain functional magnetic resonance image results are outlined, covering the
processing categories of data storage, interactive vs batch mode operations,
visualization, spatial normalization (Talairach coordinates, etc.), analysis of
functional activation, integration of multiple datasets, and interface standards. One
freely available software package is described in some detail. The features and
scope that a generally useful and extensible fMRI toolset should have are
contrasted with what is available today. The article ends with a discussion of how
the fMRI research community can cooperate to create standards and develop
software that meets the community's needs.. 7782-44-7.
72. Crivello, F.; Tzourio, N.; Poline, J. B.; Woods, R. P.; Mazziotta, J. C.; Mazoyer, B.
Intersubject variability in functional neuroanatomy of silent verb generation:
assessment by a new activation detection algorithm based on amplitude and size
information. Neuroimage. 1995 Dec; 2(4): 253-63; ISSN: 1053-8119.
UNITED-STATES. We present an experimental evaluation of a new algorithm
for the detection of activated areas in brain functional maps. The new algorithm,
named HMSD, is based on a hierarchical multiscale description of the difference
image in terms of connected objects. Size and magnitude of each object are
simultaneously tested with respect to a bidimensional frequency distribution
derived using Monte-Carlo simulations under the null hypothesis. In the present
work. HMSD was applied to the analysis of a silent verb generation PET
activation protocol conducted in six right-handed subjects. Applied to single-
subject data. HMSD reveals activation located in the left inferior frontal gyrus in
three subjects (two in the pars opercularis, one in the pars triangularis), and in the
pars opercularis of the right inferior frontal gyrus in one case, the latter being
combined to a crossed cerebellar activation. Overall, single-case results were
consistent with the analyses of stereotactically averaged data. Despite a 2D
implentation. HMSD detection performances of averaged data were better than
that obtained with the 2D version of statistical parametric mapping (SPM) and
comparable to that of the 3D version of SPM.
73. da Silva, E. A.; Chugani, D. C.; Muzik, O.; Chugani, H. T. Landau-Kleffner
syndrome: metabolic abnormalities in temporal lobe are a common feature. J-
Child-Neurol. 1997 Nov; 12(8): 489-95; ISSN: 0883-0738.
UNITED-STATES. Landau-Kleffner syndrome (acquired epileptic aphasia) is
characterized by language regression following normal acquisition of language
skills, accompanied by epileptiform abnormalities on the electroencephalogram
(EEG) with or without clinical seizures. Continuous spikes and waves during
slow wave sleep may be seen on the EEG, but are not required to make the
diagnosis. Structural neuroimaging with computed tomography (CT) and magnetic
resonance imaging (MRI) is typically normal. We have evaluated 17 children (aged
2.4 to 10.6 yr) with Landau-Kleffner syndrome using positron emission
tomography (PET) with 2-deoxy-2-[18F]fluoro-D-glucose (FDG) in order to
determine whether there are metabolic abnormalities common to this syndrome.
Patients were awake for the uptake period of FDG, and the EEG was monitored.
On a visual analysis of the PET images, patients showed metabolic abnormalities
in the temporal lobes. Two children had focal hypermetabolism in the left
temporal cortex, one of whom also showed right temporal cortex
hypometabolism. The remaining patients (n = 15) showed bilateral temporal
hypometabolism, and comparison of these patients with a neurologically normal
age-matched control group (n = 8) demonstrated significantly reduced glucose
metabolism bilaterally in middle temporal gyrus (P < .02). In addition, other
cortical regions displayed hypometabolism, although these regions were not
consistently abnormal in all patients. The finding of temporal lobe abnormalities
in all Landau-Kleffner syndrome patients suggests that temporal lobe structures
are important in the pathophysiology of this syndrome, whereas the presence of
additional cortical abnormalities in many patients indicates that extensive brain
functional disturbances are common.. 0; 50-99-7; 63503-12-8.
74. Dassonville, P.; Zhu, X. H.; Uurbil, K.; Kim, S. G.; Ashe, J. Functional activation in
motor cortex reflects the direction and the degree of handedness. Proc-Natl-Acad-
Sci-U-S-A. 1997 Dec 9; 94(25): 14015-8; ISSN: 0027-8424.
UNITED-STATES. Handedness is the clearest example of behavioral
lateralization in humans. It is not known whether the obvious asymmetry
manifested by hand preference is associated with similar asymmetry in brain
activation during movement. We examined the functional activation in cortical
motor areas during movement of the dominant and nondominant hand in groups of
right-handed and left-handed subjects and found that use of the dominant hand
was associated with a greater volume of activation in the contralateral motor
cortex. Furthermore, there was a separate relation between the degree of
handedness and the extent of functional lateralization in the motor cortex. The
patterns of functional activation associated with the direction and degree of
handedness suggest that these aspects are independent and are coded separately in
the brain.
75. DeCarli, C.; Hatta, J.; Fazilat, S.; Fazilat, S.; Gaillard, W. D.; Theodore, W. H.
Extratemporal atrophy in patients with complex partial seizures of left temporal
origin. Ann-Neurol. 1998 Jan; 43(1): 41-5; ISSN: 0364-5134.
UNITED-STATES. Total cerebral, temporal lobe, hippocampal, caudate, and
lenticular nuclei volumes were quantified from magnetic resonance images of 21
patients with left temporal lobe epilepsy and medically intractable complex
partial seizures. These regional brain volumes were compared with the same
measures in 19 controls. No significant differences in total cerebral, left temporal
lobe, right temporal lobe, or total temporal lobe volumes were found. As expected,
left hippocampal volumes were significantly smaller in the patients with epilepsy
than in control subjects. The left hippocampus-to-right hippocampus volume
ratio was significantly lower in patients than in control subjects. In addition to left
hippocampal volumes, mean left thalamic, left caudate, and bilateral lenticular
volumes were significantly smaller in the patients with epilepsy than in control
subjects. The left-to-right thalamic volume ratio was also significantly lower in the
patients with epilepsy compared with control subjects, but there were no
significant group differences in caudate or lenticular ratios. These results show
that medically intractable temporal lobe epilepsy is associated with volume loss in
brain structures outside the presumably involved hippocampus. The
pathophysiological significance of our findings is uncertain. They could be related
to the underlying cause of the disorder. However, volume loss also may reflect
damage due to involvement of these structures in recurrent seizure activity.
76. Decety, J.; Grezes, J.; Costes, N.; Perani, D.; Jeannerod, M.; Procyk, E.; Grassi, F.;
Fazio, F. Brain activity during observation of actions. Influence of action content
and subject's strategy. Brain. 1997 Oct; 120( Pt 10): 1763-77; ISSN: 0006-8950.
ENGLAND. PET was used to map brain regions that are associated with the
observation of meaningful and meaningless hand actions. Subjects were scanned
under four conditions which consisted of visually presented actions. In each of the
four experimental conditions, they were instructed to watch the actions with one
of two aims: to be able to recognize or to imitate them later. We found that
differences in the meaning of the action, irrespective of the strategy used during
observation, lead to different patterns of brain activity and clear left/right
asymmetries. Meaningful actions strongly engaged the left hemisphere in frontal
and temporal regions while meaningless actions involved mainly the right
occipitoparietal pathway. Observing with the intent to recognize activated
memory-encoding structures. In contrast, observation with the intent to imitate
was associated with activation in the regions involved in the planning and in the
generation of actions. Thus, the pattern of brain activation during observation of
actions is dependent both on the nature of the required executive processing and
the type of the extrinsic properties of the action presented.
77. Deckel, A. W. Hemispheric control of territorial aggression in Anolis carolinensis:
effects of mild stress. Brain-Behav-Evol. 1998; 51(1): 33-9; ISSN: 0006-8977.
SWITZERLAND. Previous work has demonstrated that the brain of Anolis
carolinensis is functionally split, in that the left and right eyes project
predominantly to the contralateral hemisphere, and as there are minimal
connections between the left and right hemispheres. Using this model, the current
experiment examined the effect of mild acute stress on hemispheric regulation of
territorial aggression. Thirteen adult male Anolis were paired with an antagonistic
males, and eye use and behavioral responses were repeatedly measured during 3
minute behavioral trials. Trials were conducted either after exposure to mild
stress, produced by handling the subject, or without stress, and they were run
either in the subject's home cage or in a cage foreign to the subject. Left eye
preference for aggressive movements was found during the trials run in the non-
stressed conditions (p < 0.05). Conversely, stressed subjects showed a reduction
in left eye/right hemisphere mediated aggressive movements relative to the non-
stressed subjects but no changes in right eye/left hemisphere aggression. This
effect was independent of whether or not the subject was in its home or a foreign
cage. No laterality in aggressive responding was found when the subjects were
placed in separate cages with visual contact. These findings suggest that territorial
aggression in Anolis is preferentially initiated and processed by the left eye/right
hemisphere but is subject to right-hemispheric inhibition following exposure to
acute mild stress.
78. Dehaene, S.; Dupoux, E.; Mehler, J.; Cohen, L.; Paulesu, E.; Perani, D.; van, de
Moortele PF; Lehericy, S.; Le Bihan, D. Anatomical variability in the cortical
representation of first and second language. Neuroreport. 1997 Dec 1; 8(17):
3809-15; ISSN: 0959-4965.
ENGLAND. Functional magnetic resonance imaging was used to assess inter-
subject variability in the cortical representation of language comprehension
processes. Moderately fluent French-English bilinguals were scanned while they
listened to stories in their first language (L1 = French) or in a second language (L2
= English) acquired at school after the age of seven. In all subjects, listening to L1
always activated a similar set of areas in the left temporal lobe, clustered along the
left superior temporal sulcus. Listening to L2, however, activated a highly variable
network of left and right temporal and frontal areas, sometimes restricted only to
right-hemispheric regions. These results support the hypothesis that first
language acquisition relies on a dedicated left-hemispheric cerebral network, while
late second language acquisition is not necessarily associated with a reproducible
biological substrate. The postulated contribution of the right hemisphere to L2
comprehension is found to hold only on average, individual subjects varying from
complete right lateralization to standard left lateralization for L2.
79. Deicken, R. F.; Zhou, L.; Schuff, N.; Weiner, M. W. Proton magnetic resonance
spectroscopy of the anterior cingulate region in schizophrenia. Schizophr-Res.
1997 Oct 17; 27(1): 65-71; ISSN: 0920-9964.
NETHERLANDS. The authors measured N-acetylaspartate (NAA, a putative
neuronal marker), choline and creatine in the anterior cingulate region of 26
schizophrenic patients and 16 control subjects using in vivo proton magnetic
resonance spectroscopic imaging (1H MRSI). Relative to the control group, the
patients with schizophrenia demonstrated significantly lower NAA in both the
right and left anterior cingulate regions. There was no association between NAA
and duration of illness or medication dosage. No group differences or lateralized
asymmetries in choline or creatine were noted. The NAA findings provide
support for either neuronal dysfunction or neuronal loss in the anterior cingulate
region in schizophrenia. The absence of choline signal elevation does not support
accelerated turnover of membrane phospholipids which might be expected if there
were ongoing neuronal atrophy or neuronal necrosis.. 0; 56-84-8; 57-00-1; 62-49-
7; 997-55-7.
80. Delazer, M.; Benke, T. Arithmetic facts without meaning. Cortex. 1997 Dec; 33(4):
697-710; ISSN: 0010-9452.
ITALY. The paper presents a single-case study of patient J.G. showing severe
calculation problems (and also agraphia, finger agnosia, right-left disorientation
and apraxia) after the surgery of a left parietal tumor. Although the patient
completely lost conceptual knowledge of arithmetic, she preserved part of
memorised fact knowledge (multiplications and some additions and subtractions).
The study indicates that arithmetic facts can be represented at a superficial level
without understanding of the operation performed. The study completes a valid
double dissociation between two types of knowledge involved in calculation
(memorised facts and conceptual knowledge).
81. Deng, C.; Rogers, L. J. Differential contributions of the two visual pathways to
functional lateralization in chicks. Behav-Brain-Res. 1997 Sep; 87(2): 173-82;
ISSN: 0166-4328.
NETHERLANDS. The contribution of the two visual pathways to lateralization
of visual behaviour in chicks was assessed using unilateral injections of 0.5
microliters of 100 mM monosodium glutamate into localized regions of the
forebrain. Chicks treated with glutamate in the left visual hyperstriatum made
more errors in a visual discrimination task (pebble-floor test) than did chicks
treated in the right visual hyperstriatum. Glutamate injection into the left visual
hyperstriatum also elevated attack and copulation scores, but this did not occur
following injection of the right visual hyperstriatum. The performance of chicks
treated in the right visual hyperstriatum did not differ from that of sham-operated
controls. Thus, only the left visual hyperstriatum is involved in the control of
these three visually guided behaviours. By contrast, glutamate injections of the
left ectostriatum affected only the attack behavior and not performance in the
pebble-floor test or copulation responses. Glutamate treatment of the right
ectostriatum had no affect on any of the behaviours tested and this was also the
case for glutamate treatment of both the left and right neostriata. Although
injecting glutamate in a larger volume that allows glutamate to spread over a wide
area of the left hemisphere is known to retard auditory habituation, localized
injection of glutamate in the areas chosen for this study had no effect on auditory
habituation. The results suggest that the tectofugal and thalamofugal pathways
have different roles in the lateralization of visual functions. The forebrain region
which receives input from the thalamofugal visual system has a lateralized role in
categorising pebbles as different from food grains, and also a role in controlling
attack and copulation responses. The forebrain region which receives input from
the tectofugal visual system is involved in the control of attack responses only..
56-86-0.
82. Desmond, J. E.; Gabrieli, J. D.; Wagner, A. D.; Ginier, B. L.; Glover, G. H. Lobular
patterns of cerebellar activation in verbal working-memory and finger-tapping
tasks as revealed by functional MRI. J-Neurosci. 1997 Dec 15; 17(24): 9675-85;
ISSN: 0270-6474.
UNITED-STATES. The lobular distributions of functional activation of the
cerebellum during verbal working-memory and finger movement tasks were
investigated using functional magnetic resonance imaging (fMRI). Relative to a
rest control, finger tapping of the right hand produced ipsilateral-increased
activation in HIV/HV [Roman numeral designations based on Larsell's ()
nomenclature] and HVI and weaker activation in HVIII that was stronger on the
ipsilateral side. For a working-memory task, subjects were asked to remember six
(high load) or one (low load) visually presented letters across a brief delay. To
assess the motoric aspects of rehearsal in the absence of working memory, we
asked the subjects to repeatedly read subvocally six or one letters at a rate that
approximated the internally generated rehearsal of working memory (motoric
rehearsal task). For both tasks, bilateral regions of the superior cerebellar
hemispheres (left superior HVIIA and right HVI) and portions of posterior vermis
(VI and superior VIIA) exhibited increased activation during high relative to low
load conditions. In contrast, the right inferior cerebellar hemisphere (HVIIB)
exhibited this load effect only during the working-memory task. We hypothesize
that HVI and superior HVIIA activation represents input from the articulatory
control system of working memory from the frontal lobes and that HVIIB
activation is derived from the phonological store in temporal and parietal regions.
From these inputs, the cerebellum could compute the discrepancy between actual
and intended phonological rehearsal and use this information to update a
feedforward command to the frontal lobes, thereby facilitating the phonological
loop.
83. Dolan, R. J.; Fletcher, P.; Morris, J.; Kapur, N.; Deakin, J. F.; Frith, C. D. Neural
activation during covert processing of positive emotional facial expressions.
Neuroimage. 1996 Dec; 4(3 Pt 1): 194-200; ISSN: 1053-8119.
UNITED-STATES. Lesion studies indicate distinct neural systems for
recognition of facial identity and emotion. Split-brain experiments also suggest
that emotional evaluation of a stimulus can occur without conscious identification.
The present study tested a hypothesis of a differential neural response,
independent of explicit conscious mediation, to emotional compared to
nonemotional faces. The experimental paradigm involved holding in mind an image
of a face across a 45-s delay while regional cerebral blood flow was measured
using positron emission tomography. Prior to the delay, a single face was
presented with an explicit instruction to match it to one of two faces,
photographed at different angles from the target face, presented at the end of the
delay. Repeated blood flow measures were obtained while subjects held happy or
neutral faces in mind or during a neutral control fixation condition without initial
face presentation. The representation of emotional faces over a delay period,
compared to either the nonemotional or the fixation condition, was associated
with significant activation in the left ventral prefrontal cortex, the left anterior
cingulate cortex, and the right fusiform gyrus. The findings support our
hypothesis of a differential neural response to facial emotion, independent of
conscious mediation, in regions implicated in the processing of faces and of
emotions.
84. Duyn, J. H.; Yang, Y.; Frank, J. A.; Mattay, V. S.; Hou, L. Functional magnetic
resonance neuroimaging data acquisition techniques. Neuroimage. 1996 Dec; 4(3
Pt 3): S76-83; ISSN: 1053-8119.
UNITED-STATES. Functional MRI studies of human brain require rapid data
acquisition techniques, to map dynamic changes with sufficient anatomical
coverage. In addition, task activation studies employing functional MRI require a
high scan sensitivity, in order to discriminate the small, activation-related signal
changes from background noise. An overview is given of current fast scan
methods, which are sensitized to detect susceptibility changes related to task-
induced changes in blood oxygenation. Sources of artifacts are discussed, as well
as their effect on image quality.
85. Edlinger, G.; Pfurtscheller, G.; van Burik, M.; Wach, P. Post-movement EEG
synchronization studied with different high resolution methods. Brain-Topogr.
1997 Dec; 10(2): 103-13; ISSN: 0896-0267.
UNITED-STATES. In this paper we present a study of spline surface Laplacian
(LP), linear estimation (LE) and analytical deblurring (AD) utilized to improve the
spatial resolution of single trial EEG data. AD is a method to reconstruct the
potential distribution on the cortical surface. The dependency of AD on the
electrode grid size as well as the sensitivity to uncorrelated noise and errors in the
volume conductor model are investigated in detail and compared with LP. Finally,
all methods (LP,LE and AD) are applied to single trial EEG data recorded in three
subjects during voluntary and self-paced extension and flexion movements of the
right index finger. In each subject postmovement beta oscillations were found in
specific frequency bands. Cortical dipolar source strengths were reconstructed by
LE and cortex potentials were estimated with AD. Both results are compared with
LP calculated from the scalp EEG. All methods, although having different
theoretical basis, yield similar results and reveal a maximal event-related
synchronization over the left sensorimotor area approximately 500-875 ms after
termination of the movement.
86. Eiselt, M.; Schendel, M.; Witte, H.; Dorschel, J.; Curzi Dascalova, L.; D'Allest, A.
M.; Zwiener, U. Quantitative analysis of discontinuous EEG in premature and
full-term newborns during quiet sleep. Electroencephalogr-Clin-Neurophysiol.
1997 Nov; 103(5): 528-34; ISSN: 0013-4694.
IRELAND. To assess the spatio-temporal structure of discontinuous EEG
tracing in mature and immature newborns, we analysed mean spectral power in
frequency bands between 0.8 and 16.8 Hz in 6 full-term newborns and 7
premature newborns < 32 weeks of conceptional age. The most striking results
showed a significantly higher mean spectral power for the first half of bursts than
for the second half recorded in > 2.8-14.8 Hz frequency bands. This pattern was
more pronounced in premature than in full-term newborns. No clear differences
were observed in comparisons between the first and the second half of the
interburst periods. In addition, as far as mid and high frequency band spectra were
considered, the mean spectral power of burst was, in both groups, higher in the
right as compared to the left occipital regions.
87. Elger, B.; Hornberger, W.; Schwarz, M.; Seega, J. MRI study on delayed ancrod
therapy of focal cerebral ischaemia in rats. Eur-J-Pharmacol. 1997 Oct 1; 336(1):
7-14; ISSN: 0014-2999.
NETHERLANDS. The therapeutic window for efficient post-treatment of focal
cerebral ischaemia with the fibrinogen lowering agent ancrod was studied by
magnetic resonance imaging (MRI) in spontaneously hypertensive rats (SHR).
Ancrod or vehicle solution (0.9% NaCl) were i.v. infused (0.12 IU/kg per min) via
implanted mini pumps starting 0.5, 1.5, 3 or 6 h after permanent proximal middle
cerebral artery occlusion and lasting until brain mapping by multislice T2-
weighted magnetic resonance imaging in vivo 24 h after middle cerebral artery
occlusion. Plasma fibrinogen concentrations were measured before middle cerebral
artery occlusion, before pump implantation and after magnetic resonance imaging.
Total brain lesion volumes as determined by magnetic resonance imaging 24 h after
middle cerebral artery occlusion were 131 +/- 36 (188 +/- 28)*, 151 +/- 39 (194
+/- 39)*, 147 +/- 44 (207 +/- 33)* and 209 +/- 60 (214 +/- 42) mm3 in rats with
0.5, 1.5, 3 and 6 h, respectively, delay of ancrod treatment (means +/- S.D., 8-11
animals/group, corresponding control groups in parentheses, *P < 0.05).
Continuous i.v. ancrod infusions reduced plasma fibrinogen levels significantly (P
< 0.05) in all ancrod-treated groups as compared to vehicle-treated controls until
the end of the experiments 24 h after middle cerebral artery occlusion. In
conclusion, significant cerebroprotection was achieved even when the onset of
ancrod therapy for lowering of the plasma fibrinogen level was delayed for up to 3
h. To the best of our knowledge no drug efficacy has been reported so far with a
therapeutic window of 3 h after permanent middle cerebral artery occlusion in
spontaneously hypertensive rats suggesting that ancrod may provide an efficient
therapy of acute human stroke.. EC 3.4.21.28; 0; 9001-32-5.
88. Epstein, J. N.; Conners, C. K.; Erhardt, D.; March, J. S.; Swanson, J. M.
Asymmetrical hemispheric control of visual-spatial attention in adults with
attention deficit hyperactivity disorder. Neuropsychology. 1997 Oct; 11(4): 467-
73; ISSN: 0894-4105.
UNITED-STATES. As neuropsychological mechanisms for attention have been
hypothesized to be located in the right hemisphere of the brain, several
investigators have begun to conceptualize attention deficit hyperactivity disorder
(ADHD)-related attentional deficits as involving right-hemispheric abnormalities.
The authors evaluated and compared adult patients diagnosed with ADHD with a
non-ADHD group of patients using a chronometric visual-spatial attention task
that is sensitive to hemispheric differences in efficiency of information processing.
Reaction times across different cuing conditions, cue-target delays, and visual
fields were assessed. When participants' attention was misdirected with cues in
the right visual field and attention had to be switched to a target on the left visual
field, there was a longer delay among ADHD adults than non-ADHD adults,
specifically when the interval between the cue and target was 800 ms as compared
with 100 ms. This specific pattern of dysfunction was interpreted as a difficulty
with maintaining attention possibly associated with anterior attention mechanisms
in the right hemisphere.
89. Ernst, M.; Cohen, R. M.; Liebenauer, L. L.; Jons, P. H.; Zametkin, A. J. Cerebral
glucose metabolism in adolescent girls with attention-deficit/hyperactivity
disorder. J-Am-Acad-Child-Adolesc-Psychiatry. 1997 Oct; 36(10): 1399-406;
ISSN: 0890-8567.
UNITED-STATES. OBJECTIVE: Low cerebral metabolic rates for glucose
(CMRglc) have been reported in a small sample of girls with attention-
deficit/hyperactivity disorder (ADHD). This study was an effort to replicate this
finding in a larger independent sample. METHOD: Using positron emission
tomography and [18F]fluorodeoxyglucose, CMRglc were compared between 10
girls with ADHD (14.10 +/- 1.91 years) and 11 normal girls (14.3 +/- 1.70 years).
RESULTS: Global CMRglc was similar between ADHD and control girls.
Lateralization of normalized CMRglc differed significantly between ADHD and
control girls in parietal and subcortical regions, with rCMRglc lower on the left
than on the right side in girls with ADHD, and conversely in control girls. The
sylvian area of the parietal region and the anterior putamen of the subcortical
region were the main contributors to this effect. Normalized rCMRglc of the
hippocampus was higher in ADHD than in control girls. Sexual maturation was
the only clinical characteristic that differed between present and previous
samples, and it correlated with global CMRglc. CONCLUSIONS: Although failing
to confirm abnormally low CMRglc in girls with ADHD, this study suggested
that (1) functional interactions between sex and brain development may contribute
to ADHD pathophysiology, and (2) sexual maturation should be controlled in
future CMRglc studies of adolescent girls.. 50-99-7.
90. Esser, K. H.; Condon, C. J.; Suga, N.; Kanwal, J. S. Syntax processing by auditory
cortical neurons in the FM-FM area of the mustached bat Pteronotus parnellii.
Proc-Natl-Acad-Sci-U-S-A. 1997 Dec 9; 94(25): 14019-24; ISSN: 0027-8424.
UNITED-STATES. Syntax denotes a rule system that allows one to predict the
sequencing of communication signals. Despite its significance for both human
speech processing and animal acoustic communication, the representation of
syntactic structure in the mammalian brain has not been studied
electrophysiologically at the single-unit level. In the search for a neuronal correlate
for syntax, we used playback of natural and temporally destructured complex
species-specific communication calls-so-called composites-while recording
extracellularly from neurons in a physiologically well defined area (the FM-FM
area) of the mustached bat's auditory cortex. Even though this area is known to be
involved in the processing of target distance information for echolocation, we
found that units in the FM-FM area were highly responsive to composites. The
finding that neuronal responses were strongly affected by manipulation in the
time domain of the natural composite structure lends support to the hypothesis
that syntax processing in mammals occurs at least at the level of the nonprimary
auditory cortex.
91. Fallgatter, A. J.; Roesler, M.; Sitzmann, L.; Heidrich, A.; Mueller, T. J.; Strik, W. K.
Loss of functional hemispheric asymmetry in Alzheimer's dementia assessed with
near-infrared spectroscopy. Brain-Res-Cogn-Brain-Res. 1997 Jul; 6(1): 67-72;
ISSN: 0926-6410.
NETHERLANDS. In a total of 10 patients with dementia of the Alzheimer-type
(DAT) and in 10 healthy controls near-infrared spectroscopy (NIRS), a new non-
invasive optical method, was used to measure the changes of concentrations of
oxy- (O2HB) and deoxyhemoglobin (HHB) in left and right hemispheric
prefrontal brain tissue areas during performance of the Verbal Fluency Test
(VFT). On a neuropsychological level, the healthy subjects performed better in
the VFT than patients with DAT. Statistical analysis of the relative
concentrations of O2HB and HHB measured with NIRS during performance of
the VFT revealed a significant interaction of the hemispheric effects with the
diagnosis. A possible interpretation of this finding is that a good performance in
the VFT relies on a predominantly left hemispheric activation observed in
controls, whereas a low number of correct responses is associated with a loss of
this asymmetric activation in patients with DAT. Although both, patients and
controls, performed better in the category version of the VFT, the metabolic
effects of this task were significantly less pronounced than in the letter version.
This indicates that different energy demands, according to the type of access to
the memory stores, may be interpreted as the result of a less energy-demanding
access to categorically stored information and adds further evidence to the view
that memory departments in humans are organized according to categorical
principles.
92. Favaretto, A. L.; Ballejo, G. O.; Albuquerque Araujo, W. I.; Gutkowska, J.; Antunes
Rodrigues, J.; McCann, S. M. Oxytocin releases atrial natriuretic peptide from rat
atria in vitro that exerts negative inotropic and chronotropic action. Peptides.
1997; 18(9): 1377-81; ISSN: 0196-9781.
UNITED-STATES. Our previous experiments suggested that natriuresis induced
by blood volume expansion, was brought about by oxytocin (OT)-stimulated
atrial natriuretic peptide (ANP) release from the right atrium. We hypothesized
that the ANP released might exert effects on the atrium itself and therefore carried
out in vitro experiments to test this hypothesis. Heart rate and isometric tension
were recorded from isolated rat atria mounted in an organ bath. Oxytocin exerted a
dose-related, negative chrono- and inotropic effect with a minimal effective
concentration (MEC) of 3 microM, 10-fold higher than required for ANP to exert
comparable effects. The effects of OT were not blocked by atropine suggesting
that they were not mediated via release of acetylcholine. Eight-bromoguanosine 3'-
5'-cyclic monophosphate (cGMP) had similar effects to those of OT and ANP,
suggesting that the effects of ANP were mediated by cGMP. When isolated
ventricles, left or right atria, were incubated in vitro, OT had a dose-related effect
to stimulate the release of ANP into the medium only from right atria with a MEC
of 0.1 microM. A specific OT antagonist, F792 (1 microM), inhibited basal
release of ANP and blocked the stimulatory action of OT on ANP release. The
results support the hypothesis that OT, acting on its putative receptors in the
right atrium, stimulates the release of ANP which then exerts a negative chrono-
and inotropic effect via activation of guanylyl cyclase and release of cGMP. The
ability of the oxytocin antagonist to reduce basal release of ANP from atria
incubated in vitro supports the hypothesis that these effects could be
physiologically significant. We hypothesize that blood volume expansion via
baroreceptor input to the brain causes the release of OT which circulates to the
heart and stimulates the release of ANP from the right atrium. This ANP then has
a negative ino- and chronotropic effect in the atrium and possibly a negative
inotropic effect in the right ventricle, left atrium and left ventricle, to produce an
acute reduction in cardiac output that, coupled with its peripheral vasodilating
actions, causes a rapid reduction in effective circulating blood volume. The ANP
released would also act on the kidneys to cause natriuresis and ANP acts within
the brain to inhibit water and salt intake leading to a gradual recovery of circulating
blood volume to normal.. 50-56-6; 85637-73-6.
93. Fernandez, G.; Weyerts, H.; Schrader Bolsche, M.; Tendolkar, I.; Smid, H. G.;
Tempelmann, C.; Hinrichs, H.; Scheich, H.; Elger, C. E.; Mangun, G. R.; Heinze,
H. J. Successful verbal encoding into episodic memory engages the posterior
hippocampus: a parametrically analyzed functional magnetic resonance imaging
study. J-Neurosci. 1998 Mar 1; 18(5): 1841-7; ISSN: 0270-6474.
UNITED-STATES. The medial temporal lobe (MTL) is essential for episodic
memory encoding, as evidenced by memory deficits in patients with MTL
damage. However, previous functional neuroimaging studies have either failed to
show MTL activation during encoding or they did not differentiate between two
MTL related processes: novelty assessment and episodic memory encoding.
Furthermore, there is evidence that the MTL can be subdivided into
subcomponents serving different memory processes, but the extent of this
functional subdivision remains unknown. The aim of the present functional
magnetic resonance imaging (fMRI) study was to investigate the role of the MTL
in episodic encoding and to determine whether this function might be restricted to
anatomical subdivisions of the MTL. Thirteen healthy volunteers performed a
word list learning paradigm with free recall after distraction. Functional images
acquired during encoding were analyzed separately for each participant by a
voxel-wise correlation (Kendall's tau) between the time series of the T2*-signal
intensity and the number of subsequently recalled words encoded during each
particular scan. Of the 13 participants, 11 showed voxel clusters with statistically
significant, positive correlations in the posterior part of the hippocampus. Across
participants, an ANOVA on the number of voxels with significant, positive
correlations within individually defined volumes of interest confirmed a
statistically significant difference in activation for anterior versus posterior regions
of the hippocampus. However, no differences between left and right hippocampal
activation were revealed. Thus, these findings demonstrate that successful
encoding into episodic memory engages neural circuits in the posterior part of the
hippocampus.
94. Fink, G. R.; Dolan, R. J.; Halligan, P. W.; Marshall, J. C.; Frith, C. D. Space-based
and object-based visual attention: shared and specific neural domains. Brain. 1997
Nov; 120( Pt 11): 2013-28; ISSN: 0006-8950.
ENGLAND. Visual attention can be primarily allocated to either where an object
is in space (with little emphasis on the structure of the object itself) or to the
structure of the object (with little emphasis on where in space the object is
located). Using PET measures of regional cerebral blood flow (rCBF) to index
neural activity, we investigated the shared and specific functional anatomy
underlying both of these types of visual attention in a controlled non-cueing non-
blocked paradigm that involved identical stimuli across the conditions of interest.
The interaction of eye movements with these attentional systems was studied by
introducing fixation or free vision as an additional factor. Relative to the control
condition, object-based and space-based attention showed significant activations
of the left and right medial superior parietal cortex and the left lateral inferior
parietal cortex, the left prefrontal cortex and the cerebellar vermis. Significant
differential activations were observed during object-based attention in the left
striate and prestriate cortex. Space-based attention activated the right prefrontal
cortex and the right inferior temporal-occipital cortex. Differential neural activity
due to free vision or fixation was observed in occipital areas only. Significant
interactions of free vision/fixation on activations due to object-based and space-
based attention were observed in the right medial superior parietal cortex and left
lateral inferior parietal cortex, respectively. The study provides direct evidence for
the importance of the parietal cortex in the control of object-based and space-
based visual attention. The results show that object-based and space-based
attention share common neural mechanisms in the parietal lobes, in addition to
task specific mechanisms in early visual processing areas of temporal and occipital
cortices.
95. Fink, G. R.; Halligan, P. W.; Marshall, J. C.; Frith, C. D.; Frackowiak, R. S.; Dolan,
R. J. Neural mechanisms involved in the processing of global and local aspects of
hierarchically organized visual stimuli. Brain. 1997 Oct; 120( Pt 10): 1779-91;
ISSN: 0006-8950.
ENGLAND. We investigated the functional anatomy involved in sustaining or
switching visual attention between different perceptual levels, using functional
imaging measures of neural activity. Two experiments were carried out using
hierarchically organized letters (i.e. large letters made out of small letters). In a
divided-attention task, subjects were required to switch attention between local
and global levels. The number of successive stimuli for which subjects had to
sustain attention to either the global or local level co-varied significantly with
temporal-parietal activations bilaterally. Other activations were also observed in
the right orbitofrontal cortex, the right dorsolateral prefrontal cortex, and the right
middle temporal gyrus. The number of switches between levels co-varied
significantly with activations in the left supplementary motor area and the left
medial parietal cortex. In the directed-attention task, subjects were required to
attend to either the global or local level of the stimuli throughout all trials;
attention to the global aspect resulted in significant activation of the right lingual
gyrus while attention to the local aspect significantly activated the left inferior
occipital cortex. We suggest that left hemisphere activations with increasing
numbers of switches between perceptual levels reflect increased demands on an
executive attentional system, while sustained attention to either level activates a
predominantly right hemispheric network involving temporal-parietal and
dorsolateral prefrontal regions. Overall, the results provide evidence for relative
hemispheric specialization for global and local processing in accordance with
previous neuropsychological studies. In addition, the findings demonstrate that
early visual processing mechanisms in the prestriate cortex are influenced by an
attentional system in temporal-parietal areas.
96. Fransson, P.; Kruger, G.; Merboldt, K. D.; Frahm, J. A comparative FLASH and EPI
study of repetitive and sustained visual activation. NMR-Biomed. 1997 Jun;
10(4-5): 204-7; ISSN: 0952-3480.
ENGLAND. Functional responses to either brief repetitive or sustained
activation of the human visual cortex (movie presentation) were monitored using
both fast low angle shot and echo planar imaging sequences. To allow for proper
comparisons, native image contrasts were equally sensitized to changes in cerebral
blood oxygenation with other experimental conditions matched as much as
possible. Putative influences of receiver bandwidth and absolute voxel size were
specifically addressed. In all cases resulting correlation maps and regional signal
intensity time courses showed excellent spatial and temporal congruence,
respectively. In particular, for a 6 min protocol of sustained activation, both
FLASH and EPI yielded an initial signal increase (oxygenation overshoot), a
subsequent signal decrease during ongoing stimulation, and a marked signal drop
(oxygenation undershoot) after the end of stimulation. These findings exclude
technical differences between FLASH and EPI as the source of previous
contradictory observations more likely to be explained by differences in stimulus
design.
97. Fritsch, M.; Manwaring, K. H. Endoscopic treatment of brain abscess in children.
Minim-Invasive-Neurosurg. 1997 Sep; 40(3): 103-6; ISSN: 0946-7211.
GERMANY. Three children with intracerebral abscesses were treated
endoscopically. Two of the treated abscesses were located in the left temporal
lobe and one in the right parietal lobe. The presenting symptoms included
headaches, seizures, hemiparesis and signs of infection. Burr hole craniotomy,
insertion of a peelaway sheath, obtaining of a specimen, introduction of
endoscope, and complete irrigation under view was performed. After this a
draining catheter was positioned in the abscess. All three abscesses grew multiple
organisms. The patients received longstanding intravenous treatment with
antibiotics. The follow-up period in this group ranges between 5 and 32 months.
The initial neurological deficits were relieved in all three patients. The follow-up
MRI studies revealed minor residual changes without evidence of significant
sequelae. Neuroendoscopic treatment of brain abscesses has additional advantages
compared to stereotactic aspiration or more complete drainage and lavage.
98. Fukushima, K. Corticovestibular interactions: anatomy, electrophysiology, and
functional considerations. Exp-Brain-Res. 1997 Oct; 117(1): 1-16; ISSN: 0014-
4819.
GERMANY. This review summarizes anatomical and electrophysiological
observations related to corticovestibular interactions as a step toward
understanding their possible functions. Vestibular information is represented in at
least three distinct regions of the cerebral cortex in cats and monkeys: the parietal
and somatosensory cortex and the parietoinsular vestibular cortex. In addition,
vestibular-related signals are found in more extensive regions, including the motor
and premotor regions and frontal eye fields. Most of these regions also project
directly to the vestibular nuclei. In monkeys, at least six cortical regions have been
identified, including the motor, somatosensory, parietal and temporal areas. Most
of these regions receive vestibular projections via the thalamus. Most neurons in
those cortical areas respond to head velocity and receive converging vestibular,
visual and somatosensory input. Electrical stimulation of some of these cortical
areas in anesthetized cats influences the activity of many vestibular nuclear
neurons including those projecting to the spinal cord. Lesions of the parietal
vestibular regions impair the vestibulo-ocular reflex (VOR) and visual suppression
of the VOR as well as vestibular-related cognitive functions such as spatial
perception and memory in human subjects. Diffuse cortical damage also results in
similar impairment of the VOR and suppression of the VOR and possibly the
vestibulo-collic reflex. Such impairments after cortical lesions may well be due in
part to interruption of cortico-vestibular connections. Future studies in alert
animals should focus on the role of different cortical regions projecting to the
vestibular nuclei, specifically on how each affects the processing of vestibular
signals that mediate vestibulo-motor reflexes and that are used for vestibular
related cognitive processes.
99. Fushiki, H.; Barmack, N. H. Topography and reciprocal activity of cerebellar Purkinje
cells in the uvula-nodulus modulated by vestibular stimulation. J-Neurophysiol.
1997 Dec; 78(6): 3083-94; ISSN: 0022-3077.
UNITED-STATES. In the rabbit uvula-nodulus, vestibular and optokinetic
information is mapped onto parasagittal zones by climbing fibers. These zones are
related functionally to different pairs of vertical semicircular canals, otolithic
inputs and horizontal optokinetic inputs. Vestibular stimulation restricted to one
of these zones modulates climbing fiber responses (CFRs). Within each of these
zones, simple spikes (SSs) are modulated reciprocally with CFRs. In rabbits
anesthetized with chloralose-urethan, we have used vestibular and optokinetic
stimulation to evoke CFRs within a parasagittal zone while recording from
Purkinje cells in adjacent zones. We have examined whether the CFRs evoked by
vestibular stimulation in one zone influence the SSs of an adjacent zone. CFRs and
SSs were recorded during roll vestibular stimulation. The orientation of the head of
the rabbit with respect to the axis of rotation was varied systematically so that a
climbing fiber null plane could be determined. This null plane was the orientation
of the head about the vertical axis at which no modulation of the CFR was
observed during rotation about the longitudinal axis of the vestibular rate table. In
the left uvula-nodulus, a medial sagittal strip extending through all the folia
contained Purkinje cells with CFRs that had optimal planes of stimulation
coplanar with the left posterior-right anterior semicircular canals (LPC-RAC).
Lateral to this strip was a strip of Purkinje cells with CFRs that were
characterized by optimal planes corresponding to stimulation of the left anterior-
right posterior semicircular canals (LAC-RPC). SSs in Purkinje cells were
modulated out of phase with CFRs from the same Purkinje cell. The depth of
modulation of both CFRs and SSs was reduced during rotation in the climbing
fiber "null plane". The depth of modulation of SSs was greatest when recorded
from Purkinje cells located at the center of semicircular canal-related strip. We
observed that 1) all folia of the uvula-nodulus receive vestibular climbing fiber
inputs; 2) these climbing fiber inputs convey information from the vertical
semicircular canals and otoliths but not the horizontal semicircular canals; 3)
CFRs evoked in a particular sagittal zone do not influence SSs in adjacent zones;
4) modulation of a CFRs in a particular Purkinje cell can occur without
modulation of SSs in the same Purkinje cell, although modulation of SSs was not
observed in the absence of CFR modulation; and 5) modulation of SSs sometimes
preceded that of CFRs in the same cell, implying that interneuronal pathways
may contribute to SS modulation. Climbing fiber-driven Golgi cells, the inhibitory
axon terminals of which end on granule cell dendrites in the classic glomerular
synapse, may provide this interneuronal mechanism.
100. Gabrieli, J. D.; Poldrack, R. A.; Desmond, J. E. The role of left prefrontal cortex in
language and memory. Proc-Natl-Acad-Sci-U-S-A. 1998 Feb 3; 95(3): 906-13;
ISSN: 0027-8424.
UNITED-STATES. This article reviews attempts to characterize the mental
operations mediated by left inferior prefrontal cortex, especially the anterior and
inferior portion of the gyrus, with the functional neuroimaging techniques of
positron emission tomography and functional magnetic resonance imaging.
Activations in this region occur during semantic, relative to nonsemantic, tasks for
the generation of words to semantic cues or the classification of words or pictures
into semantic categories. This activation appears in the right prefrontal cortex of
people known to be atypically right-hemisphere dominant for language. In this
region, activations are associated with meaningful encoding that leads to superior
explicit memory for stimuli and deactivations with implicit semantic memory
(repetition priming) for words and pictures. New findings are reported showing
that patients with global amnesia show deactivations in the same region associated
with repetition priming, that activation in this region reflects selection of a
response from among numerous relative to few alternatives, and that activations in
a portion of this region are associated specifically with semantic relative to
phonological processing. It is hypothesized that activations in left inferior
prefrontal cortex reflect a domain-specific semantic working memory capacity
that is invoked more for semantic than nonsemantic analyses regardless of
stimulus modality, more for initial than for repeated semantic analysis of a word
or picture, more when a response must be selected from among many than few
legitimate alternatives, and that yields superior later explicit memory for
experiences.
101. Gainotti, G.; Azzoni, A.; Gasparini, F.; Marra, C.; Razzano, C. Relation of lesion
location to verbal and nonverbal mood measures in stroke patients. Stroke. 1997
Nov; 28(11): 2145-9; ISSN: 0039-2499.
UNITED-STATES. BACKGROUND AND PURPOSE: The aim of the present
study was to evaluate the relation between poststroke depression and lesion
location, avoiding previous methodological shortcomings. In particular, we
intended to determine whether patients with left frontal lesions showed the
highest depression scores. METHODS: Patients in the study, categorized on the
basis of lesion location, included 149 stroke patients with lesions located in the
anterior, central, or posterior regions of the right or left hemisphere. Verbal and
nonverbal mood measures as well as the Hamilton Depression Scale Overall Score
were the dependent measures of our investigation. Furthermore, the number of
patients who could not be assessed or could be evaluated only with the nonverbal
mood measure due to the presence of severe language disorders was recorded.
RESULTS: No significant relation was observed between depressed mood and
lesion location. Approximately one quarter of the left brain-damaged patients
were partially or totally excluded from the study because of severe language
disorders. CONCLUSIONS: Our data appeared to show that when
methodological pitfalls and selection bias are carefully controlled, left frontal
lesions are not a major determinant of poststroke depression.
102. Gannon, P. J.; Holloway, R. L.; Broadfield, D. C.; Braun, A. R. Asymmetry of
chimpanzee planum temporale: humanlike pattern of Wernicke's brain language
area homolog. Science. 1998 Jan 9; 279(5348): 220-2; ISSN: 0036-8075.
UNITED-STATES. The anatomic pattern and left hemisphere size predominance
of the planum temporale, a language area of the human brain, are also present in
chimpanzees (Pan troglodytes). The left planum temporale was significantly
larger in 94 percent (17 of 18) of chimpanzee brains examined. It is widely
accepted that the planum temporale is a key component of Wernicke's receptive
language area, which is also implicated in human communication-related disorders
such as schizophrenia and in normal variations such as musical talent. However,
anatomic hemispheric asymmetry of this cerebrocortical site is clearly not unique
to humans, as is currently thought. The evolutionary origin of human language
may have been founded on this basal anatomic substrate, which was already
lateralized to the left hemisphere in the common ancestor of chimpanzees and
humans 8 million years ago.
103. Gaschler Markefski, B.; Baumgart, F.; Tempelmann, C.; Schindler, F.; Stiller, D.;
Heinze, H. J.; Scheich, H. Statistical methods in functional magnetic resonance
imaging with respect to nonstationary time-series: auditory cortex activity. Magn-
Reson-Med. 1997 Nov; 38(5): 811-20; ISSN: 0740-3194.
UNITED-STATES. In awake animal and human auditory cortices, it is a common
experience with electrophysiological and suitable imaging methods for responses
to steady stimulation to be strongly state-dependent and to exhibit
nonstationarities, even over short periods of observation. If such nonstationary
behavior is also reflected by hemodynamic responses in the human auditory
cortex, conventional methods of analysis of fMRI data, although applicable for
instance to largely stationary responses in visual and other cortices, may be
misleading in attempts to parcellate auditory cortex into fields and to demonstrate
functional maps. Time-Windows, described in this article as a convenient tool for
the detection and analysis of time-variant brain activities, solves some of these
problems. Time-Windows demonstrates that activity is evoked reliably in three
separate territories of human auditory cortex, parts of which may show
nonstationary behavior, depending on the auditory stimuli and tasks.
104. Gati, I.; Papp, L.; Polgar, T. Infrared imaging of human brain sections. A new
biomedical application of the thermocamera. APMIS. 1997 Oct; 105(10): 801-5;
ISSN: 0903-4641.
DENMARK. Human brains, removed at routine autopsy, were subjected to
neuropathological investigation. The usual gross morphological investigation of
the brains was extended to include the detection of their infrared emissions.
Fundamental structures, such as the grey and the white matter, were separated on
the infrared images. Furthermore, pathological processes, such as ischaemic
damage, haemorrhage, and sclerotic plaques, hardly seen on the normal
photographs, gave a strong signal on the infrared pictures. These pilot
experiments demonstrated that infrared detection is a reproducible method in this
type of biomedical application, and potentially a very useful tool in macroscopic
pathology.. 50-00-0.
105. Gauger, L. M.; Lombardino, L. J.; Leonard, C. M. Brain morphology in children with
specific language impairment. J-Speech-Lang-Hear-Res. 1997 Dec; 40(6): 1272-
84; ISSN: 1092-4388.
UNITED-STATES. The planum temporale and pars triangularis have been found
to be larger in the left hemisphere than the right in individuals with normal
language skills. Brain morphology studies of individuals with developmental
language disorders report reversed asymmetry or symmetry of the planum,
although the bulk of this research has been completed on adults with dyslexia.
Pars triangularis has not been studied in the developmental language impaired
population. In this study, magnetic resonance imaging (MRI) was used for
quantitative comparisons of the planum temporale (Wernicke's area) and pars
triangularis (Broca's area) in children with specific language impairment (SLI) and
children with normal language skills. The subjects were 11 children with SLI and
19 age- and sex-matched controls between 5.6 and 13.0 years old. Each subject
received a neurolinguistic battery of tests and a high resolution volumetric MRI
scan. Major results were that (a) pars triangularis was significantly smaller in the
left hemisphere of children with SLI, and (b) children with SLI were more likely to
have rightward asymmetry of language structures. Furthermore, anomalous
morphology in these language areas correlated with depressed language ability.
These findings support the hypothesis that language impairment is a consequence
of an underlying neurobiological defect in areas of the brain known to subserve
language.
106. Gemba, H.; Miki, N.; Sasaki, K. Cortical field potentials preceding vocalization in
monkeys. Acta-Otolaryngol-Suppl-Stockh. 1997; 532: 96-8; ISSN: 0365-5237.
NORWAY. Field potentials before vocalization were studied with electrodes
chronically implanted on the surface and at a 2.0-3.0 mm depth in various cortical
areas in three monkeys. Surface-negative, depth-positive (s-N, d-P) slow
potentials prior to vocalization were recorded in the premotor (including the
Broca's homolog), motor and somatosensory cortices, and the supplementary
motor area (SMA). Such premovement potentials were recorded also in the
cingulate and prefrontal cortices when a monkey uttered a sound with intense
motivation for reward. Cerebellar hemispherectomy on the right side eliminated
the s-N, d-P premovement potentials in the motor cortex and in the posterior
bank of inferior limb of the arcuate sulcus (homolog of Broca's area) in the left
hemisphere. After the operation, the tone came to have less components of
different frequencies, and its duration varied much more than before. These facts
suggest that the neocortical area homologous to the human speech area takes part
in the generation and control of monkey vocalization together with the cerebellum
possibly through cerebro-cerebellar interactions. This is against ideas so far
proposed on nonhuman primate vocalization, i.e., it is generally considered that
animal vocalization differs fundamentally from human speech.
107. Ghatan, P. H.; Hsieh, J. C.; Petersson, K. M.; Stone Elander, S.; Ingvar, M.
Coexistence of attention-based facilitation and inhibition in the human cortex.
Neuroimage. 1998 Jan; 7(1): 23-9; ISSN: 1053-8119.
UNITED-STATES. A key function of attention is to select an appropriate
subset of available information by facilitation of attended processes and/or
inhibition of irrelevant processing. Functional imaging studies, using positron
emission tomography, have during different experimental tasks revealed decreased
neuronal activity in areas that process input from unattended sensory modalities.
It has been hypothesized that these decreases reflect a selective inhibitory
modulation of nonrelevant cortical processing. In this study we addressed this
question using a continuous arithmetical task with and without concomitant
disturbing auditory input (task-irrelevant speech). During the arithmetical task,
irrelevant speech did not affect task-performance but yielded decreased activity in
the auditory and midcingulate cortices and increased activity in the left posterior
parietal cortex. This pattern of modulation is consistent with a top down
inhibitory modulation of a nonattended input to the auditory cortex and a
coexisting, attention-based facilitation of task-relevant processing in higher order
cortices. These findings suggest that task-related decreases in cortical activity may
be of functional importance in the understanding of both attentional mechanisms
and task-related information processing.
108. Giedd, J. N.; Castellanos, F. X.; Rajapakse, J. C.; Vaituzis, A. C.; Rapoport, J. L.
Sexual dimorphism of the developing human brain. Prog-Neuropsychopharmacol-
Biol-Psychiatry. 1997 Nov; 21(8): 1185-201; ISSN: 0278-5846.
ENGLAND. 1. Sexual dimorphism of human brain anatomy has not been well-
studied between 4 and 18 years of age, a time of emerging sex differences in
behavior and the sexually specific hormonal changes of adrenarche (the
predominantly androgenic augmentation of adrenal cortex function occurring at
approximately age 8) and puberty. 2. To assess sex differences in brain structures
during this developmental period volumes of the cerebrum, lateral ventricles,
caudate, putamen, globus pallidus temporal lobe, amygdala, and hippocampus,
and midsagittal area measurements of the corpus callosum were quantified from
brain magnetic resonance images of 121 healthy children and adolescent and
examined in relation to age and sex. 3. Males had a 9% larger cerebral volume.
When adjusted for cerebral volume by ANCOVA only the basal ganglia
demonstrated sex differences in mean volume with the caudate being relatively
larger in females and the globus pallidus being relatively larger in males. The lateral
ventricles demonstrated a prominent sex difference in brain maturation with
robust increases in size in males only. A piecewise-linear model revealed a
significant change in the linear regression slope of lateral ventricular volume in
males after age 11 that was not shared by females at that or other ages. 4.
Amygdala and hippocampal volume increased for both sexes but with the
amygdala increasing significantly more in males than females and hippocampal
volume increasing more in females. 5. These sexually dimorphic patterns of brain
development may be related to the observed sex differences in age of onset,
prevalence, and symptomatology seen in nearly all neuropsychiatric disorders of
childhood.
109. Glass, I.; Sazbon, L.; Groswasser, Z. Mapping "cognitive" event-related potentials in
prolonged postcoma unawareness state. Clin-Electroencephalogr. 1998 Jan; 29(1):
19-30; ISSN: 0009-9155.
UNITED-STATES. "Cognitive" auditory event-related potentials (ERPs) were
mapped to examine the putative conscious responsiveness of eight patients in a
postcoma unawareness (PCU) state and of eight matched normal controls. A
"passive P3" paradigm was used to evaluate waves N2, P3, and Slow Waves of
the ERPs. Results showed that the signal/noise ratio of the patients' waveshapes
was poorer than that of the controls. Yet, on the whole, no between-group
significant differences were noted for most of the averaged characteristics of the
waves. In general, in the patients, the left hemisphere was dominated by negative
potentials relative to the right one, whereas in the controls, the opposite
asymmetry was apparent. Thirty-eight percent of the patients had passive N2
and P3 waves, and 67% of the responders regained consciousness (versus none of
the non-responders). These findings suggest that the presence of intact "cognitive"
waves is compatible with a higher probability for improvement, although
nondetection of certain waves at the postcoma unawareness state does not
necessarily indicate the worst prognosis.
110. Glass, M.; Dragunow, M.; Faull, R. L. Cannabinoid receptors in the human brain: a
detailed anatomical and quantitative autoradiographic study in the fetal, neonatal
and adult human brain. Neuroscience. 1997 Mar; 77(2): 299-318; ISSN: 0306-
4522.
UNITED-STATES. The anatomical distribution and density of cannabinoid
receptors in the human brain was studied in one fetal (33 weeks gestation), two
neonatal (aged three to six months) and eight adult (aged 21-81 years) human cases
using quantitative receptor autoradiography following in vitro labelling of sections
with the synthetic cannabinoid agonist [3H]CP55,940. Cannabinoid receptors
were distributed in a heterogeneous fashion throughout the adult human brain and
spinal cord. The allocortex contained very high concentrations of cannabinoid
receptor binding sites in the dentate gyrus, Ammons's horn and subiculum of the
hippocampal formation; high concentrations of receptors were also present in the
entorhinal cortex and amygdaloid complex. Cannabinoid receptor binding sites
were also present throughout all regions of the neocortex, where they showed a
marked variation in density between the primary, secondary and associational
cortical regions: the greatest densities of receptors were present in the
associational cortical regions of the frontal and limbic lobes, with moderate
densities in the secondary sensory and motor cortical regions, and with the lowest
densities of receptors in the primary sensory and motor cortical regions.
Relatively high concentrations of cannabinoid receptors were consistently seen in
cortical regions of the left (dominant) hemisphere, known to be associated with
verbal language functions. In all of the cortical regions, the pattern and density of
receptor labelling followed the neocortical laminar organization, with the greatest
density of receptors localized in two discrete bands--a clearly delineated narrow
superficial band which coincided with lamina I and a deeper broader, conspicuous
band of labelling which corresponded to laminae V and VI. Labelling in the
intervening cortical laminae (II-IV) showed lower densities, with a well delineated
narrow band of label in the middle of laminae IV in the associational cortical
regions. The thalamus showed a distinctive heterogeneous distribution of
cannabinoid receptors, with the highest concentration of receptors localized in the
mediodorsal nucleus, anterior nuclear complex, and in the midline and intralaminar
complex of nuclei, i.e. in thalamic nuclei which have connectional affiliations with
the associational cortical areas. The basal ganglia showed a distinctive
heterogeneous pattern of receptor binding, with the very highest concentrations in
the globus pallidus internus, moderate concentrations in the globus pallidus
externus and ventral pallidum, and moderately low levels of binding throughout
the striatal complex. In the midbrain, some of the highest levels of cannabinoid
receptor binding sites in the human brain were present in the substantia nigra pars
reticulata, with very low levels of labelling in all other midbrain areas. The highest
densities of cannabinoid receptor binding in the hindbrain were localized in the
molecular layer of the cerebellar cortex and the dorsal motor nucleus of the vagus,
with moderate densities of receptors in the nucleus of the solitary tract. The
spinal cord showed very low levels of receptor binding. Studies on the
distribution of cannabinoid receptors in the fetal and neonatal human brain
showed similar patterns of receptor distribution to that observed in the adult
human brain, except that the density of receptor binding was generally markedly
higher, especially in the basal ganglia and substantia nigra. The pattern of
cannabinoid receptor labelling in the striatum showed a striking patchy pattern of
organization which was especially conspicuous in the fetal brain. These results
show that cannabinoid receptor binding sites in the human brain are localized
mainly in: forebrain areas associated with higher cognitive functions; forebrain,
midbrain and hindbrain areas associated with the control of movement; and in
hindbrain areas associated with the control of motor and sensory functions of the
autonomic nervous system. (AB. 0; 0; 0; 0.
111. Glass, M.; Dragunow, M.; Faull, R. L. Cannabinoid receptors in the human brain: a
detailed anatomical and quantitative autoradiographic study in the fetal, neonatal
and adult human brain. Neuroscience. 1997 Mar; 77(2): 299-318; ISSN: 0306-
4522.
UNITED-STATES. The anatomical distribution and density of cannabinoid
receptors in the human brain was studied in one fetal (33 weeks gestation), two
neonatal (aged three to six months) and eight adult (aged 21-81 years) human cases
using quantitative receptor autoradiography following in vitro labelling of sections
with the synthetic cannabinoid agonist [3H]CP55,940. Cannabinoid receptors
were distributed in a heterogeneous fashion throughout the adult human brain and
spinal cord. The allocortex contained very high concentrations of cannabinoid
receptor binding sites in the dentate gyrus, Ammons's horn and subiculum of the
hippocampal formation; high concentrations of receptors were also present in the
entorhinal cortex and amygdaloid complex. Cannabinoid receptor binding sites
were also present throughout all regions of the neocortex, where they showed a
marked variation in density between the primary, secondary and associational
cortical regions: the greatest densities of receptors were present in the
associational cortical regions of the frontal and limbic lobes, with moderate
densities in the secondary sensory and motor cortical regions, and with the lowest
densities of receptors in the primary sensory and motor cortical regions.
Relatively high concentrations of cannabinoid receptors were consistently seen in
cortical regions of the left (dominant) hemisphere, known to be associated with
verbal language functions. In all of the cortical regions, the pattern and density of
receptor labelling followed the neocortical laminar organization, with the greatest
density of receptors localized in two discrete bands--a clearly delineated narrow
superficial band which coincided with lamina I and a deeper broader, conspicuous
band of labelling which corresponded to laminae V and VI. Labelling in the
intervening cortical laminae (II-IV) showed lower densities, with a well delineated
narrow band of label in the middle of laminae IV in the associational cortical
regions. The thalamus showed a distinctive heterogeneous distribution of
cannabinoid receptors, with the highest concentration of receptors localized in the
mediodorsal nucleus, anterior nuclear complex, and in the midline and intralaminar
complex of nuclei, i.e. in thalamic nuclei which have connectional affiliations with
the associational cortical areas. The basal ganglia showed a distinctive
heterogeneous pattern of receptor binding, with the very highest concentrations in
the globus pallidus internus, moderate concentrations in the globus pallidus
externus and ventral pallidum, and moderately low levels of binding throughout
the striatal complex. In the midbrain, some of the highest levels of cannabinoid
receptor binding sites in the human brain were present in the substantia nigra pars
reticulata, with very low levels of labelling in all other midbrain areas. The highest
densities of cannabinoid receptor binding in the hindbrain were localized in the
molecular layer of the cerebellar cortex and the dorsal motor nucleus of the vagus,
with moderate densities of receptors in the nucleus of the solitary tract. The
spinal cord showed very low levels of receptor binding. Studies on the
distribution of cannabinoid receptors in the fetal and neonatal human brain
showed similar patterns of receptor distribution to that observed in the adult
human brain, except that the density of receptor binding was generally markedly
higher, especially in the basal ganglia and substantia nigra. The pattern of
cannabinoid receptor labelling in the striatum showed a striking patchy pattern of
organization which was especially conspicuous in the fetal brain. These results
show that cannabinoid receptor binding sites in the human brain are localized
mainly in: forebrain areas associated with higher cognitive functions; forebrain,
midbrain and hindbrain areas associated with the control of movement; and in
hindbrain areas associated with the control of motor and sensory functions of the
autonomic nervous system. (AB. 0; 0; 0; 0.
112. Gonen, O.; Murdoch, J. B.; Stoyanova, R.; Goelman, G. 3D multivoxel proton
spectroscopy of human brain using a hybrid of 8th-order Hadamard encoding with
2D chemical shift imaging. Magn-Reson-Med. 1998 Jan; 39(1): 34-40; ISSN:
0740-3194.
UNITED-STATES. Multivoxel 3D localized proton spectroscopy using a hybrid
of 1D 8th-order transverse Hadamard spectroscopic imaging (HSI) with 2D
chemical shift imaging (CSI) is demonstrated in human brain. The spatially
selective HSI pulse incorporates naturally into the PRESS sequence (TE = 135
ms), which then both excites an 8 x 8 x 6 cm parallelepiped volume of interest
(VOI) and subdivides it into eight slices. The planes of these slices are further
partitioned into 16 x 16 voxel arrays using 2D CSI to yield 8 x 8 x 8 voxels within
the VOI. Simultaneous 3D coverage yields good voxel signal-to-noise (8, 12, and
22 for choline, creatine, and N-acetylaspartate, respectively) from these 0.75-ml
voxels, in approximately 45 min. The high spatial isolation allows localization to
within less than 1 cm from the skull without fat contamination.. 0.
113. Goscinski, I.; Kwiatkowski, S.; Polak, J.; Orlowiejska, M.; Partyk, A. The Kluver-
Bucy syndrome. J-Neurosurg-Sci. 1997 Sep; 41(3): 269-72; ISSN: 0390-5616.
ITALY. Evolution of psychological disorders following head injury including
memory disorders and other cognitive ones are common. The best known are
psychiatric disturbances of various kind after lesions of frontal lobes. Cognitive,
behavioural and emotional disorders are not usually seen in patients with bilateral
temporal lesions. In our Department of Neurotraumatology we observed 4
patients with post-traumatic lesions localized bitemporally. They developed
Kluver-Bucy syndrome--rarity in human pathology--with combination of three or
more the following syndromes: increased oral activity, hypersexuality,
hypermetamorphosis, memory disorders, placidity, loss of people recognition,
bulimia. Several symptoms responded dramatically to carbamazepine. We
conclude that it may be a useful agent in treatment of this unusual syndrome.
114. Grachev, I. D. MRI-based morphometric topographic parcellation of human
neocortex in trichotillomania. Psychiatry-Clin-Neurosci. 1997 Oct; 51(5): 315-21;
ISSN: 1323-1316.
AUSTRALIA. The purpose of the present study was to test specific
hypotheses regarding volumetric changes of the neocortex between 10 female
trichotillomania (TTM) subjects and 10 female normal controls. A standard three-
dimensional (3-D) brain coordinate system was imposed over each newly acquired
native magnetic resonance imaging (MRI) scan for positional normalization and 3-
D shape/geometric localization analyses were based on the midpoints of anterior
and posterior commissures, and the longitudinal fissure. The brain segmentation
method, using well-characterized semiautomated intensity and differential contour
algorithms by signal intensity-frequency histograms, was used blind to segment
the principal gray and white matter structures. The segmented neocortical ribbon
was subdivided into 48 regions (i.e. parcellation units) per hemisphere via a new
method of morphometric topographic parcellation. There were no significant
volumetric changes of the precentral gyrus, postcentral gyrus, supplementary
motor cortex or opercular cortex in TTM patients compared with control
subjects. A broader analysis as a hypothesis-generating post-hoc effort showed
that TTM subjects exhibited significantly reduced left inferior frontal gyrus
volume of 27% (t = 2.21, d.f. = 18, P = 0.04) and enlarged right cuneal cortex
volume of 40% (t = -2.30, d.f. = 18, P = 0.03) compared to normal controls. This
is the first report of a structural neocortex abnormality in TTM. Results are
discussed in terms of the behavioral specialization of these two brain neocortical
regions and the complex interractions between visual and sensorimotor cortices.
The results also showed the feasibility of the MRI-based morphometric
topographic parcellation for investigation of the human neocortex in neuroscience
research.
115. Grady, C. L.; Van Meter, J. W.; Maisog, J. M.; Pietrini, P.; Krasuski, J.; Rauschecker,
J. P. Attention-related modulation of activity in primary and secondary auditory
cortex. Neuroreport. 1997 Jul 28; 8(11): 2511-6; ISSN: 0959-4965.
ENGLAND. We investigated the effects of auditory attention on brain activity
using functional magnetic resonance imaging. Subjects listened to three word lists,
three times each, and were instructed to count the number of times they heard a
target word during two of these presentations. For the third, they listened to the
words without counting. All subjects showed significant areas of activation in
auditory cortex during the listening conditions compared to rest. There was
significantly more activation and a larger area of activation, particularly in
association cortex, in the left temporal lobe during counting of targets compared to
the no-target conditions, with a similar trend in the right hemisphere. These
results provide evidence of an attention-related enhancement of both activation
magnitude and extent in auditory cortex.
116. Grafton, S. T.; Fadiga, L.; Arbib, M. A.; Rizzolatti, G. Premotor cortex activation
during observation and naming of familiar tools. Neuroimage. 1997 Nov; 6(4):
231-6; ISSN: 1053-8119.
UNITED-STATES. Positron emission tomography was used to investigate
whether observation of real objects (tools of common use) activates premotor
areas in the absence of any overt motor demand. Silent naming of the presented
tools and silent naming of their use were also studied. Right-handed normal
subjects were employed. Tool observation strongly activated the left dorsal
premotor cortex. In contrast, silent tool naming activated Broca's area without
additional activity in the dorsal premotor cortex. Silent tool-use naming, in
addition to activating Broca's area, increased the activity in the left dorsal
premotor cortex and recruited the left ventral premotor cortex and the left
supplementary motor area. These data indicate that, even in the absence of any
subsequent movement, the left premotor cortex processes objects that, like tools,
have a motor valence. This dorsal premotor activation, which further augments
when the subject names the tool use, should reflect the neural activity related to
motor schemata for object use. The presence of an activation of both dorsal
premotor cortex and ventral premotor cortex during tool-use naming suggests a
role for these two areas in understanding object semantics. Copyright 1997
Academic Press.
117. Gratton, G.; Fabiani, M.; Corballis, P. M.; Hood, D. C.; Goodman Wood, M. R.;
Hirsch, J.; Kim, K.; Friedman, D.; Gratton, E. Fast and localized event-related
optical signals (EROS) in the human occipital cortex: comparisons with the visual
evoked potential and fMRI. Neuroimage. 1997 Oct; 6(3): 168-80; ISSN: 1053-
8119.
UNITED-STATES. Localized evoked activity of the human cortex produces fast
changes in optical properties that can be detected noninvasively (event-related
optical signal, or EROS). In the present study a fast EROS response (latency
approximately 100 ms) elicited in the occipital cortex by visual stimuli showed
spatial congruence with fMRI signals and temporal correspondence with VEPs,
thus combining subcentimeter spatial localization with subsecond temporal
resolution. fMRI signals were recorded from striate and extrastriate cortex. Both
areas showed EROS peaks, but at different latencies after stimulation (100 and
200-300 ms, respectively). These results suggest that EROS manifests localized
neuronal activity associated with information processing. The temporal resolution
and spatial localization of this signal make it a promising tool for studying the
time course of activity in localized brain areas and for bridging the gap between
electrical and hemodynamic imaging methods. Copyright 1997 Academic Press.
118. Graziani, L. J.; Gringlas, M.; Baumgart, S. Cerebrovascular complications and
neurodevelopmental sequelae of neonatal ECMO. Clin-Perinatol. 1997 Sep; 24(3):
655-75; ISSN: 0095-5108.
UNITED-STATES. A total of 355 infants have been treated with ECMO at our
hospital between 1985 and 1996, 271 of whom have been enrolled in an ongoing
prospective study; of the 271 infants enrolled, 223 (82%) survived, and most
function within the normal range of development. Nevertheless, handicapping
sequelae, including spastic forms of CP, hearing loss, and cognitive deficiencies at
school age, have been noted in a significant minority of ECMO-treated survivors.
The need for RCCA cannulation during venoarterial ECMO may increase the risk
of a cerebrovascular injury, and lateralized CBF abnormalities have been noted on
CDI and pulsed Doppler ultrasound studies during and after venoarterial bypass;
however, post-ECMO CT scans, HUS, MR images, or clinical evaluations have
not indicated selective or greater injury to the right, compared with the left,
cerebral hemisphere in our survivors, nor was there a significant predilection for
right, rather than left, cerebral hemispheric EEG abnormalities during or following
venoarterial bypass. Although we routinely repair the RCCA following
venoarterial ECMO, the long-term consequences of a permanently ligated artery
have not as yet been demonstrated. We have noted the ominous predictive value
of two or more recordings that disclose ES and BS EEG abnormalities before or
during venoarterial ECMO and found that the need for vigorous CPR before or
during RCCA cannulation significantly increased the risk of these two markedly
abnormal bioelectric patterns. Because 85% of infants with severe respiratory
failure have moderate to marked EEG abnormalities (including 23% who have BS
or ES patterns) before ECMO, we believe that fetal and neonatal complications
related to the occurrence and treatment of severe cardiorespiratory failure are
responsible in large part for the neurologic sequelae in ECMO survivors. The risk
for CP was significantly increased in survivors of neonatal venoarterial ECMO
treated at our hospital who required CPR or who independently had a systolic BP
below 39 mm Hg before or during ECMO. We also noted that the risk for hearing
loss was increased significantly in surviving neonates who had a PaCO2 below 14
mm Hg before ECMO. The possibility that undetected confounding variables
were, in part, responsible for the neurologic, audiologic, and cognitive sequelae in
ECMO survivors could not be excluded entirely by our data analyses. Although
the pathogenesis of severe brain damage has not been defined fully in neonates
treated with ECMO, focal, multifocal, or diffuse cerebral ischemia is the most
likely final common pathway; thrombosis, infarction, or hemorrhage may follow
and contribute to the brain injury. The cause of isolated SNHL is unknown in
most affected ECMO survivors, but in some very likely is associated with the
complications and treatment of severe cardiorespiratory failure, including
profound hypocarbia prior to ECMO. The results of our studies to date are
consistent with the following conclusions: (1) hypotension before or during
ECMO and the need for CPR before ECMO contribute to the pathogenesis of
CP, probably through the mechanism of cerebral ischemia; (2) profound
hypocarbia before ECMO and delayed ECMO treatment are associated with a
significantly increased risk of hearing loss; (3) hypoxemia without hypotension
does not result in CP; (4) the type and severity of neurologic and cognitive
sequelae in ECMO survivors depends, in part, on the primary cause of the
neonatal cardiorespiratory failure; (5) early neurodevelopment, except for severe
deficits, may not predict school-age performance; and (6) abnormally low or
borderline WPPSI-R IQ scores and academic deficiencies at early school age,
without evidence of a congenital abnormality of brain or CP or SNHL, remain
unexplained. The criteria for initiating ECMO in the neonate with severe
cardiorespiratory failure include decreasing oxygenation despite mechanical
hyperventilation with 100% oxygen. (ABSTRACT TRUNCATED).
119. Gruetter, R.; Ugurbil, K.; Seaquist, E. R. Steady-state cerebral glucose concentrations
and transport in the human brain. J-Neurochem. 1998 Jan; 70(1): 397-408; ISSN:
0022-3042.
UNITED-STATES. Understanding the mechanism of brain glucose transport
across the blood-brain barrier is of importance to understanding brain energy
metabolism. The specific kinetics of glucose transport have been generally
described using standard Michaelis-Menten kinetics. These models predict that
the steady-state glucose concentration approaches an upper limit in the human
brain when the plasma glucose level is well above the Michaelis-Menten constant
for half-maximal transport, Kt. In experiments where steady-state plasma glucose
content was varied from 4 to 30 mM, the brain glucose level was a linear function
of plasma glucose concentration. At plasma concentrations nearing 30 mM, the
brain glucose level approached 9 mM, which was significantly higher than
predicted from the previously reported Kt of approximately 4 mM (p < 0.05).
The high brain glucose concentration measured in the human brain suggests that
ablumenal brain glucose may compete with lumenal glucose for transport. We
developed a model based on a reversible Michaelis-Menten kinetic formulation of
unidirectional transport rates. Fitting this model to brain glucose level as a
function of plasma glucose level gave a substantially lower Kt of 0.6 +/- 2.0 mM,
which was consistent with the previously reported millimolar Km of GLUT-1 in
erythrocyte model systems. Previously reported and reanalyzed quantification
provided consistent kinetic parameters. We conclude that cerebral glucose
transport is most consistently described when using reversible Michaelis-Menten
kinetics.. 50-99-7.
120. Gugliemotti, V.; Fiorino, L. Asymmetry in the left and right habenulo-interpeduncular
tracts in the frog. Brain-Res-Bull. 1998; 45(1): 105-10; ISSN: 0361-9230.
UNITED-STATES. In the frog Rana esculenta the left dorsal habenula includes a
lateral and a medial component, whereas the right dorsal habenula is only
represented by one nucleus. The efferents of the habenular nuclei to the
interpeduncular nucleus were herein investigated with the retrograde horseradish
peroxidase tracing. Injections of cobaltic-lysine complex in the interpeduncular
nucleus were also performed. Intensely labeled fibers of the fasciculus retroflexus
on the right and left sides of the brain were found to reach the interpeduncular
nucleus from the habenular nuclei running prevalently in two routes--one through
the medial, and the other through the lateral region of the diencephalon. On the
right side, these fibers originated from the entire dorsal habenula. On the left side,
the fibers of the medial route derived from the medial habenular subnucleus, while
those of the lateral route derived from the lateral habenular subnucleus. In the
dorsal habenulae of both sides, a large number of neurons displayed a Golgi-like
labeling, while few such cells were detected in the ventral habenulae. Labeled
neurons in the right dorsal habenula resembled those labeled in the lateral
subnucleus of the left dorsal habenula, while larger and ramified neurons were
detected in the left medial subnucleus. The present findings provide the first
description of the pathway originating from the medial and the lateral subnucleus
of the left dorsal habenula in the frog and point out that projection neurons of the
medial habenular subnucleus are morphologically different from those of the other
habenular nuclei. The present data indicate that in the frog the habenular
asymmetry could underlie distinct functional correlates of the left and right
habenulae.. EC 1.11.1.-; 0; 56-87-1.
121. Gunduz, K.; Gunalp, I.; Erden, I. Focal dermal hypoplasia (Goltz's syndrome).
Ophthalmic-Genet. 1997 Sep; 18(3): 143-9; ISSN: 0167-6784.
NETHERLANDS. A 17-year-old female with Goltz's syndrome was examined
because of visual acuity loss in her right eye. Ocular examination revealed
microcornea, iris, choroid and optic disc coloboma in the right eye. There were
several erthematous and hyperpigmented areas on the body. Magnetic resonance
(MR) imaging of the orbits and brain demonstrated right optic nerve hypoplasia
and diffuse cortical and cerebellar atrophy. Skeletal manifestations were short
stature, scoliosis, syndactyly, clinodactyly, and osteopathia striata. Dental
defects included hypodontia, developmental defects, and malocclusion. There
were multiple papillomatous lesions on the lids and perioral skin and the nose was
asymmetric. Her mental development was apparently normal. She had left bifid
ureter and renal pelvis, scant hair on the pubic and genital region, and poor breast
development. Histopathologic examination of the biopsy taken from a
characteristic skin lesion revealed attenuated epidermis, hypoplastic dermis, and
subcutaneous fat close to epidermis. Immunofluorescence staining was negative
for IgG, IgM, IgA, C3, C4, fibrin, and albumin. Ultrastructural examination
showed that no viral particles were present. Prometaphase chromosome analysis
revealed a normal 46, XX female karyotype. Cortical and cerebellar atrophy can
occur in a patient with Goltz's syndrome.
122. Gunturkun, O. Morphological asymmetries of the tectum opticum in the pigeon. Exp-
Brain-Res. 1997 Oct; 116(3): 561-6; ISSN: 0014-4819.
GERMANY. Pigeons are visually lateralized with a dominance of the right eye.
Due to the virtually complete decussation of the optic nerves in birds, a right eye
superiority probably depends on a left brain hemisphere dominance. The aim of
the present study was to analyze whether morphological asymmetries in the
cross-sectional area of perikarya can be found within the retina and the optic
tectum. With an image-analyzing system the cross-sectional areas of the somata of
retinal ganglion cells and tectal neurons were measured in the left and the right side
under blind conditions. The results reveal significant morphological left-right
differences, with cells in superficial layers 2-12 being larger on the left side while
neurons in laminae 13-15 have larger somata in the right tectum. No retinal
asymmetries could be revealed. Since pigeon embryos keep their head turned to
the right within the egg, such that the right eye is stimulated by light shining
through the shell, it is possible that the morphological asymmetries at the tectal
level are induced by left-right differences in prehatching photic stimulation. This
embryonic sensory asymmetry might lead to a higher activity level of right eye
ganglion cells and to a larger amount of released neurotrophins in the left tectum.
This in turn could exert the morphological effects on soma sizes in the superficial
retinorecipient layers.
123. Hadjikhani, N.; Roland, P. E. Cross-modal transfer of information between the tactile
and the visual representations in the human brain: A positron emission
tomographic study. J-Neurosci. 1998 Feb 1; 18(3): 1072-84; ISSN: 0270-6474.
UNITED-STATES. Positron emission tomography in three-dimensional
acquisition mode was used to identify the neural populations involved in tactile-
visual cross-modal transfer of shape. Eight young male volunteers went through
three runs of three different matching conditions: tactile-tactile (TT), tactile-visual
(TV), and visual-visual (VV), and a motor control condition. Fifteen spherical
ellipsoids were used as stimuli. By subtracting the different matching conditions
and calculating the intersections of statistically significant activations, we could
identify cortical functional fields involved in the formation of visual and tactile
representation of the objects alone and those involved in cross-modal transfer of
the shapes of the objects. Fields engaged in representation of visual shape,
revealed in VV-control, TV-control and TV-TT, were found bilaterally in the
lingual, fusiform, and middle occipital gyri and the cuneus. Fields engaged in the
formation of the tactile representation of shape, appearing in TT-control, TV-
control and TV-VV, were found in the left postcentral gyrus, left superior parietal
lobule, and right cerebellum. Finally, fields active in both TV-VV and TV-TT were
considered as those involved in cross-modal transfer of information. One field was
found, situated in the right insula-claustrum. This region has been shown to be
activated in other studies involving cross-modal transfer of information. The
claustrum may play an important role in cross-modal matching, because it receives
and gives rise to multimodal cortical projections. We propose here that modality-
specific areas can communicate, exchange information, and interact via the
claustrum.
124. Hadjikhani, N.; Roland, P. E. Cross-modal transfer of information between the tactile
and the visual representations in the human brain: A positron emission
tomographic study. J-Neurosci. 1998 Feb 1; 18(3): 1072-84; ISSN: 0270-6474.
UNITED-STATES. Positron emission tomography in three-dimensional
acquisition mode was used to identify the neural populations involved in tactile-
visual cross-modal transfer of shape. Eight young male volunteers went through
three runs of three different matching conditions: tactile-tactile (TT), tactile-visual
(TV), and visual-visual (VV), and a motor control condition. Fifteen spherical
ellipsoids were used as stimuli. By subtracting the different matching conditions
and calculating the intersections of statistically significant activations, we could
identify cortical functional fields involved in the formation of visual and tactile
representation of the objects alone and those involved in cross-modal transfer of
the shapes of the objects. Fields engaged in representation of visual shape,
revealed in VV-control, TV-control and TV-TT, were found bilaterally in the
lingual, fusiform, and middle occipital gyri and the cuneus. Fields engaged in the
formation of the tactile representation of shape, appearing in TT-control, TV-
control and TV-VV, were found in the left postcentral gyrus, left superior parietal
lobule, and right cerebellum. Finally, fields active in both TV-VV and TV-TT were
considered as those involved in cross-modal transfer of information. One field was
found, situated in the right insula-claustrum. This region has been shown to be
activated in other studies involving cross-modal transfer of information. The
claustrum may play an important role in cross-modal matching, because it receives
and gives rise to multimodal cortical projections. We propose here that modality-
specific areas can communicate, exchange information, and interact via the
claustrum.
125. Hamada, H.; Takahashi, H.; Teramoto, A.; Yoshii, T. [Effect of arginine vasopressin
(AVP) inhibitor in the inhibition of the peritumoral edema]. No-To-Shinkei. 1997
Nov; 49(11): 1001-6; ISSN: 0006-8969.
JAPAN. We investigated the effect of RU599 Arginine Vasopressin (AVP)
inhibitor on peritumoral edema of Wistar rats implanted with C6 glioma. C6
glioma was implanted into the right caudoputamen of 3 week-old rat's brain. Five
weeks after the implantation, the changes of the brain water contents were
measured by the dry-weight method. RU599 (1 mg/ml/kg body weight) was
administered into Wistar rats via the tail vein every one hour (total 4 times), and
the same dose of saline was used as control. Rats were sacrificed 1 hour after the
last administration, and the brain of each rat was divided into 3 parts such as the
anterior part without a tumor, the middle part with a tumor and the posterior part
without a tumor. After that each part was separated into the right and left parts.
The tumor was removed from the brain. The water contents of the brain were
increased in the area around the tumor and the contralateral cerebral hemisphere
excluding the anterior part. RU599 could reduce the increased water contents
significantly in all areas except in the tumor itself and the area surrounding the
tumor. Tumor-origin brain edema includes not only localized one but also diffuse
one in the brain, and this study suggests RU599 has an effect of inhibiting the
diffuse brain edema.. 0; 0; 0; 113-79-1.
126. Hamlyn, P. J. Neurovascular relationships in the posterior cranial fossa, with special
reference to trigeminal neuralgia. 1. Review of the literature and development of a
new method of vascular injection-filling in cadaveric controls. Clin-Anat. 1997;
10(6): 371-9; ISSN: 0897-3806.
UNITED-STATES. Vascular compression of cranial nerves adjacent to the brain
stem has been implicated in a wide variety of disorders affecting their function.
The considerable conflicts in published results relate primarily to flaws in study
design. The design required of an adequate study is defined and a technique is
presented, in 16 fresh human cadavers, of reliable and physiological injection-
filling of both the cerebral arterial and venous systems. It allowed for the accurate
observation of the normal neurovascular relationships in the posterior cranial
fossa during operative simulation. Part 2 of this article concerns the use of this
design in the study of trigeminal neuralgia, a disorder thought to relate to vascular
compression of the fifth cranial nerve.. 0.
127. Hanke, J.; Yilmazer Hanke, D. M. Variabilities in the distribution of neurofibrillary
tangles in the anterior parahippocampal gyrus at initial stages of Alzheimer's
disease. Clin-Neuropathol. 1997 Nov; 16(6): 299-302; ISSN: 0722-5091.
GERMANY. The entorhinal region is located in the ventromedial surface of the
temporal lobe on the parahippocampal gyrus. Occurrence of early argyrophilic
neurofibrillary tangles was investigated in brain sections of the left and right
entorhinal region of 9 individuals of both sexes between the age of 26 to 54 years.
Parasagittal serial sections at 100 microns were performed to include the very
anterior part of the entorhinal region. An advanced silver method was used for
staining neurofibrillary changes. The neurofibrillary tangles were counted via light
microscopy, marked on the sections and staged as proposed by Braak and Braak.
In 1 case we found a left-right difference by 1 stage (right: stage I, left: stage II).
The tangle distribution in another case exhibited several neurofibrillary tangles
only in the very anterior part of the entorhinal cortex on both sides (stage 0). In 3
cases some neurofibrillary tangles occurred in the very anterior part of the right
entorhinal region, while a few are present in more posterior parts (stage I). The
corresponding left hemisphere showed the same anterior-posterior distribution
pattern as on the right in only 1 of these cases. In the remaining 4 cases, no
neurofibrillary changes were visible. In conclusion, the very anterior part of the
entorhinal region is among the earliest sites for development of neurofibrillary
tangles. Distribution of early Alzheimer-related neurofibrillary changes in the
entorhinal region displays variabilities in the anterior-posterior direction as well as
in a left-right comparison.
128. Hari, R.; Nagamine, T.; Nishitani, N.; Mikuni, N.; Sato, T.; Tarkiainen, A.; Shibasaki,
H. Time-varying activation of different cytoarchitectonic areas of the human SI
cortex after tibial nerve stimulation. Neuroimage. 1996 Oct; 4(2): 111-8; ISSN:
1053-8119.
UNITED-STATES. We followed cortical activation in eight healthy adults after
electric stimulation of the left tibial nerve at the ankle. The recordings were made
noninvasively with a whole-scalp neuromagnetometer. The first cortical activation
peaked in different subjects at 37-45 ms in the foot area of the right (contralateral)
primary somato-sensory (SI) cortex, with mean source current orientation
perpendicular to the longitudinal fissure. The current orientation changed within
the next 5 ms counterclockwise in all subjects, with a mean rotation of 64 degrees.
A two-dipole time-varying model, with two dipoles differing by 28-119 degrees in
orientation but less than 1 cm in location in the right SI cortex, explained the signal
pattern satisfactorily during the first 100 ms. We suggest that the observed field
patterns reflect sequential activation of different cytoarchitectonic areas in the
foot SI cortex and imply considerable differences in the structural organization
between the foot and the hand SI cortices. The initial activation is considered to
take place in area 3b facing the interhemispheric fissure, and the later source, due
to the systematic rotations of the field patterns, is assumed to reflect activation of
area 5 in the anterior wall of the marginal ramus of the cingulate sulcus.
129. Harrington, D. L.; Haaland, K. Y.; Knight, R. T. Cortical networks underlying
mechanisms of time perception. J-Neurosci. 1998 Feb 1; 18(3): 1085-95; ISSN:
0270-6474.
UNITED-STATES. Precise timing of sensory information from multiple sensory
streams is essential for many aspects of human perception and action. Animal and
human research implicates the basal ganglia and cerebellar systems in timekeeping
operations, but investigations into the role of the cerebral cortex have been limited.
Individuals with focal left (LHD) or right hemisphere (RHD) lesions and control
subjects performed two time perception tasks (duration perception, wherein the
standard tone pair interval was 300 or 600 msec) and a frequency perception task,
which controlled for deficits in time-independent processes shared by both tasks.
When frequency perception deficits were controlled, only patients with RHD
showed time perception deficits. Time perception competency was correlated
with an independent test of switching nonspatial attention in the RHD but not the
LHD patients, despite attention deficits in both groups. Lesion overlays of
patients with RHD and impaired timing showed that 100% of the patients with
anterior damage had lesions in premotor and prefrontal cortex (Brodmann areas 6,
8, 9, and 46), and 100% with posterior damage had lesions in the inferior parietal
cortex. All LHD patients with normal timing had damage in these same regions,
whereas few, if any, RHD patients with normal timing had similar lesion
distributions. These results implicate a right hemisphere prefrontal-inferior
parietal network in timing. Time-dependent attention and working memory
functions may contribute to temporal perception deficits observed after damage to
this network.
130. Hashimoto, Y.; Terasaki, T.; Hara, Y.; Yonehara, T.; Uchino, M. [Cerebral embolism
due to lone atrial septal aneurysm]. Rinsho-Shinkeigaku. 1997 Sep; 37(9): 851-3;
ISSN: 0009-918X.
JAPAN. A 71-year-old man was admitted to our hospital because of headache
and left hemiparesis. Brain CT scan showed hemorrhagic infarction of the right
frontal lobe. Intravenous digital subtraction angiography revealed no occlusion of
cerebral arteries. No arrhythmias were observed by the holter ECG. Transthoracic
echocardiography showed no abnormalities. Anticoagulation therapy (heparin and
warfarin) was started under the diagnosis of cerebral embolism without definite
embolic source and there was no recurrence during following four years.
Transesophageal echocardiography showed an atrial septal aneurysm (ASA)
without patent foramen ovale. A potential cause of cerebral embolism due to atrial
septal aneurysm is paradoxical embolization through an interatrial shunt (patent
foramen ovale). It was speculated that ASA was a direct source of thrombus
formation in this case (lone ASA). Transesophageal echocardiography should be
performed to find atrial septal aneurysm in patients with cryptogenic stroke,
especially embolic stroke without definite embolic sources.
131. Hassanali, J. Quantitative and somatotopic mapping of neurones in the trigeminal
mesencephalic nucleus and ganglion innervating teeth in monkey and baboon.
Arch-Oral-Biol. 1997 Oct; 42(10-11): 673-82; ISSN: 0003-9969.
ENGLAND. Neurones of the trigeminal mesencephalic nucleus (Mes V) and
ganglion innervating the periodontium of incisor, canine and molar teeth in 10
monkeys and 10 baboons were counted and mapped using the horseradish
peroxidase (Hrp), retrograde axonal transport method. Periodontal afferent
neurones of all these teeth were well represented in the Mes V, although the
incisors had a significantly higher number of labelled neurones than the canines or
molars. The primary cell bodies of the periodontal afferents were located mainly
in the caudal part of the ipsilateral Mes V from the level of the inferior colliculus
to the floor of the fourth ventricle in the pons. The caudal periodontal Mes V
neurones may be favourably located to make collateral connections with the
trigeminal motor nucleus for jaw reflexes. Incisors and canines had a large and
predominantly ipsilateral representation of Hrp-labelled neurones in the ganglion.
In contrast, molar representation in the ganglion was sparse and all labelled
neurones supplied ipsilateral teeth. The maxillary and mandibular teeth had a
somatotopic distribution within the respective maxillary (middle) and mandibular
(posterolateral) compartments of the trigeminal ganglion. It is suggested that the
anterior teeth with greater connections to the Mes V and the ganglion may impart
greater sensory perception and be involved in jaw reflexes to ensure a good
occlusal relation during mastication, while the afferent connections of the molars
may initiate complex jaw reflexes during the occlusal phase of mastication.. EC
1.11.1.-.
132. Hayashi, N.; Nishijo, H.; Endo, S.; Ono, T. Three-dimensional localization of dipoles
for potentials evoked by posterior tibial nerve stimulation in the monkey. Brain-
Res. 1997 Nov 7; 774(1-2): 44-50; ISSN: 0006-8993.
NETHERLANDS. Somatosensory evoked potentials (SEPs) elicited by right
posterior tibial nerve stimulation were simultaneously recorded from 21-27
epidural electrodes in three monkeys. N23-P40 was recorded anterior to the left
central sulcus, and P23-N40 was recorded on the parietal midline and the middle
portion of the right hemisphere. These potentials were thought to be the primary
cortical responses elicited by posterior tibial nerve stimulation in the monkey,
since a topographical map made of them corresponded to the paradoxical
lateralization of the primary cortical components in human posterior tibial nerve
SEPs. Current source generators (dipoles) of these potentials were 3-
dimensionally identified dipoles located in the left side of the mesial wall of the
anterior parietal cortex, and oriented obliquely toward the right hemisphere by a
dipole tracing (DT) method in which the 3-dimensional localization of dipoles in
the brain were estimated and superimposed on magnetic resonance imaging (MRI)
images.
133. Hayashi, N.; Nishijo, H.; Endo, S.; Ono, T. Three-dimensional localization of dipoles
for potentials evoked by posterior tibial nerve stimulation in the monkey. Brain-
Res. 1997 Nov 7; 774(1-2): 44-50; ISSN: 0006-8993.
NETHERLANDS. Somatosensory evoked potentials (SEPs) elicited by right
posterior tibial nerve stimulation were simultaneously recorded from 21-27
epidural electrodes in three monkeys. N23-P40 was recorded anterior to the left
central sulcus, and P23-N40 was recorded on the parietal midline and the middle
portion of the right hemisphere. These potentials were thought to be the primary
cortical responses elicited by posterior tibial nerve stimulation in the monkey,
since a topographical map made of them corresponded to the paradoxical
lateralization of the primary cortical components in human posterior tibial nerve
SEPs. Current source generators (dipoles) of these potentials were 3-
dimensionally identified dipoles located in the left side of the mesial wall of the
anterior parietal cortex, and oriented obliquely toward the right hemisphere by a
dipole tracing (DT) method in which the 3-dimensional localization of dipoles in
the brain were estimated and superimposed on magnetic resonance imaging (MRI)
images.
134. Hellige, J. B.; Scott, G. B. Effects of output order on hemispheric asymmetry for
processing letter trigrams. Brain-Lang. 1997 Oct 1; 59(3): 523-30; ISSN: 0093-
934X.
UNITED-STATES. Observers identified consonant-vowel-consonant trigrams
with the letters arranged vertically by pronouncing the stimulus (treating the
bottom letter as the first letter) and spelling it from bottom to top. On each trial,
the trigram was presented to the left visual field/right hemisphere (LVF/RH), to
the right visual field/left hemisphere (RVF/LH), or to both visual fields
simultaneously (BILATERAL trials). Quantitative and qualitative visual field
differences were identical to those found when observers used a more natural
response output order, treating the top letter of the trigram as the first letter. The
results suggest that, regardless of output order, attention is distributed across the
three letters in a relatively slow, top-to-bottom fashion on LVF/RH and
BILATERAL trials, whereas attention is distributed more rapidly and evenly
across the three letters on RVF/LH trials.
135. Helmstaedter, C.; Grunwald, T.; Lehnertz, K.; Gleissner, U.; Elger, C. E. Differential
involvement of left temporolateral and temporomesial structures in verbal
declarative learning and memory: evidence from temporal lobe epilepsy. Brain-
Cogn. 1997 Oct; 35(1): 110-31; ISSN: 0278-2626.
UNITED-STATES. A wealth of animal and human research has pointed to a
significant involvement of the temporal lobes in memory processing, and yet the
different functional roles of temporal cortical vs. mesial structures remain unclear.
We studied verbal declarative memory, by using a word list paradigm that
differentiates among learning (immediate recall), memory (delayed recall), and
recognition, in epilepsy patients being considered for surgical resection of the left
temporal lobe. Verbal memory was evaluated preoperatively and during the
recording of intracranial event related potentials and postoperatively after
selective hippocampectomy, temporal cortical lesionectomy, or anterior two-
thirds en bloc temporal lobe resection procedures. Preoperative differences in
verbal memory performance as a function of differences in underlying
neuropathology, concurrent event-related potentials, and specific patterns of
postoperative memory impairments lead to converging evidence that verbal
declarative memory relies on a synergistic interaction of at least two functionally
distinct brain systems. Material-specific data acquisition, or working memory, is
mediated by neocortical temporal structures, whereas long-term
consolidation/retrieval is particularly mediated by temporomesial structures. In
contrast to the left temporal neocortex, the function of the temporomesial system
appears to be material nonspecific. Apparently, its preferential involvement in
verbal memory is due to its close interaction with overlying neocortical structures
that are specialized for language processing.
136. Henriques, J. B.; Davidson, R. J. Brain electrical asymmetries during cognitive task
performance in depressed and nondepressed subjects. Biol-Psychiatry. 1997 Dec
1; 42(11): 1039-50; ISSN: 0006-3223.
UNITED-STATES. BACKGROUND: Studies using electroencephalogram
(EEG) measures of activation asymmetry have reported differences in anterior
asymmetry between depressed and nondepressed subjects. Several studies have
suggested reciprocal relations between measures of anterior and posterior
activation asymmetries. We hypothesized that depressed subjects would fail to
show the normal activation of posterior right hemisphere regions in response to an
appropriate cognitive challenge. METHODS: EEG activity was recorded from 11
depressed and 19 nondepressed subjects during the performance of
psychometrically matched verbal (word finding) and spatial (dot localization)
tasks. Band power was extracted from all epochs of artifact-free data and averaged
within each condition. Task performance was also assessed. RESULTS:
Depressed subjects showed a specific deficit in the performance of the spatial
task, whereas no group differences were evident on verbal performance. In
posterior scalp regions, nondepressed controls had a pattern of relative left-sided
activation during the verbal task and relative right-sided activation during the
spatial task. In contrast, depressed subjects failed to show activation in posterior
right hemisphere regions during spatial task performance. CONCLUSIONS:
These findings suggest that deficits in right posterior functioning underlie the
observed impairments in spatial functioning among depressed subjects.
137. Henry, J. P. Psychological and physiological responses to stress: the right hemisphere
and the hypothalamo-pituitary-adrenal axis, an inquiry into problems of human
bonding. Acta-Physiol-Scand-Suppl. 1997; 640: 10-25; ISSN: 0302-2994.
ENGLAND. In addition to repeated reexperiencing of the event, the delayed
effects of severe psychological trauma, i.e., post traumatic stress disorder
(PTSD), present a paradoxical mix of symptoms. There is enhancement of the
self-preservative catecholamine states; anger and fear with a contrasting sense of
meaninglessness and blunting of the emotional responses of the attachment
behavior so critical for species preservation. Hormonally, there is a striking
separation of the catecholamine response, which stays elevated and that of the
hypothalamo-pituitary-adrenal (HPA) axis, which may remain at normal levels.
Pathophysiologically, the reexperienceing of the trauma and the arousal may be
associated with dysfunction of the locus coeruleus, amygdala and hippocampal
systems. This article explores the consequences of an additional dysfunction: a
dissociation of the hemispheres that appears to be responsible for the alexithymic
avoidance and failure of the cortisol response that so often follow severe
psychological trauma. There is neurophysiological evidence that the left the right
hemispheres subserve different emotional sets that correspond to "control" and
"appraisal," i.e., very approximately to the self and species preservative
behavioral complexes, respectively. Several studies point to physiological
dissociation of hemispheric functions during alexithymia. This raises the question:
What has been lost if in this condition the right side no longer fully contributes to
integrated cerebral function? Right hemispheric damaged children lose critical
social skills and in adults the related sense of familiarity critical for bonding is lost.
Such losses of social sensibilities may account for the lack of empathy and
difficulties with bonding found in sociopathy and borderline personality:
conditions now believed to result from repeated psychological trauma during
development. On the other hand, systems that promote right hemispheric
contributions provide solacing access to a "Higher Power." They also appear to
protect against socially disordered behavior, substance abuse, the failure of the
HPA axis and some aspects of the pathophysiology of chronic disease.
138. Herholz, K.; Thiel, A.; Wienhard, K.; Pietrzyk, U.; von Stockhausen, H. M.; Karbe,
H.; Kessler, J.; Bruckbauer, T.; Halber, M.; Heiss, W. D. Individual functional
anatomy of verb generation. Neuroimage. 1996 Jun; 3(3 Pt 1): 185-94; ISSN:
1053-8119.
UNITED-STATES. Examination of the individual functional anatomy of language
is of particular interest in clinical neurology to explain the variability of aphasic
symptoms after focal lesions and to avoid damage of language-related brain areas
by surgery. For a silent verb generation task, we examined whether activation PET
with 3D data acquisition, multiple replication of conditions, and coregistration
with MRI provides results that are consistent and reproducible enough to be
useful clinically. Visual analysis was performed on PET-MRI fusion images,
including renderings of the brain surface. Quantitative analysis was based on
volumes of interest. In seven right-handed normals, activation of the triangular
part of the left inferior frontal cortex [Brodman area (BA) 45] was the most
significant finding that was present in each subject. Two subjects showed minor
anatomical variants of the ascending or horizontal ramus of the sylvian fissure that
were associated with the least activation of BA 45. In the left hemisphere the
other frontal gyri, the superior temporal and posterior part of the middle temporal
gyrus, and the paracingulate gyrus were also significantly activated. There was
significant bilateral cerebellar activation, but it was significantly more intense on
the right than on the left side. The consistency and high interindividual
reproducibility of these findings suggest that this technique may be useful for
clinical assessment of language-related areas.
139. Heyne, J. P.; Schleicher, C.; Soldner, J.; Neumann, R.; Kaiser, W. A. [Radiation
exposure of the ocular lens and thyroid gland in digital subtraction angiography of
brain-supplying arteries]. Strahlenexposition der Augenlinse und der Schilddruse
bei der Digitalen Subtraktionsangiographie der hirnversorgenden Arterien. Rofo-
Fortschr-Geb-Rontgenstr-Neuen-Bildgeb-Verfahr. 1997 Nov; 167(5): 479-85;
ISSN: 0936-6652.
GERMANY. PURPOSE: To find out the individual level of radiation exposure of
the ocular lens and thyroid gland during DSA of arteries supplying the brain,
considering the indication. MATERIAL AND METHOD: The study was
conducted on 72 patients during aortic arch and cerebral artery angiographies using
thermoluminescent dosimetry. RESULTS: During 20 aortic arch angiographies the
measured values were within non-critical limits, whereas during carotid, vertebral
or cerebral four-vessel angiography of the left ocular lens exposure values of more
than 500 mGy (max. 782 mGy) were stated in two of 52 cases. The highest
measured exposure relating to the right ocular lens was 126 mGy, to the thyroid
gland 88 mGy. However, in 51 of 52 cases thyroid gland doses of below 51 mGy
were measured. In 71 of 72 cases there was a lateral difference between right and
left lens exposure up to twice the measured dose for the right ocular lens during
aortic arch angiographies and up to sixteen-fold in respect of the left lens during
cerebral angiographies. CONCLUSION: In addition to the fluoroscopic time,
number of images, fade-in and zoom some other dose-influencing factors, radiation
geometry is especially decisive for organ exposure. The risk of cataracts or
thyroid gland carcinomas/hypothyrosis can be neglected with median values of 40
and 70 mGy relating to the ocular lens and 17 mGy for the thyroid gland during
cerebral angiographies.
140. Hopkins, D. F.; Williams, G. Insulin receptors are widely distributed in human brain
and bind human and porcine insulin with equal affinity. Diabet-Med. 1997 Dec;
14(12): 1044-50; ISSN: 0742-3071.
ENGLAND. Insulin receptors differing structurally from those in other tissues
have been demonstrated in brain from many species. Subtle differences in binding
properties have been reported between insulin receptors in brain and other
tissues, including differences in affinity of pig brain receptors for human and
porcine insulin. Insulin binding has been demonstrated in human cerebral cortex,
but insulin binding has not been characterized in other areas of human brain. We
have studied the binding of 125I labelled human insulin, and its displacement by
unlabelled human and porcine insulin, in homogenates prepared from human
hypothalamus, cerebral cortex and cerebellum obtained post-mortem from eight
non-diabetic subjects. Specific binding was demonstrated in all brain regions
studied, and displacement curves obtained with unlabelled human and porcine
insulin were identical. By contrast, unlabelled insulin-like growth factor-1 did not
significantly displace 125I labelled human insulin over the same concentration
range. We therefore conclude that insulin receptors are widely distributed in
human brain and do not differ in their affinity for human and porcine insulin.. 0;
0; 0; 11061-68-0; 67763-96-6.
141. Hopper, K. D.; Patel, S.; Cann, T. S.; Wilcox, T.; Schaeffer, J. M. The relationship of
age, gender, handedness, and sidedness to the size of the corpus callosum. Acad-
Radiol. 1994 Nov; 1(3): 243-8; ISSN: 1076-6332.
UNITED-STATES. OBJECTIVES: We correlated the area and size of the corpus
callosum, as measured by MR imaging, with the individual's handedness,
sidedness, age, and gender. MATERIALS AND METHODS: A total of 117
patients (59 male, 58 female) aged 15-75 years were selected for this study. This
included 12 persons who were either left-handed or ambidextrous. Each patient
was tested extensively to determine handedness and sidedness. Callosal areas and
thickness were measured and correlated with brain size. RESULTS: The body of
the corpus callosum decreases in size with age and is larger in right-handed
persons. The cross-sectional areas of the genu, splenium, and corpus callosum,
overall, do not vary significantly with respect to age, gender, sidedness, or
handedness. CONCLUSIONS: The size of the corpus callosum consistently
decreases with age. Otherwise, few statistical differences in callosal size relate to
gender, sidedness, or handedness.
142. Hornig, M.; Mozley, P. D.; Amsterdam, J. D. HMPAO SPECT brain imaging in
treatment-resistant depression. Prog-Neuropsychopharmacol-Biol-Psychiatry.
1997 Oct; 21(7): 1097-114; ISSN: 0278-5846.
ENGLAND. 1. There is little published research on brain function in treatment-
resistant depression (TRD). This study examined regional cerebral blood flow
using 99mTechnetium-hexamethylpropanolamine oxime (HMPAO) single photon
emission computed tomography in 8 patients with a history of TRD, 13
depressed patients without TRD (non-TRD) and 16 normal controls. 2. Relative
HMPAO activity in selected brain regions revealed a significant increase in
hippocampus-amygdala activity in TRD patients compared to non-TRD patients
and healthy controls. The mean value of relative HMPAO activity did not differ
in any other brain region, nor were there any differences in right-left symmetry
among the subject groups. 3. The observation of increased hippocampus-
amygdala HMPAO activity in TRD patients suggests that functional
abnormalities in limbic circuitry may play a role in the pathophysiology of
treatment-resistance.. 0; 0.
143. Hugdahl, K.; Carlsson, G.; Uvebrant, P.; Lundervold, A. J. Dichotic-listening
performance and intracarotid injections of amobarbital in children and adolescents.
Preoperative and postoperative comparisons. Arch-Neurol. 1997 Dec; 54(12):
1494-500; ISSN: 0003-9942.
UNITED-STATES. BACKGROUND: Dichotic listening (DL) to consonant-
vowel syllables is frequently used in clinical and experimental studies of brain
laterality. However, the paradigm of consonant-vowel syllables has not been
thoroughly validated through a comparison with injections of amobarbital sodium
(Amytal). OBJECTIVE: To validate the DL test for hemisphere dominance
preoperatively vs postoperatively with the results from intracarotid injections of
amobarbital (i.e., the Wada test) in epileptic children and adolescents. DESIGN
AND MAIN OUTCOME MEASURES: Patients were tested with DL
preoperatively and at 6-month follow-up. Correct reports in the DL tests were
entered in a stepwise discriminant analysis for calculation of correct classification
of hemisphere dominance with the results from the injections of amobarbital as
the grouping variable. Correct reports from the right and left ears on the
consonant-vowel DL test were compared preoperatively and postoperatively,
separated for the subjects with regard to language dominance in the left and right
hemispheres. SETTING: The Department of Pediatrics, Ostra Hospital,
University of Goteborg, Goteborg, Sweden. PATIENTS: Thirteen children and
adolescents between the ages of 10 and 19 years, who were surgically treated for
resistant epilepsy, were included in the study. The operated area corresponded
with morphological changes and functional dysfunctions according to findings
from computed tomography, magnetic resonance imaging, single photon emission
computed tomography, and electroencephalography. RESULTS: The results of
the Wada tests revealed that 10 subjects had left hemisphere language dominance,
with 3 subjects having right hemisphere language dominance. All 3 subjects with
right hemisphere language dominance showed a left ear advantage on the DL test
preoperatively and postoperatively, with 8 and 7 of the 10 subjects with left
hemisphere dominance showing a right ear advantage, preoperatively and
postoperatively, respectively. However, according to discriminant analysis,
knowledge of the DL performance led to a correct classification according to the
Wada test results in 12 (92%) of the 13 subjects. CONCLUSIONS: A
quantitative classification procedure like discriminant analysis may be more
sensitive when predicting hemisphere speech dominance from DL data than a
qualitative procedure based on the ear advantage dichotomy. The ear advantage
dichotomy may actually introduce arbitrary left-right categories that do not
correspond to the actual clustering of the data.. 57-43-2.
144. Hunt, P. J.; Richards, A. M.; Nicholls, M. G.; Yandle, T. G.; Doughty, R. N.;
Espiner, E. A. Immunoreactive amino-terminal pro-brain natriuretic peptide (NT-
PROBNP): a new marker of cardiac impairment. Clin-Endocrinol-Oxf. 1997 Sep;
47(3): 287-96; ISSN: 0300-0664.
ENGLAND. OBJECTIVE: Human brain natriuretic peptide-32 (BNP) (i.e.
proBNP(77-108)), the mature form of BNP and secreted predominantly by the
cardiac ventricle, is formed from a high molecular weight precursor, proBNP(1-
108). We have recently identified the aminoterminal form proBNP(1-76) (NT-
proBNP) in human plasma but its source, metabolism and production in
circulatory disorders are unknown. We have investigated the relationship between
immunoreactive (IR) NT-proBNP and BNP-32 in normal and hypertensive
subjects and in patients with cardiac impairment, as well as the regional plasma
concentrations in patients undergoing routine cardiac catheterization. DESIGN
AND PATIENTS: Plasma hormone measurements were made in 26 normal
subjects, 20 subjects with untreated mild hypertension and 111 treated patients
with a history of coronary heart disease and documented cardiac impairment (left
ventricular election fraction (LVEF) < 45% (mean 29%); 25 NYHA Class I, 65
Class II and 21 Class III). Regional blood sampling from the femoral artery,
femoral vein, renal vein and coronary sinus was undertaken in 14 patients
presenting for left and right cardiac catheterization studies in the course of
standard investigation for a range of cardiac disorders. MEASUREMENTS:
Plasma samples were assayed for IR NT-proBNP and IR BNP-32 (and atrial
natriuretic peptide (ANP) in the regional blood samples). In the patients with
cardiac impairment, LVEF was determined by gated radionuclide
ventriculography, exercise capacity was measured using a modified Naughton
multistage protocol and creatinine clearance was calculated from plasma creatinine,
age and weight. In the regional study, extraction ratios across the kidney and lower
limb (and step-ups across the heart) were calculated from plasma peptide
concentrations. RESULTS: In normal subjects mean IR NT-proBNP levels (10.8
+/- 1.3 pmol/L) were similar to levels of IR BNP-32 (9.7 +/- 0.5 pmol/L). In
hypertensive patients the levels of IR NT-proBNP and IR BNP-32 tended to be
higher than but were not significantly different from normal subjects. Both IR
NT-proBNP and IR BNP-32 were raised in NYHA Classes I, II and III compared
with normals (P < 0.001 for all) with higher levels of both BNP forms seen with
increasing cardiac impairment. The levels of IR NT-proBNP were greater than IR
BNP-32 in all NYHA Classes (P < 0.001) for all). Overall, the levels of IR NT-
proBNP (129 +/- 12 pmol/L) were 4-fold higher than concomitant BNP-32 levels
(29 +/- 2 pmol/L). Multivariate analysis showed that LVEF, exercise test time and
creatinine clearance were independent predictors of IR NT-proBNP. In all study
groups, the levels of IR NT-proBNP and IR BNP-32 levels were highly
correlated. Regional plasma sampling showed similar step-ups in IR NT-proBNP
and IR BNP-32 levels across the heart, together with similar extraction of both
BNP forms across the kidney and lower limb. For both BNP forms, these changes
across tissues were significantly less than for ANP. CONCLUSIONS: Plasma
levels of immunoreactive amino terminal-proBNP are raised in cardiac impairment,
including NYHA Class I, and rise with increasing cardiac decompensation.
Metabolism and tissue uptake of immunoreactive amino terminal-proBNP and
immunoreactive BNP-32 appear similar. In cardiac impairment the proportional
and absolute increment above normal levels of the aminoterminal BNP peptide
exceeds that for BNP-32 and suggest that amino terminal-proBNP may be a more
discerning marker of early cardiac dysfunction than BNP-32.. 0; 0; 0; 117217-27-
3.
145. Huppi, P. S.; Warfield, S.; Kikinis, R.; Barnes, P. D.; Zientara, G. P.; Jolesz, F. A.;
Tsuji, M. K.; Volpe, J. J. Quantitative magnetic resonance imaging of brain
development in premature and mature newborns. Ann-Neurol. 1998 Feb; 43(2):
224-35; ISSN: 0364-5134.
UNITED-STATES. Definition in the living premature infant of the anatomical
and temporal characteristics of development of critical brain structures is crucial
for insight into the time of greatest vulnerability of such brain structures. We used
three-dimensional magnetic resonance imaging (3D MRI) and image-processing
algorithms to quantitate total brain volume and total volumes of cerebral gray
matter (GM), unmyelinated white matter (WM), myelinated WM, and
cerebrospinal fluid (CSF) in 78 premature and mature newborns
(postconceptional age, 29-41 weeks). Total brain tissue volume was shown to
increase linearly at a rate of 22 ml/wk. Total GM showed a linear increase in
relative intracranial volume of approximately 1.4% or 15 ml in absolute volume
per week. The pronounced increase in total GM reflected primarily a fourfold
increase in cortical GM. Unmyelinated WM was found to be the most prominent
brain tissue class in the preterm infant younger than 36 weeks of
postconceptional age. Although minimal myelinated WM was present in the
preterm infant at 29 weeks, between 35 and 41 weeks an abrupt fivefold increase
in absolute volume of myelinated WM was documented. Extracerebral and
intraventricular CSF was readily quantitated by this technique and found to
change minimally. The application of 3D MRI and tissue segmentation to the
study of human infant brain from 29 to 41 weeks of postconceptional age has
provided new insights into cerebral cortical development and myelination and has
for the first time provided means of quantitative assessment in vivo of early
human brain development.
146. Iavorskii, A. B.; Kobrin, V. I.; Sologubov, E. G.; Sinel'nikova, A. N.; Nemkova, S. A.
[Changes in individual profiles of cerebral hemispheric asymmetry during
somatosensory stimulation due to wearing of G-suits by healthy adults and
children]. Izmenenie individual'nogo profilia mezhpolusharnoi asimmetrii mozga
pri somatosensornoi stimuliatsii nosheniem kosmicheskogo nagruzochnogo
kostiuma u zdorovykh vzroslykh i detei. Aviakosm-Ekolog-Med. 1997; 31(6):
18-23; ISSN: 0233-528X.
RUSSIA. Presented are results of the investigations of individual profiles of the
brain interhemispheric asymmetry (IPIHA) in healthy grown-ups and children
prior to, during, and immediately after somatosensory stimulation. The
somatosensory stimulation was performed by one-time wearing of space g-loading
suit PENGUIN and its modification ADELIE. IPIHA was studied by the main
functional asymmetries including motor hand asymmetry, sensory asymmetry of
the visual hemispheres, body mass center asymmetry (BMA) using a
computerized stabilimeter indirectly measuring the muscle tone of contralateral
extensor. Results demonstrate differences in IPIHA of grown-ups and children,
persons with right- and left-hand motor asymmetry. It was shown that peculiar
features of standing posture acquisition with and without visual control are
original IPIHA and age dependent. Initial stability was higher in grown-ups than
children and right-handed grown-ups and left-handed children. IPIHA and
stability of the vertical posture can be modified even during single somatosensory
stimulation. Unequal effects of the somatosensory stimulation on IPIHA in right-
and left-handed subjects of varying age dictate the necessity to allow for these
differences when assessing effects of the somatosensory stimulation in grown-ups
and developing criteria of effective therapy of patients with CNS pathology,
specifically, infantile cerebral paralysis.
147. Imaizumi, S.; Arai, S.; Sakurai, Y.; Uenohara, H.; Nishino, A. Regional cerebral blood
flow measured with 99mTc-HMPAO based on two-dimensional 133Xe study in
ischemic brain. Neurol-Med-Chir-Tokyo. 1996 Nov; 36(11): 775-81; discussion
781-2; ISSN: 0470-8105.
JAPAN. Two-dimensional regional cerebral blood flow (rCBF) was measured
using the xenon-133 inhalation method, and used to calibrate the rCBF measured
by single photon emission computed tomography (SPECT) in the non-affected
middle cerebral artery (MCA) area. The value of the rCBF in the target area could
then be measured by SPECT and compared between patients. Technetium-99m-
d,l-hexamethyl-propylene-amine-oxime and technetium-99m-
diethylenetriaminepenta-acetic acid-human serum albumin D were used to
measure rCBF and regional cerebral blood volume (rCBV), respectively, in the
ischemic area of 16 patients who underwent surgical revascularization in the
chronic stage. No significant increase in rCBF was obtained after the bypass
surgery. The delta rCBF and delta CBF/CBV ratio correlated well with the extent
of vascularization in the MCA area on postoperative angiograms. Patients with a
low CBF/CBV ratio on preoperative SPECT scans tended to show favorable
postoperative vascularization and rCBF in the MCA area. Since the angiographic
findings and the delta rCBF or delta CBF/CBV were correlated well, this simple
and non-invasive method could be used for the analysis of rCBF in a group of
patients.. 0; 0; 0.
148. Inoue, K.; Kawashima, R.; Satoh, K.; Kinomura, S.; Goto, R.; Koyama, M.; Sugiura,
M.; Ito, M.; Fukuda, H. PET study of pointing with visual feedback of moving
hands. J-Neurophysiol. 1998 Jan; 79(1): 117-25; ISSN: 0022-3077.
UNITED-STATES. This study was conducted to determine where in the human
brain visual feedback of hand movements is processed to allow accurate pointing.
Regional cerebral blood flow (rCBF) was measured with positron emission
tomography (PET) and H2 15O in nine normal volunteers while performing one
control and two reaching tasks. In all tasks, visual stimuli were presented on a
head mounted display (HMD). A target board was placed in front of the subjects
bearing six red light-emitting diodes (LEDs) aligned on a circle with a green LED at
its center. The center green LED and one of the six red LEDs, randomly selected,
were repeatedly switched on and off, alternatively. In the control task, subjects
were instructed to gaze at the lit LED. In the two reaching tasks, the reaching with
visual feedback (RwithF) task and the reaching without visual feedback
(RwithoutF) task, they had to point to the lit red LED with their right index
fingers. In the RwithF task, their right hands were visible on the HMD before
touching the target, whereas in the RwithoutF task, they were not visible. For
each subject, subtraction images of each reaching task minus the control and the
RwithF task minus the RwithoutF task were calculated after transformation of
PET images into the standard brain shape with an adjustable computerized brain
atlas. These subtraction rCBF images were then averaged among the subjects, and
significant changes of rCBF were identified. Significant increases in rCBF not only
in the RwithF task minus control image but also in the RwithF task minus the
RwithoutF task image were observed in the supramarginal cortex, the premotor
cortex and the posterior cingulate cortex of the left hemisphere, the caudate
nucleus and the thalamus of the right hemisphere, and the right cerebellum and
vermis. These results indicate that the supramarginal cortex, the premotor cortex,
and the posterior cingulate cortex of the left hemisphere and the cerebellum are
involved in integrating visual feedback of hand movements and execution of
accurate pointing.. 0.
149. Itoh, K.; Weis, S.; Mehraein, P.; Muller Hocker, J. Cytochrome c oxidase defects of
the human substantia nigra in normal aging. Neurobiol-Aging. 1996 Nov; 17(6):
843-8; ISSN: 0197-4580.
UNITED-STATES. Based on morphological, biochemical, and molecular biologic
analyses, degeneration of the dopaminergic nigrostriatal system has been reported
to occur with normal aging. In the present study, the substantia nigra of 36 human
brains with normal aging was investigated by means of morphometry and
immunohistochemistry. The anteromedial (Am), anterointermediolateral (Ail),
posteromedial (Pm), and posterolateral (Pl) nuclei of the substantia nigra were
analyzed using antibodies directed against the subunits II/III of cytochrome c
oxidase (COX), the complex IV of the respiratory chain. The numerical density of
melanin-positive neurons with COX defects was significantly increased in the
four investigated nuclei, namely Am, Ail, Pm, and Pl. These cells did not show
any histologic signs of degeneration. The numerical density of melanin-positive
neurons without COX defects was decreased with aging. The data of the present
study indicate that complex IV defects of neurons in the substantia nigra might be
one cause of neuronal dysfunction occurring during aging.. EC 1.9.3.1; 51-61-6.
150. Jacobs, A.; Neveling, M.; Horst, M.; Ghaemi, M.; Kessler, J.; Eichstaedt, H.; Rudolf,
J.; Model, P.; Bonner, H.; de Vivie, E. R.; Heiss, W. D. Alterations of
neuropsychological function and cerebral glucose metabolism after cardiac surgery
are not related only to intraoperative microembolic events. Stroke. 1998 Mar;
29(3): 660-7; ISSN: 0039-2499.
UNITED-STATES. BACKGROUND AND PURPOSE: High-intensity
transient signals (HITS) during cardiac surgery are capable of causing
encephalopathy and cognitive deficits. This study was undertaken to determine
whether intraoperative HITS cause alterations of neuropsychological function
(NPF) and/or cerebral glucose metabolism (CMRGlc), even in a low-risk patient
group, and whether induced changes are interrelated. METHODS: Eighteen
patients without signs of cerebrovascular disease underwent elective coronary
artery bypass grafting (CABG), and two of these additionally underwent valve
replacement in normothermia. Intraoperatively, HITS were recorded by means of
transcranial Doppler ultrasonography (TCD). Perioperatively, NPF and CMRGlc
were assessed using a standardized complex test battery and positron emission
tomography with 18F-2-fluoro-2-deoxy-D-glucose (FDG-PET), respectively.
RESULTS: Intraoperatively, the number of HITS ranged from 90 to 1710 per
patient and hemisphere, more on the right side than on the left (P<.05). HITS
occurred primarily during cardiopulmonary bypass (71.3%) and, to a lesser
extent, during aortic manipulation (22.2%). Changes in global and regional
CMRGlc between first (one day preoperatively) and second (8 to 12 days
postoperatively) FDG-PET scans were mild. No correlations were found between
the number of HITS, age of patient, duration of cardiac ischemia or
cardiopulmonary bypass and the changes in CMRGlc. In patients with recorded
HITS and a postoperative decrease of regional CMRGlc (n=11), the maximal
decrease of rCMR Glc in each hemisphere below the individual global change of
CMRGlc correlated with the number of HITS (r= -0.46, P<.05). Limitations in
NPF occurred 8 to 12 days postoperatively, resolved within 3 months, and were
not found to be correlated to the absolute number of HITS or changes in
CMRGlc. CONCLUSIONS: HITS during cardiac surgery can cause alterations of
both NPF and CMRGlc, even in a low-risk patient group. However, the number
of HITS and changes in NPF and CMRGlc are not necessarily interrelated, which
indicates that (1) the location of brain damage related to HITS is more important
for the development of NPF than is the absolute number of HITS, and (2) factors
in addition to HITS might contribute to surgery-related brain damage.. 50-99-7.
151. Jahan, R.; Mischel, P. S.; Curran, J. G.; Peacock, W. J.; Shields, D. W.; Vinters, H. V.
Bilateral neuropathologic changes in a child with hemimegalencephaly. Pediatr-
Neurol. 1997 Nov; 17(4): 344-9; ISSN: 0887-8994.
UNITED-STATES. Evaluation of a 7-month-old girl with developmental delay
and intractable seizures revealed hemispheric asymmetry and an enlarged right
cerebral hemisphere. Because of a history of seizures refractory to medical
therapy, she was admitted for right hemispherectomy, but died of complications
of surgery. Postmortem brain examination revealed asymmetric enlargement of the
right cerebral hemisphere but no gross abnormalities in the left hemisphere.
Microscopic examination demonstrated bilateral neuropathologic changes
consistent with severe cortical dysplasia in the right cerebral hemisphere and mild
cortical dysplasia in the left. Although white matter abnormalities in the
unaffected hemisphere have been reported in hemimegalencephaly, bilateral
cortical abnormalities, not reported previously in patients with
hemimegalencephaly, may account for the varied clinical outcome with medical
therapy or after hemispherectomy.
152. Jennings, J. M.; McIntosh, A. R.; Kapur, S.; Tulving, E.; Houle, S. Cognitive
subtractions may not add up: the interaction between semantic processing and
response mode. Neuroimage. 1997 Apr; 5(3): 229-39; ISSN: 1053-8119.
UNITED-STATES. Determining the areas of brain activity associated with
cognitive processing has typically relied on the use of a subtraction paradigm,
which is based on the premise that the neural processes underlying behavior are
additive. If the additivity assumption is valid then brain regions associated with a
semantic processing task should be the same regardless of how participants make
a response. To investigate this proposition, participants underwent six PET
scans, in which they made semantic or letter word judgments, responding "yes" or
"no" in three different modes: mouse-clicking, spoken response, or silent thought.
Analyses showed an increase in regional cerebral blood flow associated with
semantic processing in the left inferior frontal cortex, anterior cingulate, and right
cerebellum for all three response conditions. However, there was a significant
interaction: the greatest increase was observed in the mouse-click condition and
the weakest change seen with silent thought. Moreover, other areas of the brain
were uniquely activated for each response mode. The results indicate that
different areas of the brain were recruited for semantic processing depending on
how participants had to organize their responses. Implications for the additivity
assumption and methods of analysis to be used in conjunction with the
subtraction technique are discussed.
153. Jeong, S. C.; Bae, J. C.; Hwang, S. H.; Kim, H. C.; Lee, B. C. Cerebral sparganosis
with intracerebral hemorrhage: a case report. Neurology. 1998 Feb; 50(2): 503-6;
ISSN: 0028-3878.
UNITED-STATES. We describe the clinical case and radiologic findings in a
woman with cerebral sparganosis in which intracerebral hemorrhage was the
presenting feature with hemiparesis and dysarthria. CT demonstrated high-
density lesions in the right frontoparietal area, suggesting a hematoma. With
conservative management, hemiparesis improved and follow-up CT revealed what
looked like a resolving hematoma. Two weeks later, she complained once again of
aggravated left hemiparesis and facial weakness. Diagnosis of sparganosis was
made on the basis of brain MRI and ELISA. Stereotactic surgery was performed,
and a live larva of sparganum was successfully removed.
154. Jitsufuchi, N.; Kudo, K.; Imamura, T.; Kimura, K.; Ikeda, N. Distribution of drugs in
various tissues in a brain dead man. Forensic-Sci-Int. 1997 Nov 10; 90(1-2): 103-
9; ISSN: 0379-0738.
IRELAND. We examined the distribution of drugs in a 49-year-old brain-dead
man. Our objective was to determine the possibility of diagnosing how and at
what point the patient became brain dead. The presence of mepivacaine,
pentazocine, lidocaine and thiamylal in various tissues, including seven regions of
the brain were confirmed, using gas chromatography/mass spectrometry. Tissue-
to-blood concentration ratios of mepivacaine, pentazocine and lidocaine in the
brain were higher than these ratios in other tissues, while ratios of thiamylal were
lower. Therefore, cerebral blood flow was likely to have ceased between the
administration of the former drugs and that of the latter drug, in agreement with
clinical records. Among seven regions of the brain, the ratios of the former three
drugs were high in occipital and parietal lobes, and were low in the cerebellum and
medulla oblongata. On the other hand, the ratios of the latter drug were high in the
cerebellum and the medulla oblongata. Therefore, cerebral blood flow presumably
ceased first in occipital and parietal lobes, and last in the cerebellum and the
medulla oblongata. Based on these results, assessment of concentrations of drugs
in human tissues, including various regions of brain is useful to determine the time
and progression of brain death.. 0; 0; 0; 137-58-6; 359-83-1; 77-27-0; 96-88-8.
155. Jokeit, H.; Seitz, R. J.; Markowitsch, H. J.; Neumann, N.; Witte, O. W.; Ebner, A.
Prefrontal asymmetric interictal glucose hypometabolism and cognitive
impairment in patients with temporal lobe epilepsy. Brain. 1997 Dec; 120( Pt
12): 2283-94; ISSN: 0006-8950.
ENGLAND. Depressions of regional cerebral metabolism beyond the
epileptogenic zone have been demonstrated in patients with intractable temporal
lobe epilepsy. However, their clinical relevance, and the causes of prefrontal
metabolic asymmetries are less well understood. We investigated 96 temporal lobe
epilepsy patients by FDG-PET and neuropsychological assessment who had a
corresponding unilateral temporal hypometabolism, left hemisphere speech
dominance, full scale IQ of > 70 and no extratemporal lesion in MRIs. The
regional glucose metabolism was determined in each patient in homologous regions
including prefrontal cortex, and normalized to whole brain metabolism. Regional
differences of > 10% were regarded as asymmetrical. Prefrontal metabolic
asymmetries were more frequent in patients with left temporal lobe epilepsy (21
left, six right) and a history of secondarily generalized seizures. A multivariate
analysis of variance revealed a main effect for prefrontal metabolic asymmetry on
neuropsychological 'frontal lobe measures', including verbal and performance
intelligence measures. Prefrontal metabolic asymmetry was not related to
'measures of episodic memory', presence of psychiatric symptoms or frontal
interictal epileptiform discharges. We conclude that prefrontal metabolic
asymmetry is associated with cognitive impairment. Patients with temporal lobe
epilepsy of the left speech dominant hemisphere and a history of secondarily
generalized seizures are at considerable risk of developing prefrontal metabolic
asymmetry.. 63503-12-8.
156. Jones, A. K.; Derbyshire, S. W. Reduced cortical responses to noxious heat in
patients with rheumatoid arthritis. Ann-Rheum-Dis. 1997 Oct; 56(10): 601-7;
ISSN: 0003-4967.
ENGLAND. OBJECTIVES: To test the hypothesis that patients with chronic
inflammatory pain develop adaptive cortical responses to noxious stimulation
characterised by reduced anterior cingulate responses. METHODS: Positron
emission tomography was used to measure changes in regional cerebral blood flow
(rCBF) in response to an acute experimental pain stimulus in six patients with
rheumatoid arthritis (RA) in comparison to six age and sex matched controls. A
standardised and reproducible non-painful and painful phasic heat stimulus was
delivered by a thermal probe to the back of the right hand during six two minute
periods during which time rCBF measurements were made. The effects of non-
painful heat were subtracted from those of painful heat to weight the analysis
towards the non-discriminatory or 'suffering' components of pain processing.
Significance maps of pain processing were generated and compared in each group
and contrasted with results obtained in a group of patients with atypical facial
pain (AFP) that have been previously published. RESULTS: The RA patients
showed remarkably damped cortical and subcortical responses to pain compared
with the control group. Significant differences between the two groups were
observed in the prefrontal (BA 10) and anterior cingulate (BA 24) and
cingulofrontal transition cortical (BA 32) areas. The reduced anterior cingulate
responses to standardised heat pain were compared with the increased cingulate
responses seen in patients with psychogenically maintained pain (AFP) who had
both lower pain tolerance and mood than the RA group. CONCLUSIONS: Major
cortical adaptive responses to standardised noxious heat can be measured and
contrasted in patients with different types of chronic pain. The different pattern
of cingulate and frontal cortical responses in the patients with inflammatory and
non-nociceptive pain suggest that different mechanisms are operating, possibly at
a thalamocortical level. Implications for treatment strategies for chronic pain are
discussed.
157. Jones, K. J.; Drengler, S. M.; Oblinger, M. M. Gonadal steroid regulation of growth-
associated protein GAP-43 mRNA expression in axotomized hamster facial motor
neurons. Neurochem-Res. 1997 Nov; 22(11): 1367-74; ISSN: 0364-3190.
UNITED-STATES. Treatment with testosterone propionate (TP) after nerve
injury is known to accelerate both the rate of axonal regeneration and functional
recovery from facial paralysis in the adult male hamster. Peripheral nerve injury is
also known to increase the expression of a 43 kilodalton growth-associated
protein (GAP-43). In the intact brain, GAP-43 expression is affected by gonadal
steroids. We thus postulated that steroidal modulation of GAP-43 gene
expression may be a component of the neurotrophic action of TP in regenerating
neurons. This issue was examined in hamster facial motor neurons (FMN) which
contain androgen receptors and which have been shown to respond to exogenous
steroids in a number of previous studies. Castrated adult male hamsters were
subjected to right facial nerve transection and treated with either TP via
subcutaneous hormone capsule implants, or left untreated (no hormone
replacement). At post-injury/treatment times of 0.25, 2, 4, 7, and 14 d, the brain
stem regions were harvested, cryostat sections were collected through the facial
motor nucleus, and in situ hybridization was done using a 33P-labeled GAP-43
cDNA probe. Quantitative analysis of the autoradiograms by computer assisted
grain counting revealed that axotomy produced a dramatic increase in GAP-43
mRNA levels in FMN by 2 d post-axotomy and that this increase remained
through 14 d post-injury in both the TP-treated and the untreated group. In the
nonhormone-treated group, there was a statistically significant dip in GAP-43
mRNA levels in FMN at 7 d post-operative, relative to 4 d post-operative levels.
TP-treatment prevented this transient decline in GAP-43 mRNA levels in
axotomized FMN.. 0; 0; 57-85-2.
158. Jueptner, M.; Ottinger, S.; Fellows, S. J.; Adamschewski, J.; Flerich, L.; Muller, S. P.;
Diener, H. C.; Thilmann, A. F.; Weiller, C. The relevance of sensory input for the
cerebellar control of movements. Neuroimage. 1997 Jan; 5(1): 41-8; ISSN: 1053-
8119.
UNITED-STATES. The performance of a motor task not only requires subjects
to plan, prepare, and initiate but also to monitor how a movement is performed.
We used positron emission tomography to examine to what extent the human
cerebellum is involved in controlling motor output or sensory input from
movements in normal subjects. In the first study, we compared the active
performance of a motor task (flexion and extension of the right elbow) to the
passive execution of the same movements. Passive movements were driven by a
motor with the arm fixed in a guide hinge. Active movements (compared to rest)
elicited increases of rCBF mainly in the ipsilateral neocerebellar hemisphere and
vermis of the posterior lobe. During passive movements, almost identical parts of
the cerebellar hemispheres and vermis were activated (compared to the rest
condition). The direct comparison of active and passive movement conditions
revealed a small activation of the neocerebellar hemisphere of the posterior lobe
and cerebellar nuclei ipsilateral to the movement. Approximately 90% of
cerebellar neuronal activity was related to sensory input. In the second study, we
compared the execution of a free selection joystick movement task to a condition
in which subjects simply imagined the movements. The execution of movements
(compared to rest) was associated with increases of rCBF in the ipsilateral
neocerebellar hemisphere and vermis of the posterior lobe. During movement
imagination, a small part of the ipsilateral cerebellar hemisphere and vermis of the
posterior lobe was activated (compared to rest). The increase of rCBF during
movement imagination accounted for only 20% of the signal seen during
movement execution. Our results indicate that the neocerebellum may be much
more concerned with sensory information processing than has been considered
previously.
159. Kaas, J. H. What comparative studies of neocortex tell us about the human brain.
Rev-Bras-Biol. 1996 Dec; 56 Su 1 Pt 2: 315-22; ISSN: 0034-7108.
BRAZIL. There are several ways in which comparative studies of brain
organization and function can be informative in attempts to understand the human
brain. Often investigators study a favorable and sometimes specialized species in
order to reveal features that may reflect general or widespread principles. The
example used here is that the cortical representation of the unique and highly
specialized receptor sheet of the nose of the star-nosed mole provides further
evidence that the receptor sheet instructs the development of cortex. Comparative
studies are also used to reconstruct the evolution of brain systems. As an
example, comparative studies suggest that the visual area MT in the upper
temporal lobe of primates evolved from a visual area along the border of V2. A
third and very important use of comparative studies is to provide another level of
evaluation of theories developed from a particular species. Since the brains of
different mammals are modifications of an ancestral plan, conclusions about brain
organization in any given species should be consistent with those for other
species, within the framework of evolutionary change. When current proposals
for how visual cortex is organized in rats and humans are considered from a
comparative point of view, key concepts are clearly challenged.
160. Kanaya, K.; Katsunuma, H.; Tabata, M.; Akiba, Y.; Umahara, T.; Takasaki, M.
[Deterrent factors in rehabilitation training following cerebral vascular disease--
comparison of elderly and non-elderly patients]. Nippon-Ronen-Igakkai-Zasshi.
1997 Aug; 34(8): 639-45; ISSN: 0300-9173.
JAPAN. The purpose of the present study was to clarify the deterrent factors
for rehabilitation training (rehab) of chronic cerebral vascular disease (CVD)
patients, and also to evaluate the influence of age on these factors. Sixty-five CVD
impatients with sequelae treated at the Cerebral Vascular Center of Nanasawa
Hospital were included in the study. Patients were classified into two groups
using the Barthel index score: good effect group (n = 21) or no effect group (n =
22). The following factors were compared between the two groups in order to
investigate which factor most affects the results of rehab: age, sex, the site of brain
damage, extent of motor paralysis, character (Type A character or not), aphasia,
hemispacial neglect, depression, and positive attitude toward training. A possible
association between depression, and the site of brain damage and Type A
character was investigated. Also, the difference in mood disorders was compared
between elderly and non-elderly stroke patients. In the elderly group, hemispacial
neglect, a negative attitude toward training, and depression all adversely affected
the outcome of the rehab. In the non-elderly group, aging, hemispacial neglect, and
a negative attitude toward training influenced the effect of the rehab, but there was
no correlation with depression. Depression was seen in 64% of the patients
(38/59). Of the 38 patients in a depressed state, 24 (63%) had right hemisphere
brain damage, 13 (34%) had left hemisphere brain damage, and 1 (3%) had brain
stem damage. Twenty-seven of the 38 depressed patients (71%) were Type A
character, significantly more than in the non-depressed group (92/21, 43%). In
addition, 14 of the 27 Type A patients were aged over 65 years (52%), which was
more than in the non-depression group (11/38, 29%).
161. Kareken, D. A.; Unverzagt, F.; Caldemeyer, K.; Farlow, M. R.; Hutchins, G. D.
Functional brain imaging in apraxia. Arch-Neurol. 1998 Jan; 55(1): 107-13; ISSN:
0003-9942.
UNITED-STATES. BACKGROUND: An extensive literature describes
structural lesions in apraxia, but few studies have used functional neuroimaging.
We used positron emission tomography (PET) to characterize relative cerebral
glucose metabolism in a 65-year-old, right-handed woman with progressive decline
in ability to manipulate objects, write, and articulate speech. OBJECTIVE: To
characterize functional brain organization in apraxia. DESIGN AND METHODS:
The patient underwent a neurological examination, neuropsychological testing,
magnetic resonance imaging, and fludeoxyglucose F 18 PET. The patient's
magnetic resonance image was coregistered to her PET image, which was
compared with the PET images of 7 right-handed, healthy controls. Hemispheric
regions of interest were normalized by calcrine cortex. RESULTS: Except for
apraxia and mild grip weakness, results of the neurological examination were
normal. There was ideomotor apraxia of both hands (command, imitation, and
object) and buccofacial apraxia. The patient could recognize meaningful gestures
performed by the examiner and discriminate between his accurate and awkward
pantomime. The magnetic resonance image showed moderate generalized atrophy
and mild ischemic changes. Positron emission tomographic scans showed
abnormal fludeoxyglucose F 18 uptake in the posterior frontal, supplementary
motor, and parietal regions, the left affected more than the right. Focal metabolic
deficit was present in the angular gyrus, an area hypothesized to store conceptual
knowledge of skilled movement. CONCLUSIONS: Greater parietal than frontal
physiological dysfunction and preserved gesture recognition are not consistent
with the theory that knowledge of limb praxis is stored in the dominant parietal
cortex. Gesture comprehension may be more diffusely distributed.. 0; 50-99-7;
63503-12-8.
162. Kashihara, K.; Shiro, Y.; Shohmori, T.; Nomura, A.; Hara, H. [A man with systemic
lupus erythematosus presenting with spastic paraplegia]. No-To-Shinkei. 1997
Oct; 49(10): 915-8; ISSN: 0006-8969.
JAPAN. We report a 38-year-old man systemic lupus erythematosus who
presented with an acute onset of paraplegia and urinary retention. The man had a
12-year history of nodular cutaneous mucinosis and arthralgia. In 1994, he was
admitted to our hospital with a sudden onset of weakness and numbness of the
right leg followed by an emergence of similar symptoms in the left leg. His elder
sister had died at 16 years of age after suffering from systemic lupus
erythematosus for 6 years. On examination, the patient had skin rash on his chest,
back, head, forehead, and extremities. The neurological examination revealed that
his tongue deviated to the right on protrusion. The muscle power was reduced to
2-3/5 in the right leg and to 4/5 in the left leg. The sensory disturbance was noted
in the lower extremities with predominant involvement of the right leg. Reflexes
were increased in the right biceps, triceps, both patellas, and Achilles tendons.
Babinski sign was noted bilaterally. Urinary retention and constipation were also
noted. The results of the blood cell count and hepatic and renal function tests
were normal. Serum levels of C-reactive protein and complements (C3, C4, CH50)
were also normal. Serological examinations showed increased anti-DNA antibody
(14 U/ml, [normal, < 6]). Antinuclear antibody was positive at a titer of 1:1380.
CSF study showed an increased protein concentration of 83 mg/dl and an IgG
level of 14 mg/dl with a normal number of cells. MR images revealed a T1-low,
T2-high signal lesion at the upper part of the left ventral medulla. MR images of
the brain and spinal cord were normal. The patient was diagnosed as having SLE.
High-dose intravenous methylprednisolone (1 g/day) pulse treatment that was
started 25 days after the onset of neurological symptoms, produced partial relief.
Our case presented with paraplegia with a focal lesion in the left upper ventral
part of the medulla on MR images. The incidence of male SLE is low, and
paraplegia is a rare complication of SLE. Thus, the medullary lesion in SLE
observed in our case appears to be rare. SLE should be considered as a cause of
acute onset paraplegia or myelopathy.
163. Kato, H.; Mashiyama, S.; Fukawa, O.; Sasaki, T.; Yamane, Y.; Asano, S. [A case of
thymic carcinoma with brain metastasis]. Kyobu-Geka. 1997 Nov; 50(12): 1059-
63; ISSN: 0021-5252.
JAPAN. A 43-year-old female with a thymic carcinoma spreading to the
extrathorac region is reported. She had received radiation and chemotherapy, after
that thymic carcinoma was extirpated. Five months later, the patient was noticed
to have a right side hemiparesis, following consciousness disturbance. CT and
MRI revealed a left thalamic mass with a heterogenous enhancement effect. The
tumor was diminished dramatically due to radiation. Metastasis of thymic
carcinoma to the central nervous system is discussed.
164. Kawahata, N.; Daitoh, N.; Shirai, F.; Hara, S. [Reduction in mean cerebral blood flow
measurements using 99mTc-ECD-SPECT during normal aging]. Kaku-Igaku. 1997
Oct; 34(10): 909-16; ISSN: 0022-7854.
JAPAN. Mean cerebral blood flow (mCBF) was measured by SPECT using the
99mTc-ECD-Patlak-Plot method in a selected group of 61 normal non-
hospitalized subjects aged 51 to 91 years. The mCBF values showed 48.4 +/- 4.7
ml/100 g/min in aged 50-59 years group, 49.9 +/- 5.9 ml/100 g/min in aged 60-69
years group, 46.4 +/- 6.5 ml/100 g/min in aged 70-79 group, 38.0 +/- 3.7 ml/100
g/min in aged 80-89 years group, 38.9 ml/100 g/min in aged 90-99 years group.
There was a statistically significant reduction of mCBF with advancing age (R = -
0.41; p = 0.001). Women have significantly higher mCBF values than men up to
aged 70 years group. In this study, there was no significant laterality in the mCBF
between right and left hemispheres in all decade groups. The history of
hypertension, alcohol consumption, and cigarette smoking failed to show
significant difference in the mCBF values. The present study shows that normal
aging is associated with mCBF reduction.. 0; 0; 0; 4371-52-2.
165. Keles, P.; Diyarbakirli, S.; Tan, M.; Tan, U. Facial asymmetry in right- and left-
handed men and women. Int-J-Neurosci. 1997 Oct; 91(3-4): 147-59; ISSN: 0020-
7454.
ENGLAND. A posteroanterior cephalometric radiographic study was performed
on the right- and left-handed men and women with normal occlusion. A
posteroanterior cephalometric radiography was conducted in these subjects.
Method of triangulation was used to measure various face areas. The surface areas
of these triangles were compared with their equivalents on the contralateral side.
Sex and its interactions with handedness and side were significant factors
influencing facial areas. Areas on the left were found to be significantly larger than
those on the right in right-handers. Left-handers were inconsistent in facial
asymmetry, but they tended to have larger facial areas on the right than the left.
Sex was especially significant for left-handers. It was suggested that an
asymmetric development in some brain regions may be responsible for the
development of asymmetric facial regions.
166. Kim, H. J.; Im, J. H.; Yang, S. O.; Moon, D. H.; Ryu, J. S.; Bong, J. K.; Nam, K. P.;
Cheon, J. H.; Lee, M. C.; Lee, H. K. Imaging and quantitation of dopamine
transporters with iodine-123-IPT in normal and Parkinson's disease subjects. J-
Nucl-Med. 1997 Nov; 38(11): 1703-11; ISSN: 0161-5505.
UNITED-STATES. Iodine-123-N-(3-iodopropene-2-yl)-2beta-carbomethoxy-
3beta-( 4-chlorophenyl) tropane (123I-IPT) is a new dopamine transporter ligand
that selectively binds the dopamine reuptake sites. Transporter concentrations
have been known to decrease in Parkinson's disease patients. The purpose of this
study was to evaluate the usefulness of IPT as an imaging agent for measuring
changes in transporter concentrations in Parkinson's disease. METHODS: IPT
labeled with 6.78 +/- 0.67 mCi 123I was injected intravenously as a bolus into
eight normal controls (mean age 41 +/- 12 yr) and 17 Parkinson's disease patients
(mean age 55 +/- 9 yr). Dynamic SPECT scans of the brain were then performed
for 5 min each over 120 min on a triple-headed gamma camera equipped with
medium-energy collimators. Regions of interest were drawn on the middle set of
the image at the level of the basal ganglia (BG) for each subject. Time-activity
curves were generated for the left BG, right BG and occipital cortex (OCC). The
empirical ratios between BG-OCC and OCC, which represent specific-to-
nonspecific binding ratios, were computed at various time points. The statistical
parameter k3/k4 was estimated by two methods: a variation of the graphic method
that derives the ratio of ligand distribution volumes (R[V]) and the area ratio
method (R[A]), in which the ratio is calculated from the areas under the specific
and nonspecific binding activity curves. RESULTS: The mean (BG-OCC)/OCC
ratio for normal controls (3.07 +/- 0.73) was significantly higher than that for
Parkinson's disease patients at 115 min (1.10 +/- 0.56) (p = 2.76 x 10[-5]). The
mean R(V) and R(A) for normal controls were 2.06 +/- 0.27 and 1.50 +/- 0.15,
respectively. The mean R(V) and R(A) for Parkinson's disease patients were 0.78
+/- 0.31 and 0.65 +/- 0.24, respectively. Both R(V) and R(A) for normal controls
were significantly higher than those for Parkinson's disease patients (p values for
R(V) and R(A) were 1.91 x 10(-8) and 3.46 x 10(-10), respectively). The R(V) has
linear relationships with both R(A) and (BG-OCC)/OCC ratio at 115 min. The
R(V) has a higher correlation (r = 0.99) with R(A) than it does with (BG-
OCC)/OCC (r = 0.93). CONCLUSION: The R(V), R(A) and (BG-OCC)/OCC for
Parkinson's disease patients were clearly separated from those of normal controls,
and they may be useful outcome measures for clinical diagnosis. The simplest
(BG-OCC)/OCC ratio, requiring a single late time point, could be useful in clinical
situations, whereas R(V) or R(A) is preferred when the dynamic data are
available. The findings suggest that 123I-IPT is a useful tracer for diagnosing
Parkinson's disease and studying dopamine reuptake sites.. 0; 0; 0; 0; 155509-52-
7; 51-61-6.
167. Kleinschmidt, A.; Nitschke, M. F.; Frahm, J. Somatotopy in the human motor cortex
hand area. A high-resolution functional MRI study. Eur-J-Neurosci. 1997 Oct;
9(10): 2178-86; ISSN: 0953-816X.
ENGLAND. Fine-scale somatotopic encoding in brain areas devoted to
sensorimotor processing has recently been questioned by functional neuroimaging
studies which suggested its absence within the hand area of the human primary
motor cortex. We re-examined this issue by addressing somatotopy both in terms
of functional segregation and of cortical response preference using oxygenation-
sensitive magnetic resonance imaging at high spatial resolution. In a first step,
spatial representations of self-paced isolated finger movements were mapped by
using motor rest as a control state. A subsequent experimental design studied the
predominance of individual finger movements by using contrasting finger
movements as the control task. While the first approach confirmed previous
reports of extensive overlap in spatial representations, the second approach
revealed foci of differential activation which displayed an orderly mediolateral
progression in accordance with the classical cortical motor homunculus. We
conclude that somatotopy within the hand area of the primary motor cortex does
not present as qualitative functional segregation but as quantitative predominance
of certain movement or digit representation embedded in an overall joint hand area.
168. Knecht, S.; Deppe, M.; Ebner, A.; Henningsen, H.; Huber, T.; Jokeit, H.; Ringelstein,
E. B. Noninvasive determination of language lateralization by functional
transcranial Doppler sonography: a comparison with the Wada test. Stroke. 1998
Jan; 29(1): 82-6; ISSN: 0039-2499.
UNITED-STATES. BACKGROUND AND PURPOSE: Functional transcranial
Doppler ultrasonography (fTCD) can assess event-related changes in cerebral
blood flow velocities and, by comparison between sides, can provide a measure of
hemispheric perfusional lateralization. It is easily applicable, insensitive to
movement artifacts, and can be used in patients with less than perfect
cooperation. In the present study we investigated the validity of fTCD in
determining the hemispheric dominance for language by direct comparison of
fTCD with intracarotid amobarbital anesthesia (Wada test). METHODS: fTCD
and the Wada test were performed in 19 patients evaluated for epilepsy surgery.
By the Wada test, 13 patients were classified as left-hemisphere dominant and 6
as right-hemisphere dominant for language. fTCD was based on the continuous
bilateral measurements of blood flow velocities in the middle cerebral arteries and
event-related averaging during a cued word generation task previously shown to
activate lateralized language areas in normal adults. RESULTS: In 4 patients fTCD
assessment was not possible because of lack of an acoustic temporal bone
window. In the remaining 15 candidates, determination of language dominance was
concordant with the Wada test in every case. Moreover, the correlation of the
lateralization measures from both procedures was highly significant (r=.92,
P<.0001). CONCLUSIONS: This strong correlation validates fTCD as a
noninvasive and practical tool for the determination of language lateralization that
can be applied for clinical and investigative purposes.. 0; 0; 57-43-2.
169. Knipst, I. N.; Cheremushkin, E. A.; Iakovenko, I. A. [The subsystems of the spatial-
temporal organization of cortical potentials and their role in EEG spatial
synchronization]. Podsistemy prostrantsvenno-vremennoi organizatsii
korkovykh potentsialov i ikh rol' v prostranstvennoi sinkhronizatsii EEG. Zh-
Vyssh-Nerv-Deiat-Im-I-P-Pavlova. 1997 Sep; 47(5): 812-27; ISSN: 0044-4677.
RUSSIA. Studying successive topograms of potentials made it possible to reveal
different types (subsystems) of the spatio-temporal organization of human and
animal cortical electrical activity, which covered significant cortical surface. The
dominance of the inversion of the sagittal potential gradient in the topograms of
the resting state or complicated relief forms in the active states co-existed with
oscillations of the mean level of topogram potentials, the contribution of which to
the spatial EEG synchronization changed depending on the functional state of the
brain. The role of the ratio between these subsystems was shown and the
influence of this ratio was demonstrated on the spatial synchronization of cortical
potentials in experiments with 11 rabbits (in the course of their adaptation to the
environment and learning) and examination of 50 healthy adult subjects (during
motor task performance and elaboration of verbal set). The spatial
synchronization of cortical potentials was found to have a complex structure,
which was determined by the ratio between the effects of subsystems of the
spatio-temporal organization of cortical potentials.
170. Kobayashi, T.; Takanashi, M.; Mori, H.; Suzuki, M.; Suda, K.; Takubo, H.; Mizuno,
Y. [A 85-year-old woman with one year history of convulsion, dementia, and
consciousness disturbance (clinical conference)]. No-To-Shinkei. 1997 Oct;
49(10): 953-61; ISSN: 0006-8969.
JAPAN. We report a 85-year-old woman who died after one year history of
convulsion, dementia, and consciousness disturbance. She was apparently well
until January 6, 1995 when she was 85 year old; on that evening, she suddenly
stated that some one was in her room and she became confused. A local MD gave
her diazepam and she fell into sleep. At 3 o'clock in the following morning, she
developed tonic-clonic convulsion in her right lower extremity which showed a
march to her right upper extremity and the left lower extremity. She was admitted
to our hospital. On admission, she was comatose with respiratory acidosis. She
was intubated and placed on a ventilator. She was treated with intravenous
phenytoin. She gradually gained consciousness and became alert. Respiration
became normal. Her MRI revealed ventricular dilatation, fronto-parietal cortical
atrophy, and a T1-low and T2-high signal intensity lesion in the left occipital
lobe. She was discharged for out patient follow-up on February 4, 1995. Since
then, she noted loss of memory and small step gait. A follow-up CT scan revealed
a mass lesion which showed a ring-shaped enhancement in the left occipital lobe
and was admitted again. On admission, she was alert but markedly demented. The
optic fundi was unremarkable, but she appeared to have right homonymous
hemianopsia. No motor weakness was noted. In Gd-DTPA enhanced MRI, the
above tumor showed a ring enhancement. The diagnosis of glioblastoma was
entertained, however, considering her age, she was treated with intravenous
glycerol and intramuscular steroid. She was discharged for out-patient follow-up
on July 15, 1995. Her gait disturbance had progressively become worse and she
developed nausea and vomiting and was admitted again on October 2, 1995. On
admission, she was somnolent and markedly demented. Brain stem responses
were retained normally. She was unable to stand or walk. Deep tendon reflexes
were slightly increased in the right upper extremity and the plantar response was
extensor on the right. Her hospital course was complicated by respiratory tract
infection and respiratory acidosis. She expired on November 2, 1995. The patient
was discussed in a neurological CPC and the chief discussant arrived at the
conclusion that she had a glioblastoma involving the left occipital lobe and the
adjacent areas. Post-mortem examination revealed an infiltrating tumor in the left
occipital lobe. On microscopic examination, the tumor was very cellular; nuclear
atypism was marked and tumor cells undergoing mitosis were seen. In some areas,
capillary proliferation was seen. Histologic characteristics were consistent with
glioblastoma.
171. Kopelman, M. D.; Stanhope, N.; Kingsley, D. Temporal and spatial context memory
in patients with focal frontal, temporal lobe, and diencephalic lesions.
Neuropsychologia. 1997 Dec; 35(12): 1533-45; ISSN: 0028-3932.
ENGLAND. Patients with focal frontal, temporal lobe, or diencephalic lesions
were investigated on measures of temporal (recency) and spatial (position)
context memory, after manipulating exposure times to match recognition memory
for targets (pictorial stimuli) as closely as possible. Patients with diencephalic
lesions from an alcoholic Korsakoff syndrome showed significant impairment on
the temporal context (recency) task, as did patients with frontal lesions
penetrating the dorsolateral frontal cortex, according to MRI (and PET) evidence.
Patients with temporal lobe lesions showed only a moderate (non-significant)
impairment on this task, and patients with medial frontal lesions, or large frontal
lesions not penetrating the dorsolateral cortical margins, performed as well as
healthy controls at this task. On the spatial context memory task, patients with
lesions in the temporal lobes showed significant impairment, and patients with
right temporal lesions performed significantly worse than patients with left
temporal lesions. Patients with diencephalic lesions showed only a modest (non-
significant) impairment on this task, and the frontal lobe group performed
normally. When a group of patients with temporal lobe lesions resulting from
herpes encephalitis were examined separately, an identical pattern of results was
obtained, the herpes group being significantly impaired on spatial memory and
showing a trend towards impairment for temporal context memory. There were
strong correlations between anterograde memory quotients and context memory
performance (despite the use of an exposure time titration procedure) and a weak
association with one frontal/executive task (card-sorting perseverations). It is
predicted that correlations between temporal context memory and
frontal/executive tasks will be greater in samples of patients all of whom have
frontal lesions invading the dorsolateral cortical margin.
172. Korkman, M.; von Wendt, L. Evidence of altered dominance in children with
congenital spastic hemiplegia. J-Int-Neuropsychol-Soc. 1995 May; 1(3): 261-70;
ISSN: 1355-6177.
ENGLAND. The study aimed at investigating lateralization effects and signs of
transfer and crowding in children with congenital lateralized brain damage with the
aid of a dichotic listening test, a chimeric test, and verbal and nonverbal
neuropsychological tests. Thirty-three children with spastic hemiplegia and 86
control children (age 5.0-12.0 yr) were assessed. Children with left-hemisphere
damage (n = 17) were found to have a pathological left-ear advantage for verbal
material, and children with right-hemisphere damage (n = 16) were found to have a
pathological right visual half-field advantage for visual material. Children with left-
hemisphere damage and a left-ear advantage on the dichotic test were also found to
have a right visual half-field advantage on the chimeric test, which was regarded as
a sign of reversed dominance. No verbal or nonverbal differences emerged between
the left-hemisphere and the right-hemisphere damage groups, nor did differences
emerge when the children were reclassified by considering children with left
hemisphere damage and signs of reversed dominance as having damage to the
nondominant hemisphere. It was concluded that although lateralized brain damage
may alter the dominance for verbal and visual functions, there is still considerable
inter-individual variability with respect to inter- and intrahemispheric neural
adjustment to damage. The dichotic and the chimeric tests did not indicate the
presence of brain damage accurately, but they indicated the lateralization of
damage in children with stated abnormality with a high degree (91.3%) of
accuracy.
173. Koyama, Y.; Ishiai, S.; Seki, K.; Nakayama, T. Distinct processes in line bisection
according to severity of left unilateral spatial neglect. Brain-Cogn. 1997 Nov;
35(2): 271-81; ISSN: 0278-2626.
UNITED-STATES. We investigated the line bisection performances in 24
patients with left unilateral spatial neglect. They bisected lines of two lengths in
three positions relative to the sagittal midplane of the body. The results showed
that in the mild or moderate neglect patients, length and spatial locations of the
lines affected the placement of the subjective midpoint. In the severe neglect
patients, however, length had little effect on their performances, and location of
the right endpoint in the egocentric space mainly determined the subjective
midpoint. The line bisection process of the severe neglect patients was not only
quantitatively but also qualitatively different from that of the mild or moderate
cases. Copyright 1997 Academic Press.
174. Krimer, L. S.; Herman, M. M.; Saunders, R. C.; Boyd, J. C.; Hyde, T. M.; Carter, J.
M.; Kleinman, J. E.; Weinberger, D. R. A qualitative and quantitative analysis of
the entorhinal cortex in schizophrenia. Cereb-Cortex. 1997 Dec; 7(8): 732-9;
ISSN: 1047-3211.
UNITED-STATES. The entorhinal cortex (ERC) has been implicated in
schizophrenia by a number of studies. There is anatomical observation of neuronal
heterotopias in the rostral ERC, which is consistent with a hypothesis of
neurodevelopmental abnormalities in this disease. In view of the significant
cytoarchitectonic variation of the ERC throughout its rostro-caudal extent, we
performed a detailed subareal analysis of the rostral two-thirds of the entorhinal
cortex (ERCr) in 14 postmortem schizophrenic brains and 14 matched controls
(mean ages of 48 and 47 respectively). This systematic evaluation included both a
qualitative microscopic analysis of morphogenetic anomalies that would be
consistent with neurodevelopmental pathology and quantitative measurements of
total neuronal number, average neuronal density, laminar volume and laminar
depth from the cortical surface in cytoarchitectonically matched subareas of
schizophrenic and control brains. Parcellation of the entire ERC on the basis of
cytoarchitectonic criteria identified five distinct regions, similar to those described
in the macaque, except that in the human brain three of the regions were further
divisible into two or three subareas, yielding nine distinct cellular compartments.
Five rostral areas, prorhinal (Pr), lateral (28L), intermediate rostral and caudal
(281r and 281c), and sulcal (28S), comprise the ERCr. Gross and microscopic
examination of these subdivisions throughout the ERCr failed to reveal laminar
disorganization in any of the schizophrenic brains. The brains also did not differ
significantly with respect to total neuronal number, total volume and neuronal
density per laminar and subareal subdivision, or laminar thickness per entorhinal
subarea. However, neuronal number and density were reduced by 12-18% in Pr
and 28L, suggesting that mild quantitative abnormalities may exist in the ERCr
and might possibly be revealed in a larger sample of schizophrenic brains. We
have failed to confirm previous reports of laminar disorganization in the ERCr in
brains of patients with schizophrenia; to the extent that this region is implicated
in schizophrenia, the structural changes are likely to consist of more subtle cellular
disturbances.
175. Krimer, L. S.; Hyde, T. M.; Herman, M. M.; Saunders, R. C. The entorhinal cortex:
an examination of cyto- and myeloarchitectonic organization in humans. Cereb-
Cortex. 1997 Dec; 7(8): 722-31; ISSN: 1047-3211.
UNITED-STATES. The entorhinal cortex (ERC) has been implicated in the
pathophysiology of Alzheimer's disease, schizophrenia and other disorders
affecting cognitive functions. While powerful anatomical and histochemical
methods (immunohistochemistry, in situ hybridization, etc.) may be applied
(although with limitations) to postmortem human brain, each analysis should
utilize a cytoarchitectonic approach to provide appropriate comparisons within
the subdivisions of the ERC. Accordingly, we describe here the normal cyto- and
myeloarchitecture of the human ERC as a prerequisite for the accompanying
study of this region in schizophrenia. Our parcellation of this cortex differs from
previous treatments in three ways. First, we adopted specific criteria of inclusion
to define each subdivision of the region. Although distinctive ERC features are
most prominent in the intermediate portion of this region, at least one of these
features was considered the minimum necessary criterion to include adjacent
tissue in the entorhinal area. Second, we used morphometric measurements
(neuronal size and density as well as subdivisional volume and laminar thickness)
to support our qualitative evaluation. Third, we have applied to the human ERC
the conventional cytoarchitectonic nomenclature of the entorhinal cortex used
previously in studies of non-human primates. This allows a more accurate
extrapolation of the available numerous experimental anatomical, physiological
and psychological data on this region to the human. As in the monkey, the five
main subareas were recognized in the human (prorhinal, lateral, intermediate,
sulcal and medial) but three required further subdivision (intermediate, sulcal and
medial). The morphometric results obtained suggested a progression of the human
entorhinal cortex from the peripheral to the central subareas, with the intermediate
subarea (281) as the most complete entorhinal subdivision. Compared with non-
human primates, the human ERC not only retains the basic periallocortical
organization but also demonstrates further evolution. Taken together with
available experimental data on the connectivity of this brain region, these results
provide an anatomical basis for evaluating the ERC in human behavior.
176. Kubota, Y.; Iwai, T.; Nakatani, K.; Sakai, N.; Hara, A. [Central nervous system
metastasis from non-functioning adrenocortical carcinoma: report of a case]. No-
Shinkei-Geka. 1997 Nov; 25(11): 1039-42; ISSN: 0301-2603.
JAPAN. We report a rare case of brain tumor metastasizing from an
adrenocortical carcinoma. A 47-year-old man was referred to our department on
September 21, 1995, with complaints of episodic loss of consciousness and severe
left motor weakness. There was a past history of left adrenalectomy performed in
the Department of Surgery of our hospital 9 months before. On admission,
computed tomography (CT) and magnetic resonance imaging (MRI) revealed two
well circumscribed masses in the right frontal lobe with peritumoral, marked brain
edema and metastasis to the lung. The brain tumor was successfully removed via
frontal craniotomy 4 days after admission. Histological examination of the tumor
specimen revealed metastatic anaplastic cell carcinoma, indicating metastasis from
an adrenocortical carcinoma. After chemotherapy with cisplatin, pepleomycin and
pirarubicin, he was discharged without neurological deficit. Two months
postoperatively, however, the patient received 50 Gy of telecobalt radiation
therapy to the whole brain because of recurrence. Three months after-wards, the
patient returned complaining of general fatigue. Chest CT scan revealed further
enlargement of the lung lesions. Despite repeated chemotherapy, the patient died
of lung metastases eight weeks later. Central nervous system metastasis from
adrenocortical carcinoma is exceedingly rare. To the best of our knowledge, only 5
cases have been reported. We report here another case of brain metastasis from
adrenocortical carcinoma possibly via lung metastasis, and review the pertinent
medical literature.
177. Kume, N.; Hayashida, K.; Cho, I. H.; Shimotsu, Y.; Nishioeda, Y.; Matsunaga, N.
Visualization of frontal postural hypoperfusion in patients with Takayasu
arteritis with upright 99Tcm-HMPAO brain SPET. Nucl-Med-Commun. 1997
Oct; 18(10): 943-50; ISSN: 0143-3636.
ENGLAND. Takayasu arteritis is a chronic inflammatory angiopathy involving
the cerebral arteries. We performed upright and supine 99Tcm-HMPAO brain
single photon emission tomography (SPET) to investigate the cerebral perfusion
pattern in eight patients with Takayasu arteritis, and we compared the results
with those acquired using 123I-IMP and acetazolamide in six patients. SPET
images were evaluated visually and semi-quantitatively. Hypoperfusion was
visually detected in all eight patients during the provocative upright test with
99Tcm-HMPAO, and in three of six tested using acetazolamide and 123I-IMP.
Semiquantitative analysis revealed that the mean cortical-to-cerebellar ratio in the
upright position was significantly changed compared to that in the supine
position in the right frontal area (from 0.86 +/- 0.07 to 0.91 +/- 0.09; P < 0.05).
Change was also seen in the left frontal area (from 0.85 +/- 0.08 to 0.91 +/- 0.08; P
< 0.05). No significant change was seen in other cortical areas with the upright
test or in any areas with the acetazolamide test. We postulate that reduced arterial
compliance may cause frontal postural hypoperfusion in patients with Takayasu
arteritis due to poor functioning of autoregulation and arterial stenosis or
occlusion. We conclude that the provocative upright test with 99Tcm-HMPAO
brain SPET can detect abnormal patterns of cerebral perfusion in patients with
Takayasu arteritis that might be missed by brain SPET using 123I-IMP and
acetazolamide.. 0; 0; 0; 51-43-4; 59-66-5.
178. Kusunose, M.; Fukuda, O.; Saito, T.; Takaku, A.; Endo, S. [Diffuse cerebral artery
vasospasm following total resection of posterior fossa meningioma: a case report].
No-Shinkei-Geka. 1997 Oct; 25(10): 953-7; ISSN: 0301-2603.
JAPAN. Diffuse cerebral artery vasospasm following brain tumor resection is a
rare complication. The authors reported a case of symptomatic diffuse cerebral
artery vasospasm of early phase following resection of a left posterior fossa
meningioma. A 50-year-old female patient was admitted to our hospital
complaining of headache. No neurological deficits were detected at the time of
admission. Computed tomography (CT) and magnetic resonance imaging (MRI)
showed a large mass in the left posterior fossa. Cerebral angiography
demonstrated mildly diffuse stenosis of the bilateral internal carotid artery. The
tumor was resected totally. CT after operation showed a small amount of
subarachnoid hematoma in the superior aspect of the cerebellum. Pathological
specimen of the tumor showed fibrous meningioma. One day after this radical
operation, the patient was found to have weakness in her left leg. Then she
developed left hemiparesis, weakness in the right leg and left homonymous
hemianopsia. MRI showed ischemic lesions in the bilateral parietal and the
occipital lobe. Angiography demonstrated diffuse severe vasospasm throughout
the whole cerebral artery. Ten days after the operation, angiographical findings
were improved. This case indicates that vasospasm may occur even after resection
of brain tumors which are localized outside the suprasellar area.
179. Lacquaniti, F.; Perani, D.; Guigon, E.; Bettinardi, V.; Carrozzo, M.; Grassi, F.;
Rossetti, Y.; Fazio, F. Visuomotor transformations for reaching to memorized
targets: a PET study. Neuroimage. 1997 Feb; 5(2): 129-46; ISSN: 1053-8119.
UNITED-STATES. Positron emission tomography (PET) was used to identify
cortical and subcortical regions involved in the control of reaching to visual targets.
Regional cerebral blood flow (rCBF) was measured in eight healthy subjects using
H2(15)O PET during the performance of three different tasks. All tasks required
central fixation while a 400-ms target was flashed every 5 s at a random location
around a virtual circle centered on the fixation target. Additional instructions
differed according to the task: (i) visual detection of the target without overt
responses; (ii) immediate pointing to the most recent target in the sequence, and
(iii) pointing to the previous target in the sequence. By design, the two motor
tasks differed in the cognitive processing required. In each trial of immediate
pointing, the spatial location of only the most recent target needed to be
processed. In each trial of pointing to the previous, instead, while the most recent
target was stored in memory for the movement of the next trial, the previous
target had to be retrieved from memory to direct the current movement. Limb
trajectories were comparable between the two motor tasks in terms of most
spatiotemporal parameters examined. Significant rCBF increases were identified
using analysis of covariance and t statistics. Compared with visual detection there
was activation of primary sensorimotor cortex, ventrolateral precentral gyrus,
inferior frontal gyrus in the opercular region, supramarginal gyrus, and middle
occipital gyrus, all these sites in the hemisphere (left) contralateral to the moving
limb, and cerebellar vermis, during both immediate pointing and pointing to the
previous. During immediate pointing there was additional activation of left inferior
parietal lobule close to the intraparietal sulcus, and when compared with pointing
to the previous, dorsolateral prefrontal cortex bilaterally. During pointing to the
previous, instead, there was additional activation of supplementary motor cortex,
anterior and midcingulate, and inferior occipital gyrus in the left hemisphere;
superior parietal lobule, supramarginal gyrus, and posterior hippocampus in the
right hemisphere; lingual gyri and cerebellar hemispheres bilaterally; anterior
thalamus; and pulvinar. The activation of two partially distinct cerebral networks
in these two motor tasks reflects the different nature of signal processing
involved. In particular, the specific activation of intraparietal sulcus and prefrontal
cortex in immediate pointing appears characteristic of a network for visuospatial
working memory. By contrast, the corticolimbic network engaged in pointing to
the previous could mediate spatial attention and the sequence of encoding,
recording, and decoding of spatial memories required by a dual task with two
competing targets.
180. Ladavas, E.; Berti, A.; Ruozzi, E.; Barboni, F. Neglect as a deficit determined by an
imbalance between multiple spatial representations. Exp-Brain-Res. 1997 Oct;
116(3): 493-500; ISSN: 0014-4819.
GERMANY. A previous study on neglect suggested that at least two hand
parameters are crucial in producing an amelioration of neglect: the hand (left or
right) and the spatial position of the hand (left or right). The improvement
observed in perceiving left targets when the left hand acts in the left space can be
due either to proprioceptive or to visual cuing. The stimulated left hand located in
the left space may act as a powerful visual cue for the enhancement of the left
visuo-spatial representation, in the same way as any other visual stimulus
presented in the periphery of the visual field. Alternatively, it may be that the
perceived hand location (due to the activation of the proprioceptive system) acts
as an attentional field able to enhance the representation of the left space. In order
to disentangle these two hypotheses, in the present study a naming task was
executed by a group of neglect patients and by a control group. The subjects had
to name all the objects depicted on a sheet of paper which were reflected on a
mirror that inverted right and left space. While doing the naming performance, the
subjects passively moved either the right or the left hand, in the left or right space.
Stimuli and hand were reflected in the mirror that inverted right and left space and
direct view of the stimuli and of the stimulated hand was prevented by a board.
The results show that patients were more accurate at naming stimuli reflected in
the left side of the mirror when the left hand was located and moved on the left
side. In this condition, however, the left hand was seen in the right side of the
mirror. It is therefore clear that the better performance was not due to visuo-
spatial cuing but to a proprioceptive cuing effect. The results are discussed in
terms of the relevance of personal and peripersonal spatial activation in the
modulation of extrapersonal visual neglect. The coactivation of different spatial
representations seems to be very influential on stimulus coding, thus confirming
that spatial awareness is strictly related to the joint activity of multiple brain
maps.
181. Laframboise, M.; Snyder, P. J.; Cohen, H. Cerebral hemispheric control of speech
during the intracarotid sodium amytal procedure: An acoustic exploration. Brain-
Lang. 1997 Nov 15; 60(2): 243-54; ISSN: 0093-934X.
UNITED-STATES. In this study we investigated lateralized control of speech
during the intracarotid amobarbital procedure. Vowel segments were extracted
from recordings made during two separate amobarbital procedures and involving
two patients. Subjects were right-handed, presented with focal left mesial
temporal epileptogenic foci. Age of onset of seizure disorders was 1.5 years for
one subject and 16 years for the other. Recorded pre- and postinjection speech
samples were digitized. Analyses were conducted on formants 1 and 2 (F1, F2)
measures to determine the extent of formant fluctuation in the time course of the
IAP. Preliminary results showed, for these two cases, that the left hemisphere is
involved in the control of both F1 and F2 and the right in the control of F2 only.
The data reveal the potential of coupling the IAP procedure and the acoustical
analysis of speech in the study of cerebral control of speech. Copyright 1997
Academic Press.. 0; 57-43-2.
182. Lane, R. D.; Reiman, E. M.; Bradley, M. M.; Lang, P. J.; Ahern, G. L.; Davidson, R.
J.; Schwartz, G. E. Neuroanatomical correlates of pleasant and unpleasant
emotion. Neuropsychologia. 1997 Nov; 35(11): 1437-44; ISSN: 0028-3932.
ENGLAND. Substantial evidence suggests that a key distinction in the
classification of human emotion is that between an appetitive motivational system
association with positive or pleasant emotion and an aversive motivational system
associated with negative or unpleasant emotion. To explore the neural substrates
of these two systems, 12 healthy women viewed sets of pictures previously
demonstrated to elicit pleasant, unpleasant and neutral emotion, while positron
emission tomographic (PET) measurements of regional cerebral blood flow were
obtained. Pleasant and unpleasant emotions were each distinguished from neutral
emotion conditions by significantly increased cerebral blood flow in the vicinity of
the medial prefrontal cortex (Brodmann's area 9), thalamus, hypothalamus and
midbrain (P < 0.005). Unpleasant was distinguished from neutral or pleasant
emotion by activation of the bilateral occipito-temporal cortex and cerebellum, and
left parahippocampal gyrus, hippocampus and amygdala (P < 0.005). Pleasant
was also distinguished from neutral but not unpleasant emotion by activation of
the head of the left caudate nucleus (P < 0.005). These findings are consistent
with those from other recent PET studies of human emotion and demonstrate that
there are both common and unique components of the neural networks mediating
pleasant and unpleasant emotion in healthy women.
183. Leask, S. J.; Crow, T. J. How far does the brain lateralize?: an unbiased method for
determining the optimum degree of hemispheric specialization. Neuropsychologia.
1997 Oct; 35(10): 1381-7; ISSN: 0028-3932.
ENGLAND. The relationship between measures (of size or function) on one side
of the brain, in relation to the difference between the two sides on that measure,
are important components of theories of hemispheric asymmetry. For example, it
has been concluded that increasing lateralization (e.g., of hand skill or planum
temporale area) occurs at the expense of the non-dominant hemisphere. Here it is
demonstrated that such relationships could merely be a necessary consequence of
relating components of a laterality index to the index (L - R)/(L + R) itself, or
indeed to L - R. An alternative approach (using random data to exemplify the null
hypothesis) is presented together with an application to data on hand skill from
12,782 11-year-olds in a cohort study. This demonstrates a symmetry hitherto
undocumented of maximal hand skill in left and right hands in left- and right-hand
writers respectively, the point of the maximum falling short of the population
mean for relative hand skill in either case. If degrees of laterality are what is
genetically determined, this suggests that selection is present for a function
(perhaps language) associated with a greater magnitude of lateralization than is
represented by hand skill.
184. Lechevalier, B. [Perception of musical sounds: contributions of positron emission
tomography]. La perception des sons musicaux: apports de la camera a positons.
Bull-Acad-Natl-Med. 1997 Jun; 181(6): 1191-9; discussion 1199-200; ISSN:
0001-4079.
FRANCE. The perception of music is not a single global process. It encompasses
the integration into conscience of various elements, such as sound pitch, tone,
rhythm and impression of familiarity. Thus, it may be subjected to cognitive
studies based on specific and complementary abilities of both cerebral
hemispheres in these tasks. A number of selected medical cases reported
previously had already suggested anatomic-clinical correlations for the perception
of the various components of musical sounds. The left hemisphere subserves
rhythm and pitch perception, the sense of familiarity and identification of a
musical piece. The right hemisphere plays a part in the perception of tone and
melodic line. Position emission tomographic studies in normal subjects have
corroborated these assumptions on hemispheric lateralization in musical
perception. In addition, they have demonstrated previously unsuspected facts,
such as the role of visual areas in pitch perception and the role of frontal cortex
and especially of Broca's area in the perception of rhythm.
185. Lee, J. T.; Hall, T. R.; Bateman, J. B. Optic nerve hypoplasia secondary to
intracranial teratoma. Am-J-Ophthalmol. 1997 Nov; 124(5): 705-6; ISSN: 0002-
9394.
UNITED-STATES. PURPOSE: To postulate a causal relation between optic
nerve hypoplasia and a suprasellar teratoma. METHOD: Case report. RESULTS:
A 6-month-old infant with suprasellar teratoma was visually inattentive and had
searching nystagmus. He had moderately severe, bilateral optic nerve hypoplasia
with the left eye being somewhat worse than the right eye. CONCLUSIONS:
Optic nerve hypoplasia is a major cause of impaired vision in children and rarely
has been attributed to an intracranial tumor. Our case, involving a patient with a
suprasellar teratoma and optic nerve hypoplasia, supports a causal relation
between the two.
186. Lejeune, H.; Maquet, P.; Bonnet, M.; Casini, L.; Ferrara, A.; Macar, F.; Pouthas, V.;
Timsit Berthier, M.; Vidal, F. The basic pattern of activation in motor and
sensory temporal tasks: positron emission tomography data. Neurosci-Lett. 1997
Oct 10; 235(1-2): 21-4; ISSN: 0304-3940.
IRELAND. Positron emission tomography (PET) data were obtained from
subjects performing a synchronization task (target duration 2700 ms). A
conjunction analysis was run to identify areas prominently activated both in this
task and in a temporal generalization task (target duration 700 ms) used
previously. The common pattern of activation included the right prefrontal,
inferior parietal and anterior cingulate cortex, the left putamen and the left
cerebellar hemisphere. These areas are assumed to play a major role in time
processing, in relation to attention and memory mechanisms.
187. Leskinen, S.; Pulkki, K.; Knuuti, J.; Kirvela, O.; Lehikoinen, P.; Nagren, K.;
Ruotsalainen, U.; Teras, M.; Wegelius, U.; Salminen, E. Transport of carbon-11-
methionine is enhanced by insulin. J-Nucl-Med. 1997 Dec; 38(12): 1967-70;
ISSN: 0161-5505.
UNITED-STATES. The anabolic effects of insulin are not restricted to
carbohydrate and lipid metabolism but also include protein metabolism. However,
the effects of insulin on protein metabolism have been difficult to demonstrate in
vivo. Amino acid transport is partly regulated by insulin according to the
experimental data. PET provides a way to measure fractional uptake rates of
amino acids. The purpose of this study was to measure the effect of insulin on
amino acid transport from the plasma to the human parotid glands. METHODS:
We compared the uptake of L-[methyl-11C]methionine ([11C]methionine) into
the parotid glands and cerebellum in seven healthy volunteers during the fasting
state and euglycemic insulin clamp technique (1 mU/kg per minute). RESULTS:
The fractional uptake rate of [11C]methionine was increased by 31% for the right
parotid gland (p = 0.003) and by 29% for the left parotid gland (p = 0.009) during
insulin clamp, while the increase was 19% for the cerebellum (p = 0.01). The
concentration of amino acids typical for the hormone-sensitive transport system
A was 11% lower during insulin infusion than in the fasting state.
CONCLUSION: The uptake of methionine into brain tissue does not seem to be
under major control by insulin, while the transport of methionine in the parotid
glands is stimulated by insulin. PET provides a sophisticated method to study the
transport system of amino acids in vivo.. 0; 11061-68-0; 58576-49-1; 7005-18-7.
188. Levy, L. M.; Henkin, R. I.; Hutter, A.; Lin, C. S.; Martins, D.; Schellinger, D.
Functional MRI of human olfaction. J-Comput-Assist-Tomogr. 1997 Nov; 21(6):
849-56; ISSN: 0363-8715.
UNITED-STATES. PURPOSE: Our goal was to use functional MRI (fMRI) to
measure brain activation in response to olfactory stimuli. METHOD: fMRI brain
scans were obtained in 17 normal subjects (9 men, 8 women) using-multislice
FLASH MRI in response to three olfactory stimuli (pyridine, menthone, amyl
acetate) in three coronal brain sections selected from anterior to posterior
temporal brain regions. Activation images were derived using correlation analysis,
and ratios of areas of brain activated to total brain areas were calculated.
RESULTS: Activation was present in each section in all subjects. Subjective
estimation of vapor intensity followed relative vapor pressure of stimuli
presented (pyridine > amyl acetate > menthone) and were similar for both men
and women. However, brain activation did not follow subjective responsiveness
order but rather pyridine > menthone > amyl acetate, a pattern demonstrated by
both men and women. Brain activation in women was consistently lower than in
men for all vapors in all brain sections, although regions of activation did not
differ. Activation occurred in regions previously recognized as associated with
olfactory stimulation, including orbitofrontal and entorhinal cortex; however,
extensive regions within frontal cortex including cingulate gyrus were also
activated. Brain regions activated to odors considered pleasant or unpleasant did
not differ. CONCLUSION: The techniques used in this study demonstrated that
brain activation to olfactory stimuli could be measured quantitatively such that
differences between groups of subjects (in this case men and women) could be
compared. Although localization of brain activation was not the major thrust of
this study, activation to olfactory stimuli was found not only in brain regions
previously associated with processing of olfactory information but also in several
other areas of frontal cortex, in cingulate gyrus, and in several components of the
limbic system. This is the first study in which activation in human brain
parenchyma of normal humans to olfactory stimuli has been quantitated by
fMRI.. 0; 0; 0; 110-86-1; 628-63-7; 89-80-5.
189. Lewis Jack, O. O.; Campbell, A. L.; Ridley, S.; Ocampo, C.; Brown, A.; Dennis, G.;
Wood, D. L.; Weir, R. Unilateral brain lesions and performance on Russell's
version of the Wechsler Memory Scale in an African American population. Int-J-
Neurosci. 1997 Oct; 91(3-4): 229-40; ISSN: 0020-7454.
ENGLAND. Studies of patients with unilateral lesions report hemisphere-
specific and locus-specific impairments on Russell's (1975) Revision of the
Wechsler Memory Scale (RWMS). In the current investigation "race-
homogeneous" and "race-comparative" paradigms provide the context in which the
generalizability of RWMS findings are examined in a population of African
Americans with unilateral lesions. The performances of brain-damaged patients
were impaired relative to normal controls on five of the six RWMS measures.
However, patients with left and right hemisphere damage in our sample did not
differ systematically on RWMS subtests. Likewise, among patients with lesions
confined to one of the quadrants in the brain, there were no quadrant group
differences in performance on RWMS subtests. But, right posteriors were
impaired relative to controls on immediate and delayed VR subtests. The relative
merits of the race-comparative and race-homogeneous paradigms are considered in
the context of these findings.
190. Lin, J. H.; Hou, J. W.; Teng, R. J.; Tien, H. F.; Lin, K. H. Jacobsen distal 11q deletion
syndrome with a myelodysplastic change of hemopoietic cells. Am-J-Med-Genet.
1998 Feb 3; 75(4): 341-4; ISSN: 0148-7299.
UNITED-STATES. We describe a male infant with unusual facial appearance,
relative pancytopenia, bilateral simian creases, and an accessory nipple.
Cytogenetic analysis showed deletion of the long arm of chromosome 11
[46,XY,del(11)(pter-->q23.2:)]. Bone-marrow study showed a myelodysplastic
change of hemopoietic cells compatible with peripheral blood findings. Pachygyria
of the temporal and frontal lobes was demonstrated by magnetic resonance image
(MRI) of the brain. We present our findings in order to contribute to the
information on 11q23 deletion.
191. Lin, K. C.; Cermak, S. A.; Kinsbourne, M.; Trombly, C. A. Effects of left-sided
movements on line bisection in unilateral neglect. J-Int-Neuropsychol-Soc. 1996
Sep; 2(5): 404-11; ISSN: 1355-6177.
ENGLAND. Thirteen patients with left neglect performed line bisection under
four conditions: no cue, visual cueing involving the report of a digit placed at the
left end of the line, circling the left-end digit, and digit circling plus tracing of the
line with the right index finger from its left end to its midpoint before bisection.
Digit circling plus finger tracing was unequivocally more effective in reducing left
neglect than digit circling alone, which was in turn more effective than visual
cueing; indeed, digit circling with tracing completely abolished the rightward
bisection bias. Thus continuously directing visuomotor control to the left side of
the line (even with the right hand) until bisection is performed reduces neglect
more than only requiring patients to attend to left-sided visual cues. The
facilitatory effects of the cueing procedures may reflect their differential efficacy
in constraining as well as attracting attention and action to the left part of the
target line. These findings have implications for neglect rehabilitation.
192. Litscher, G.; Schwarz, G.; Jobstmann, R.; Kehl, G.; Kleinert, R. Brain-stem auditory
evoked potential monitoring. The increase of the stimulus artifact in the
development of brain death: a biological phenomenon? Int-J-Neurosci. 1997 Sep;
91(1-2): 95-103; ISSN: 0020-7454.
ENGLAND. Brain-stem auditory evoked potentials (BAEPs) were recorded in
12 dead subjects (mean age, 72.6 +/- 14.8 years), 30.6 +/- 19.5 hours (range 9-70)
after abolished systemic circulation. Death was due to cardiac failure (n = 10),
intracerebral hemorrhage (n = 1) and larynx cancer (n = 1). The presence and
amplitude of the stimulus artifact were evaluated. The mean (+/- SD) amplitudes
of the stimulus artifact was 0.03 +/- 0.02 microV on the left side and 0.01 +/- 0.02
microV on the right side. These findings in accordance with previous studies on
comatose patients and brain dead subjects confirm that the increase of the
stimulus artifact in the development of brain death, in spite of stimulation with
alternating polarity, seems to reflect a biological phenomenon which is not found
in dead subjects after complete cessation of systemic circulation.
193. Liu, X. H.; Wang, P.; Barks, J. D. The non-competitive AMPA antagonist LY
300168 (GYKI 53655) attenuates AMPA-induced hippocampal injury in
neonatal rodents. Neurosci-Lett. 1997 Oct 10; 235(1-2): 93-7; ISSN: 0304-3940.
IRELAND. In contrast with the neuroprotective efficacy of competitive and non-
competitive N-methyl-D-aspartate (NMDA) antagonists versus NMDA
neurotoxicity, reported neuroprotective effects of non-NMDA antagonists in
limiting alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)
toxicity have been less robust. We tested the effect of the non-competitive
AMPA receptor antagonist LY 300168 (GYKI 53655; E. Lilly) (0.25 or 2.5 mg/kg
per dose i.p. x 3 doses vs. vehicle) on AMPA-induced excitotoxic injury in
postnatal day 7 (P7) rats. To assess specificity, we tested the effect of LY
300168 (2.5 mg/kg per dose x 3 doses) on NMDA-induced excitotoxic injury. P7
rats received right intrahippocampal injections of either (S)-AMPA (2.5 nmol, n =
67) or NMDA (12.5 nmol, n = 11). Injection of AMPA resulted in right
hippocampal atrophy with pyramidal cell loss. LY 300168 treatment produced
dose-dependent attenuation of AMPA-induced right hippocampal injury; based
on comparisons with left hippocampal volumes, 2.5 nmol AMPA resulted in 42
+/- 3% (mean +/- SEM) right hippocampal volume loss in controls, but only 10
+/- 5% after LY 300168 2.5 mg/kg per dose (P < 0.001; ANOVA). LY 300168
had no effect on NMDA-induced hippocampal injury. The data support the
hypothesis that drugs that allosterically regulate AMPA receptor activity can
modulate the response of immature brain to AMPA-mediated injury.. 0; 0;
146908-67-0; 6384-92-5; 77521-29-0.
194. Lohr, J. B.; Caligiuri, M. P. Lateralized hemispheric dysfunction in the major
psychotic disorders: historical perspectives and findings from a study of motor
asymmetry in older patients. Schizophr-Res. 1997 Oct 30; 27(2-3): 191-8; ISSN:
0920-9964.
NETHERLANDS. Differences in functioning between the two cerebral
hemispheres have been reported for more than a century. In recent decades, issues
related to lateralized dysfunction have been raised in psychiatric illnesses such as
schizophrenia and bipolar disorder. In particular, evidence suggests that
schizophrenia may be particularly associated with left hemisphere dysfunction
and bipolar disorder with right hemisphere dysfunction. We discuss these issues,
along with a conceptual framework for integrating hypotheses about the
relationship between the major psychotic illnesses based on a two-dimensional
continuum. We also present new findings from our study of motor asymmetry in
older patients with psychosis that support this framework. Our results indicate
that schizophrenia may be associated with left hemisphere pathology to a greater
extent than right, whereas the reverse may occur in bipolar disorder.
195. Longmore, J.; Shaw, D.; Smith, D.; Hopkins, R.; McAllister, G.; Pickard, J. D.;
Sirinathsinghji, D. J.; Butler, A. J.; Hill, R. G. Differential distribution of 5HT1D-
and 5HT1B-immunoreactivity within the human trigemino-cerebrovascular
system: implications for the discovery of new antimigraine drugs. Cephalalgia.
1997 Dec; 17(8): 833-42; ISSN: 0333-1024.
NORWAY. Sumatriptan, a 5HT1B/1D-receptor agonist, is clinically effective as
an antimigraine agent. Its therapeutic action may result partly from
vasoconstriction of excessively dilated cranial blood vessels (a 5HT1B-receptor
mediated response). The antimigraine activity of sumatriptan may also result from
inhibition of the release of vasoactive neuropeptides from trigeminal sensory
fibres within the meninges. The identity of the 5HT1B/1D-receptor subtype
mediating this effect is unknown. Using 5HT1D- and 5HT1B-receptor-specific
antibodies we have demonstrated a differential distribution of these receptor
subtypes within the human trigemino-cerebrovascular system. Only 5HT1B-
receptor protein was detected on dural arteries. In contrast, only 5HT1D-receptor
protein was detected on trigeminal sensory neurones including peripheral and
central projections to dural blood vessels and to the medulla. Within the medulla
5HT1D-receptor protein was confined to discrete areas associated with the
trigeminal sensory system. These findings have important implications for the
design of new antimigraine drugs.. 50-67-9.
196. Lucey, J. V.; Costa, D. C.; Adshead, G.; Deahl, M.; Busatto, G.; Gacinovic, S.;
Travis, M.; Pilowsky, L.; Ell, P. J.; Marks, I. M.; Kerwin, R. W. Brain blood flow
in anxiety disorders. OCD, panic disorder with agoraphobia, and post-traumatic
stress disorder on 99mTcHMPAO single photon emission tomography (SPET).
Br-J-Psychiatry. 1997 Oct; 171: 346-50; ISSN: 0007-1250.
ENGLAND. BACKGROUND: We compared regional cerebral blood flow
(rCBF) in three groups of patients with DSM-III-R anxiety disorders.
METHOD: Fifteen patients with obsessive -compulsive disorder (OCD), 15 with
panic disorder with agoraphobia (PA), and 16 with post-traumatic stress disorder
(PTSD) and a similar group of healthy controls were assessed on brain-dedicated
high-resolution SPET. RESULTS: MANOVA revealed significant rCBF
differences between diagnostic groups (F = 4.4; d.f. = 3, 57; P = 0.007) and
between cerebral regions (F = 6.4; d.f. = 1, 57; P = 0.01) in OCD and PTSD
compared with PA and healthy controls, limited to bilateral superior frontal
cortices and right caudate nuclei. Whole brain blood flow correlated positively
with anxiety (r = 0.24, n = 46, P = 0.05). Beck depression scores correlated
significantly negatively with left caudate rCBF (r = -0.24, n = 46, P = 0.05) and
right caudate rCBF (r = -0.31, n = 46, P = 0.02). PTSD syndrome severity
correlated significantly negatively with the left caudate (r = -0.49, n = 16, P =
0.03) and with right caudate rCBF (r = -0.7, n = 16, P = 0.001). CONCLUSIONS:
Functional rCBF differences in anxiety disorders could relate to repetitive,
intrusive, distressing mental activity, prominent in both OCD and PTSD.. 0; 0.
197. Luh, K. E.; Wagner, D. A. Cerebral asymmetries in processing strategies for letter and
symbol trigrams. Brain-Lang. 1997 Dec; 60(3): 464-88; ISSN: 0093-934X.
UNITED-STATES. Several studies have shown that laterally presented
consonant-vowel-consonant (CVC) strings produce both superior performance,
and a more wholistic processing strategy in the right visual field/left hemisphere
(RVF/LHEM), and a more sequential strategy in the inferior left visual field
(LVF). To determine whether these strategies are applied to other types of
trigrams subjects (n = 30) were asked to identify consonant and symbol trigrams
briefly projected unilaterally to the LVF or RVF, or bilaterally (the same trigram
in both fields--BVF). A second group of subjects (n = 30) first practiced
pronouncing consonant trigrams and then viewed them tachistoscopically. Both
tasks yield RVF advantages. Symbols are processed more wholistically in the
LVF, more sequentially in the RVF and in an intermediate pattern when presented
bilaterally. In contrast, subjects seem to chunk letters as bigrams, and do so
equally well in all fields, and visual field differences in strategies emerge for
consonants only when they are pronounced. Pronounceability of consonant
trigrams, assessed with ratings and vocal reaction times, was predicted by
orthographic regularity. Since the RHEM has limited phonetic skills, but it, like
the LHEM, is privy to information on orthographic regularity, the error pattern
on consonant strings indicates non-phonetic processing, whereas the RVF
wholistic strategy for consonant-vowel-consonant strings appears to reflect
phonetic processing.
198. Lyden, P. D.; Lonzo, L. M.; Nunez, S. Y.; Dockstader, T.; Mathieu Costello, O.;
Zivin, J. A. Effect of ischemic cerebral volume changes on behavior. Behav-Brain-
Res. 1997 Aug; 87(1): 59-67; ISSN: 0166-4328.
NETHERLANDS. Ischemia causes long-term effects on brain volume and
neurologic function but the relationship between the two is poorly characterized.
We studied the relationships between brain volume and three measures of rodent
behavior after cerebral ischemia was induced by injecting several thousand
microspheres into the internal carotid arteries of rats. Forty eight hours later, each
subject was rated using a global neurologic rating scale. Several weeks later, the
subjects were tested for open field activity and visual spatial learning. Post-
mortem we measured the volume of the cerebral hemispheres and estimated the
volume densities of cortex, white matter, hippocampus, basal ganglia, thalamus,
ventricle, and visible infarction. Ischemia caused significant impairment, as
measured by the global rating scale; the probability of an abnormal rating was
correlated with the number of microspheres trapped in the brains. Visual spatial
learning was significantly impaired by ischemia, but this deficit was independent
of the count of microspheres, whether the subject was abnormal at 48 h, and
whether the left or right hemisphere was embolized. Cerebral hemisphere volume
was reduced from 430 mm3 to 376 mm3 (P < 0.05). The cortex was reduced from
22 to 19% of cerebrum (P < 0.05) and the white matter compartment was reduced
to similar degree. The lesion volume was 6% of cerebrum, comparable to that seen
with other ischemia methods. The global outcome rating was significantly related
to total cerebral volume, but not to volume changes in any single compartment.
On the other hand, visual spatial learning was significantly influenced by volume
changes in the cortex and white matter, but not by the topography of the visible
infarctions. Open field activity was not altered by infarction. Our data suggests
that the total volume of brain tissue lost to infarction may partially determine
global neurological rating independently of the topography of the volume loss.
Integrative functions such as learning may depend more on the integrity of
specific compartments and less on the total volume of intact brain. The volume of
visible cystic infarction was not related to long term behavioral outcome. These
results should be confirmed using another method of inducing ischemia.. 0.
199. Maas, L. C.; Lukas, S. E.; Kaufman, M. J.; Weiss, R. D.; Daniels, S. L.; Rogers, V.
W.; Kukes, T. J.; Renshaw, P. F. Functional magnetic resonance imaging of human
brain activation during cue-induced cocaine craving. Am-J-Psychiatry. 1998 Jan;
155(1): 124-6; ISSN: 0002-953X.
UNITED-STATES. OBJECTIVE: Functional magnetic resonance imaging (MRI)
was used to test whether brain activation was detectable in regions previously
associated with cocaine cue-induced craving. METHOD: Blood oxygenation level
dependent (BOLD) functional activation was measured during presentation of
audiovisual stimuli containing alternating intervals of drug-related and neutral
scenes to six male subjects with a history of crack cocaine use and six male
comparison subjects. RESULTS: Significant activation was detected in the
anterior cingulate and left dorsolateral prefrontal cortex in the cocaine-using group.
In addition, a correlation between self-reported levels of craving and activation in
these regions was found. CONCLUSIONS: These results suggest that functional
MRI may be a useful tool to study the neurobiological basis of cue-induced
craving.. 0; 7782-44-7.
200. MacLeod, A. K.; Buckner, R. L.; Miezin, F. M.; Petersen, S. E.; Raichle, M. E. Right
anterior prefrontal cortex activation during semantic monitoring and working
memory. Neuroimage. 1998 Jan; 7(1): 41-8; ISSN: 1053-8119.
UNITED-STATES. Areas of the adult human brain used for semantic monitoring
were identified using positron emission tomography. For a series of tasks,
subjects viewed a list of familiar English nouns and monitored the words for
names of dangerous animals. The monitoring task used here also contained an
instruction to keep track of the number or percentage of targets for report after
the scan. Surface characteristics of the tasks such as stimulus rate, number of
targets, and whether subjects were asked to count or estimate the number of
targets were varied across multiple conditions within and between subjects. A
passive word viewing condition was used as the control in all subjects. Reliable
activations were identified in anterior and dorsal right prefrontal cortex [Brodmann
areas (BA) 9 and 10] and left extrastriate cortex. The right prefrontal cortical
locations are similar to areas that have been activated during many episodic
memory tasks. This surprising finding led to a thorough review of the literature
for examples of other activations within 16-mm vector distance of this right
prefrontal area. Activations in the vicinity of right BA10 due to episodic memory
retrieval, to various forms of working memory, and to miscellaneous tasks were
found. The right prefrontal activations in the current experiment and the additional
working memory and miscellaneous tasks demonstrate that, although right BA10
is routinely activated by episodic retrieval tasks, it is not uniquely activated by
episodic retrieval tasks.
201. MacLusky, N. J.; Bowlby, D. A.; Brown, T. J.; Peterson, R. E.; Hochberg, R. B. Sex
and the developing brain: suppression of neuronal estrogen sensitivity by
developmental androgen exposure. Neurochem-Res. 1997 Nov; 22(11): 1395-414;
ISSN: 0364-3190.
UNITED-STATES. The developmental effects of androgen play a central role in
sexual differentiation of the mammalian central nervous system. The cellular
mechanisms responsible for mediating these effects remain incompletely
understood. A considerable amount of evidence has accumulated indicating that
one of the earliest detectable events in the mechanism of sexual differentiation is a
selective and permanent reduction in estrogen receptor concentrations in specific
regions of the brain. Using quantitative autoradiographic methods, it has been
possible to precisely map the regional distribution of estrogen receptors in the
brains of male and female rats, as well as to study the development of sexual
dimorphisms in receptor distribution. Despite previous data suggesting that the
left and right sides of the brain may be differentially responsive to early androgen
exposure, there is no significant right-left asymmetry in estrogen receptor
distribution, in either sex. Significant sex differences in receptor density are,
however, observed in several regions of the preoptic area, the bed nucleus of the
stria terminalis and the ventromedial nucleus of the hypothalamus, particularly in
its most rostral and caudal aspects. In the periventricular preoptic area of the
female, highest estrogen receptor density occurs in the anteroventral
periventricular region: binding in this region is reduced by approximately 50% in
the male, as compared to the female. These data are consistent with the
hypothesis that androgen-induced defeminization of feminine behavioral and
neuroendocrine responses to estrogen may involve selective reductions in the
estrogen sensitivity of critical components of the neural circuitry regulating these
responses, mediated in part through a reduction in estrogen receptor
biosynthesis.. 0; 0.
202. Madden, D. J.; Turkington, T. G.; Coleman, R. E.; Provenzale, J. M.; DeGrado, T.
R.; Hoffman, J. M. Adult age differences in regional cerebral blood flow during
visual world identification: evidence from H215O PET. Neuroimage. 1996 Apr;
3(2): 127-42; ISSN: 1053-8119.
UNITED-STATES. We used H215O PET to investigate adult age differences in
regional cerebral blood flow (rCBF) during the performance of a visual word
identification task. The study participants were 20 healthy, right-handed men: 10
young adults between 18 and 27 years of age, and 10 older adults between 63 and
75 years of age. The word identification task comprised six blocks of test trials
representing four task conditions; subjects responded manually. The task
conditions varied with regard to whether semantic retrieval was required (e.g.,
word/nonword discrimination vs simple response to each stimulus) and with
regard to the difficulty of visual encoding (e.g., words presented normally vs
words with asterisks inserted between adjacent letters). Each subject performed
all six trial blocks, concurrently with each of six H215O PET scans. Analyses of
quantitative CBF data obtained from the arterial time-activity curve demonstrated
a significant age-related decline in global CBF rate. Analyses of the changes in
rCBF between task conditions indicated that retrieval of semantic information
sufficient to distinguish words from nonwords is mediated by a ventral
occipitotemporal cortical pathway. Specific areas within this pathway were also
associated with visual encoding processes. Several rCBF activations were
significantly greater for young adults than for older adults, indicating an age-
related decline in processing efficiency within this ventral occipitotemporal
pathway. Although the performance data demonstrated a greater age-related
slowing for visual encoding than for semantic retrieval, these age-related
performance changes were not associated with corresponding changes in rCBF
activation.
203. Maeda, T.; Hashizume, K.; Kunimoto, M.; Tanaka, T.; Yonemasu, Y. [Experimental
bilateral focus model of complex partial seizure: clinical, electrophysiological and
pathological studies]. No-To-Shinkei. 1997 Sep; 49(9): 813-8; ISSN: 0006-8969.
JAPAN. Stereotactic surgery was performed in Wistar rats and stainless steel
injection chemitrode were inserted in bilateral amygdala (AM). Stainless steel
screws were placed on the dura over bilateral motor cortex (Cx). One week after
the surgery, rats were placed in the recording chamber. Kainic acid (KA) injection
was performed into the left AM and focal AM seizure status was induced.
Seizures evolved into limbic seizure status during 3 days. Seven days after the
first KA injection, KA was injected into the right AM. The limbic seizure status
was elicited again, however, these seizures subsided within 3 days. About 3 week
after the first KA injection, spontaneous limbic seizures developed. Three ictal
EEG patterns were seen (1) Bilateral independent seizures, (2) Synchronous ictal
discharge over the bilateral AM, and (3) Switch of lateralized ictal activity from
one to the other AM. The histological study demonstrated bilateral hippocampal
cell loss and hippocampal atrophy. These changes are very similar to those
observed in human intractable complex partial seizures with bilateral mesial
temporal focus. The result suggests that this model will be a good tool in order to
resolve intractability of complex partial seizure in patients with bilateral temporal
focus.. 487-79-6.
204. Magga, J.; Vuolteenaho, O.; Marttila, M.; Ruskoaho, H. Endothelin-1 is involved in
stretch-induced early activation of B-type natriuretic peptide gene expression in
atrial but not in ventricular myocytes: acute effects of mixed ET(A)/ET(B) and
AT1 receptor antagonists in vivo and in vitro. Circulation. 1997 Nov 4; 96(9):
3053-62; ISSN: 0009-7322.
UNITED-STATES. BACKGROUND: The precise role of paracrine and
autocrine factors in mechanical load-induced activation of cardiac gene expression
is unknown. Here we report the effects of endothelin-1 (ET-1) and angiotensin II
(Ang II) receptor antagonism on acute pressure overload-induced activation of
cardiac B-type natriuretic peptide (BNP) gene expression in spontaneously
hypertensive rats (SHRs) in vivo and on mechanical stretch-induced increase in
atrial BNP gene expression in vitro. METHODS AND RESULTS: Acute
pressure overload produced in conscious SHRs by infusion of arginine8-
vasopressin (0.05 microg x kg(-1) x min(-1)) for 2 hours resulted in an increase in
BNP mRNA levels in the left ventricle as well as in the atrium. Bolus injections of
bosentan (mixed ET(A)/ET(B) receptor antagonist, 10 mg/kg I.V.) but not losartan
(AT1 receptor antagonist, 10 mg/kg I.V.) blocked the increase of the BNP mRNA
levels produced by pressure overload in the left atria, whereas the elevation of
BNP mRNA levels was similar (a 1.9-fold increase) in the left ventricles of
vehicle-, losartan-, and bosentan-infused SHRs. In an isolated perfused rat heart
preparation, infusion of bosentan (1 micromol/L) for 2 hours inhibited the
mechanical stretch-induced increase in BNP mRNA levels in the right atria,
whereas an AT1 receptor antagonist, CV-11974 (10 nmol/L), had no effect.
CONCLUSIONS: The findings of the present study demonstrate that Ang II and
ET-1 are not obligatorily required for stretch to trigger the increased BNP gene
expression in ventricular myocytes in vivo. In contrast, mechanical load on the
atrial myocytes did initiate an ET-1-dependent expression of BNP gene showing
that endogenous ET-1 production differentially regulates BNP gene expression in
atrial and ventricular myocytes.. 0; 0; 0; 0; 0; 0; 0; 0; 0; 0; 114471-18-0; 114798-
26-4; 139481-59-7; 147536-97-8.
205. Makino, S.; Chikazawa, H.; Yorimitsu, A.; Suehiro, T.; Hashimoto, K.; Ohashi, Y.;
Morioka, M.; Sasano, H. A rare case of Cushing's syndrome due to bilateral
adrenocortical adenomas. Endocr-J. 1997 Aug; 44(4): 533-40; ISSN: 0918-8959.
JAPAN. We report a rare case of Cushing's syndrome due to bilateral
adrenocortical adenomas in a 45-year-old female. She suffered from diabetes
mellitus and hypertension for a decade, but her appearance was not Cushingoid.
The plasma cortisol level in the morning was at the upper limit of the normal
range, but did not show a diurnal rhythm or was suppressed by 1 mg of
dexamethasone. The plasma level of ACTH was undetectable, and it failed to
respond to human CRH (hCRH). Plasma cortisol responded well to synthetic
ACTH. The urinary 17-OHCS level was high, and was not suppressed by 4 mg of
dexamethasone. While these findings were consistent with a diagnosis of
adrenocortical adenoma, computed tomography showed several nodules in both
adrenal glands that suggested the presence of huge nodular adrenocortical
hyperplasia or bilateral adrenocortical adenomas. Bilateral adrenalectomy
demonstrated the presence of three adenomas, two in the right and one in the left
adrenal. Analysis of the extract from each adenoma revealed that two of the three
produced an excess amount of cortisol. Magnetic resonance imaging (MRI) of the
brain suggested the presence of pituitary adenoma. Prior to adrenalectomy, TSH,
GH or LH showed a low response to TRH, GHRH or LHRH, respectively. Since
normal responses were restored after bilateral adrenalectomy, these abnormalities
were attributed to hypercortisolemia.. 50-02-2; 50-23-7; 9002-60-2.
206. Makris, N.; Worth, A. J.; Sorensen, A. G.; Papadimitriou, G. M.; Wu, O.; Reese, T.
G.; Wedeen, V. J.; Davis, T. L.; Stakes, J. W.; Caviness, V. S.; Kaplan, E.; Rosen,
B. R.; Pandya, D. N.; Kennedy, D. N. Morphometry of in vivo human white
matter association pathways with diffusion-weighted magnetic resonance imaging.
Ann-Neurol. 1997 Dec; 42(6): 951-62; ISSN: 0364-5134.
UNITED-STATES. The precise characterization of cortical connectivity is
important for the understanding of brain morphological and functional
organization. Such connectivity is conveyed by specific pathways or tracts in the
white matter. Diffusion-weighted magnetic resonance imaging detects the
diffusivity of water molecules in three dimensions. Diffusivity is anisotropic in
oriented tissues such as fiber tracts. In the present study, we used this method to
map (in terms of orientation, location, and size) the "stem" (compact portion) of
the principal association, projection, and commissural white matter pathways of
the human brain in vivo, in 3 normal subjects. In addition, its use in clinical
neurology is illustrated in a patient with left inferior parietal lobule embolic
infarction in whom a significant reduction in relative size of the stem of the left
superior longitudinal fasciculus was observed. This represents an important
method for the characterization of major association pathways in the living human
that are not discernible by conventional magnetic resonance imaging. In the clinical
domain, this method will have a potential impact on the understanding of the
diseases that involve white matter such as stroke, multiple sclerosis, amyotrophic
lateral sclerosis, head injury, and spinal cord injury.
207. Maldjian, J. A.; Schulder, M.; Liu, W. C.; Mun, I. K.; Hirschorn, D.; Murthy, R.;
Carmel, P.; Kalnin, A. Intraoperative functional MRI using a real-time
neurosurgical navigation system. J-Comput-Assist-Tomogr. 1997 Nov; 21(6):
910-2; ISSN: 0363-8715.
UNITED-STATES. A 42-year-old-man had focal left hand motor seizures. MR
studies demonstrated a right posterior frontal brain tumor. Functional MRI was
performed, localizing the motor cortex posterior to the lesion. The functional
images were integrated with a neurosurgical navigation computer. A real-time
intraoperative display of the anatomic and functional images was produced,
registered to a neurosurgical probe. Excellent correlation was demonstrated
between the functional maps and invasive electrophysiologic mapping performed
at the time of craniotomy.
208. Maquet, P.; Lejeune, H.; Pouthas, V.; Bonnet, M.; Casini, L.; Macar, F.; Timsit
Berthier, M.; Vidal, F.; Ferrara, A.; Degueldre, C.; Quaglia, L.; Delfiore, G.; Luxen,
A.; Woods, R.; Mazziotta, J. C.; Comar, D. Brain activation induced by
estimation of duration: a PET study. Neuroimage. 1996 Apr; 3(2): 119-26; ISSN:
1053-8119.
UNITED-STATES. Duration information about a visual stimulus requires
processing as do other visual features such as size or intensity. Using positron
emission tomography, iterative H215O infusions, and statistical parametric
mapping, we investigated the neural correlates of time processing. Nine normal
subjects underwent six serial rCBF. Three tasks were studied: (a) A temporal
generalization task (D task) in which the subjects had to judge (by pressing one of
two keys) whether the duration of the illumination of a green LED was equal to or
different from that of a previously presented standard; (b) An intensity
generalization task (I task) in which the judgment concerned the intensity of the
LED; and (c) A control task (C task) in which the subjects had to press one of the
two keys at random in response to LED illumination. A significant increase in
rCBF during the D task, compared to that during the C task, was observed in right
prefontal cortex, right inferior parietal lobule, anterior cingulate cortex, vermis, and
a region corresponding to the left fusiform gyrus. A significant increase in rCBF
during the I task, compared to that during the C task, was observed in right
prefontal cortex, right inferior parietal lobule, right extrastriate cortex, anterior
cingulate cortex, left inferior parietal lobule, vermis, and two symmetrical regions
corresponding to the fusiform gyri. No significant activation was observed in the
D task when compared to that in the I task. We propose that these cortical maps
are best explained by the recruitment of visual attention and memory structures,
which play a major role in prospective time judgements as indicated by behavioral
studies. The data also suggest that the temporal dimension of a visual stimulus is
processed in the same areas as other visual attributes.
209. Mark, V. W.; Heilman, K. M. Diagonal neglect on cancellation. Neuropsychologia.
1997 Nov; 35(11): 1425-36; ISSN: 0028-3932.
ENGLAND. Patients with right hemisphere injury frequently neglect to cancel
targets primarily in the left part of the page nearest the body. Since this region is
diagonally opposite the area from where such patients usually begin cancelling,
near left ('diagonal') neglect may be consequent to stimulus order effects ('fatigue').
We evaluated the persistence of near left neglect in nine stroke patients when they
had to cancel either the near or the far half of the page before proceeding to the
other half. Our results showed that near left neglect on the page was largely
unaffected by cancellation order. Furthermore, a near left gradient of omissions
was established within both radial (near and far) halves of the page, as well as for
the entire page. Our findings suggest that diagonal cancellation neglect is unrelated
to fatigue and reflects a consistent, two-dimensional disorder of spatial attention.
Such neglect may be related to the extent of the visible stimulus array, as well as
to the array's location in egocentric space.
210. Marshall, J. C.; Halligan, P. W.; Fink, G. R.; Wade, D. T.; Frackowiak, R. S. The
functional anatomy of a hysterical paralysis. Cognition. 1997 Jul; 64(1): B1-8;
ISSN: 0010-0277.
NETHERLANDS. The concept of a conversion disorder (such as hysterical
paralysis) has always been controversial (Ron, M.A. (1996). Somatization and
conversion disorders. In: B.S. Fogel, R.B. Schiffer & S.M. Rao (Eds.),
Neuropsychiatry. Williams and Wilkins, Baltimore, MD). Although the diagnosis
is recognised by current psychiatric taxonomies, many physicians still regard such
disorders either as feigned or as failure to find the responsible organic cause for the
patient's symptoms. We report a woman with left sided paralysis (and without
somatosensory loss) in whom no organic disease or structural lesion could be
found. By contrast, psychological trauma was associated with the onset and
recurrent exacerbation of her hemiparalysis. We recorded brain activity when the
patient prepared to move and tried to move her paralysed (left) leg and when she
prepared to move and did move her good (right) leg. Preparing to move or moving
her good leg, and also preparing to move her paralysed leg, activated motor and/or
premotor areas previously described with movement preparation and execution.
The attempt to move the paralysed leg failed to activate right primary motor
cortex. Instead, the right orbito-frontal and right anterior cingulate cortex were
significantly activated. We suggest that these two areas inhibit prefrontal (willed)
effects on the right primary motor cortex when the patient tries to move her left
leg.
211. Martin, A.; Wiggs, C. L.; Weisberg, J. Modulation of human medial temporal lobe
activity by form, meaning, and experience. Hippocampus. 1997; 7(6): 587-93;
ISSN: 1050-9631.
UNITED-STATES. Clinically, the hallmark of the human amnesic syndrome is
an impaired ability to consciously recollect or remember daily events. If the
medial region of the temporal lobes, including the hippocampus and related
structures, is critical for establishing these new memories, then this brain region
should be active whenever events are experienced, regardless of whether subjects
are asked explicitly to learn and remember. Here we show that the medial
temporal region is active during encoding and that the hemisphere activated and
the amount of activation depend on the type of stimulus presented (objects or
words), whether the stimulus can be encoded for meaning (real objects and words
versus nonsense objects and words), and task experience (first versus the second
time a task is performed). These findings demonstrate that the medial temporal
lobe memory system is engaged automatically when we attend to a perceptual
event and that the location and amount of activation depend on stimulus
characteristics (physical form, meaning) and experience.
212. Martin, A.; Wiggs, C. L.; Weisberg, J. Modulation of human medial temporal lobe
activity by form, meaning, and experience. Hippocampus. 1997; 7(6): 587-93;
ISSN: 1050-9631.
UNITED-STATES. Clinically, the hallmark of the human amnesic syndrome is
an impaired ability to consciously recollect or remember daily events. If the
medial region of the temporal lobes, including the hippocampus and related
structures, is critical for establishing these new memories, then this brain region
should be active whenever events are experienced, regardless of whether subjects
are asked explicitly to learn and remember. Here we show that the medial
temporal region is active during encoding and that the hemisphere activated and
the amount of activation depend on the type of stimulus presented (objects or
words), whether the stimulus can be encoded for meaning (real objects and words
versus nonsense objects and words), and task experience (first versus the second
time a task is performed). These findings demonstrate that the medial temporal
lobe memory system is engaged automatically when we attend to a perceptual
event and that the location and amount of activation depend on stimulus
characteristics (physical form, meaning) and experience.
213. Martin Loeches, M.; Rubia, F. J. Encoding into working memory of spatial location,
color, and shape: electrophysiological investigations. Int-J-Neurosci. 1997 Oct;
91(3-4): 277-94; ISSN: 0020-7454.
ENGLAND. Event-related potentials (ERP) were recorded while subjects
memorized either the location, the color or the shape of stimuli which could be
located in 1 of 4 positions relative to a central fixation point (top, bottom, left or
right), be of 1 of 4 positions relative to a central fixation point (top, bottom, left
or right), be of 1 of 4 colors (white, green, red or blue), and present 1 of 4 shapes
(triangle, cross, circle or square). These ERP were compared to ERP recorded
while subjects looked at the same stimuli but performed other control,
nonmemory tasks. Only ERP corresponding to the memorization of spatial
location showed a differential pattern which could be specifically attributed to
memory encoding processes. This reveals an important difference in ERP
modulation between a working memory subsystem for spatial location and other
subsystem (or subsystems) for color or shape, which would provide evidence
supporting the existence of different working memory subsystems for visual
information in the brain.
214. Martin, R. F.; Bowden, D. M. A stereotaxic template atlas of the macaque brain for
digital imaging and quantitative neuroanatomy. Neuroimage. 1996 Oct; 4(2): 119-
50; ISSN: 1053-8119.
UNITED-STATES. A stereotaxic brain atlas of the longtailed macaque (Macaca
fascicularis) is presented in a format suitable for use as a template atlas of the
macaque brain. It includes most of the brain segmented to show the boundaries of
landmark structures such that every point in the brain can be represented by a
unique set of coordinates in three-dimensional space and ascribed unambiguously
to one and only one primary structure. More than 400 structures are represented,
including 360 volumetric structures, which constitute the substance of the brain,
and 50 superficial features. To facilitate use with ventriculography, magnetic
resonance imaging, and other noninvasive imaging techniques, the stereotaxic space
is referenced to internal landmarks, viz., the anterior commissure and posterior
commissure; the center of the anterior commissure at the midline is the origin of
the stereotaxic axes. Reference of stereotaxis to this bicommissural space
facilitates structural comparison with human brain atlases, which are commonly
referenced to the biocommissural line. It also facilitates comparison of brains of
different nonhuman primate species by providing a template brain against which
to compare size and internal variability. Thirty-three coronal sections at 1-mm
intervals from the spinomedullary junction to the rostral extreme of the caudate
nucleus show most structures of the hindbrain, midbrain, and subcortical
forebrain. Separately, four side views and 16 coronal sections show cortical
structures. Structures are represented by outlines of their boundaries and labeled
according to NeuroNames, a systematic English nomenclature of human and
nonhuman primate neuroanatomy. Abbreviations are based on a protocol designed
to facilitate cross-species comparisons. Instructions are provided for: (1) locating
sites from the Template Atlas in the conventional stereotaxic space of an
experimental animal, (2) locating sites identified by conventional stereotaxis in the
Template Atlas, and (3) using the Template Atlas to collate, compare, and display
image information (e.g., labeled cells, recording sites, stimulation sites, lesions)
from multiple animals.
215. Mason, G. F.; Harshbarger, T.; Hetherington, H. P.; Zhang, Y.; Pohost, G. M.;
Twieg, D. B. A method to measure arbitrary k-space trajectories for rapid MR
imaging. Magn-Reson-Med. 1997 Sep; 38(3): 492-6; ISSN: 0740-3194.
UNITED-STATES. A method to measure arbitrary k-space trajectories was
developed to compensate for nonideal gradient performance during rapid magnetic
resonance (MR) imaging with actively or nonactively shielded gradients at a
magnetic field strength of 4.1 T. Accurate MR image reconstruction requires
knowledge of the k-trajectory produced by the gradient waveforms during k-space
sampling. Even with shielded gradients, residual eddy currents and imperfections
in gradient amplifier performance can cause the true k-space trajectory to deviate
from the ideal trajectory. The k-space determination was used for spiral gradient-
echo imaging fo the human brain. While individual calibrations are needed for new
pulse sequences, the method of k-space determination can be used for any
sequence of preparation pulses and readout gradient waveforms and should prove
useful for other trajectories, including the rastered lines of echo-planar imaging.
216. Matsumoto, T.; Yokoi, K.; Mukaida, N.; Harada, A.; Yamashita, J.; Watanabe, Y.;
Matsushima, K. Pivotal role of interleukin-8 in the acute respiratory distress
syndrome and cerebral reperfusion injury. J-Leukoc-Biol. 1997 Nov; 62(5): 581-7;
ISSN: 0741-5400.
UNITED-STATES. Neutrophil recruitment is one of the hallmarks of acute
inflammation. A potent neutrophil chemotactic and activating factor, interleukin-8
(IL-8), has been demonstrated to be elevated in body fluids in various human
diseases and experimental animal models. Recent investigations on animal disease
models using blocking antibodies to IL-8 have revealed the essential involvement
of IL-8 in acute inflammation. We previously reported that the administration of a
neutralizing antibody against IL-8 prevented the neutrophil infiltration and
neutrophil-mediated tissue injury in several animal studies. In addition, we have
recently demonstrated that anti-IL-8 treatment is also effective in prevention of
two models that are very relevant to clinical situations: cerebral reperfusion injury
and endotoxemia-induced acute respiratory distress syndrome-like lung injury.
These results further support the hypothesis that IL-8 has a pivotal role and is a
novel target for therapeutic intervention in neutrophil-mediated injury.. 0.
217. Matthew, E.; Hill, T. C. Brain mapping with single photon emission CT. Radiology.
1998 Feb; 206(2): 483-9; ISSN: 0033-8419.
UNITED-STATES. PURPOSE: To investigate the feasibility of performing brain
mapping studies by using cortical activation paradigms and single photon
emission computed tomography (SPECT) and to evaluate methods of analysis.
MATERIALS AND METHODS: Twenty healthy volunteers underwent
technetium-99m bicisate SPECT under baseline conditions and during either full-
field or right hemifield visual stimulation with a black and white reversing
checkerboard pattern. Changes in regional cerebral perfusion were measured by
using regions of interest (ROIs) and statistical parametric mapping. RESULTS:
ROI analysis identified statistically significant increases in perfusion in the
occipital cortex with full-field visual stimulation (mean +/- standard error of the
mean percentage change from baseline: left, 8.0 +/- 1.5; right, 6.6 +/- 2.4). With
right hemifield visual stimulation, perfusion was significantly increased only in the
left occipital cortex (left, 5.2 +/- 1.5; right, -0.2 +/- 1.9). Statistical parametric
mapping showed areas of activation (more than 100 voxel clusters showed
significant change from baseline at a threshold value of P < or = .005 or z > or =
2.58) in the left primary visual cortex (right hemifield visual stimulation) and in
both right and left primary visual areas (full-field visual stimulation).
CONCLUSION: Brain mapping studies were preformed with Tc-99m bicisate
SPECT, and activation-induced changes were visualized and measured. These
methods can be applied to develop improved methods of diagnosis and
assessment of treatment outcome in patients with neuropsychiatric disorders.. 0;
0; 0; 4371-52-2.
218. May, J.; White, G. H.; Waugh, R.; Brennan, J. Endoluminal repair of internal carotid
artery aneurysm: a feasible but hazardous procedure. J-Vasc-Surg. 1997 Dec;
26(6): 1055-60; ISSN: 0741-5214.
UNITED-STATES. PURPOSE: The aim of this study was to report the repair
of an aneurysm of the internal carotid artery using the endoluminal method.
METHODS: A 70-year-old male patient noted a swelling in the right side of his
neck 22 years after endarterectomy of the right internal carotid artery. Duplex
ultrasound confirmed the clinical diagnosis of aneurysm of the internal carotid
artery. Further investigation included contrast-enhanced computed tomographic
(CT) scanning and carotid angiography performed via a retrograde femoral
approach. The aneurysm contained thrombus and was 3 cm in diameter and in
length. It extended superiorly from a point 0.5 cm above the carotid bifurcation to
a point estimated to be 2 cm from the base of the skull. Repair of the aneurysm
was undertaken using the endoluminal method. A self-expanding endograft 8 mm
in diameter and 4 cm in length was introduced through a 12F sheath in the
common carotid artery. An on-table completion angiogram of the right-sided
extracranial carotid arteries and the intracranial internal carotid artery and branches
was obtained. RESULTS: The completion angiogram and postoperative CT scan
confirmed exclusion of the aneurysm sac from the circulation. The patient awoke
from anesthesia with complete paralysis of the left arm. Recovery of movement
commenced 1 hour later. A brain CT scan demonstrated the event to be an embolic
stroke. Strength had returned by 7 days. Function of the arm was good 1 month
after operation, but coordination for fine movements was lacking. At the 6-month
follow-up, good arm function was maintained. A duplex ultrasound scan
demonstrated not only continued exclusion of the aneurysm sac but occlusion of
the endograft, also. CONCLUSIONS: Endoluminal repair of aneurysms of the
internal carotid artery is feasible but carries the risk of major morbidity as a result
of peripheral embolization and early occlusion of the endograft.
219. McCarley, R. W.; Shenton, M. E.; O'Donnell, B. F.; Nestor, P. G. Uniting Kraepelin
and Bleuler: the psychology of schizophrenia and the biology of temporal lobe
abnormalities. Harv-Rev-Psychiatry. 1993 May; 1(1): 36-56; ISSN: 1067-3229.
UNITED-STATES. Bleuler and Kraepelin are described as icons of the
aggressively psychological and aggressively biologic approaches to schizophrenia.
We suggest that methodologic advances in studying the function and structure of
the brain now allow a reconciliation of these seemingly dissimilar approaches,
particularly in the temporal lobe. We begin with a brief historic overview of these
different approaches to schizophrenia and then describe structural (magnetic
resonance imaging [MRI]), functional (event-related potential [ERP]), and
neuropsychological studies in this disorder, including a summary of work
conducted in our own laboratory. Recent MRI investigations agree on the
presence of volume reductions in schizophrenia in the medial temporal lobe
structures of the hippocampus-amygdala complex and of the para-hippocampal
gyrus. Furthermore, two recent studies also indicate volume reductions in the
superior temporal gyrus (STG). These volume reductions are most prominent in
male patients and in the left hemisphere of right-handed patients with
schizophrenia. Along with structural studies, there has been a burgeoning interest
in MRI-clinical correlations, with volume reductions in the anterior STG being
associated with hallucinations and those in the posterior STG being associated
with thought disorder. Functional ERP studies also implicate the importance of
the temporal lobe in schizophrenia; in addition, ERP abnormalities have been
directly associated with a left greater than right MRI volume reduction of the
posterior STG. Neuropsychological studies in nonpsychiatric patients are also
consistent with a pattern of functional deficits shown to arise from temporal lobe
abnormalities, whereas direct MRI-neuropsychological correlations in
schizophrenic patients show that decreased performance on tests of verbal
memory, abstraction, and categorization correlates with reduced MRI volume of
left and right temporal lobe structures. Integration of these findings with those
from basic neuroscience suggests a possible role of excitatory amino acid
neurotransmission dysregulation and excitotoxicity in the pathology of
schizophrenia. A data-based pathophysiologic characterization of schizophrenia
is now becoming a reality, and the next few years should see a further unification
of the Kraepelinian and Bleulerian approaches to this disorder.
220. McClellan, A. D.; Hagevik, A. Descending control of turning locomotor activity in
larval lamprey: neurophysiology and computer modeling. J-Neurophysiol. 1997
Jul; 78(1): 214-28; ISSN: 0022-3077.
UNITED-STATES. The purpose of the present study was to examine the
mechanisms that produce natural spontaneous turning maneuvers in larval
lamprey. During swimming, spontaneous turning movements began with a larger-
than-normal bending of the head to one side. Subsequently, undulations
propagated down the body with greater amplitude on the side ipsilateral to the
turn. During turning to one side, which usually occurred within one cycle, the
amplitude and duration of ipsilateral muscle burst activity as well as overall cycle
time increased significantly with increasing turn angle. In in vitro brain/spinal cord
preparations, brief electrical stimulation applied to the left side of the oral hood at
the onset of locomotor burst activity on the right side of the spinal cord produced
turninglike motor activity. During the perturbed cycle, the duration and amplitude
of the burst on the right as well as cycle time were significantly larger than during
preceding control cycles. In several lower vertebrates, unilateral stimulation in
brain stem locomotor regions elicits asymmetric, turninglike locomotor activity. In
the lamprey, unilateral chemical microstimulation in brain stem locomotor regions
elicited continuous asymmetric locomotor activity, but there was little change in
cycle time, as occurs during the single turning cycles in whole animals. The
descending mechanisms responsible for producing turning locomotor activity were
examined with the use of a computer model consisting of left and right phase
oscillators in the spinal cord that were coupled by net reciprocal inhibition. With
relatively weak reciprocal coupling, a brief unilateral descending excitatory input
to one oscillator produced effects ipsilaterally, but there was little effect on the
contralateral oscillator. Turninglike patterns could be produced by each of the
following modifications of the model: 1) unilateral descending input and relatively
strong reciprocal coupling; 2) unilateral descending input that phase shifted as
well as increased the amplitude of the waveform generated by an oscillator on one
side; and 3) brief descending modulatory inputs that excited the oscillator on one
side and inhibited the contralateral oscillator. In all three cases, there was an
increase in "burst" duration ipsilateral to the excitatory input and an increase in
cycle time, similar to turning locomotor activity in whole animals. It is likely that
turning maneuvers are mediated by descending modulatory inputs primarily to the
spinal oscillator networks, which control the timing of burst activity, but perhaps
also to motoneurons for axial musculature.
221. McGlinchey Berroth, R.; Bullis, D. P.; Milberg, W. P.; Verfaellie, M.; Alexander, M.;
D'Esposito, M. Assessment of neglect reveals dissociable behavioral but not
neuroanatomical subtypes. J-Int-Neuropsychol-Soc. 1996 Sep; 2(5): 441-51;
ISSN: 1355-6177.
ENGLAND. In the current study, we investigated whether standard assessment
techniques of visuospatial neglect are sensitive to detecting dissociable subtypes.
We administered a battery of tasks commonly used to detect the presence of
visuospatial neglect to 120 patients with unilateral right hemisphere infarcts and,
in most cases, performed a systematic analysis of their lesions to quantify and
localize brain damage. Using a factor analysis, we discovered seven relatively
independent constructs, three of which were specifically related to the presence of
left hemispatial neglect: Left Attentional Processing, Line Bisection, and Word
Reading. Impairments in two of these factors, Left Attentional Processing and
Line Bisection, occurred together in most cases but also occurred independently in
38 cases. There were no cases in whom Word Reading was present without
concomitant deficits in one or the other two factors. These three factors could not
be distinguished neuroanatomically; that is, lesions were equally likely in the
temporal/parietal cortex, dorsolateral frontal cortex, or in deep frontal structures.
These data confirm the notion that hemispatial neglect is a complex and
multifaceted disorder composed of cognitively independent processes. These
processes, however, cannot be dissociated neuroanatomically based on currently
available assessment techniques.
222. McIntyre, D. J.; Hennel, F.; Morris, P. G. SPARE: A robust method for magnetic
resonance imaging in inhomogeneous fields. J-Magn-Reson. 1998 Jan; 130(1): 58-
62; ISSN: 1090-7807.
UNITED-STATES. An imaging sequence based on a spin-echo train has been
developed which is free from geometric distortions in the imaging plane due to
main field inhomogeneity. Such inhomogeneities, and chemical shifts, cause only a
displacement in the selected slice, which is minimized by the use of high gradient
strengths and short radiofrequency pulses. Additionally, variations in the
radiofrequency field strength cause variations in the image amplitude but cause no
other artifacts. This allows the use of low-flip-angle refocusing pulses, reducing
the power deposition to levels which are safe in vivo at high field strengths. The
sequence was implemented on a Bruker whole-body 3T system. Example images
from a perfluorocarbon phantom and a human head are presented.. 0.
223. McKeefry, D. J.; Watson, J. D.; Frackowiak, R. S.; Fong, K.; Zeki, S. The activity in
human areas V1/V2, V3, and V5 during the perception of coherent and incoherent
motion. Neuroimage. 1997 Jan; 5(1): 1-12; ISSN: 1053-8119.
UNITED-STATES. We have used the technique of positron emission
tomography to study and compare the cortical activity produced when humans
view a pattern of small squares moving incoherently with respect to one another
and when the same pattern moves coherently and unidirectionally. A stationary
version of the stimulus acted as a control. Our choice of paradigm was inspired by
psychophysical models and physiological studies in the macaque monkey which
show that directionally selective cells in V5 respond optimally to unidirectional
coherent motion, whereas those of V1 respond to motion within their receptive
fields, regardless of the motion in surrounding parts. Our results show that human
V1/V2, V3, and V5 are all activated by both types of motion stimuli. Incoherent
motion, however, proved to be more effective than coherent motion in activating
V1/V2 and V5. Thus the higher perceptual salience of unidirectional coherent
motion in comparison to incoherent motion is not reflected by any increased
activation of human area V5.
224. McKeefry, D. J.; Zeki, S. The position and topography of the human colour centre as
revealed by functional magnetic resonance imaging. Brain. 1997 Dec; 120( Pt 12):
2229-42; ISSN: 0006-8950.
ENGLAND. We used a colour Mondrian--an abstract scene with no recognizable
objects--and its achromatic version to image the change in blood oxygenation in
the brains of 12 human subjects, with the aim of learning more about the position
and variability of the colour centre in the human brain. The results showed a
consistent association of colour stimulation with activation of an area that is
distinct from the primary visual areas, and lies in the ventral occipitotemporal
cortex; we refer to it as human V4. The position of human V4, as defined on
functional grounds, varies between individuals in absolute terms but is invariably
found on the lateral aspect of the collateral sulcus on the fusiform gyrus. There
was no indication of lingual gyral activation. In further studies designed to reveal
the topographic map within V4, we stimulated the superior and inferior visual
fields separately, using the same stimuli. We found that human V4 contains a
representation of both the superior and inferior visual fields. In addition, there
appears to be retinotopic organization of V4 with the superior visual field being
represented more medially on the fusiform gyrus and the inferior field more
laterally, the two areas abutting on one another. We find no evidence that suggests
the existence of a separate representation of the inferior hemifield for colour in
more dorsolateral regions of the occipital lobe.. 7782-44-7.
225. McKeefry, D. J.; Zeki, S. The position and topography of the human colour centre as
revealed by functional magnetic resonance imaging. Brain. 1997 Dec; 120( Pt 12):
2229-42; ISSN: 0006-8950.
ENGLAND. We used a colour Mondrian--an abstract scene with no recognizable
objects--and its achromatic version to image the change in blood oxygenation in
the brains of 12 human subjects, with the aim of learning more about the position
and variability of the colour centre in the human brain. The results showed a
consistent association of colour stimulation with activation of an area that is
distinct from the primary visual areas, and lies in the ventral occipitotemporal
cortex; we refer to it as human V4. The position of human V4, as defined on
functional grounds, varies between individuals in absolute terms but is invariably
found on the lateral aspect of the collateral sulcus on the fusiform gyrus. There
was no indication of lingual gyral activation. In further studies designed to reveal
the topographic map within V4, we stimulated the superior and inferior visual
fields separately, using the same stimuli. We found that human V4 contains a
representation of both the superior and inferior visual fields. In addition, there
appears to be retinotopic organization of V4 with the superior visual field being
represented more medially on the fusiform gyrus and the inferior field more
laterally, the two areas abutting on one another. We find no evidence that suggests
the existence of a separate representation of the inferior hemifield for colour in
more dorsolateral regions of the occipital lobe.. 7782-44-7.
226. Mega, M. S.; Thompson, P. M.; Cummings, J. L.; Back, C. L.; Xu, M. L.; Zohoori,
S.; Goldkorn, A.; Moussai, J.; Fairbanks, L.; Small, G. W.; Toga, A. W. Sulcal
variability in the Alzheimer's brain: correlations with cognition. Neurology. 1998
Jan; 50(1): 145-51; ISSN: 0028-3878.
UNITED-STATES. We mapped the three dimensional (3D) extents and
variability of selected sulci in the Alzheimer's brain and explored the relationship
between sulcal pattern and patient's cognitive performance. High-resolution MRIs
of 10 patients with probable Alzheimer's disease (AD) were linearly transformed
into a standard "normalized" 3D atlas (known as the Talairach coordinate system)
and, on each relevant slice, contours of the left and right Sylvian fissure, anterior
and posterior calcarine, callosal, parietooccipital, and cingulate sulci and the floor
of the temporal horn of the lateral ventricle were traced. These landmarks were
chosen because of their relative invariant location across individuals and because
they demarcate functional boundaries relevant in AD. The sulcal contours were
resolved into two-dimensional surfaces that cut through a brain volume. All 10
patients' sulcal surfaces were averaged to determine their mean spatial locations in
the Talairach coordinate system. The 3D spatial extents of each patient's sulci
were compared with their disease severity based on neuropsychological
performance. The 3D sulcal variability, within the "normalized" atlas space,
ranged from 4.0 mm for the left callosal sulcus to 9.1 mm for the left Sylvian
fissure. Significant correlations were found among the spatial extents for the
posterior floor of the right temporal horn of the lateral ventricle (r = -0.89, p <
0.001 for vertical extent) and right anterior calcarine sulcus (r = -0.75, p < 0.01 for
anterior-posterior extent) with copying ability of the Rey-Osterrieth Complex
Figure; the right anterior calcarine also had a significant relationship (r = -0.72, p =
0.02 for anterior-posterior extent) with performance on the Block Design subtest
from the Wechsler Adult Intelligence Scale-Revised. Verbal fluency performance
measured by the Controlled Oral Word Association Test was significantly related
to the left cingulate (r = 0.91, p < 0.001 for anterior-posterior extent, and r = -
0.82, p < 0.01 for vertical extent) and right cingulate (r = -0.72, p < or = 0.02 for
vertical extent) sulci. This exploratory study is the first to evaluate the
relationship between 3D sulcal variability and cognition; our preliminary findings
suggest that the 3D pattern of sulci in the AD brain is related to the severity of
the disease as reflected by cognitive performance. In the Talairach brain atlas,
sulcal variability, within an AD population, approaches 1 cm. This large
variability requires correction when functional imaging data are transformed into
the Talairach atlas space to "normalize" individual morphologic differences.
227. Mehta, Z.; Newcombe, F. Dissociable contributions of the two cerebral hemispheres
to judgments of line orientation. J-Int-Neuropsychol-Soc. 1996 Jul; 2(4): 335-9;
ISSN: 1355-6177.
ENGLAND. A previous study of the performance of men with chronic unilateral
focal brain lesions (due to wartime missile injury) on a standard test of line
orientation suggested a left hemisphere (LH) as well as a right hemisphere (RH)
contribution to visuospatial processing. The present study was designed to
fractionate the variables that could underlie this unexpected finding and thereby to
tease out the mechanisms involved in LH as compared with RH processing. A
simpler ("purer") version of the standard line orientation task was used, as were
two other versions in which matching in an array and matching with distractors
were measured. The findings confirmed the hypothesis of RH involvement in the
purer task of metric measurement and suggested that the LH has an important role
in keeping track decisions and updating decisions in more complex aspects of line
orientation judgment.
228. Mentis, M. J.; Alexander, G. E.; Grady, C. L.; Horwitz, B.; Krasuski, J.; Pietrini, P.;
Strassburger, T.; Hampel, H.; Schapiro, M. B.; Rapoport, S. I. Frequency
variation of a pattern-flash visual stimulus during PET differentially activates
brain from striate through frontal cortex. Neuroimage. 1997 Feb; 5(2): 116-28;
ISSN: 1053-8119.
UNITED-STATES. We evaluate regional cerebral blood flow (rCBF) in 19
healthy elderly subjects, mean age 64 +/- 11 (SD, years), during a passive visual
stimulus in which pattern-flash frequency was parametrically manipulated. Using
goggles with a grid of red lights imbedded into each lens, we performed five
positron emission tomography (PET) H2(15)O water scans on each subject at
alternating (left to right eye) flash frequencies of 0, 1, 4, 7, and 14 Hz. We found a
biphasic rising and falling rCBF response in the striate cortex (7 Hz peak) and left
anterior cingulate (4 Hz peak), 1 Hz activation in left middle temporal gyrus (V5),
monotonically increasing rCBF in posterior areas (lateral and inferior visual
association areas, Brodmann 18 and 19), and monotonically decreasing rCBF in
anterior areas (frontal, cingulate, and superior temporal) predominantly in right
hemisphere. We suggest the striate rCBF changes at all frequencies primarily
reflect lateral geniculate input, the middle temporal activation at 1 Hz reflects
perception of apparent motion, and the posterior extrastriate rCBF monotonic
increase represents a neural response to increasing luminance intensity and form
and color complexity that occur as pattern-flash frequency increases. The anterior
monotonic rCBF decrease may represent active cross-modal functional
suppression of brain areas irrelevant for processing the passive visual stimulus.
Pattern-flash rCBF responses were highly reproducible (no series effect), more so
in posterior than in anterior brain regions. The reproducibility and systematically
changing rCBF responses to this passive stimulus suggest that it could be
successfully used as a disease probe to evaluate neural function and drug effects in
cognitively impaired patients.
229. Merians, A. S.; Clark, M.; Poizner, H.; Macauley, B.; Gonzalez Rothi, L. J.; Heilman,
K. M. Visual-imitative dissociation apraxia. Neuropsychologia. 1997 Nov; 35(11):
1483-90; ISSN: 0028-3932.
ENGLAND. Liepmann posited that, in right handers, the left parietal lobe
contains movement formulas or representations. Therefore, performance failures
may be induced by degraded representations, a failure of these representations to
influence motor systems or a failure of stimuli to fully access these
representations. Imitation may help the performance of subjects with degraded
representations. However, patients who have impaired visual access to movement
representations may perform more poorly with imitation than to verbal command.
Trajectories of repetitive 'slicing' gestures made by a previously reported subject
(Raymer et al.) with an infarction in the left visual association cortex (left occipital
and inferior temporal lobe) that spared the parietal lobe were contrasted with
those of three apraxic subjects with lesions that included the left parietal lobe and
four non-brain-damaged control subjects. All subjects were asked to produce the
gesture to verbal command and to imitation. Movements of the left hand, wrist,
elbow and shoulder were digitized from neighboring views, reconstructed in three
dimensions, and analysed graphically and numerically. The apraxic subjects with
left parietal damage were unable to maintain the proper linearity and
spatiotemporal attributes of their wrist motions and showed interjoint
coordination deficits. Their deficits were most pronounced to verbal command,
with their movements improving though remaining poorly performed when they
imitated. The subject with the left occipital and inferior temporal lesion that
spared parietal cortex, however, showed an opposite pattern. This subject
exhibited close to normal performance when producing the movement to verbal
command, but significant deficits when imitating.
230. Mikkonen, M.; Soininen, H.; Pitkanen, A. Distribution of parvalbumin-, calretinin-,
and calbindin-D28k-immunoreactive neurons and fibers in the human entorhinal
cortex. J-Comp-Neurol. 1997 Nov 10; 388(1): 64-88; ISSN: 0021-9967.
UNITED-STATES. Parvalbumin, calretinin, and calbindin-D28k are calcium-
binding proteins that are located in largely nonoverlapping neuronal populations
in the brain. The authors studied the distribution of parvalbumin-, calretinin-, and
calbindin-D28k-immunoreactive (ir) cells, fibers, terminals, and neuropil in the
eight subfields of the human entorhinal cortex. The distribution of each of the
three calcium-binding proteins largely followed the cytoarchitectonic borders of
the eight entorhinal subfields, although the regional and laminar distributions of
the three proteins were segregated rather than overlapping. The highest density of
parvalbumin-ir neurons and terminals was found in the caudal and lateral subfields
of the entorhinal cortex. Calretinin and calbindin-D28k immunoreactivities were
high rostromedially, although a large number of calretinin and calbindin-D28k
neurons were also found in the caudal subfields. All parvalbumin-ir cells had a
morphological appearance of nonpyramidal neurons. Parvalbumin-ir terminals
formed basket-like formations around unstained somata and cartridges, suggesting
that parvalbumin neurons compose a subpopulation of gamma-aminobutyric acid
(GABA)ergic basket cells and chandelier cells, respectively. Although calretinin
and calbindin-D28k were also found in numerous nonpyramidal neurons, both
were also located in pyramidal-shaped neurons in layers V and VI (calretinin) and
in layers II and III (calbindin) of the entorhinal cortex, suggesting that they play
roles in projection neurons as well. Moreover, the high density of nonpyramidal
neurons containing calcium-binding proteins in layers II and III of the entorhinal
cortex suggests that they form an integral component of a network that controls
the entorhinal outputs to the hippocampus. Furthermore, the largely
nonoverlapping distributions of the parvalbumin-, calretinin-, and calbindin-ir
neuronal populations in the entorhinal cortex indicate that each of them may
modulate a different subset of topographically organized entorhinal outputs.. 0;
0; 0; 0.
231. Milner, B.; Johnsrude, I.; Crane, J. Right medial temporal-lobe contribution to object-
location memory. Philos-Trans-R-Soc-Lond-B-Biol-Sci. 1997 Oct 29; 352(1360):
1469-74; ISSN: 0962-8436.
ENGLAND. An important aspect of normal human memory, and one humans
share with many other species, is the ability to remember the location of objects
in their environment. There is by now strong evidence from the study of epileptic
patients undergoing brain surgery that right temporal-lobe lesions that encroach
extensively upon the hippocampal and parahippocampal gyrus impair the
delayed, but not the immediate, recall of the location of objects within a random
array. These findings have now been extended to a multiple-trial, spatial-array
learning task; by including not only patients tested after unilateral anterior
temporal lobectomy but also those with a selective left or right
amygdalohippocampectomy, it has been shown that the deficits associated with
right hippocampal lesions are not dependent upon conjoint damage to the lateral
temporal neocortex. Furthermore, the fact that on the learning task no group
differences were seen on Trial 1, at zero delay, strengthened the view that the
impairment was in the maintenance and subsequent retrieval of information rather
than in its initial encoding. These results left unresolved the question of whether
the deficit was in the mediation of object-place associations or whether it could be
reduced to a more general impairment in memory for location as such. Also left
unanswered was the neuroanatomical question as to the relative contributions of
the hippocampus and the parahippocampal gyrus to the performance of the
experimental tasks. These questions were addressed in two blood-flow activation
studies that made use of positron emission tomography (PET) and magnetic
resonance imaging (MRI) and incorporated computerized versions of object-
location and simple-location memory tasks. Taken together, the results point to a
special contribution from the anterior part of the right parahippocampal gyrus,
probably corresponding to the entorhinal cortex, to the retrieval of object-place
associations, a result consonant with neurophysiological findings in non-human
primates.
232. Mize, R. R.; Thouron, C.; Lucas, L.; Harlan, R. Semiautomatic image analysis for
grain counting in in situ hybridization experiments. Neuroimage. 1994 Jun; 1(3):
163-72; ISSN: 1053-8119.
UNITED-STATES. We have developed a computer image analysis procedure for
counting autoradiographic grains in in situ hybridization experiments. The
procedure automatically estimates the number of autoradiographic grains over
cells and measures cell number and size so that grain density per unit cell area can
be calculated. Advantages include the clear separation of grains and cells, using
chromatic and spatial filters to enhance the image; the use of gray level operators
to extract cells from grains; and the use of binary operators for separating apposed
or partially overlapping cells and grains. Comparison of manual and automated
grain counts revealed a significant correlation between human and computer
estimations of grain number. However, the automatic grain counting technique
consistently underestimated the number of grains when grain density was high.
Measures of the fractional area occupied by grains normalized by the average area
of a single grain were a better estimate at high grain densities. The procedure can
be modified easily to operate on most image analyzers.. 0; 0; 0; 0.
233. Moe, G. W.; Howard, R. J.; Grima, E. A.; Armstrong, P. W. How does intermittent
pacing modify the response to rapid ventricular pacing in experimental heart
failure? J-Card-Fail. 1995 Jun; 1(3): 223-8; ISSN: 1071-9164.
UNITED-STATES. Rapid ventricular pacing is widely accepted as a useful
model to produce heart failure. The heart failure is associated with reduced
myocardial energy stores and absence of cardiac hypertrophy. In this study, it
was hypothesized that a modification of the protocol to intermittent pacing
would permit time for partial recovery of myocardial energetics leading to
improved cardiac function and development of hypertrophy. Eight dogs
underwent conventional continuous right ventricular pacing to a biologic endpoint
of severe heart failure (group 1). Another eight dogs underwent an intermittent
pacing protocol over 7 weeks, consisting of 48-hour pacing alternating with 24-
hour sinus rhythm (group 2) so as to produce the same total exposure to
continuous pacing as in group 1. Six additional normal dogs were used as control
animals for tissue metabolic data. Although both paced groups had similar
directional changes in hemodynamic, neurohormonal, and echocardiographic
variables, the absolute increases in pulmonary capillary wedge and right atrial
pressures in group 2 (13 +/- 8 and 3 +/- 4 mmHg, respectively) were less marked
than in group 1 (29 +/- 5 and 12 +/- 4 mmHg, respectively; both P = .002). Group
2 also had a more modest rise in plasma atrial natriuretic peptide and
norepinephrine concentrations. There was no significant increase, however, in left
ventricular mass in either group, and myocardial adenosine 5'-triphosphate levels
were reduced to a similar extent compared to the control animals. Intermittent
pacing produces a less advanced syndrome of heart failure than continuous pacing.
Furthermore, the data suggest that reduced energy stores are not the predominant
mechanism for impaired cardiac function, although they may contribute to the
failure to hypertrophy in this model.. 0; 114471-18-0; 85637-73-6.
234. Moffat, S. D.; Hampson, E.; Wickett, J. C.; Vernon, P. A.; Lee, D. H. Testosterone is
correlated with regional morphology of the human corpus callosum. Brain-Res.
1997 Sep 5; 767(2): 297-304; ISSN: 0006-8993.
NETHERLANDS. Theoretical speculation in humans (S.F. Witelson,
Psychoneuroendocrinology 16 (1991) 131-153) and empirical findings in animals
(R.H. Fitch, P.E. Cowell, L.M. Schrott, V.H. Denenberg, Int. J. Dev. Neurosci. 9
(1991) 35-38) suggest that testosterone (T) may play a significant role in the
development of the corpus callosum (CC). However, there are currently no
empirical studies directly relating T concentrations to callosal morphology in
humans. The purpose of the present study was to investigate the relationship
between free T concentrations as determined by radioimmunoassay, and the mid-
sagittal area of the corpus callosum, as determined by magnetic resonance imaging
(MRI). Subjects were 68 young adult (20-35 years), neurologically normal, right-
handed males. All subjects underwent MRI and provided two samples of saliva
for radioimmunoassay of T and cortisol. Anatomical regions of interest included
total brain volume, left and right hemisphere volume and regional areas of the CC.
CC regions were defined using two different measurement techniques, each
dividing the CC into six sub-sections. Anatomical measurements were performed
blind with respect to the hormone levels of subjects. A significant positive
correlation between T concentration and cross-sectional area of the posterior body
of the CC was found. This finding was consistent across the two measurement
techniques and was not attributable to individual differences in total brain volume.
All correlations between cortisol and CC sub-regions were non-significant. The
results of this study are consistent with the notion that T, at an earlier stage in
development, may play a significant role in modulating cortical/callosal
architecture in humans.. 50-23-7; 57-85-2.
235. Moffat, S. D.; Hampson, E.; Wickett, J. C.; Vernon, P. A.; Lee, D. H. Testosterone is
correlated with regional morphology of the human corpus callosum. Brain-Res.
1997 Sep 5; 767(2): 297-304; ISSN: 0006-8993.
NETHERLANDS. Theoretical speculation in humans (S.F. Witelson,
Psychoneuroendocrinology 16 (1991) 131-153) and empirical findings in animals
(R.H. Fitch, P.E. Cowell, L.M. Schrott, V.H. Denenberg, Int. J. Dev. Neurosci. 9
(1991) 35-38) suggest that testosterone (T) may play a significant role in the
development of the corpus callosum (CC). However, there are currently no
empirical studies directly relating T concentrations to callosal morphology in
humans. The purpose of the present study was to investigate the relationship
between free T concentrations as determined by radioimmunoassay, and the mid-
sagittal area of the corpus callosum, as determined by magnetic resonance imaging
(MRI). Subjects were 68 young adult (20-35 years), neurologically normal, right-
handed males. All subjects underwent MRI and provided two samples of saliva
for radioimmunoassay of T and cortisol. Anatomical regions of interest included
total brain volume, left and right hemisphere volume and regional areas of the CC.
CC regions were defined using two different measurement techniques, each
dividing the CC into six sub-sections. Anatomical measurements were performed
blind with respect to the hormone levels of subjects. A significant positive
correlation between T concentration and cross-sectional area of the posterior body
of the CC was found. This finding was consistent across the two measurement
techniques and was not attributable to individual differences in total brain volume.
All correlations between cortisol and CC sub-regions were non-significant. The
results of this study are consistent with the notion that T, at an earlier stage in
development, may play a significant role in modulating cortical/callosal
architecture in humans.. 50-23-7; 57-85-2.
236. Moller, H. E.; Vollmer Haase, J.; Wiedermann, D.; Schuierer, G. Localized proton
NMR spectroscopy in the striatum of patients with idiopathic spasmodic
torticollis. Magn-Reson-Med. 1998 Feb; 39(2): 309-12; ISSN: 0740-3194.
UNITED-STATES. Single voxel proton spectroscopy was used to study brain
metabolism in idiopathic spasmodic torticollis. Peak metabolite ratios in long echo
time (135 ms) spectra were evaluated in the basal ganglia of 16 patients (29-65
years). Eight of them were untreated; the other eight were examined 4-6 weeks
after administration of botulinum toxin type A. As compared with 60 control
spectra, patients showed a significant, therapy-resistant decrease in N-acetyl-L-
aspartate (NAA)/choline (Cho). NAA/creatine (Cr) and Cho/Cr were close to
normal in the post-treatment group but significantly reduced in untreated patients.
This result is consistent with the hypothesis that striatal Cr is reversibly elevated
in chronic muscle stimulation. The right and left striatum were affected to the
same extent.. 0; 0; 56-84-8; 57-00-1; 62-49-7; 997-55-7.
237. Morel, A.; Magnin, M.; Jeanmonod, D. Multiarchitectonic and stereotactic atlas of
the human thalamus. J-Comp-Neurol. 1997 Nov 3; 387(4): 588-630; ISSN: 0021-
9967.
UNITED-STATES. To improve anatomical definition and stereotactic precision
of thalamic targets in neurosurgical treatments of chronic functional disorders, a
new atlas of the human thalamus has been developed. This atlas is based on
multiarchitectonic parcellation in sections parallel or perpendicular to the standard
intercommissural reference plane. The calcium-binding proteins parvalbumin (PV),
calbindin D-28K (CB), and calretinin (CR) were used as neurochemical markers to
further characterize thalamic nuclei and delimit subterritories of functional
significance for stereotactic explorations. Their overall distribution reveals a
subcompartmentalization of thalamic nuclei into several groups. Predominant PV
immunostaining characterizes primary somatosensory, visual and auditory nuclei,
the ventral lateral posterior nucleus, reticular nucleus (R), and to a lesser degree
also, lateral part of the centre median nucleus, and anterior, lateral, and inferior
divisions of the pulvinar complex. In contrast, CB immunoreactivity is prevalent
in medial thalamic nuclei (intralaminar and midline), the posterior complex, ventral
posterior inferior nucleus, the ventral lateral anterior nucleus, ventral anterior, and
ventral medial nuclei. The complementary distributions of PV and CB appear to
correlate with distinct lemniscal and spinothalamic somatosensory pathways and
to cerebellar and pallidal motor territories, respectively. Calretinin, while
overlapping with CB in medial thalamic territories, is also expressed in R and
limbic associated anterior group nuclei that contain little or no CB. Preliminary
analysis indicates that interindividual nuclear variations cannot easily be taken
into account by standardization procedures. Nevertheless, some corrections in
antero-posterior coordinates in relation to different intercommissural distances are
proposed.. 0; 0; 0; 0.
238. Moser, E.; Diemling, M.; Baumgartner, R. Fuzzy clustering of gradient-echo
functional MRI in the human visual cortex. Part II: quantification. J-Magn-Reson-
Imaging. 1997 Nov; 7(6): 1102-8; ISSN: 1053-1807.
UNITED-STATES. Fuzzy cluster analysis (FCA) is a new exploratory method
for analyzing fMRI data. Using simulated functional MRI (fMRI) data, the
performance of FCA, as implemented in the software package Evident, was tested
and a quantitative comparison with correlation analysis is presented. Furthermore,
the fMRI model fit allows separation and quantification of flow and blood oxygen
level dependent (BOLD) contributions in the human visual cortex. In gradient-
recalled echo fMRI at 1.5 T (TR = 60 ms, TE = 42 ms, radiofrequency excitation
flip angle [theta] = 10 degrees-60 degrees) total signal enhancement in the human
visual cortex, ie, flow-enhanced BOLD plus inflow contributions, on average
varies from 5% to 10% in or close to the visual cortex (average cerebral blood
volume [CBV] = 4%) and from 100% to 20% in areas containing medium-sized
vessels (ie, average CBV = 12% per voxel), respectively. Inflow enhancement,
however, is restricted to intravascular space (= CBV) and increases with
increasing radiofrequency (RF) flip angle, whereas BOLD contributions may be
obtained from a region up to three times larger and, applying an unspoiled
gradient-echo (GRE) sequence, also show a flip angle dependency with a
minimum at approximately 30 degrees. This result suggests that a localized
hemodynamic response from the microvasculature at 1.5 T may be extracted via
fuzzy clustering. In summary, fuzzy clustering of fMRI data, as realized in the
Evident software, is a robust and efficient method to (a) separate functional brain
activation from noise or other sources resulting in time-dependent signal changes
as proven by simulated fMRI data analysis and in vivo data from the visual
cortex, and (b) allows separation of different levels of activation even if the
temporal pattern is indistinguishable. Combining fuzzy cluster separation of brain
activation with appropriate model calculations allows quantification of flow and
(flow-enhanced) BOLD contributions in areas with different vascularization.
239. Mullaney, P. B.; Jacquemin, C.; Abboud, E.; Karcioglu, Z. A. Tuberous sclerosis in
infancy. J-Pediatr-Ophthalmol-Strabismus. 1997 Nov; 34(6): 372-5; ISSN: 0191-
3913.
UNITED-STATES. PURPOSE: To report two infants with tuberous sclerosis
who initially were considered to have retinoblastoma. PATIENTS AND
METHODS: An 8-day-old infant was referred with small tumors in the posterior
poles of both eyes. A left microphthalmos with ciliochoroidal coloboma was
present. Computed tomographic (CT) scanning of the brain showed scattered
high-density subependymal foci in the lateral ventricle thought to be consistent
with calcification resulting from intrauterine viral infection. Argon laser
photocoagulation was applied to lesions in the right eye. Because one tumor was
situated on the retina straddling the coloboma in the left eye, external beam
radiotherapy was administered. A 5-month-old girl presented with a large mass in
a left microphthalmic eye. Calcification was present on B-scan ultrasonography
and CT scanning. Vitreous seeding was noted to originate from the tumor. The
contralateral eye manifested four small gray translucent retinal tumors in the
posterior pole. CT scan and magnetic resonance imaging (MRI) revealed multiple
periventricular subependymal lesions, including one at the foramen of Monro.
RESULTS: Repeated examinations in the younger child under anesthesia revealed
small new retinal lesions that appeared to enlarge gradually. She developed
intractable seizures and her electroencephalogram revealed a modified
hypsarrhythmia recording. A careful review of available CT scans and MRI
displays suggested the diagnosis of tuberous sclerosis. The child's most recent
examination under anesthesia revealed multiple newly developed hamartomas. In
the older child, prompt diagnosis was made on the basis of the intracranial
radiologic findings. CONCLUSION: Retinal hamartoma presentation may vary in
infancy. Small, initially fleck-like gliotic lesions appear to enlarge gradually and
eventually may form gray, translucent tumors. Large astrocytic hamartomas of the
retina associated with tuberous sclerosis may resemble retinoblastoma,
particularly if the mass is large, calcified, and associated with vitreous seeding.
Although ophthalmic presentation was reminiscent of retinoblastoma in both
patients, radiologic evidence of subependymal hamartomas pathognomic for
tuberous sclerosis helped establish the correct diagnosis. We stress the importance
of intracranial radiologic findings in this regard.
240. Nagaya, N.; Nishikimi, T.; Okano, Y.; Uematsu, M.; Satoh, T.; Kyotani, S.;
Kuribayashi, S.; Hamada, S.; Kakishita, M.; Nakanishi, N.; Takamiya, M.;
Kunieda, T.; Matsuo, H.; Kangawa, K. Plasma brain natriuretic peptide levels
increase in proportion to the extent of right ventricular dysfunction in pulmonary
hypertension. J-Am-Coll-Cardiol. 1998 Jan; 31(1): 202-8; ISSN: 0735-1097.
UNITED-STATES. OBJECTIVES: This study sought to investigate the
influence of right ventricular (RV) hemodynamic variables and function on the
secretion of brain natriuretic peptide (BNP) in patients with isolated RV overload.
BACKGROUND: Plasma BNP is known to increase in proportion to the degree
of left ventricular (LV) overload. However, whether BNP secretion is also
regulated in the presence of RV overload remains unknown. METHODS: Plasma
BNP and atrial natriuretic peptide (ANP) levels in the pulmonary artery were
measured in 44 patients with RV overload: 18 with RV volume overload (RVVO)
due to atrial septal defect and 26 with RV pressure overload (RVPO) due to
primary or thromboembolic pulmonary hypertension. Right heart catheterization
was performed in all patients. RV and LV ejection fraction, myocardial mass and
volume of the four chambers were determined by using electron beam computed
tomography. RESULTS: Although both plasma BNP and ANP levels were
significantly elevated in patients with RV overload compared with values in
control subjects, plasma BNP and the BNP/ANP ratio were significantly higher in
patients with RVPO than with RVVO (BNP 294 +/- 72 vs. 48 +/- 14 pg/ml;
BNP/ANP 1.6 +/- 0.2 vs. 0.8 +/- 0.2, both p < 0.05). Plasma BNP correlated
positively with mean pulmonary artery pressure (r = 0.73), total pulmonary
resistance (r = 0.79), mean right atrial pressure (r = 0.79), RV end-diastolic
pressure (r = 0.76) and RV myocardial mass (r = 0.71); it correlated negatively
with cardiac output (r = -0.33) and RV ejection fraction (r = -0.71). Plasma BNP
significantly decreased from 315 +/- 120 to 144 +/- 54 pg/ml with long-term
vasodilator therapy (total pulmonary resistance decreased from 23 +/- 4 to 15 +/-
3 Wood U). CONCLUSIONS: Plasma BNP increases in proportion to the extent
of RV dysfunction in pulmonary hypertension.. 0; 114471-18-0; 85637-73-6.
241. Nakayama, Y.; Omote, K.; Chiba, S.; Satoh, O.; Matsumoto, M.; Namiki, A. [A case
of right cranial polyneuropathy following the onset of herpetic eruptions
associated with severe pain on the left cranial and cervical regions]. Masui. 1997
Sep; 46(9): 1230-4; ISSN: 0021-4892.
JAPAN. We describe a case presenting herpetic eruptions and pain in the left
cranial and cervical regions, followed by right cranial polyneuropathy. The
patient, a 66-yr-old male, developed a diphasic syndrome which was first
characterized by herpetic eruptions on the whole of his left cranial and cervical
regions with severe pain and left facial nerve palsy. Two weeks later, right
multiple cranial nerve palsies of III, V, and VII and an increase in CSF protein
appeared in a second phase. Neuroimaging technique (MRI) did not provide any
evidence of brain involvement. The immediate use of steroid therapy led to
improvement of the symptoms of cranial polyneuropathy. The clinical course
suggests that reactivation of a latent herpes simplex virus may have been the
etiologic cause of the cranial polyneuropathy. Steroid therapy should be applied
to the treatment of cranial polyneuropathy in patients showing a similar pattern
to this case.. 0; 50-24-8.
242. Natsopoulos, D.; Katsarou, Z.; Alevriadou, A.; Grouios, G.; Bostantzopoulou, S.;
Mentenopoulos, G. Deductive and inductive reasoning in Parkinson's disease
patients and normal controls: review and experimental evidence. Cortex. 1997 Sep;
33(3): 463-81; ISSN: 0010-9452.
ITALY. In the present study, fifty-four subjects were tested; twenty-seven with
idiopathic Parkinson's disease and twenty-seven normal controls matched in age,
education, verbal ability, level of depression, sex and socio-economic status. The
subjects were tested on eight tasks. Five of the tasks were the classic deductive
reasoning syllogisms, modus ponens, modus tollendo tollens, affirming the
consequent, denying the antecedent and three-term series problems phrased in a
factual context (brief scripts). Three of the tasks were inductive reasoning,
including logical inferences, metaphors and similes. All tasks were presented to
subjects in a multiple choice format. The results, overall, have shown
nonsignificant differences between the two groups in deductive and inductive
reasoning, an ability traditionally associated with frontal lobes involvement. Of
the comparisons performed between subgroups of the patients and normal
controls concerning disease duration, disease onset and predominant involvement
of the left and/or right hemisphere, significant differences were found between
patients with earlier disease onset and normal controls and between bilaterally
affected patients and normal controls, demonstrating an additive effect of
lateralization to reasoning ability.
243. Naveen, K. V.; Nagarathna, R.; Nagendra, H. R.; Telles, S. Yoga breathing through a
particular nostril increases spatial memory scores without lateralized effects.
Psychol-Rep. 1997 Oct; 81(2): 555-61; ISSN: 0033-2941.
UNITED-STATES. Uninostril breathing facilitates the performance on spatial
and verbal cognitive tasks, said to be right and left brain functions, respectively.
Since hemispheric memory functions are also known to be lateralized, the present
study assessed the effects of uninostril breathing on the performance in verbal and
spatial memory tests. School children (N = 108 whose ages ranged from 10 to 17
years) were randomly assigned to four groups. Each group practiced a specific
yoga breathing technique: (i) right nostril breathing, (ii) left nostril breathing, (iii)
alternate nostril breathing, or (iv) breath awareness without manipulation of
nostrils. These techniques were practiced for 10 days. Verbal and spatial memory
was assessed initially and after 10 days. An age-matched control group of 27 were
similarly assessed. All 4 trained groups showed a significant increase in spatial
test scores at retest, but the control group showed no change. Average increase in
spatial memory scores for the trained groups was 84%. It appears yoga breathing
increases spatial rather than verbal scores, without a lateralized effect.
244. Nerkelun, S.; Kellermann, S.; Nenning, H. [Acute blindness caused by fungal infection
in chronic myeloid leukemia]. Akute Erblindung durch Pilzinfektion bei chronisch
myeloischer Leukamie. Klin-Monatsbl-Augenheilkd. 1997 Oct; 211(4): 272-4;
ISSN: 0023-2165.
GERMANY. PATIENT: A 35-year-old man had suffered from leukemia since
September 1990. A transplantation of bone marrow was carried out in February
1994. He developed a graft-versus-host disease in November 1995. In December
1995 a keratoplasty was necessary because of a perforated corneal ulcer. 17 days
later the patient noted a complete loss of vision, first in the left and one day later
in the right eye. The optic nerve head was white and the retina looked ischaemic
like in central retinal artery occlusion. A hypodensic area was found in the frontal
brain reaching up to the optic chiasm in computer tomography. Inspite of
intensive treatment the immunosuppressed patient died 4 days after he had
become blind. Autopsy showed a mycotic infiltration by mucormycosis of the
brain and the right optic nerve sheath. This human- pathogenic fungal infection
belongs to the group of mould as well as aspergillus. CONCLUSION: Mycosis
should be considered in the differential diagnosis of acute visual loss in
immunosuppressed patients.
245. Neville, H. J.; Bavelier, D.; Corina, D.; Rauschecker, J.; Karni, A.; Lalwani, A.; Braun,
A.; Clark, V.; Jezzard, P.; Turner, R. Cerebral organization for language in deaf
and hearing subjects: biological constraints and effects of experience. Proc-Natl-
Acad-Sci-U-S-A. 1998 Feb 3; 95(3): 922-9; ISSN: 0027-8424.
UNITED-STATES. Cerebral organization during sentence processing in English
and in American Sign Language (ASL) was characterized by employing functional
magnetic resonance imaging (fMRI) at 4 T. Effects of deafness, age of language
acquisition, and bilingualism were assessed by comparing results from (i) normally
hearing, monolingual, native speakers of English, (ii) congenitally, genetically deaf,
native signers of ASL who learned English late and through the visual modality,
and (iii) normally hearing bilinguals who were native signers of ASL and speakers
of English. All groups, hearing and deaf, processing their native language, English
or ASL, displayed strong and repeated activation within classical language areas of
the left hemisphere. Deaf subjects reading English did not display activation in
these regions. These results suggest that the early acquisition of a natural language
is important in the expression of the strong bias for these areas to mediate
language, independently of the form of the language. In addition, native signers,
hearing and deaf, displayed extensive activation of homologous areas within the
right hemisphere, indicating that the specific processing requirements of the
language also in part determine the organization of the language systems of the
brain.
246. Nizet, V.; Kim, K. S.; Stins, M.; Jonas, M.; Chi, E. Y.; Nguyen, D.; Rubens, C. E.
Invasion of brain microvascular endothelial cells by group B streptococci. Infect-
Immun. 1997 Dec; 65(12): 5074-81; ISSN: 0019-9567.
UNITED-STATES. Group B streptococci (GBS) are the leading cause of
meningitis in newborns. Although meningitis develops following bacteremia, the
precise mechanism or mechanisms whereby GBS leave the bloodstream and gain
access to the central nervous system (CNS) are not known. We hypothesized that
GBS produce meningitis because of a unique capacity to invade human brain
microvascular endothelial cells (BMEC), the single-cell layer which constitutes the
blood-brain barrier. In order to test this hypothesis, we developed an in vitro
model with BMEC isolated from a human, immortalized by simian virus 40
transformation, and propagated in tissue culture monolayers. GBS invasion of
BMEC monolayers was demonstrated by electron microscopy. Intracellular GBS
were found within membrane-bound vacuoles, suggesting the organism induced its
own endocytic uptake. GBS invasion of BMEC was quantified with a gentamicin
protection assay. Serotype III strains, which account for the majority of CNS
isolates, invaded BMEC more efficiently than strains from other common GBS
serotypes. GBS survived within BMEC for up to 20 h without significant
intracellular replication. GBS invasion of BMEC required active bacterial DNA,
RNA, and protein synthesis, as well as microfilament and microtubule elements of
the eukaryotic cytoskeleton. The polysaccharide capsule of GBS attenuated the
invasive ability of the organism. At high bacterial densities, GBS invasion of
BMEC was accompanied by evidence of cellular injury; this cytotoxicity was
correlated to beta-hemolysin production by the bacterium. Finally, GBS
demonstrated transcytosis across intact, polar BMEC monolayers grown on
Transwell membranes. GBS invasion of BMEC may be a primary step in the
pathogenesis of meningitis, allowing bacteria access to the CNS by transcytosis or
by injury and disruption of the endothelial blood-brain barrier.
247. Noachtar, S.; Holthausen, H.; Luders, H. O. Epileptic negative myoclonus. Subdural
EEG recordings indicate a postcentral generator. Neurology. 1997 Dec; 49(6):
1534-7; ISSN: 0028-3878.
UNITED-STATES. We report a patient with epileptic negative myoclonus
(ENM) presenting as status epilepticus of the right arm. The etiology was a
cortical malformation in the contralateral postcentral gyrus. Electrical stimulation
of the right median nerve revealed giant surface somatosensory evoked potentials.
Subdural recordings, performed to plan epilepsy surgery, demonstrated that the
epileptogenic zone was in the left postcentral gyrus. Repetitive left postcentral
spikes were consistently followed by an EMG silent period in the right arm with
a latency of about 20 to 30 msec. The silent period in the EMG reflected the
negative myoclonus and lasted 30 to 340 msec, mostly between 100 and 200
msec. Spikes in other regions of the cortex did not elicit ENM. The amplitude and
duration of the spikes correlated with the EMG silent period: the more cortex
involved in the spike generation, the longer the duration of the silent period. This
suggests that epileptic activation of postcentral cortex leads to an inhibition of
tonic activity of motor neurons. Focal ENM may be related to a hyperexcitability
of the postcentral cortex.
248. Nohara, C.; Matsumine, H.; Suzuki, K.; Saito, A.; Ohtaka, M.; Mori, H.; Suda, K.;
Kondo, T.; Hayakawa, M.; Kanai, J.; Mizuno, Y. [(Neurological CPC-59). A 65-
year-old man with a history of gastric cancer who presented progressive loss of
vision, memory loss and consciousness disturbance (clinical conference)]. No-To-
Shinkei. 1997 Nov; 49(11): 1041-51; ISSN: 0006-8969.
JAPAN. We report a 65-year-old man with progressive loss of vision and
consciousness disturbance. The patient was well until his age of 63 when he was
found to have a gastric cancer. He was treated by the tumor resection and
chemotherapy; he was apparently well, but hepatic metastases were found in the
next year (1996). In June, 1996, he noted an onset of blurred vision more on the
left. He was admitted to the ophthalmology service of our hospital on July 14,
1996. His vision was 0.8 on the right and 0.15 on the left. He was treated with
oral prednisolone with slight improvement. He was also found to have IgM
kappa-type monoclonal gammopathy; Bence-Jones protein was positive and a
bone marrow aspiration revealed that approximately 10% of bone marrow cells
were atypical plasma cells. His vision had progressively got worse and he became
blind by the end of October 1996. A chest X-ray and cranial CT scan revealed
multiple abnormal nodular densities. In the middle of November 1996, he became
confused, disoriented and agitated. His mental symptoms had progressively
became worse, and a neurologic consultation was asked on December 10, 1996.
Neurologic examination revealed that he was somnolent with decreased attention
to his surroundings. He showed marked disorientation and memory loss. Higher
cerebral functions appeared intact. He was able to recognize only light and dark.
Pupils were moderately dilated with very sluggish light reflex remained. Vertical
gaze was moderately restricted and horizontal nystagmus was noted upon left and
right lateral gaze. The remaining of the neurologic examination were unremarkable.
General physical examination revealed hepatosplenomegaly; the liver was
palpable by 3 cm below the right costal margin. Laboratory examination revealed
anemia (Hb10.1 g/dl) and thrombocytopenia (43,000/microliter). A cranial CT
scan and MRI revealed a mass lesion in involving the chiasmatic and bilateral
hypothalamic areas. The tumor showed intense homogeneous enhancement after
Gd-DTPA infusion. The patient was treated with dexamethasone and radiation.
After 9 Gray radiation, he showed deterioration in the sensorium; a cranial CT
scan revealed a hydrocephalus of the right ventricle with the midline shift towards
left. The radiation was discontinued. The subsequent clinical course was
complicated by aspiration pneumonia and thrombocytopenia. He expired on
January 4, 1997. The patient was discussed in a neurological CPC and the chief
discussant arrived at the conclusion that the patient had systemic malignant
lymphoma with metastasis to the brain judging from the characteristics of MRI
and CT findings. Opinions were divided between malignant lymphoma and
metastatic brain tumor. Post-mortem examination revealed plasmacytoid
lymphocytic infiltration in the bone marrow. Immunologically, these cells were
positive for IgM and kappa-type light chain. These plasmacytic infiltrations were
seen in the lungs and lymph nodes. These findings were consistent with the
diagnosis of Waldenstrom's macroglobulinemia. In the liver metastatic cancer
tissues were seen; microscopic pictures were essentially similar to those of
resected gastric cancer. No local recidive was noted in the stomach. In the central
nervous system, a necrotic tissue was involving the hypothalamic area bilaterally;
no clear neoplastic cells were found, however, lymphocytic and plasmacytic
infiltrations were seen in the perivascular space. In the optic nerves, loss of
myelin and axons were seen. These findings most likely mass formation from
macroglobulinemia which underwent necrotic change after radiation. Mass
formation in the brain is rare for Waldenstrom's macroglobulinemia, although it has
been reported. The relation between gastric cancer and macroglobulinemia in this
patient is unclear.
249. Ohnishi, M.; Kusakawa, N.; Masaki, S.; Honda, K.; Hayashi, N.; Shimada, Y.;
Fujimoto, I.; Hirao, K. Measurement of hemodynamics of auditory cortex using
magnetoencephalography and near infrared spectroscopy. Acta-Otolaryngol-
Suppl-Stockh. 1997; 532: 129-31; ISSN: 0365-5237.
NORWAY. Near infrared (NIR) spectroscopy, a non-invasive optical method for
monitoring hemodynamics, was applied to record evoked auditory response of the
human brain. Our newly developed system detected the amount of oxygenated
and deoxygenated hemoglobin in the area of the local brain located beneath the
probes. In the study, we used magnetoencephalography (MEG) and NIR
spectroscopy to observe the blood component change near the auditory cortex.
The sound stimulus of 1 kHz sine wave at 70 dB SPL was used to elicit evoked
responses in both experiments. The active region of the auditory cortex was
determined by MEG, and the same area was examined by the NIR system. The
results from the NIR experiments showed significant increases of total hemoglobin
and deoxygenated hemoglobin, indicating that both blood flow and oxygen
consumption at the cortical area increased in response to the sound stimuli. The
NIR recordings at the two different depths revealed that the increases of local
blood flow and oxygen consumption were observed at depths ranging between 20
and 30 mm from the scalp.
250. Ohtagaki, A.; Maeoka, Y.; Shiota, M.; Koeda, T. [A case of learning-disabled child
with a white matter lesion in the left parietal lobe]. No-To-Hattatsu. 1998 Jan;
30(1): 69-74; ISSN: 0029-0831.
JAPAN. We reported a learning-disabled boy, 7-year-old and right handedness,
who was similar to developmental Gerstmann syndrome. Dyscalcuria, right-left
disorientation, dysgraphia and finger agnosia were correlated with his sequential
disorder which was clearly presented by Kaufman Assessment Battery for
Children. In this case, a small infarcted lesion was found in the white matter near
the left semioval center on MRI. Hypoperfusion of left parietal lobe was also
detected by SPECT. The hemisphere dominant in language was assumed to be on
the left side by dichotic listening test. We suggested that left parietal lesion was
associated with his higher cortical dysfunction.
251. Ohtomo, S.; Nakasato, N.; Kawamura, T.; Kanno, A.; Seki, K.; Fujita, S.; Shimizu,
H.; Fujiwara, S.; Yoshimoto, T. Correspondence of anatomy and function in the
human digit sensory cortex revealed by an MRI-linked whole-head MEG system.
Electroencephalogr-Clin-Neurophysiol-Suppl. 1996; 47: 91-5; ISSN: 0424-8155.
IRELAND.
252. Ojemann, J. G.; Neil, J. M.; MacLeod, A. M.; Silbergeld, D. L.; Dacey, RG Jr;
Petersen, S. E.; Raichle, M. E. Increased functional vascular response in the region
of a glioma. J-Cereb-Blood-Flow-Metab. 1998 Feb; 18(2): 148-53; ISSN: 0271-
678X.
UNITED-STATES. Functional imaging of a language task using positron
emission tomography was performed as part of the preoperative assessment of a
patient with a left supplementary motor area (SMA) tumor. Positron emission
tomography scans were obtained during language tasks (verb generation and word
reading of visually presented nouns) that normally lead to increased blood flow in
the SMA relative to a control condition (visual fixation). In the patient, the normal
SMA response was an order of magnitude larger in the region of the tumor. Other
regions, such as left inferior frontal cortex and right cerebellum, showed equivalent
activation in the patient and normal subjects. Histopathologic study revealed an
anaplastic astrocytoma. Thus, this exaggerated vascular response to local neuronal
activation occurred in the setting of a proliferation of glial cells. This is consistent
with models of coupling of regional CBF and neuronal activity that implicate glia
as the mediator between neurons and vasculature. The concept that tumoral
disruption of normal vascular responses could, in some cases, potentially enhance
rather than dampen the response is proposed.
253. Ono, J.; Harada, K.; Kodaka, R.; Ishida, M.; Okada, S. Regional cortical dysplasia
associated with suspected hypomelanosis of Ito. Pediatr-Neurol. 1997 Oct; 17(3):
252-4; ISSN: 0887-8994.
UNITED-STATES. A 15-year-old girl with epilepsy, whose skin lesions were
reminiscent of hypomelanosis of Ito, is reported. She manifested hypopigmented
linear streaks on her upper and lower limbs. Brain magnetic resonance imaging
examinations demonstrated poor differentiation of cerebral gray and white matter
of her left occipital lobe, with accompanying gliosis. This region also revealed
narrowing of sulci, considered to be mass effect. In this region, almost continuous
spike discharges were evident on electroencephalograms, and low-perfusion status
was observed on single photon emission computed tomography at rest. She also
manifested right lower homonymous quadrant anopsia, which may have its origin
in the lesion detected, which appeared to be a migration disorder of neuroblasts in
our patient, suggesting that the spectrum of hypomelanosis of Ito might be
involved.
254. Ottaviani, F.; Di Girolamo, S.; Briglia, G.; De Rossi, G.; Di Giuda, D.; Di Nardo, W.
Tonotopic organization of human auditory cortex analyzed by SPET. Audiology.
1997 Sep; 36(5): 241-8; ISSN: 0020-6091.
FRANCE. Single photon emission tomography (SPET) was used to map blood
flow increases in the temporal and parietal cortex of 16 normally-hearing subjects
after auditory stimulation. Eight subjects were stimulated with a multifrequency
40 dB HL pure tone at 250, 500, 1000, 2000, 4000 Hz, each frequency varying
every 30 s. Single 500 Hz pure tones at 40 dB HL were delivered to the remainder
of the subjects. Five bilaterally deaf subjects were used as controls. Marked
cerebral flow increase following acoustic stimulation with a significantly prevalent
activation of the contralateral temporal cortex was achieved (p < 0.001).
According to the tonotopic organization of the human auditory cortex, low
monofrequency stimulation activated the most lateral sagittal tomograms (from
48.75 to 56.25 mm laterally to the brain midline) only, while multifrequency
stimuli activated all sagittal tomograms (from 18.75 to 56.25 mm). On the basis of
these results, it is likely that SPET is able to give real information on the cortical
distribution of the auditory frequency range, taking into account the number and
position of the activated slices. Further clinical investigations in order to define
the relationships among blood flow cortical increases, stimulus intensity and
auditory threshold, are in progress.
255. Owen, A. M. Cognitive planning in humans: neuropsychological, neuroanatomical and
neuropharmacological perspectives. Prog-Neurobiol. 1997 Nov; 53(4): 431-50;
ISSN: 0301-0082.
ENGLAND. In recent years, considerable progress has been made in
understanding the cognitive and neuroanatomical basis of high-level planning
behaviour through a combination of neuropsychological, neuropharmacological
and functional neuroimaging approaches. In this article, early evidence suggesting a
relationship between planning impairments and damage to the frontal lobe is
reviewed and several contemporary studies of planning behaviour in patients with
circumscribed frontal lobe excisions are described in detail. These
neuropsychological investigations, together with recent functional neuroimaging
studies of normal control subjects, have identified a specific area within the mid-
dorsolateral frontal cortex of humans which appears to be critically involved in the
cognitive processes that mediate efficient planning. The functions of this region,
both in cognitive planning and in related functions such as working memory, are
then discussed in the context of a general theoretical framework for understanding
the functional organization of "executive" processes within the human lateral
frontal cortex. In the final sections, the relationship between the planning deficits
observed after intrinsic frontal lobe damage and those exhibited by patients with
neuropathology of primarily sub-cortical origin, such as Parkinson's disease, is
discussed. A central model for much of this work has been the concept of cortico-
striatal circuitry which emphasizes the relationship between the neocortex and the
striatum. The combined evidence from comparative studies in patients and from
functional neuroimaging studies on Parkinson's disease suggests that altered
cortico-striatal interactions may disrupt normal planning function at a number of
levels, possibly consequent upon intrinsic striatal pathology on the one hand and
the partial loss of (frontal) cortical input to the basal ganglia on the other.
256. Owen, A. J.; Ijaz, S.; Miyashita, H.; Wishart, T.; Howlett, W.; Shuaib, A. Zonisamide
as a neuroprotective agent in an adult gerbil model of global forebrain ischemia: a
histological, in vivo microdialysis and behavioral study. Brain-Res. 1997 Oct 3;
770(1-2): 115-22; ISSN: 0006-8993.
NETHERLANDS. Brief periods of global cerebral ischemia are known to
produce characteristic patterns of neuronal injury both in human studies and in
experimental animal models. Ischemic damage to vulnerable areas such as the CA1
sector of the hippocampus is thought to result from excitotoxic amino acid
neurotransmission. The objective of this study was to determine the ability of a
novel sodium channel blocking compound, zonisamide, to reduce neuronal damage
by preventing the ischemia-associated accumulation of extracellular glutamate.
Using a gerbil model, animals were subjected to 5 min ischemic insults. Both pre-
and post-ischemic drug administration (zonisamide 150 mg/kg) were studied.
Histological brain sections were prepared using a silver stain at 7 and 28 days
post ischemia. The animals sacrificed at 28 days also underwent behavioral testing
using a modified Morris water maze. In vivo microdialysis was performed on a
separate group of animals in order to determine the patterns of ischemia-induced
glutamate accumulation in the CA1 sector of the hippocampus. Pyramidal cell
damage scores in the CA1 region of the hippocampus were significantly reduced
in animals pre-treated with zonisamide compared to saline-treated controls, both
at 7 days (drug pre-treated: 0.812 +/- 0.28, n = 8; controls: 1.625 +/- 0.24, n = 8;
*P < 0.05) and 28 (drug pre-treated: 0.833 +/- 0.22, n = 12; controls: 1.955 +/-
0.26, n = 11; **P < 0.01) days post ischemia. However, animals receiving
zonisamide post-treatment did not display significant differences from controls.
Behavioral studies also showed significant preservation of function in drug-treated
animals. Microdialysis studies confirmed a reduction in glutamate release in drug-
treated animals compared to saline-treated controls. Our data suggest that
zonisamide is effective in reducing neuronal damage by a mechanism involving
decreased ischemia-induced extracellular glutamate accumulation and interruption
of excitotoxic pathways.. 0; 0; 0; 56-86-0; 68291-97-4.
257. Palestini, P.; Toppi, N.; Ferraretto, A.; Pitto, M.; Masserini, M. Ganglioside
lateralization in the brain of female rats. J-Neurosci-Res. 1997 Nov 15; 50(4):
643-8; ISSN: 0360-4012.
UNITED-STATES. The ganglioside composition of the cerebral hemispheres of
young and adult rats of either sex has been herein assessed for the first time. In
females, the total ganglioside content at any age, the content of GM1, GD1a, and
GD1b at 8 days, and the content of GM1, GD1b, GT1b, and GQ1b at 60 days
were higher in the right than in the left hemisphere. In males, no difference was
observed. Concerning the ceramide moiety, a difference was displayed by C18:1
long-chain base in GD1a, whose proportion was higher in the left than in the right
hemisphere of females aged 8 days. The comparison between homolateral
hemispheres of rats of different sex revealed several differences. On average, in 8-
day-old animals, the content of gangliosides was higher in females than in males.
At 60 days the amount of gangliosides was on average lower in females than in
males, even if with some exception. The data obtained with the current
investigation show the existence of a ganglioside lateralization in rat brain,
exclusively in females, and almost entirely at charge of the oligosaccharide portion.
Moreover, age-dependent changes of ganglioside pattern and content show a
dependence on brain lateralization.. 0.
258. Paradiso, S.; Crespo Facorro, B.; Andreasen, N. C.; O'Leary, D. S.; Watkins, L. G.;
Boles Ponto, L.; Hichwa, R. D. Brain activity assessed with PET during recall of
word lists and narratives. Neuroreport. 1997 Sep 29; 8(14): 3091-6; ISSN: 0959-
4965.
ENGLAND. This study investigated the functional neuroanatomy involved in
retrieval of structured versus unstructured verbal information. We compared
cerebral blood flow using PET with the [15O]water method while subjects
engaged in recall of novel and practised narratives and lists of unrelated words.
Left orbital frontal cortex was activated during recall of both novel and practised
unrelated words. Right parietal cortex was relatively more active during recall of
the novel word list. Right orbital frontal cortex and anterior cingulate were
relatively more active during recall of the practised but not the novel word list.
These results are consistent with the role of left orbital frontal cortex in retrieval
of unstructured verbal information. Right orbital frontal activity suggests that
cognitive strategies may be involved in retrieval of well-practised words.
259. Parfenova, H.; Balabanova, L.; Leffler, C. W. Posttranslational regulation of
cyclooxygenase by tyrosine phosphorylation in cerebral endothelial cells. Am-J-
Physiol. 1998 Jan; 274(1 Pt 1): C72-81; ISSN: 0002-9513.
UNITED-STATES. Endothelium-derived cyclooxygenase (COX) products
regulate cerebral vascular tone in newborn pigs. Both COX-1 and COX-2 are
constitutively expressed in endothelial cells from newborn pig cerebral
microvessels. We investigated the role of protein phosphorylation in the
regulation of COX activity. The protein tyrosine phosphatase (PTP) inhibitors
phenylarsine oxide, vanadate, and benzylphosphonic acid rapidly stimulated
COX activity, whereas the protein tyrosine kinase inhibitors, genistein and
tyrphostins, inhibited it. Protein synthesis inhibitors did not reverse the
stimulation of COX activity evoked by PTP inhibitors. Similar changes were
observed in other vascular cells from newborn pigs that also express COX-1 and
COX-2 (cerebral microvascular smooth muscle cells and aortic endothelial cells)
but not in human umbilical vein endothelial cells or Swiss 3T3 fibroblasts that
express COX-1 only. Tyrosine-phosphorylated proteins were immunodetected in
endothelial cell lysates. COX-2 immunoprecipitated from 32P-loaded endothelial
cells incorporated 32P that was increased by PTP inhibitors. COX-2, but not
COX-1, was detected in endothelial fractions immunoprecipitated with anti-
phosphotyrosine. These data indicate that tyrosine phosphorylation
posttranslationally regulates COX activity in newborn pig vascular cells and that
COX-2 is a substrate for phosphorylation.. EC 1.14.99.-; EC 1.14.99.-; EC
1.14.99.1; EC 2.7.1.112; 0; 0; 0; 0; 0; 0; 0; 0; 0; 123653-11-2; 21820-51-9; 363-
24-6; 3735-59-9; 58962-34-8.
260. Park, C. K.; Jun, S. S.; Cho, S. H.; Kang, J. K. Assessment of the relationship
between ischemic damage and brain swelling in frozen brain slices. Acta-
Neurochir-Suppl-Wien. 1997; 70: 17-9; ISSN: 0065-1419.
AUSTRIA. The purpose of the study was to verify a method for the
measurement of both cerebral infarction and brain swelling in frozen brain slices
for histology. The animals were divided into two groups sham-operated control (n
= 10) and focal cerebral ischemia group (n = 10). Focal cerebral ischemia was
produced by permanent occlusion of the left middle cerebral artery. The rats were
sacrificed 24 hours postocclusion. The brain was divided into two through the
corpus callosum. Each hemisphere was weighted and frozen. Cerebral infarction
and brain swelling were each assessed at 8 predetermined coronal planes. The
volume of brain swelling was obtained by subtracting the total volume of
nonischemic hemisphere from the total volume of the ischemic one. In the MCA
occlusion group, brain infarction and the differences of hemispheric volume and
weight between the right and left hemispheres were consistently observed,
whereas sham-operated rats demonstrated no brain infarction or significant
differences between two hemispheres. There were good corelationships not only
between the volumes of brain edema and infarction (p < 0.05) but between the
volume of brain edema and the difference in weight (p < 0.01) also. The results
indicate that the measurement of the volume of ischemic brain edema in frozen
brain slices may be useful in elusidating relationship with ischemic brain damage.
261. Park, D. Y.; Kim, Y. M.; Chi, J. G. Intracranial metastasis from clear cell sarcoma of
the kidney--a case report. J-Korean-Med-Sci. 1997 Oct; 12(5): 473-6; ISSN:
1011-8934.
KOREA. Childhood kidney tumors seldom metastasize into the cranial cavity
unless it is a special histological variant. We report a 4-year-old boy with multiple
intracranial metastases in the left parietotemporal and right cerebellar area from
primary clear cell sarcoma of the kidney without evidence of bony metastases.
Metastatic tumor revealed nests of uniformly polygonal cells with clear
cytoplasm demarcated by delicate fibrovascular arcades. Tumor cells were
positive for vimentin and negative for cytokeratin, S-100 protein, desmin, and
myoglobin. Cellular proliferation rate measured by PCNA, and Ki-67 was not
significantly different between primary tumor mass and metastatic brain lesion.
Expression of p53 oncoprotein was not evident in both lesions. These findings
suggested that the relapse and metastasis of clear cell sarcoma of the kidney was
probably due to regrowth of micro-metastases which were present at an early
stage of disease.
262. Parsadanian, A. S.; Cheng, Y.; Keller Peck, C. R.; Holtzman, D. M.; Snider, W. D.
Bcl-xL is an antiapoptotic regulator for postnatal CNS neurons. J-Neurosci. 1998
Feb 1; 18(3): 1009-19; ISSN: 0270-6474.
UNITED-STATES. Bcl-xL is a death-inhibiting member of the Bcl-2/Ced9 family
of proteins which either promote or inhibit apoptosis. Gene targeting has revealed
that Bcl-xL is required for neuronal survival during brain development; however,
Bcl-xL knock-out mice do not survive past embryonic day 13.5, precluding an
analysis of Bcl-xL function at later stages of development. Bcl-xL expression is
maintained at a high level postnatally in the CNS, suggesting that it may also
regulate neuron survival in the postnatal period. To explore functions of Bcl-xL
related to neuron survival in postnatal life, we generated transgenic mice
overexpressing human Bcl-xL under the control of a pan-neuronal promoter. A
line that showed strong overexpression in brainstem and a line that showed
overexpression in hippocampus and cortex were chosen for analysis. We asked
whether overexpression of Bcl-xL influences neuronal survival in the postnatal
period by studying two injury paradigms that result in massive neuronal
apoptosis. In the standard neonatal facial axotomy paradigm, Bcl-xL
overexpression had substantial effects, with survival of 65% of the motor neurons
7 d after axotomy, as opposed to only 15% in nontransgenic littermates. To
investigate whether Bcl-xL regulates survival of CNS neurons in the forebrain, we
used a hypoxia-ischemia paradigm in neonatal mice. We show here that hypoxia-
ischemia leads to substantial apoptosis in the hippocampus and cortex of wild-
type neonatal mice. Furthermore, we show that overexpression of Bcl-xL is
neuroprotective in this paradigm. We conclude that levels of Bcl-xL in postnatal
neurons may be a critical determinant of their susceptibility to apoptosis.. 0; 0.
263. Partanen, J.; Soininen, H.; Helkala, E. L.; Kononen, M.; Kilpelainen, R.; Riekkinen, P.
Relationship between EEG reactivity and neuropsychological tests in vascular
dementia. J-Neural-Transm. 1997; 104(8-9): 905-12; ISSN: 0300-9564.
AUSTRIA. 17 patients with vascular dementia (VaD) representing moderate to
severe stage of the disease and 11 age-matched control subjects were examined
with spectral analysis of EEG and a neuropsychological test battery comprising
visual, praxic, verbal and memory functions as well as Mini-Mental Status test.
VaD patients did not have less activity in the alpha band than control subjects,
but the alpha amplitude ratio between eyes closed (EC) and eyes open (EO)
situations (EC/EO ratio) was decreased in VaD patients, compared to controls. In
VaD the variables of the awake background EEG with eyes closed (amplitude of
alpha, beta, theta and delta activity; mean frequency) had only a few correlations
to neuropsychological test scores. However, the (EC)/(EO) alpha ratio showed
significant correlations with several neuropsychological variables in the temporo-
occipital and centro-parietal derivations and some of these correlations were
lateralized to the left or right hemisphere. Frontal EEG derivations with less alpha
activity did not reveal any correlations to neuropsychological variables. We
conclude that the dynamic EC/EO alpha ratio variable may be even more sensitive
in the assessment of brain dysfunction in VaD than the background EEG
variables.
264. Pashek, G. V. A case study of gesturally cued naming in aphasia: dominant versus
nondominant hand training. J-Commun-Disord. 1997 Sep; 30(5): 349-65; quiz
365-6; ISSN: 0021-9924.
UNITED-STATES. Gestural plus verbal facilitation of naming was investigated
in an aphasic right handed adult with apraxia and hemisensory deficit but no
hemiplegia secondary to a left hemisphere lesion. An alternating treatments design
was followed in combined gesture/speech training of picture naming to compare
speech facilitation with dominant vs. nondominant hand iconic gesturing. A small
but consistent facilitation effect was observed for naming associated with verbal
plus left hand gestural training over naming of items trained in association with
verbal plus right hand gesturing. This same pattern of gestural facilitation was
replicated with a second set of lexical targets, those for which only verbal training
was initially provided. Overall gains were retained over a six-month follow-up
period for trained stimuli. Although findings are limited to the performance of a
single subject, results of this study may provide data relevant to understanding
mechanisms of facilitation in gesture-cued naming in aphasia.
265. Peru, A.; Pinna, G. Right personal neglect following a left hemisphere stroke. A case
report. Cortex. 1997 Sep; 33(3): 585-90; ISSN: 0010-9452.
ITALY. Neglect phenomena may occur in both extrapersonal and personal space.
Whereas extrapersonal neglect has been found associated with both right- and left-
sided brain lesions, no case of right personal neglect following a left-sided lesion
has been so far reported. We describe a right-handed female patient who, after two
left-hemisphere strokes, exhibited a florid personal neglect, but no extrapersonal
neglect, anosognosia or somatoparaphrenia. The symptom persisted for a few
weeks and then gradually disappeared. At least in the early phase of disease, a
personal neglect can also be observed in patients with left brain damage.
266. Petersen, S. E.; van Mier, H.; Fiez, J. A.; Raichle, M. E. The effects of practice on the
functional anatomy of task performance. Proc-Natl-Acad-Sci-U-S-A. 1998 Feb 3;
95(3): 853-60; ISSN: 0027-8424.
UNITED-STATES. The effects of practice on the functional anatomy observed
in two different tasks, a verbal and a motor task, are reviewed in this paper. In the
first, people practiced a verbal production task, generating an appropriate verb in
response to a visually presented noun. Both practiced and unpracticed conditions
utilized common regions such as visual and motor cortex. However, there was a
set of regions that was affected by practice. Practice produced a shift in activity
from left frontal, anterior cingulate, and right cerebellar hemisphere to activity in
Sylvian-insular cortex. Similar changes were also observed in the second task, a
task in a very different domain, namely the tracing of a maze. Some areas were
significantly more activated during initial unskilled performance (right premotor
and parietal cortex and left cerebellar hemisphere); a different region (medial
frontal cortex, "supplementary motor area") showed greater activity during skilled
performance conditions. Activations were also found in regions that most likely
control movement execution irrespective of skill level (e.g., primary motor cortex
was related to velocity of movement). One way of interpreting these results is in a
"scaffolding-storage" framework. For unskilled, effortful performance, a
scaffolding set of regions is used to cope with novel task demands. Following
practice, a different set of regions is used, possibly representing storage of
particular associations or capabilities that allow for skilled performance. The
specific regions used for scaffolding and storage appear to be task dependent.
267. Petroni, S.; Marrone, A. C. Study of the trabecular projections (Chordae Willisii) of
the superior sagittal sinus. Ital-J-Anat-Embryol. 1997 Jul; 102(3): 155-63; ISSN:
1122-6714.
ITALY. The trabecular projections or Chordae Willisii were studied in the
internal surface of the human superior sagittal sinus, being defined and quantified
as to having relation with afferent veins to the sinus, as to their lateral or medial
location and also in the anteroposterior direction. The results indicate a
predominance of trabecular projections with no relation to afferent vessels to the
sinus in its medial portion and central region, as well as predominance of these
projections on the left side. The number of trabecular projections related to
afferent vessels was nearly the same when left and right sides of the superior
sagittal sinus were compared.
268. Petty, M. A.; Elands, J.; Johnson, M. P.; Linnik, M. D.; Hamel, E.; Moskowitz, M.
A.; Lee, W. S.; McCarty, D. R.; Hibert, M.; Baron, B. M. The selectivity of
MDL 74,721 in models of neurogenic versus vascular components of migraine.
Eur-J-Pharmacol. 1997 Oct 8; 336(2-3): 127-36; ISSN: 0014-2999.
NETHERLANDS. MDL 74,721 (R)-2-(N1,N1-dipropylamino)-8-
methylaminosulfonylmethyl-1,2,3,4-te trahydronaphthalene, a
sulfonamidotetralin, has been found to exhibit a 10,000-fold greater potency in
neurogenic versus vascular models of migraine. Sumatriptan, a relatively pure 5-
HT1D/5-HT1B receptor agonist, also showed higher potency versus neurogenic
inflammation. However, for sumatriptan the potency difference (100-fold) in the
two pathophysiological models was less pronounced than seen for MDL 74,721.
The affinity profile of MDL 74,721 at 5-HT1 receptor subtypes may in part
explain its ability to differentiate these two physiological responses. MDL 74,721
demonstrated nanomolar affinity for 5-HT1A (12.7 +/- 0.3 nM) and 5-HT1D
(41.3 +/- 10.9 nM) but considerably lower affinity for 5-HT1B receptors (> 1000
nM). Serotonin-like activity was seen in in vitro functional assays including
inhibition of forskolin-stimulated cAMP accumulation in human 5-HT1D
receptor-transfected fibroblasts or eliciting vasoconstriction in isolated human pial
arteries. The intrinsic activity (relative to 5 - HT[E(Amax)]) and affinity (pD2)
for the human cerebrovascular 5-HT receptors were: 5-HT (100%, 7.51 +/- 0.09),
sumatriptan (94%, 6.85 +/- 0.1) and MDL 74,721 (66%, 5.70 +/- 0.23). In
anaesthetised cats, treatment with MDL 74,721 resulted in a dose-related
reduction in the percentage of carotid flow going through the arteriovenous
anastomoses to the lungs, with an ED50 of 0.3 mg/kg i.v., the same as
sumatriptan. However, in the guinea-pig neurogenic model, MDL 74,721 inhibited
plasma protein extravasation with an ED50 of 0.023 microg/kg compared to 2.5
microg/kg for sumatriptan. MDL 74,721 was also effective in this model (in rats)
after oral administration. In conclusion, MDL 74,721 demonstrates a preclinical
profile consistent with anti-migraine efficacy. Its marked preference for inhibiting
neurogenic inflammation makes this compound a useful tool for assessing the
relative contribution of this pathophysiological mechanism to the human disease
state.. 0; 0; 0; 0; 0; 0; 0; 103628-46-2; 112692-38-3; 60-92-4.
269. Pine, D. S.; Bruder, G. E.; Wasserman, G. A.; Miller, L. S.; Musabegovic, A.; Watson,
J. B. Verbal dichotic listening in boys at risk for behavior disorders. J-Am-Acad-
Child-Adolesc-Psychiatry. 1997 Oct; 36(10): 1465-73; ISSN: 0890-8567.
UNITED-STATES. OBJECTIVE: The association between deficits in verbal
processing skills and disruptive psychopathology remains one of the most
frequently replicated findings in all of child psychiatry. This study uses a dichotic
consonant-vowel listening test to examine the potential neural basis for this
association. METHOD: A series of 87 young boys recruited from a sample at risk
for disruptive disorders received standardized psychiatric, neuropsychological,
and language skills assessments. Approximately 1 year later, these boys received a
reassessment of their psychiatric status and a test that assesses the neural basis of
language-processing ability, a dichotic consonant-vowel listening test. RESULTS:
Disruptive psychopathology predicted reduced right ear accuracy for dichotic
syllables, indicative of a deficit in left hemisphere processing ability. Deficits in
reading and language ability also correlated with right ear accuracy for dichotic
syllables. CONCLUSIONS: Boys with disruptive behavior disorders, relative to
at-risk but nondisruptive boys, exhibit a deficit in verbal processing abilities on
dichotic listening tasks. This deficit in verbal processing ability is also manifested
as low scores on standardized tests of reading achievement and language
comprehension.
270. Pizzamiglio, L.; Vallar, G.; Doricchi, F. Gravitational inputs modulate visuospatial
neglect. Exp-Brain-Res. 1997 Nov; 117(2): 341-5; ISSN: 0014-4819.
GERMANY. Right brain-damaged patients with left visuospatial neglect were
required to bisect a line placed in front of them in two different body positions
(upright and supine) and two different light conditions (light and dark). The
neglect patients, unlike right brain-damaged patients without neglect, strongly
reduced their rightward directional error in the supine compared with the upright
position. No systematic changes were produced by the light-dark manipulation.
The present result cannot be explained with an attentional interpretation of
hemispatial neglect. We suggest that the present data provide further evidence that
hemineglect is the consequence of a mismatch between different afferent
information integrated into an egocentric space representation. According to this
model, the presence of a lateralized brain lesion produces asymmetries in some
intermediate spatial representations (eye-head, head-trunk, body-environment)
but not in the retinotopic one. Any experimental manipulation that reduces the
asymmetry of the intermediate representation such as the reduction of
gravitational inputs may improve the dynamic integration of the egocentric
coordinates.
271. Polagaeva, E. B.; Egorov, A. I. u.; Pirogov, A. A. [Asymmetry of skin resistance
response under activation of the right and left cerebral hemisphere]. Asimmetriia
reaktsii soprotivleniia kozhi pri aktivatsii pravogo i levogo polusharii mozga.
Fiziol-Cheloveka. 1997 Sep; 23(5): 21-6; ISSN: 0131-1646.
RUSSIA.
272. Pollock, H.; Hutchings, M.; Weller, R. O.; Zhang, E. T. Perivascular spaces in the
basal ganglia of the human brain: their relationship to lacunes. J-Anat. 1997 Oct;
191( Pt 3): 337-46; ISSN: 0021-8782.
ENGLAND. There is evidence for lymphatic drainage of interstitial fluid from
the brain along perivascular spaces in a number of mammalian species.
Ultrastructural studies suggest that there are similar drainage pathways in the
human cerebral cortex. Perivascular spaces in the basal ganglia, however, differ
from those in the cortex in that they dilate to form lacunes and rarely accumulate
beta-amyloid (amyloid angiopathy) in Alzheimer's disease; in the cortex, lacunes
are rare but amyloid angiopathy is common. The aim of the present study is to
compare the structure of perivascular spaces in the basal ganglia and at the
anterior perforated substance with perivascular spaces in the cerebral cortex. Eight
postmortem brains from patients aged 23-80 years (mean 68 y) were examined by
light microscopy, by scanning and transmission electron microscopy and by direct
visualisation of etched paraffin blocks. The results show that arteries in the basal
ganglia are surrounded by 2 distinct coats of leptomeninges separated by a
perivascular space which is continuous with the perivascular space around arteries
in the subarachnoid space. The inner layer of leptomeninges closely invests the
adventitia of the vessel wall and the outer layer is continuous with the pia mater
on the surface of the brain at the anterior perforated substance. Veins in the basal
ganglia have no outer layer of leptomeninges and thus the perivascular space is
continuous with the subpial space. The anatomy of the periarterial spaces in the
basal ganglia differs significantly from that in the cerebral cortex where there is
only a single periarterial layer of leptomeninges. Differences in structure of
perivascular spaces around arteries may reflect relative efficiencies in the drainage
of interstitial fluid from different sites in the brain. Furthermore, the structure of
the perivascular spaces may contribute to the relatively high frequency of lacunes
in the basal ganglia, and the low frequency of amyloid angiopathy at this site in
Alzheimer's disease.
273. Port, N. L.; Lee, D.; Dassonville, P.; Georgopoulos, A. P. Manual interception of
moving targets. I. Performance and movement initiation. Exp-Brain-Res. 1997
Oct; 116(3): 406-20; ISSN: 0014-4819.
GERMANY. We investigated the capacities of human subjects to intercept
moving targets in a two-dimensional (2D) space. Subjects were instructed to
intercept moving targets on a computer screen using a cursor controlled by an
articulated 2D manipulandum. A target was presented in 1 of 18 combinations of
three acceleration types (constant acceleration, constant deceleration, and constant
velocity) and six target motion times, from 0.5 to 2.0 s. First, subjects held the
cursor in a start zone located at the bottom of the screen along the vertical
meridian. After a pseudorandom hold period, the target appeared in the lower left
or right corner of the screen and traveled at 45 degrees toward an interception
zone located on the vertical meridian 12.5 cm above the start zone. For a trial to
be considered successful, the subject's cursor had to enter the interception zone
within 100 ms of the target's arrival at the center of the interception zone and stay
inside a slightly larger hold zone. Trials in which the cursor arrived more than 100
ms before the target were classified as "early errors," whereas trials in which the
cursor arrived more than 100 ms after the target were classified as "late errors."
Given the criteria above, the task proved to be difficult for the subjects. Only
41.3% (1080 out of 2614) of the movements were successful, whereas the
remaining 58.7% were temporal (i.e., early or late) errors. A large majority of the
early errors occurred in trials with decelerating targets, and their percentage tended
to increase with longer target motion times. In contrast, late errors occurred in
relation to all three target acceleration types, and their percentage tended to
decrease with longer target motion times. Three models of movement initiation
were investigated. First, the threshold-distance model, originally proposed for
optokinetic eye movements to constant-velocity visual stimuli, maintains that
response time is composed of two parts, a constant processing time and the time
required for the stimulus to travel a threshold distance. This model only partially
fit our data. Second, the threshold-tau model, originally proposed as a strategy for
movement initiation, assumes that the subject uses the first-order estimate of
time-to-contact (tau) to determine when to initiate the interception movement.
Similar to the threshold distance model, the threshold-tau model only partially fit
the data. Finally, a dual-strategy model was developed which allowed for the
adoption of either of the two strategies for movement initiation; namely, a
strategy based on the threshold-distance model ("reactive" strategy) and another
based on the threshold-tau model ("predictive" strategy). This model provided a
good fit to the data. In fact, individual subjects preferred to use one or the other
strategy. This preference was allowed to be manifested at long target motion
times, whereas shorter target motion times (i.e., 0.5 s and 0.8 s) forced the
subjects to use only the reactive strategy.
274. Posner, M. I.; Raichle, M. E. The neuroimaging of human brain function. Proc-Natl-
Acad-Sci-U-S-A. 1998 Feb 3; 95(3): 763-4; ISSN: 0027-8424.
UNITED-STATES.
275. Price, C. J.; Friston, K. J. The temporal dynamics of reading: a PET study. Proc-R-
Soc-Lond-B-Biol-Sci. 1997 Dec 22; 264(1389): 1785-91; ISSN: 0962-8452.
ENGLAND. The temporal dynamics of evoked brain responses are normally
characterized using electrophysiological techniques but the positron emission
tomography study presented here revealed a temporal aspect of reading by
correlating the duration a word remained in the visual field with evoked
haemodynamic response. Three distinct types of effects were observed: in visual
processing areas, there were linear increases in activity with duration suggesting
that visual processing endures throughout the time the stimulus remains in the
visual field. In right hemisphere areas, there were monotonic decreases in activity
with increased duration which we relate to decreased attention for longer stimulus
durations. In left hemisphere word processing areas there were inverted U-shaped
dependencies between activity and word duration indicating that, after 400-600
ms, activity in word processing areas is progressively reduced if the word remains
in the visual field. We conclude that these inverted U effects in left hemisphere
language areas reflect the temporal dynamics of visual word processing and we
highlight the implication of these effects for the design of activation studies
involving reading.
276. Puumala, T.; Sirvio, J. Changes in activities of dopamine and serotonin systems in the
frontal cortex underlie poor choice accuracy and impulsivity of rats in an attention
task. Neuroscience. 1998 Mar; 83(2): 489-99; ISSN: 0306-4522.
UNITED-STATES. The purpose of the present study was to investigate
whether differences in the function of monoaminergic systems could account for
the variability in attention and impulsive behaviour between rats tested in the
five-choice serial reaction time task in a model of attention deficit hyperactivity
disorder. The ability of a rat to sustain its attention in this task can be assessed by
measuring choice accuracy (percent correct responses) to visual stimuli, whereas
the percentage of premature responses indicates the level of impulsivity.
Following training with the five-choice serial reaction time task, rats were
decapitated and brain pieces taken for neurochemical determination. Levels of
dopamine, noradrenaline, 5-hydroxytryptamine, the dopamine metabolites, 3,4-
dihydroxyphenylacetic acid and homovanillic acid and the 5-hydroxytryptamine
metabolite, 5-hydroxyindoleacetic acid were determined in the frontal cortex,
nucleus accumbens, dorsal striatum and hippocampus. Multivariate regression
analysis with a stepwise method revealed that the indeces of utilization of
serotonin (5-hydroxyindoleacetic acid/5-hydroxytryptamine) in the left frontal
cortex and dopamine (3,4-dihydroxyphenylacetic acid/dopamine) in the right
frontal cortex together accounted for 49% of the variability in attentional
performance between subjects. According to the regression analysis, a negative
correlation existed between the left frontal cortex 5-hydroxyindoleacetic acid/5-
hydroxytryptamine and choice accuracy, and a positive correlation was observed
between 3,4-dihydroxyphenylacetic acid/dopamine ratio and choice accuracy on
the opposite hemisphere. Additionally, right frontal cortex serotonin utilization
was found to correlate positively with the proportion of premature hole
responses and this relation accounted for about 24% of the variability in this index
of impulsivity between animals. These data indicate that frontal cortex dopamine
and serotonin play an important role in the modulation of attention and response
control.. 306-08-1; 50-67-9; 51-41-2; 51-61-6; 54-16-0.
277. Quesson, B.; Thiaudiere, E.; Delalande, C.; Dousset, V.; Chateil, J. F.; Canioni, P.
Magnetization transfer imaging in vivo of the rat brain at 4.7 T: interpretation
using a binary spin-bath model with a superLorentzian lineshape. Magn-Reson-
Med. 1997 Dec; 38(6): 974-80; ISSN: 0740-3194.
UNITED-STATES. Proton magnetization transfer contrast (MTC) imaging,
using continuous wave off-resonance irradiation, was performed on the rat brain in
vivo at 4.7 Tesla. The observed MTC was studied in three different brain regions:
the corpus callosum, the basal ganglia, and the temporal lobe. By systematically
varying the offset frequency and the amplitude of the RF irradiation, the observed
signal intensities for each region of interest were modeled using a system including
free water and a pool of protons with restricted motions (R. M. Henkelman, X.
Huang, Q. Xiang, G. J. Stanisz, SD Swanson, M. J. Bronskill, Magn. Res. Med.
29, 759 (1993)). Most of the relaxation parameters of both proton pools remained
fairly constant for the three regions of interest, with a T2 value of about 9 micros
for the immobilized protons, whereas the rate of exchange increased significantly
from the temporal lobe to the corpus callosum. The optimal acquisition
parameters for the improved MTC under steady-state saturation were found to be
2-10 kHz offset frequency and 500-800 Hz RF irradiation amplitude. Conversely,
an irradiation amplitude of 3 kHz at an offset frequency of 12 kHz is required to
minimize the direct effect of off-resonance irradiation. Such an approach could be
extended to human brain imaging with the aim of characterizing tissue-specific
disease.
278. Rauch, S. L.; Savage, C. R.; Alpert, N. M.; Dougherty, D.; Kendrick, A.; Curran, T.;
Brown, H. D.; Manzo, P.; Fischman, A. J.; Jenike, M. A. Probing striatal function
in obsessive-compulsive disorder: a PET study of implicit sequence learning. J-
Neuropsychiatry-Clin-Neurosci. 1997 Sep; 9(4): 568-73; ISSN: 0895-0172.
UNITED-STATES. Positron emission tomography was employed to contrast
the brain activation pattern in patients with obsessive-compulsive disorder
(OCD) to that of matched control subjects while they performed an implicit
learning task. Although patients and control subjects evidenced comparable
learning, imaging data from control subjects indicated bilateral inferior striatal
activation, whereas OCD patients did not activate right or left inferior striatum
and instead showed bilateral medial temporal activation. The findings further
implicate corticostriatal dysfunction in obsessive-compulsive disorder.
Furthermore, when OCD patients are confronted with stimuli that call for
recruitment of corticostriatal systems, they instead appear to access brain regions
normally associated with explicit (conscious) information processing.
279. Rebai, M.; Bernard, C.; Lannou, J. The Stroop's test evokes a negative brain potential,
the N400. Int-J-Neurosci. 1997 Sep; 91(1-2): 85-94; ISSN: 0020-7454.
ENGLAND. The Event Related Potential (ERP) of 8 french right handed subjects
were recorded with 5 active electrodes located in frontal (Fz), central (Cz),
occipital (Oz) and right/left parietal (RH, LH) sites while they were performing a
modified version of the test of Stroop. They had either to read the names of basic
colors (yellow, green, blue, red) written in the same colors (red written in red:
concordant stimuli) or in a different color (red written in blue: discordant stimuli)
or to name mentally the color in which was written the name of a color, both
colors being concordant or discordant. The ERPs for reading were similar for
concordant and discordant stimuli and showed no sign of a N400 wave, this was
also the case for the mental naming of a color associated to the written name of the
same color. A N400 wave with a Cz location was evident for the mental naming of
a color when it was associated to the written name of another color. In this last
case, the automatic reading of the name of a color would correspond to a priming
which interferes with the access to the target word: the name of another color that
the subject is required to evoke mentally.
280. Reichenbach, A.; Siegel, A.; Senitz, D.; Smith, TG Jr. A comparative fractal analysis
of various mammalian astroglial cell types. Neuroimage. 1992 Aug; 1(1): 69-77;
ISSN: 1053-8119.
UNITED-STATES. Camera-lucida drawings of Golgi-impregnated astroglial cells
and their processes are described by the fractal dimension of their borders, which
is an objective, quantitative measure of morphological complexity. Protoplasmic
astrocytes from human neocortex have fractal dimensions (D) that are larger than
those of fibrous astrocytes from the cat optic nerve. Marginal astrocytes from
monkey cerebropontile angle have two kinds of processes: (1) short, thick
processes with endfeet abutting the pial surface, with relatively high D's, and (2)
very long, thin processes extending into the neuronal tissue, with very low D's.
These data indicate that short astrocytic processes may have a complex surface
(and have a high D), whereas long processes are rather smooth (and have a low D).
A comparison between transmission electron microscopy morphometry and
measures of D at the light microscopic level, performed on different parts of
rabbit retinal Muller glial cells, suggests that D is strongly correlated to the
surface-to-volume ratio which, in part, determines the length constant of a cable
for core-conductance of currents. We provide data supporting the hypothesis that
astroglial cell geometry is adjusted to allow for sufficient spatial buffering K+
currents, even through very long processes.
281. Reider Groswasser, I.; Costeff, H.; Sazbon, L.; Groswasser, Z. CT findings in
persistent vegetative state following blunt traumatic brain injury. Brain-Inj. 1997
Dec; 11(12): 865-70; ISSN: 0269-9052.
ENGLAND. The use of linear measurements in the analysis of CT scans of TBI
patients was found to contribute to the understanding of brain damage and were
correlated with outcome in severe traumatic close brain injured patients. The
purpose of the present study was to analyse the data obtained by the linear
measurements on CT studies of TBI patients who remained in persistent
vegetative state following blunt head trauma. All 27 patients included in the study
were reported to be neurologically normal prior to injury. Thirteen patients, 11
remaining in persistent vegetative state (responsive but unaware) and two who
died, constituted the worst outcome group. Fourteen patients who regained
consciousness, underwent multidisciplinary evaluation when their recovery
reached a plateau and were ranked according to severity of residual symptoms and
outcome. The degree of correlation with the overall vocational outcome parameter
with the various radiological indices was calculated as the Spearman rank
correlation coefficient, with correction for tied scores. Fisher's z transformation
was used to combine results with those of our previous analysis. Three
radiological parameters showed a statistically significant correlation with clinical
outcome. These were the right and left septum-caudate distance and the
cerebroventricular index 2; these showed Spearman rank coefficients of 0.52, 0.45
and 0.48; with two-tailed p-values under 0.01, 0.02 and 0.01 respectively. The
width of the third ventricle suggested correlation with the clinical scoring. The
findings of the present study point to the importance of loss of deep gray matter
of the caudate nuclei and widening of the adjacent part of the lateral ventricles in
catastrophic brain injury. This finding may highlight the role of localized ischemic
changes, in addition to diffuse axonal injury. Values of over 8 mm for the width of
the third ventricle and over 11 mm for septum caudate distance are suggestive of
catastrophic and poor prognosis for recovery.
282. Reinberg, A.; Bicakova Rocher, A.; Nouguier, J.; Gorceix, A.; Mechkouri, M.;
Touitou, Y.; Ashkenazi, I. Circadian rhythm period in reaction time to light
signals: difference between right- and left-hand side. Brain-Res-Cogn-Brain-Res.
1997 Oct; 6(2): 135-40; ISSN: 0926-6410.
NETHERLANDS. The study was designed to test the hypothesis that the
prominent rhythm period tau of simple reaction time (SRT) and three-choice
reaction time (CRT) to light signals may vary between the dominant (DH) and
non-dominant (NDH) hand. Eleven healthy subjects, 8 males (16-74 years,
including two left-handed) and 3 females (18-43 years), synchronized with a
diurnal activity (approximately 07.00 h to approximately 23.00 h) and a nocturnal
rest, volunteered for the study. A battery-powered ambulatory device was used
to self-record SRT to a yellow light signal and CRT to yellow, green and red
signals. Tests were performed 4-7 times/24 h during a 12- to 15-day span. Power
spectra, ANOVA, cosinor, chi2 and correlation tests were used to individually
analyze time series. Tau = 24 h in SRT rhythms of DH (8/11 cases) and NDH
(6/11 cases) with chi2 = 3.5 and p > 0.05. In CRT rhythms, tau = 24 h for DH
(8/11 cases) while tau = 8 h for NDH (7/11 cases), a difference which was
statistically significant (chi2 = 9.4 with p < 0.02). Concordant results were
obtained with other statistical tests leading to the conclusion that the rather
complex cognitive task (CRT) and, to a certain extent, SRT of certain individuals,
were associated with tau = 24 h for DH and tau = 8 h for NDH. These findings
are in favor of the hypothesis that functional clocks are present in the human
brain cortex, associated with the possible expression of rhythms with a prominent
period differing from the right- and left-hand side.
283. Reinoso, R. F.; Telfer, B. A.; Rowland, M. Tissue water content in rats measured by
desiccation. J-Pharmacol-Toxicol-Methods. 1997 Oct; 38(2): 87-92; ISSN: 1056-
8719.
UNITED-STATES. Tissue water content was determined by desiccation to
constant weight at 40 degrees-50 degrees C in 14 tissues from two groups of rats
weighing 200-250 and 270-430 g, respectively. The water content (mean +/- SE;
ml/g) was highest in testes (0.861 +/- 0.002) and lowest in adipose (0.183 +/-
0.017) followed by bone (0.446 +/- 0.017) and skin (0.651 +/- 0.007). The average
water content in the remaining tissues was 0.763 (+/- 0.003). Upon correction for
the water content of residual tissue blood, significant difference between the
uncorrected and corrected tissue water was observed for spleen, lungs, kidneys,
heart, liver, and brain. Tissue water was independent of body weight, and was the
same for right and left kidneys as well as testes and bone. Whereas the position of
the muscle (back, abdomen, hindlimb) and adipose tissue (perirenal and
subcutaneous) had no influence on water content, for skin, a slight difference was
found between back and abdomen. In general, the current results are in agreement
with composite literature values, but provide in one study data for all tissues used
in the development of physiologically based pharmacokinetic models of rat.
284. Rezaie, P.; Cairns, N. J.; Male, D. K. Expression of adhesion molecules on human
fetal cerebral vessels: relationship to microglial colonisation during development.
Brain-Res-Dev-Brain-Res. 1997 Dec 19; 104(1-2): 175-89; ISSN: 0165-3806.
NETHERLANDS. Microglia represent the primary immune effector cells of the
adult central nervous system (CNS). The origin of these cells has been a subject of
intense debate over the last century. However, immunohistochemical and chimera
developmental studies in rodents support the hypothesis that microglia are
monocytic in origin. There have been relatively few studies to date on microglia in
human fetal development, and the mechanisms by which microglial precursors
enter the developing CNS are as yet unknown. It is possible that microglial
precursors use combinations of adhesion molecules on cerebral endothelium to
gain entry into the developing CNS. In the present study, we have shown the
distribution of microglia within human fetal cerebral cortex between 16 and 22
weeks of gestation using RCA-1 lectin histochemistry. We have also
demonstrated dual anti-macrophage antibody labelling of these cells in conjunction
with adhesion molecules ICAM-1, ICAM-2 and PECAM on cerebral endothelium
throughout this period. We conclude that fetal microglia usually occur at highly
vascularised sites within the developing human fetal brain and are more
specifically associated with the expression of ICAM-2 on cerebral endothelium..
0; 0; 0.
285. Riehle, A.; Kornblum, S.; Requin, J. Neuronal correlates of sensorimotor association
in stimulus-response compatibility. J-Exp-Psychol-Hum-Percept-Perform. 1997
Dec; 23(6): 1708-26; ISSN: 0096-1523.
UNITED-STATES. Neuronal mechanisms underlying stimulus-response (S-R)
associations in S-R compatibility tasks were identified in 2 experiments with
monkeys. Visual stimuli were presented on the left and right calling for left-right
movements under congruent and incongruent S-R mapping instructions. High- and
low-pitched tones calling for left-right movements were presented to the left and
right ear, and the stimulus side was irrelevant. Single neurons sensitive to the S-R
mapping rule were found in the primary motor cortex. The large overlap between
the neuronal populations sensitive to the stimulus side, the S-R mapping rule, and
the response side, respectively, is consistent with the idea that sensory-to-motor
transformation is a continuous rather than a discrete process. Results partly
support the hypothesis that the increase in reaction time with incongruent
mapping is caused by the automatic activation of the congruent, but erroneous,
response.
286. Rivier, F.; Clarke, S. Cytochrome oxidase, acetylcholinesterase, and NADPH-
diaphorase staining in human supratemporal and insular cortex: evidence for
multiple auditory areas. Neuroimage. 1997 Nov; 6(4): 288-304; ISSN: 1053-8119.
UNITED-STATES. The pattern of cytochrome oxidase, acetylcholinesterase,
and NADPH-diaphorase activity was studied in the supratemporal plane, the
posterior part of the superior temporal gyrus, and the insula of normal human
brains. Five dark cytochrome oxidase regions were found: (i) on Heschl's gyrus
(area TC of von Economo and Koskinas); (ii) on the planum polare (area TC/TG);
(iii) posterior to Heschl's gyrus (within area TA); (iv) on the posterior convexity
of the superior temporal gyrus (within area TA); and (v) on the posterosuperior
insula (area IB). More lightly stained cortex separated these regions (areas IA,
TD, and part of TB). The laminar distribution of cytochrome oxidase activity
varied in different areas. Acetylcholinesterase-positive fibers predominated in area
TC and pyramidal neurons in areas TA and IA and in parts of TB; a mixture of
fiber and neuronal staining was found in TC/TG, TD, and IB. NADPH-
diaphorase positive profiles included large darkly stained nonpyramidal neurons,
mostly in infragranular layers and in subcortical white matter, small faintly stained
cells, and a dense array of fibers. The NADPH-diaphorase staining pattern did not
vary between areas. The present results suggest that the supratemporal plane, the
posterior part of the superior temporal gyrus, and the insula contain at least eight
putative cortical areas. Comparison with activation studies by others suggest that,
apart from the primary auditory area, six other putative areas may be auditory
whereas one putative area, on posterior insula, may be vestibular. Copyright 1997
Academic Press.. EC 1.6.99.1; EC 1.9.3.1; EC 3.1.1.7.
287. Roland, P. E.; Zilles, K. The developing European computerized human brain
database for all imaging modalities. Neuroimage. 1996 Dec; 4(3 Pt 2): S39-47;
ISSN: 1053-8119.
UNITED-STATES.
288. Rosen, B. R.; Buckner, R. L.; Dale, A. M. Event-related functional MRI: past,
present, and future. Proc-Natl-Acad-Sci-U-S-A. 1998 Feb 3; 95(3): 773-80; ISSN:
0027-8424.
UNITED-STATES. The past two decades have seen an enormous growth in the
field of human brain mapping. Investigators have extensively exploited techniques
such as positron emission tomography and MRI to map patterns of brain activity
based on changes in cerebral hemodynamics. However, until recently, most
studies have investigated equilibrium changes in blood flow measured over time
periods upward of 1 min. The advent of high-speed MRI methods, capable of
imaging the entire brain with a temporal resolution of a few seconds, allows for
brain mapping based on more transient aspects of the hemodynamic response.
Today it is now possible to map changes in cerebrovascular parameters
essentially in real time, conferring the ability to observe changes in brain state that
occur over time periods of seconds. Furthermore, because robust hemodynamic
alterations are detectable after neuronal stimuli lasting only a few tens of
milliseconds, a new class of task paradigms designed to measure regional
responses to single sensory or cognitive events can now be studied. Such "event
related" functional MRI should provide for fundamentally new ways to
interrogate brain function, and allow for the direct comparison and ultimately
integration of data acquired by using more traditional behavioral and
electrophysiological methods.
289. Rumsey, J. M.; Donohue, B. C.; Brady, D. R.; Nace, K.; Giedd, J. N.; Andreason, P.
A magnetic resonance imaging study of planum temporale asymmetry in men with
developmental dyslexia. Arch-Neurol. 1997 Dec; 54(12): 1481-9; ISSN: 0003-
9942.
UNITED-STATES. BACKGROUND: Imaging studies have suggested
anomalous anatomical asymmetries in language-related regions of the temporal and
parietal lobes in individuals with developmental dyslexia. Autopsy studies have
reported unusual symmetry of the planum temporale (PT) in patients with
dyslexia. Methodological limitations characterize much of this literature, however.
OBJECTIVE: To examine the size and asymmetry of the PT and its extension
into the parietal lobe (planum parietale [PP]) in men with well-characterized,
persistent dyslexia by using magnetic resonance imaging and 3-dimensional surface
rendering techniques. METHODS: The brains of 16 right-handed dyslexic men
aged 18 to 40 years and 14 matched control subjects were studied with magnetic
resonance imaging. Most of these subjects were previously studied with positron
emission tomography, which demonstrated functional abnormalities in temporal
and parietal brain regions in the dyslexic group. The area of the PT was
determined with the aid of 3-dimensional surface-rendering techniques. The size of
the PP was estimated by measuring the length of the posterior ascending ramus on
3 parasagittal slices. RESULTS: Approximately 70% to 80% of both groups
showed equivalent leftward (left > right) asymmetries of the PT; approximately
50% to 60% showed equivalent rightward (right > left) asymmetries of the PP.
These asymmetries showed equivalent moderate inverse correlations with each
other in both groups. CONCLUSIONS: These results challenge the notion that
anomalous asymmetry of the PT is strongly associated with developmental
dyslexia. Given the heterogeneity of the dyslexic population, some subgroup of
dyslexic individuals (i.e., those with developmental language disorders) may show
unusual symmetry or reversed asymmetry in this region. However, anomalous
asymmetry of the planum did not contribute to functional abnormalities
demonstrated in these patients by positron emission tomography.
290. Rushworth, M. F.; Nixon, P. D.; Renowden, S.; Wade, D. T.; Passingham, R. E. The
left parietal cortex and motor attention. Neuropsychologia. 1997 Sep; 35(9):
1261-73; ISSN: 0028-3932.
ENGLAND. The posterior parietal cortex, particularly in the right hemisphere, is
crucially important for covert orienting; lesions impair the ability to disengage the
focus of covert orienting attention from one potential saccade target to another
(Posner, M. I. et al., Journal of Neuroscience, 1984, 4, 1863-1874). We have
developed a task where precues allow subjects to covertly prepare subsequent
cued hand movements, as opposed to an orienting or eye movement. We refer to
this process as motor attention to distinguish it from orienting attention. Nine
subjects with lesions that included the left parietal cortex and nine subjects with
lesions including the right parietal cortex were compared with control subjects on
the task. The left hemisphere subjects showed the same ability as controls to
engage attention to a movement when they were forewarned by a valid precue.
The left hemisphere subjects, however, were impaired in their ability to disengage
the focus of motor attention from one movement to another when the precue was
incorrect. The results support the existence of two distinct attentional systems
allied to the orienting and limb motor systems. Damage to either system causes
analogous problems in disengaging from one orienting/movement target to another.
The left parietal cortex, particularly the supramarginal gyrus, is associated with
motor attention. All the left hemisphere subjects had ideomotor apraxia and had
particular problems performing sequences of movements. We suggest that the well
documented left hemisphere and apraxic impairment in movement sequencing is
the consequence of a difficulty in shifting the focus of motor attention from one
movement in a sequence to the next.
291. Sachdev, P.; Brodaty, H.; Rose, N.; Haindl, W. Regional cerebral blood flow in late-
onset schizophrenia: a SPECT study using 99mTc-HMPAO. Schizophr-Res.
1997 Oct 30; 27(2-3): 105-17; ISSN: 0920-9964.
NETHERLANDS. Functional neuroimaging studies have been performed in
many young patients with schizophrenia, but late-onset schizophrenia (LOS)
remains largely unexamined by these techniques. We predicted that LOS would
demonstrate regional cerebral blood flow (rCBF) abnormalities similar to those
seen in early-onset schizophrenia (EOS), but with a basis in demonstrable coarse
brain disease. The subjects were 15 LOS and 7 EOS patients and 27 healthy
controls. Each was given a detailed clinical and neuropsychological assessment and
underwent MRI and Tc99m-HMPAO single photon emission computed
tomography (SPECT) scans. The LOS subjects had a significantly lower cerebral
hemispheric perfusion than controls, with a lower perfusion in the frontal and
temporal lobes bilaterally. The LOS group also had significantly lower left-to-
right hemisphere blood flow ratios. EOS subjects had a lower frontal perfusion
than the controls, which was significant in the left frontal region. The temporal
perfusion in the EOS subjects was greater than in the LOS group, and not
different from the control subjects. Left temporal perfusion was the most
discriminating variable between LOS and control subjects on logistic regression.
Correlations of perfusion with MRI were generally low with the exception that
the asymmetry indices were significantly correlated, and basal ganglia perfusion
correlated with basal ganglia hyperintensities on MRI. The total cerebral
perfusion index correlated significantly with the mini-mental state examination
(MMSE) score, and the temporal lobe perfusion correlated with MMSE scores
and some verbal memory measures. In the schizophrenic groups, perfusion
correlated nonsignificantly with symptom profiles. We conclude that our findings
of temporal and frontal rCBF abnormalities, especially on the left side, in LOS are
similar to those reported in schizophrenia in general. The results do not provide
evidence for coarse brain disease underlying the rCBF abnormalities in LOS, or
support the specificity of these abnormalities for particular subsyndromes of
schizophrenia.. 0; 0.
292. Saino, M.; Kayama, T.; Sakurada, K.; Saito, S.; Sato, K. [A case of infantile anaplastic
astrocytoma treated with surgery and chemotherapy]. No-Shinkei-Geka. 1997
Dec; 25(12): 1121-6; ISSN: 0301-2603.
JAPAN. A 5-month-old girl presented with enlargement of the head
circumference. Neurological examination revealed right hemiparesis and bulging of
the anterior fontanel. T1-weighted magnetic resonance imaging with gadolinium
DTPA showed a well-enhanced, huge tumor extending from the left frontal lobe to
the parietal lobe. Cerebral angiography showed the main feeding arteries were the
central sulcus artery and the posterior parietal artery. The tumor was totally
removed using a sulcotomy and temporary clipping of these feeding arteries to
control bleeding. The histological diagnosis was anaplastic astrocytoma.
Postoperative radiation therapy was avoided so as to prevent the side effect of
radiation therapy such as mental retardation and growth impairment.
Chemotherapy using VP-16 and CDDP was given every six months as adjunct
therapy. No tumor recurrence has been recognized for over a period of 2 years and
5 months after surgery and growth and mental development have been
satisfactory. Total removal using great care not to damage neurological function
followed by postoperative chemotherapy is the treatment of preference to obtain
good prognosis and quality of survival in infant with such tumors.. 0; 15663-27-
1; 33419-42-0.
293. Sakakibara, R.; Hattori, T.; Fukutake, T.; Mori, M.; Yamanishi, T.; Yasuda, K.
Micturitional disturbance in herpetic brainstem encephalitis; contribution of the
pontine micturition centre. J-Neurol-Neurosurg-Psychiatry. 1998 Feb; 64(2): 269-
72; ISSN: 0022-3050.
ENGLAND. Micturitional disturbance is rarely mentioned in human herpetic
brainstem encephalitis although the pontine tegmentum, called the pontine
micturition centre, seems to regulate the lower urinary tract in experimental
animals. The case of a 45 year old man, who developed subacute coma and
hiccup-like dysrhythmic breathing, and needed assisted ventilation is reported.
Examination of CSF showed mononuclear pleocytosis and antibody against
herpes simplex virus type 1, but the opening pressure was 90 cm H2O. Brain CT
showed brain swelling, predominantly in the posterior fossa, and bilateral
subdural effusion. Herpetic brainstem encephalitis was diagnosed, and he received
900 mg/day vidarabine. On regaining consciousness, he had left trochlear nerve
palsy, left corectopia, ageusia, and urinary retention. Brain MRI showed right side
dominant, bilateral pontine segmental lesions extending slightly to the midbrain
and medulla. After two weeks he was able to urinate but showed nocturnal
urinary frequency, urinary incontinence, and voiding difficulty. Urodynamic
studies showed a residual urine volume of 350 ml and detrusor hyporeflexia on
voiding. Micturitional disturbance gradually disappeared together with the
neurological signs. The bilateral pontine tegmental lesions in this patient are
similar to those in previous findings on brainstem strokes, evidence of the
presence of a pontine micturition centre in humans.. 0.
294. Salenius, S.; Schnitzler, A.; Salmelin, R.; Jousmaki, V.; Hari, R. Modulation of human
cortical rolandic rhythms during natural sensorimotor tasks. Neuroimage. 1997
Apr; 5(3): 221-8; ISSN: 1053-8119.
UNITED-STATES. We studied modulation of cortical neuromagnetic rhythms in
association with left and right median nerve stimulation, during rest, finger
movements, and passive tactile hand stimulation, in seven healthy, right-handed
adults. In the rest condition, the amplitude of the rhythmic sensorimotor activity
decreased immediately after the median nerve stimuli and increased above the
prestimulus level within 0.4 s afterward, especially in the 7- to 25-Hz band. The
rebound occurred 100-300 ms earlier for 20 (7-15)-than for 10 (15-25)-Hz
activity. Suppressions and rebounds were strongest in the contralateral
sensorimotor hand area for the 20-Hz, but not for the 10-Hz, activity. The
maximum rebound was on average 22-34% stronger in the left than in the right
hemisphere. Active exploration of objects abolished rebounds of both 10- and 20-
Hz signals in the contralateral hemisphere and markedly diminished them
ipsilaterally. Finger movements without touching an object and passive tactile
stimulation produced a weaker effect. The sensorimotor rhythms thus show a
characteristic suppression and subsequent rebound after electrical median nerve
stimulation. The rebound is left-hemisphere dominant in right-handed subjects and
its suppression reveals bilateral cortical activation during both motor tasks and
passive tactile stimulation, especially for explorative finger movements.
295. Salisbury, D. F.; Shenton, M. E.; Sherwood, A. R.; Fischer, I. A.; Yurgelun Todd, D.
A.; Tohen, M.; McCarley, R. W. First-episode schizophrenic psychosis differs
from first-episode affective psychosis and controls in P300 amplitude over left
temporal lobe. Arch-Gen-Psychiatry. 1998 Feb; 55(2): 173-80; ISSN: 0003-990X.
UNITED-STATES. BACKGROUND: Schizophrenia is associated with central
(sagittal) midline reductions of the P300 cognitive event-related potential and
topographic asymmetry of P300, with reduced left temporal voltage. This P300
asymmetry is, in turn, linked to tissue volume asymmetry in the posterior
superior temporal gyrus. However, it is unknown whether P300 asymmetry is
specific to schizophrenia and whether central and lateral P300 abnormalities are
due to chronic morbidity, neuroleptic medication, and/or hospitalization, or
whether they are present at the onset of illness. METHODS: P300 was recorded
in first-episode schizophrenia, first-episode affective psychosis, and control
subjects (n = 14 per group). Subjects silently counted rare (15%) target tones (1.5
kHz) among trains of standard tones (1.0 kHz). Averages were constructed from
brain responses to target tones. RESULTS: Peak amplitude of P300 and integrated
voltage over 300 to 400 milliseconds were significantly different between first-
episode schizophrenics and controls over the posterior sagittal midline of the
head. First-episode schizophrenics displayed smaller amplitudes over the left
temporal lobe than first-episode affective psychotics and controls, but the groups
showed no differences over the right temporal lobe. CONCLUSIONS: Left-sided
P300 abnormality in first-episode schizophrenia relative to first-episode affective
psychosis and controls suggests that P300 asymmetry is specific to
schizophrenic psychosis and present at initial hospitalization. This P300
asymmetry suggests left temporal lobe dysfunction at the onset of schizophrenia.
296. Sass, K. J.; Silberfein, C. M.; Platis, I.; Westerveld, M.; Buchanan, C. P.; Delaney, R.
C.; Kim, J. H.; Spencer, D. D. Right hemisphere mediation of verbal learning and
memory in acquired right hemisphere speech dominant patients. J-Int-
Neuropsychol-Soc. 1995 Nov; 1(6): 554-60; ISSN: 1355-6177.
ENGLAND. Forty-eight patients with temporal lobe epilepsy completed
measures of narrative recall and list learning prior to surgery. The intracarotid
amytal procedure (IAP) established that 13 patients were right hemisphere
dominant for speech and 35 (18 left foci, 17 right foci) were left hemisphere
dominant. Hippocampal volumetric neuron densities were measured after surgery.
The left hippocampal neuron densities in subfields CA3 and the hilar area were
significantly correlated with list learning ability and percent retention for narrative
recall only for left hemisphere speech dominant patients with left seizure foci. No
significant correlations between measures of neuron volume and memory were
found for the left hemisphere speech dominant patients with right seizure foci or
the right hemisphere speech dominant patients with left seizure foci. This
suggests that the right hemisphere of right speech dominant patients mediates
verbal memory as well as speech. This conclusion is supported by patterns of
correlations among measures of verbal memory that differed for patients
undergoing resection of the dominant hemisphere versus those undergoing
resection of the nondominant hemisphere. However, it is premature to conclude
that the cerebral organization of cognitive functions of right hemisphere speech
dominant patients is equivalent albeit reversed from that of left hemisphere
speech dominant patients. Right hemisphere speech dominant patients with left
temporal foci differed from left hemisphere speech dominant patients with right
temporal foci with respect to the patterns of correlations between measures of
verbal memory and intelligence as well as the level of intellectual ability that they
demonstrated.. 57-43-2.
297. Satoh, M.; Suzuki, K.; Miyamura, M.; Katoh, R.; Kuzuhara, S. [Metamorphopsia
and transient increase in the cerebral blood flow of the left occipital pole on 123I-
IMP SPECT: a case report]. Rinsho-Shinkeigaku. 1997 Jul; 37(7): 631-5; ISSN:
0009-918X.
JAPAN. A 55-year-old right-handed man suddenly developed unformed visual
hallucination of rainbow-colored balls coming out from the lower quadrant of the
right visual field. Visual field examination revealed a right lower quadrant
homonymous hemianopia. Metamorphopsia of the hand or face appeared 6 days
later when he looked at his hands or at the face in the mirror, and persisted for
about 10 minutes. 123I-IMP SPECT demonstrated a marked increase in CBF of
the left occipital pole while the patient realized the visual symptoms, and a
marked decrease in CBF after the symptoms disappeared. T1 and T2-weighted
MRIs of the brain were unremarkable, but the Gd-DTPA-enhanced T1-weighted
MRI showed high signal in the subcortical white matter of the left occipital pole.
The metamorphopsia was induced probably by the activation of the left occipital
lesion by the epileptogenic mechanism although the nature of the lesion remained
unclarified.. 0; 0; 80529-93-7; 95896-48-3.
298. Schenk, T.; Zihl, J. Visual motion perception after brain damage: I. Deficits in global
motion perception. Neuropsychologia. 1997 Sep; 35(9): 1289-97; ISSN: 0028-
3932.
ENGLAND. We report on the test results of a group of 32 mostly unilaterally
brain-damaged patients examined for global visual motion perception. Three of
these patients had severely impaired visual motion perception in their
contralateral visual half-field, a deficit remarkably similar to the perceptual defects
found in V5-lesioned monkeys. Two of these three patients had a right-
hemisphere lesion; the remaining one had a left-hemisphere lesion. We conclude
that both hemispheres of the human brain contain an area, functionally equivalent
to V5, which subserves visual motion perception in the contralateral visual half-
field. Lesion analysis revealed that this area is located in the posterior medial
temporal gyrus.
299. Schieber, M. H.; Deuel, R. K. Primary motor cortex reorganization in a long-term
monkey amputee. Somatosens-Mot-Res. 1997; 14(3): 157-67; ISSN: 0899-0220.
ENGLAND. The primary motor cortex (M1) was mapped with intracortical
microstimulation (ICMS) in a 15 year-old macaque whose right upper extremity
was amputated at the shoulder joint prior to 2 years of age. Movements of the
right shoulder girdle and stump were evoked by ICMS throughout the left M1
upper extremity region. The size of the left M1 upper extremity region
contralateral to the amputated arm was not appreciably different from the size of
the right upper extremity region contralateral to the intact arm. Long stimulus
trains and/or higher stimulus currents were needed to evoke detectable movements
at significantly more loci in the left than in the right M1 upper extremity region.
These observations would be consistent with unmasking of a high threshold
representation of shoulder musculature that normally exists throughout the central
core of the upper extremity region, where it underlies a lower threshold
representation of the distal forelimb. Alternatively, invasion of the de-efferented
distal forelimb core by surrounding shoulder representation may have occurred.
Differences between the limited M1 reorganization observed in the present study
and the more extensive reorganization of S1 observed in other studies may reflect
fundamental differences between M1 and S1, and/or differences in the extent of
de-efferentation versus deafferentation.
300. Schiffer, F. Cognitive activity of the right hemisphere: possible contributions to
psychological function. Harv-Rev-Psychiatry. 1996 Sep; 4(3): 126-38; ISSN:
1067-3229.
UNITED-STATES. This paper reviews evidence from split-brain and other,
more recent studies that have enriched and advanced our understanding of the
cognitive and emotional abilities and characteristics of the right hemisphere. The
more recent work includes research on intact subjects (employing Wada tests,
unilateral videos, and functional imaging) and neurophysiological studies on
dissociated states such as multiple personality disorder and hypnosis. The
literature continues to support the view that in intact persons, the right
hemisphere has significant mental faculties that can operate with some
independence from those of the left hemisphere. The paper also reviews relevant
psychodynamic literature and discusses the theoretical and therapeutic
implications of the existence of these partially autonomous right hemispheric
mental faculties.
301. Schloerscheidt, A. M.; Rugg, M. D. Recognition memory for words and pictures: an
event-related potential study. Neuroreport. 1997 Oct 20; 8(15): 3281-5; ISSN:
0959-4965.
ENGLAND. Event-related potentials (ERPs) were recorded during the test phase
of recognition memory tests for words and pictures of objects. ERPs elicited by
recognized items contained a temporo-parietally distributed positive shift (the
parietal old/new effect), which was strongly left lateralized regardless of stimulus
type. This finding suggests that the lateral distribution of the parietal old/new
effect is unrelated to the lateralization of the memory functions supported by the
medial temporal lobe memory system. The ERPs to pictures, but not to words,
also demonstrated frontally distributed old/new effects, which shifted over time
from a left- to a right-sided maximum. These effects may reflect the richer
informational content associated with episodic memory for pictures.
302. Schoenborn, R.; Dmowska, M.; Unkiewicz, A.; Modrzejewski, E. Effect of electrical
stimulation of A and C fibres of the aortic nerves on arterial peripheral and
cerebral blood pressure. Folia-Biol-Krakow. 1996; 44(3-4): 123-9; ISSN: 0015-
5497.
POLAND. The effect of electrical stimulation of A and C fibres of the aortic
nerves on arterial peripheral (PBP) and cerebral blood pressure (CBP) was studied
in 12 rabbits (New Zealand White). The experiments have shown that selective
stimulation of fibres A of the aortic nerves evokes every time depression of the
arterial blood pressure in the peripheral circulation and slightly modifies pressure
in the cerebral circulation. Selective stimulation of fibres C of the aortic nerves
always elicits a significant decrease in arterial blood pressure in the peripheral
circulation, whereas in the cerebral circulation it elicits a small decrease or a slight
increase in arterial pressure. The obtained results point to a predominating role in
depressor reaction of impulsation reaching the aortic arch through amyelic fibres
C. The depressor reaction in the peripheral circulation is highest with
simultaneous stimulation of the right and left aortic nerve during stimulation of
both fibre A and C.
303. Schore, A. N. A century after Freud's project: is a rapprochement between
psychoanalysis and neurobiology at hand? J-Am-Psychoanal-Assoc. 1997; 45(3):
807-40; ISSN: 0003-0651.
UNITED-STATES. In his 1895 "Project for a Scientific Psychology" Freud
attempted to construct a model of the human mind in terms of its underlying
neurobiological mechanisms. In this endeavor "to furnish a psychology which
shall be a natural science," Freud introduced the concepts that to this day serve as
the theoretical foundation and scaffolding of psychoanalysis. As a result,
however, of his ensuing disavowal of the Project, these speculations about the
fundamental mechanisms that regulate affect, motivation, attention, and
consciousness were relegated to the shadowy realm of "metapsychology."
Nonetheless, Freud subsequently predicted that at some future date "we shall
have to find a contact point with biology." It is argued that recent advances in the
interdisciplinary study of emotion show that the central role played by regulatory
structures and functions represents such a contact point, and that the time is right
for a rapprochement between psychoanalysis and neuroscience. Current
knowledge of the psychobiological mechanisms by which the right hemisphere
processes social and emotional information at levels beneath conscious awareness,
and by which the orbital prefrontal areas regulate affect, motivation, and bodily
state, allows for a deeper understanding of the "psychic structure" described by
psychoanalytic metapsychology. The dynamic properties and ontogenetic
characteristics of this neurobiological system have important implications for both
theoretical and clinical psychoanalysis.
304. Schumacher, E. H.; Lauber, E.; Awh, E.; Jonides, J.; Smith, E. E.; Koeppe, R. A. PET
evidence for an amodal verbal working memory system. Neuroimage. 1996 Apr;
3(2): 79-88; ISSN: 1053-8119.
UNITED-STATES. Current models of verbal working memory assume that
modality-specific representations are translated into phonological representations
before entering the working memory system. We report an experiment that tests
this assumption. Positron emission tomography measures were taken while
subjects performed a verbal working memory task. Stimuli were presented either
visually or aurally, and a visual or auditory search tasks, respectively, was used as
a control. Results revealed an almost complete overlap between the active
memory areas regardless of input modality. These areas included dorsolateral
frontal, Broca's area, SMA, and premotor cortex in the left hemisphere; bilateral
superior and posterior parietal cortices and anterior cingulate; and right
cerebellum. These results correspond well with previous research and suggest that
verbal working memory is modality independent and is mediated by a circuit
involving frontal, parietal, and cerebellar mechanisms.
305. Sebag, O.; Mas, J. C.; Bebin, B.; Ferracci, J. P.; Sebag, F. [Leukoencephalitis with
hemiplegia during chickenpox]. Leucoencephalite avec hemiplegie au cours d'une
varicelle. Arch-Pediatr. 1997 Nov; 4(11): 1100-2; ISSN: 0929-693X.
FRANCE. BACKGROUND: Chickenpox encephalitis is usually mild and often
presents as an acute cerebellar ataxia. Seizures and coma are uncommon. CASE
REPORT: A 4-year old girl presented generalized seizures. Two days after the
onset of chickenpox, she developed ataxia and left hemiparesis on day 3, followed
by left hemiplegia after 24 hours. The cerebral scan showed areas of subcortical
hypodensity compatible with leuko-encephalitis. The EEG showed lesions of
acute leuko-encephalitis located in the right sub-cortical temporo-fronto-parietal
area. The patient was given cortico-steroid and recovered slowly but completely.
CONCLUSIONS: Hemiplegia, an exceptional event during the course of
chickenpox, makes the diagnosis of chickenpox leuko-encephalitis difficult; IRM
appears to be a contributing factor.
306. Seetharaman, S.; Barrand, M. A.; Maskell, L.; Scheper, R. J. Multidrug resistance-
related transport proteins in isolated human brain microvessels and in cells
cultured from these isolates. J-Neurochem. 1998 Mar; 70(3): 1151-9; ISSN: 0022-
3042.
UNITED-STATES. The multidrug transporter, P-glycoprotein (Pgp), at the
blood-brain barrier is thought to be important for limiting access of toxic agents to
the brain, but controversy surrounds its cellular location, whether on endothelium
or on adjacent astrocyte foot processes. In the present study, the distribution of
protein and mRNA for Pgp and for another transporter, multidrug resistance-
associated protein (MRP), is compared with that for the endothelial marker,
platelet-endothelial cell adhesion molecule-1 (PECAM-1) and for the astrocyte-
derived glial fibrillary acidic protein (GFAP) in microvessels isolated from human
brain and in cells grown from these microvessels. Activities of the multidrug
transporters are assessed in the cultured cells from the effects of transport
inhibitors on intracellular [3H]vincristine accumulation. The isolated microvessels
show strong immunocytochemical staining for Pgp and PECAM-1 and little or no
staining for GFAP and MRP, and they contain mRNAs detectable by RT-PCR
encoding only Pgp and PECAM-1, but not GFAP or MRP. Thus, Pgp may well
be synthesised and expressed on cells within the microvessels rather than on
adherent astrocyte foot processes. In cells grown from the microvessels, although
PECAM-1 remains, Pgp expression decreases and MRP appears. Evidence
suggests these multidrug transporters are functionally active in the cultured cells..
0; 0; 0; 0; 57-22-7.
307. Servan Schreiber, D.; Perlstein, W. M. Pharmacologic activation of limbic structures
and neuroimaging studies of emotions. J-Clin-Psychiatry. 1997; 58 Suppl 16: 13-
5; ISSN: 0160-6689.
UNITED-STATES. Two primary paradigms have been employed to study the
neurobiological basis of human emotions. These are induced emotions in normal
subjects and the comparison of patients suffering from emotional disorders with
normal control subjects. These traditional methods, which have limitations, may
be complemented by a third approach: the experimental elicitation of affect
through pharmacologic limbic stimulation with intravenous procaine
hydrochloride. In this paper, the authors review their research using the direct
stimulation approach. To determine whether procaine produces affectively laden
experiences accompanied by a reliable change in brain activity, 10 normal subjects
received two injections each of placebo (A) and procaine (B)-in ABBA order-
while in a positron emission tomography (PET) scanner. In a further study,
emotional responses were observed among 24 subjects (including the 10 subjects
in the PET study) for a total of 80 procaine injections. Procaine was shown to
induce bilateral activation of an anterior limbic network concomitant with
powerful, transient emotional and other subjective phenomena as well as
autonomic and endocrine responses. Considerable between-subject variability in
responses was noted, suggesting that this method can be used to explore
individual differences in the neurobiological basis of emotion and affective
disposition. Experimental elicitation of affect through limbic stimulation with
procaine, when used as part of a triangulation strategy with traditional imaging
paradigms, can contribute to our understanding of emotion and its disorders, of
the different components of emotion-response systems (e.g., subjective,
autonomic, and endocrine), and of individual differences in affective disposition..
0; 59-46-1.
308. Shah, P. J.; Ogilvie, A. D.; Goodwin, G. M.; Ebmeier, K. P. Clinical and
psychometric correlates of dopamine D2 binding in depression. Psychol-Med.
1997 Nov; 27(6): 1247-56; ISSN: 0033-2917.
ENGLAND. BACKGROUND: Single photon emission tomography (SPET)
with the dopamine D2/3 ligand 123I-IBZM gives a semi-quantitative estimate of
dopamine binding. In depressed patients, we predicted evidence of reduced
function, i.e. increased binding, particularly in more retarded patients.
METHODS: Fifteen depressed patients with major depressive illness and 15
healthy, age- and sex- matched volunteerS were examined with a clinical and
neuropsychological test battery and high resolution IBZM-SPET. Estimates for
specific binding were computed by averaging striatum to whole slice or frontal
uptake ratios over 8-10 scans acquired from 70 min after tracer injection.
RESULTS: Using whole slice as reference, left striatal uptake ratios did not
significantly differ for patients from controls. Right ratios were significantly
higher in patients than controls (P = 0.03). There were significant correlations
between IBZM binding in left and right striatum and measures of reaction time
and verbal fluency. CONCLUSIONS: Increased IBZM binding in striatum
probably reflects reduced dopamine function, whether due to reduced release of
dopamine, or secondary up-regulation of receptors. The observed abnormalities
may be trait or state related, an issue that needs to be addressed with longitudinal
study designs. The possible role of medication as a confounding variable requires
further exploration.. 0; 0; 0; 0; 84226-06-2.
309. Shapiro, D.; Jamner, L. D.; Spence, S. Cerebral laterality, repressive coping,
autonomic arousal, and human bonding. Acta-Physiol-Scand-Suppl. 1997; 640:
60-4; ISSN: 0302-2994.
ENGLAND. Jim Henry wrote extensively about emotional expressive styles,
such as alexithymia which is characterized by reduced awareness of one's own or
others' feelings and emotions, and their relation to cerebral hemispheric
asymmetries. The repressive coping style is a stable individual characteristic,
which is marked by reduced and minimized reports of stress coupled with higher
levels of autonomic, somatic, and behavioural responsivity. The apparent
dissociation between subjective and physiological response may be associated
with a functional disconnection between the two cerebral hemispheres and with
greater cerebral lateralization. To test this hypothesis, we reexamined data from a
study in which emotional and neutral slides were presented unilaterally to the left
and right hemisphere. Exposure duration was 200 ms. Subjects were divided into
four different coping styles based on their defensiveness and anxiety scores.
Repressive copers were the only group to show a significant cardiac response
(heart rate deceleration) to emotional material when it was presented to the right
but not to the left hemisphere. These findings and the fact that repressive copers
have a high need for social approval support Henry's views about the role of the
right hemisphere in affiliation and human bonding.
310. Shen, G. X.; Boada, F. E.; Thulborn, K. R. Dual-frequency, dual-quadrature, birdcage
RF coil design with identical B1 pattern for sodium and proton imaging of the
human brain at 1.5 T. Magn-Reson-Med. 1997 Nov; 38(5): 717-25; ISSN: 0740-
3194.
UNITED-STATES. Rapid quantification of tissue metabolites in vivo by MRS
or MRI can be achieved using dual-frequency RF coils with identical B1 field
distributions at the observation frequencies of the metabolites and tissue water
protons. Tissue sodium is used as an example for optimizing the dual-frequency,
dual-quadrature RF coils for such measurements in humans. In the setting of
sodium imaging, the challenge of dual-quadrature birdcage configurations is to
decouple the sodium and proton channels because the fourth harmonic of the
sodium frequency is very close to the proton frequency. A generalizable method
for effectively decoupling these two RF frequencies is presented in this paper.
The method is demonstrated with the design of an EPI compatible, dual-
quadrature, double-tuned, 23Na/1H birdcage coil. The performance of the RF
probe is reported at 1.5 Tesla in terms of signal-to-noise ratio, B1 homogeneity
and image quality.
311. Shenton, M. E.; O'Donnell, B. F.; Nestor, P. G.; Wible, C. G.; Kikinis, R.; Faux, S. F.;
Pollak, S. D.; Jolesz, F. A.; McCarley, R. W. Temporal lobe abnormalities in a
patient with schizophrenia who has word-finding difficulty: use of high-resolution
magnetic resonance imaging and auditory P300 event-related potentials. Harv-
Rev-Psychiatry. 1993 Jul; 1(2): 110-7; ISSN: 1067-3229.
UNITED-STATES. Postmortem, magnetic resonance, and event-related potential
studies suggest the presence of temporal lobe abnormalities in schizophrenia.
Analyses using convergent measurements of brain structure and function,
however, have rarely been done in the same patients. We recently developed a
protocol using high-spatial-resolution magnetic resonance scans, auditory P300
event-related potentials, and thought disorder scales to examine temporal lobe
structure and function in the same patients. We report a case of schizophrenia
that showed left-lateralized volume reduction in the superior temporal gyrus,
hippocampus, and parahippocampal gyrus (also on right), with associated P300
amplitude reduction and thought disorder marked by word-finding difficulties and
perseverations.
312. Sheppard, B. J.; Chrisman, C. L.; Newell, S. M.; Raskin, R. E.; Homer, B. L. Primary
encephalic plasma cell tumor in a dog. Vet-Pathol. 1997 Nov; 34(6): 621-7; ISSN:
0300-9858.
UNITED-STATES. A 5-year-old female spayed Spitz dog had a 5-week history
of right head tilt, seizures, and progressive quadriplegia. Analysis of cerebrospinal
fluid revealed 27,600 white blood cells per microliter with 63% mononuclear
phagocytes, 27% lymphocytes, 6% neutrophils, 3% plasmacytoid cells, and 1%
eosinophils, and over 2000 mg/dl protein. On contrast-enhanced magnetic
resonance images, a focal 1-cm oval lesion was identified in the right ventral
brainstem. There was also marked contrast enhancement of the meninges in the
following areas: surrounding the brainstem, outlining cerebellar folia, along the
ventral floor of the brain and extending to the falx cerebri, and partially outlining
the left frontal lobe. At necropsy, the areas of contrast enhancement corresponded
to the presence of compact cellular sheets of pleomorphic, anisocytotic, oval to
polygonal neoplastic cells with plasmacytoid differentiation. The smaller of these
plasmacytoid cells stained predominantly for cytoplasmic immunoglobulin A
using immunoperoxidase methodology. Ultrastructurally, the neoplastic cells had
morphologic features typical of plasma cells, with large amounts of
predominantly rough endoplasmic reticulum with variably prominent Golgi
formation. This is the first report of a canine primary intracranial malignant
plasma cell tumor.. 0.
313. Shimohata, T.; Ishiguro, H.; Hirota, K. [Adult onset Still's disease with a brainstem
lesion demonstrated on MRI]. Rinsho-Shinkeigaku. 1997 May; 37(5): 379-82;
ISSN: 0009-918X.
JAPAN. We report a 39-year-old man with seven-year history of adult onset
Still's disease (AOSD) who developed left abducens palsy and ataxic gait. T2-
weighted MRI demonstrated high-intensities in the left side of the lower pons,
including nucleus abducens and the inferior cerebellar peduncle, and in the right
anteromedial portion of the thalamus corresponding to his neurological
abnormalities. He responded favorably to corticosteroid treatment, and the high-
intensities in the T2-weighted MRI diminished subsequently. Previously, he had
developed bilateral sensorineural hearing loss which had responded to
corticosteroid treatment during an exacerbation of the disease. There was no
evidence of multiple sclerosis or other systemic diseases affecting the central
nervous system (CNS) in the laboratory findings. Although the precise reason for
the MRI lesions was unclear, we thought they were CNS manifestations of Still's
disease. We suggest that AOSD is one of the causes of focal CNS involvement in
young adults, particularly who has a history of fever of unknown origin.
314. Shub, Y.; Ashkenazi, I. E.; Reinberg, A. Differences between left- and right-hand
reaction time rhythms: indications of shifts in strategies of human brain activity.
Brain-Res-Cogn-Brain-Res. 1997 Oct; 6(2): 141-6; ISSN: 0926-6410.
NETHERLANDS. Reaction time (RT) measurements serve as quantitative
indices for pilots' cognitive processes of the brain. To examine if laterality exists
in the brain hemispheres we measured, by the use of a Pilot Evaluation System
(PES), right- and left-hand performance rhythms as indicative of RT to audible
and visual stimuli. The tests included sets of simple tasks and complex ones to
which a secondary task composed of audio signals was added. The accuracy of
recorded reaction time was 27 ms. Seven right-handed males, 27-42 years of age,
experienced with the PES flight simulator, were tested every 2 h, nine times daily
(starting at 08:00 h) during 3 consecutive days. The results indicated that for
simple tasks, the 24 h period of RT rhythm is either exclusive or prominent for
both hands. For complex tasks the prominent period of RT is 24 h for the right
(dominant) hand and 8 h for the left (non-dominant) hand (right-hand 24 h period
Fstat = 140, r2 = 0.62 and 8 h period Fstat = 25, r2 = 0.22; left-hand 24 h period
Fstat = 44, r2 = 0.34 and 8 h period Fstat = 100, r2 = 0.54). The findings suggest
that a laterality exists in the brain hemispheres with regard to differences in
rhythm periodicities. The expression of this laterality is dependent on the task-
load level and points to a strategy of linkage and integrity in brain activity.
315. Sigurdsson, E. M.; Lee, J. M.; Dong, X. W.; Hejna, M. J.; Lorens, S. A. Bilateral
injections of amyloid-beta 25-35 into the amygdala of young Fischer rats:
behavioral, neurochemical, and time dependent histopathological effects.
Neurobiol-Aging. 1997 Nov; 18(6): 591-608; ISSN: 0197-4580.
UNITED-STATES. To examine the time course of the histopathological effects
of bilateral injections of amyloid-beta 25-35 (A beta) and to determine if these
effects are associated with a reduction in choline acetyltransferase activity and
behavioral impairments, we injected A beta (5.0 nmol) into the amygdala of young
male Fischer rats. Control rats received vehicle infusions. For histological analysis,
animals were sacrificed at 8, 32, 64, 96, and 128 days postoperatively (n = 21-33
per timepoint). A beta induced neuronal tau-2 staining in the right, but not the left
amygdala and hippocampus. A beta also induced reactive astrocytosis and
neuronal shrinkage within the right hippocampus and amygdala, respectively. As
with tau-2, these same brain regions within the left hemisphere in the A beta-
treated rats were significantly less affected. In addition, A beta appeared to induce
microglial and neuronal interleukin-1beta staining. The histopathological effects of
A beta peaked at 32 days postoperatively but were not associated with a
reduction in amygdaloid choline acetyltransferase activity. In a separate
experiment, behavioral effects of bilateral intra-amygdaloid injections of A beta
were analyzed at 34-52 days postoperatively. In an open field test, the treatment
groups differed only in the numbers of rears emitted (p = 0.016). There was no
effect of A beta in the Morris water maze or in the acquisition and retention of a
one-way conditioned avoidance response. These data suggest a laterality in the
histopathological effects of A beta and that the effects of single injections are in
part transient. These findings also suggest a direct association between plaque and
tangle formation in Alzheimer's disease, and support the use of this rat model to
screen drugs that may alter the initial pathological events associated with
Alzheimer's disease, that occur before the manifestations of extensive behavioral
impairments become evident.. 0; 0; 0; 0; 0; 0; 0; 18472-89-4; 573-58-0.
316. Singer, C.; Schatz, N. J.; Bowen, B.; Eidelberg, D.; Kazumata, K.; Sternau, L.;
Shulman, L. M.; Weiner, W. J. Asymmetric predominantly ipsilateral
blepharospasm and contralateral parkinsonism in an elderly patient with a right
mesencephalic cyst. Mov-Disord. 1998 Jan; 13(1): 135-9; ISSN: 0885-3185.
UNITED-STATES. A 66-year-old woman presented with a 3-year history of
predominantly right-sided blepharospasm and a 1-year history of progressive
predominantly left-sided hemiparkinsonism manifested by a left upper extremity
resting tremor and left-sided bradykinesia. Magnetic resonance imaging of the
brain revealed a large right mesencephalic cyst with mass effect. Positron emission
tomography revealed bilateral striatal hypometabolism consistent with
nigrostriatal dopaminergic dysfunction. The association of predominantly
ipsilateral blepharospasm and predominantly contralateral hemiparkinsonism is
very rare, and its association with a posterior fossa space-occupying lesion has
been reported only once. This is the second report of such an association and the
first description of adult-onset symptomatology.
317. Small, J. G.; Milstein, V.; Medlock, C. E. Clinical EEG findings in mania. Clin-
Electroencephalogr. 1997 Oct; 28(4): 229-35; ISSN: 0009-9155.
UNITED-STATES. Clinical EEG findings from 202 hospitalized manic patients
repeated during 131 recurrences of mania were described. Results were considered
in the light of current issues in the literature including the incidence of EEG
abnormalities and minor variations, relationships between EEG and family
history, EEG lateralization and longitudinal course of illness. The majority of
patients had normal EEGs or mild nonspecific deviations compatible with effects
of psychoactive medications. More definitive EEG abnormalities were observed in
16-percent. Microsleep occurred in 19 percent and small sharp spikes were found
in 17 percent of those who drowsed, with lower incidences of 14 and 6 positive
bursts and 6 Hz spike-and-slow-waves. Significant relationships between
moderate or severe EEG abnormalities and negative familial loading were
identified. Lateralized EEG abnormalities appeared in 9 percent of cases, involving
the left side significantly more often than the right. With one exception EEG
recordings during subsequent episodes did not suggest structural brain changes.
Clinical EEG studies are useful in discriminating between primary and secondary
affective disorders. They are also sensitive to effects of lithium and other
psychoactive medications. The significance of EEG variations including
microsleep and other atypical features continues to be elusive. Issues relating to
heritability, hemispheric dysfunction and longitudinal course of illness merit
further investigation.
318. Smith, E. E.; Jonides, J.; Marshuetz, C.; Koeppe, R. A. Components of verbal
working memory: evidence from neuroimaging. Proc-Natl-Acad-Sci-U-S-A. 1998
Feb 3; 95(3): 876-82; ISSN: 0027-8424.
UNITED-STATES. We review research on the neural bases of verbal working
memory, focusing on human neuroimaging studies. We first consider experiments
that indicate that verbal working memory is composed of multiple components.
One component involves the subvocal rehearsal of phonological information and is
neurally implemented by left-hemisphere speech areas, including Broca's area, the
premotor area, and the supplementary motor area. Other components of verbal
working memory may be devoted to pure storage and to executive processing of
the contents of memory. These studies rest on a subtraction logic, in which two
tasks are imaged, differing only in that one task presumably has an extra process,
and the difference image is taken to reflect that process. We then review studies
that show that the previous results can be obtained with experimental methods
other than subtraction. We focus on the method of parametric variation, in which
a parameter that presumably reflects a single process is varied. In the last section,
we consider the distinction between working memory tasks that require only
storage of information vs. those that require that the stored items be processed in
some way. These experiments provide some support for the hypothesis that,
when a task requires processing the contents of working memory, the dorsolateral
prefrontal cortex is disproportionately activated.
319. Smith, G. S.; Schloesser, R.; Brodie, J. D.; Dewey, S. L.; Logan, J.; Vitkun, S. A.;
Simkowitz, P.; Hurley, A.; Cooper, T.; Volkow, N. D.; Cancro, R. Glutamate
modulation of dopamine measured in vivo with positron emission tomography
(PET) and 11C-raclopride in normal human subjects. Neuropsychopharmacology.
1998 Jan; 18(1): 18-25; ISSN: 0893-133X.
UNITED-STATES. Subanesthetic doses of the noncompetitive N-methyl-D-
aspartate (NMDA) antagonist ketamine exacerbate psychosis in schizophrenic
patients, and ketamine has significant abuse liability. These observations indicate
that a secondary effect of ketamine may be to increase dopamine concentrations.
The present study was undertaken using positron emission tomography (PET)
and the dopamine (D2) radiotracer 11C-raclopride to determine whether ketamine
would decrease D2 receptor availability, indicative of an increase in dopamine
concentrations. Two scans were performed in seven male control subjects before
and after administration of ketamine (0.5 mg/kg, i.v. infused over 20 min).
Ketamine significantly increased cortisol levels and decreased dopamine receptor
availability in the striatum (specific binding), but not in the cerebellum
(nonspecific binding). In addition, the cerebellar binding subtracted from the
striatal binding (to account for changes in nonspecific binding) was significantly
decreased after ketamine administration. These results provide in vivo evidence
for the ability of ketamine to increase striatal dopamine concentrations, consistent
with the role of the NMDA receptor in modulating dopamine function.. 0; 0; 0; 0;
306-08-1; 51-61-6; 56-86-0; 6740-88-1; 84225-95-6; 9002-62-4.
320. Soltanian Zadeh, H.; Windham, J. P. A multiresolution approach for contour
extraction from brain images. Med-Phys. 1997 Dec; 24(12): 1844-53; ISSN: 0094-
2405.
UNITED-STATES. Many image registration methods use head surface, brain
surface, or inner/outer surface of the skull to estimate rotation and translation
parameters. The inner surface of the skull is also used for intracranial volume
segmentation which is considered the first step in segmentation and analysis of
brain images. The surface is usually characterized by a set of edge or contour
points extracted from cross-sectional images. Automatic extraction of contour
points is complicated by discontinuity of edges in the back of the eyes and ears
and sometimes by a previous surgery or an inadequate field of view. We have
developed an automated method for contour extraction that connects
discontinuities using a multiresolution pyramid. Steps of the method are: (1)
Contour points are found by an edge-tracking algorithm; (2) A multiresolution
pyramid of contour points is constructed; (3) Contour points of reduced images
are found; (4) From the continuous contour found at the lowest resolution,
contour points at a higher resolution are found; (5) Step 4 is repeated until
contour points at the highest resolution (original image) are found. The method
runs fast and has been successful in extracting contours from MRI and CT images.
We illustrate the method and its performance using MRI and CT images of the
human brain.
321. Sone, M.; Takahashi, K.; Satoh, F.; Murakami, O.; Totsune, K.; Ohneda, M.; Sasano,
H.; Ito, H.; Mouri, T. Specific adrenomedullin binding sites in the human brain.
Peptides. 1997; 18(8): 1125-9; ISSN: 0196-9781.
UNITED-STATES. Binding sites for adrenomedullin in human brain were
investigated and characterized by radioligand binding. Specific binding sites for
adrenomedullin were present in every region of human brain (cerebral cortex,
cerebellum, thalamus, hypothalamus, pons and medulla oblongata) obtained at
autopsy. Despite the homology with calcitonin gene-related peptide (CGRP),
CGRP was a poor inhibitor of [125I]adrenomedullin binding (IC50 > 1 microM)
compared with adrenomedullin(1-52) (IC50 = 1.2 +/- 0.5 nM, mean +/- SEM, n =
3). Three adrenomedullin fragments, adrenomedullin(1-12), adrenomedullin(22-
52), and adrenomedullin(13-52), were also poor inhibitors of the binding (IC50 =
0.3 microM), suggesting that the whole molecule of adrenomedullin(1-52) is
required for binding to the receptor. Scatchard plots of [125I]adrenomedullin
binding in human brain (cerebral cortex) gave a dissociation constant of 0.17 +/-
0.03 nM and maximal binding of 99.3 +/- 1.9 fmol/mg protein (n = 5). These
findings suggest that specific adrenomedullin binding sites that differ from the
CGRP receptors exist in human brain. This indicates a possible novel
neurotransmitter/neuromodulator role for adrenomedullin in human brain.. 0; 0; 0;
148498-78-6; 83652-28-2.
322. Song, A. W.; Wolff, S. D.; Balaban, R. S.; Jezzard, P. The effect of off-resonance
radiofrequency pulse saturation on fMRI contrast. NMR-Biomed. 1997 Jun;
10(4-5): 208-15; ISSN: 0952-3480.
ENGLAND. This paper describes the use of off-resonance saturation to further
manipulate the blood oxygenation level dependent (BOLD) contrast of fMRI. A
customized narrow bandwidth radiofrequency pulse, applied with a range of
frequency offsets prior to selection of each slice, was designed and incorporated
into a gradient echo EPI sequence. This application takes advantage of the
resonance frequency and linewidth differences between the oxygenated and
deoxygenated state of blood in human brain during task activation and rest, and is
capable of creating an enhancement in the contrast of the BOLD effect. Because of
a possible contribution to the signal change from cerebro-spinal fluid, which has a
much narrower linewidth and smaller frequency shift compared with the brain
tissue, data were also collected using a nulling inversion pulse. The inversion pulse
was applied before the off-resonance pulse and data acquisition to eliminate the
CSF signal. Functional areas are thus more localized to the brain tissue.. 7782-44-
7.
323. Stanness, K. A.; Westrum, L. E.; Fornaciari, E.; Mascagni, P.; Nelson, J. A.; Stenglein,
S. G.; Myers, T.; Janigro, D. Morphological and functional characterization of an
in vitro blood-brain barrier model. Brain-Res. 1997 Oct 17; 771(2): 329-42; ISSN:
0006-8993.
NETHERLANDS. Cell culture models have been extensively used for studies of
blood-brain barrier (BBB) function. However, several in vitro models fail to
reproduce some, if not most, of the physiological and morphological properties of
in situ brain microvascular endothelial cells. We have recently developed a
dynamic, tridimensional BBB model where endothelial cells exposed to
intraluminal flow form a barrier to ions and proteins following prolonged co-
culturing with glia. We have further characterized this cell culture model to
determine whether these barrier properties were due to expression of a BBB
phenotype. Endothelial cells of human, bovine or rodent origin were used. When
co-cultured with glia, intraluminally grown endothelial cells developed features
similar to in vivo endothelial cells, including tight junctional contacts at
interdigitating processes and a high transendothelial resistance. This in vitro BBB
was characterized by the expression of an abluminal, ouabain-sensitive Na/K
pump, and thus favored passage of potassium ions towards the lumen while
preventing K+ extravasation. Similarly, the in vitro BBB prevented the passage of
blood-brain barrier-impermeant drugs (such as morphine, sucrose and mannitol)
while allowing extraluminal accumulation of lipophylic substances such as
theophylline. Finally, expression of stereo-selective transporters for Aspartate
was revealed by tracer studies. We conclude that the in vitro dynamic BBB model
may become an useful tool for the studies of BBB-function and for the testing of
drug passage across the brain endothelial monolayer.. 7440-09-7.
324. Stark, R. E.; McGregor, K. K. Follow-up study of a right- and a left-
hemispherectomized child: implications for localization and impairment of
language in children. Brain-Lang. 1997 Nov 15; 60(2): 222-42; ISSN: 0093-934X.
UNITED-STATES. Two hemispherectomized girls, one operated on the right,
the other on the left, were followed from time of surgery until 9 and 10 years of
age and compared with respect to course of language acquisition following
surgery. At conclusion of follow-up, receptive and expressive language, phoneme
perception and production, and sentence processing of the two
hemispherectomized children were compared with those of two control groups of
similar age, one developing language normally, the other language-impaired. The
left-hemispherectomized child's abilities were similar to those of the language-
impaired children; the right-hemispherectomized child's abilities resembled those
of the language-normal children. Implications for localization of developmental
anomalies in language-impaired children are discussed. Copyright 1997 Academic
Press.
325. Steinberg, B. A.; Augustine, J. R. Behavioral, anatomical, and physiological aspects of
recovery of motor function following stroke. Brain-Res-Brain-Res-Rev. 1997 Sep
30; 25(1): 125-32; ISSN: 0165-0173.
NETHERLANDS. Restoration of motor function is relatively common in
humans and non-human primates. Studies of the behavioral aspects of recovery
indicate that responses re-emerge in a fixed sequence that resembles initial
acquisition. The extent to which this occurs depends on factors unique to the
subject. Research suggests that the traditional view of a hierarchically organized
brain is inaccurate. Instead, the brain is comprised of parallel circuits which may
be disinhibited and/or recruited when damage occurs. In some cases, damage leads
to reorganization of cerebral cortical maps. Available data point to the utility of
interventions to promote recovery. Research suggests that recovery from other
forms of impairment (e.g., non-vascular lesions or impairment in language)
involves similar processes.
326. Sterzi, R.; Piacentini, S.; Polimeni, M.; Liverani, F.; Bisiach, E. Perceptual and
premotor components of unilateral auditory neglect. J-Int-Neuropsychol-Soc.
1996 Sep; 2(5): 419-25; ISSN: 1355-6177.
ENGLAND. Recent investigations have distinguished between ophthalmokinetic
and melokinetic factors of unilateral neglect. The aim of our study was to
investigate the possible dissociation between melokinetic (premotor) and
perceptual factors, avoiding any overt oculokinetic components. We asked four
blindfolded left neglect patients to set a dichotic sound in central position, by
moving a handle controlling the difference of intensity between the sounds
delivered to the left and to the right ears. Two conflicting conditions were used. In
the congruent condition, the sound moved in the same direction as the hand
movement; in the noncongruent condition, it moved in the opposite direction. One
patient performed as if suffering from melokinetic neglect, and another as if
suffering from perceptual neglect. The behavior of the other two subjects did not
lend itself to a clearcut interpretation.
327. Stiebler, I.; Neulist, R.; Fichtel, I.; Ehret, G. The auditory cortex of the house mouse:
left-right differences, tonotopic organization and quantitative analysis of
frequency representation. J-Comp-Physiol-A. 1997 Dec; 181(6): 559-71; ISSN:
0340-7594.
GERMANY. Multi-unit electrophysiological mapping was used to establish the
area of the left- and right-hemisphere auditory cortex (AC) of the mouse and to
characterize various fields within the AC. The AC of the left hemisphere covered
a significantly larger (factor of 1.30) area compared to that of the right side. Based
on best-frequency (BF) maps and other neuronal response characteristics to tone
and noise bursts, five fields (primary auditory field, anterior auditory field, second
auditory field, ultrasonic field, dorsoposterior field) and two small non-specified
areas could be delimited on both hemispheres. The relative sizes of these fields
and areas were similar on both sides. The primary and anterior auditory fields
were tonotopically organized with counter running frequency gradients merging in
the center of the AC. These fields covered BF ranges up to about 45 kHz. Higher
BFs up to about 70 kHz were represented non-tonotopically in the separate
ultrasonic field, part of which may be considered as belonging to the primary field.
The dorsoposterior and second auditory fields were non-tonotopically organized
and neurons had special response properties. These characteristics of the mouse
AC were compared with auditory cortical maps of other mammals.
328. Strauss, C.; Lutjen Drecoll, E.; Fahlbusch, R. Pericollicular surgical approaches to the
rhomboid fossa. Part I. Anatomical basis. J-Neurosurg. 1997 Dec; 87(6): 893-9;
ISSN: 0022-3085.
UNITED-STATES. A safe paramedian approach to the rhomboid fossa for
surgical treatment of intrinsic brainstem lesions is based on detailed knowledge of
the morphometric anatomy of superficially located motor structures. The
morphometry of the rhomboid fossa is described in this report on the basis of
histological studies conducted in six human brainstem specimens, with special
emphasis on the colliculus facialis and the trigona nervi hypoglossi and vagi.
Morphometric data include analysis of shrinkage factors in each specimen. The
colliculus is a landmark for the nervus facialis, oculomotor nuclei, and the
paramedian pontine reticular formation. In the surgeon's view from the posterior
approach, the colliculus covers an area of 5.7 mm in the mediolateral and 6.8 mm
in the craniocaudal direction and is located 0.6 mm lateral to the median sulcus.
The fibers of the nervus facialis come as close as 0.2 mm to the surface of the
fourth ventricle. The colliculus is located 15.7 mm above the obex. The trigona
nervi hypoglossi and vagi cover a rectangular area measuring 3.1 by 6.5 mm and
serve as a landmark for lower cranial nerve nuclei. These nuclei are located 0.3 mm
lateral to the midline. An area with a maximum extension of 0.9 cm between the
colliculus and trigona can be used for an infracollicular paramedian approach. The
same applies to a supracollicular approach cranial to the colliculus and caudal to
the fibers of the nervus trochlearis within the medullary velum, with a
craniocaudal extension of 4 mm. Superficial motor nuclei and fibers can be
identified by neurophysiological mapping, which helps to define safe surgical
corridors into the rhomboid fossa, thus reducing functional morbidity caused by
the operative approach in intrinsic pontine and pontomedullary lesions.
329. Sudoh, S.; Kohriyama, T.; Tohji, H.; Nakamura, S. [A case of optic-spinal form of
multiple sclerosis with lobar type large cerebral hemorrhage]. Rinsho-Shinkeigaku.
1997 Jul; 37(7): 626-30; ISSN: 0009-918X.
JAPAN. We report a 57-year-old woman with optic-spinal form of active
multiple sclerosis, who developed a large lobar type hemorrhage of the brain. She
initially suffered from left visual loss, and three month later, she was hospitalized
with paraplegia and total sensory loss up to the fourth thoracic level accompanied
by sphincteric disturbance. Diagnosis of clinically probable multiple sclerosis was
based on the relapsing-remitting clinical course and laboratory findings. Five
months after admission, she developed sudden consciousness loss. Brain CT scan
showed a massive hemorrhage in the right frontal to parietal lobe. The patient had
no risk factors for cerebral hemorrhage including hypertension. Histopathological
study of brain tissues obtained at surgical evacuation of hematoma did not reveal
any malignancy, and congo-red staining of this specimen was negative. We
analyzed coagulation, fibrinolytic, and endothelial parameters during the follow-
up period. von Willebrand factor (vWF) as a marker for endothelial damages was
elevated persistently. Moreover, thrombin-antithrombin III complex (TAT) as a
marker for activation of coagulation was also elevated constantly throughout the
clinical course. The findings suggest that fragility of the vascular walls and
permeability changes associated with immunological mechanisms might have
resulted in the cerebral hemorrhage. Although there are few reports of cerebral
hemorrhage in patients with multiple sclerosis, it has been reported that vascular
wall damage is an important aspect of the pathology of multiple sclerosis and
acute cerebral vascular damage may sometimes occur in multiple sclerosis. We
propose that coagulation studies including the endothelial marker such as vWF
would provide a useful information regarding the risk of cerebrovascular
complication in multiple sclerosis.
330. Sunden Cullberg, J.; Tedroff, J.; Aquilonius, S. M. Reversible chorea in primary
antiphospholipid syndrome. Mov-Disord. 1998 Jan; 13(1): 147-9; ISSN: 0885-
3185.
UNITED-STATES. A 20-year-old woman with acute chorea induced by primary
antiphospholipid syndrome was studied by using fluorodeoxyglucose and
positron emission tomography (PET). PET sessions were conducted during an
episode of severe chorea and after recovery. The symptoms predominantly
affected the right side of her face and body, and PET demonstrated a
corresponding increase in lentiform and caudate nucleus metabolism prevailing on
the left side. After recovery, PET showed normal values in the regions previously
studied. This study adds further evidence to support the theory that acute
choreas are somehow the result of striatal hypermetabolism.
331. Szelies, B.; Weber Luxenburger, G.; Pawlik, G.; Kessler, J.; Holthoff, V.; Mielke, R.;
Herholz, K.; Bauer, B.; Wienhard, K.; Heiss, W. D. MRI-guided flumazenil- and
FDG-PET in temporal lobe epilepsy. Neuroimage. 1996 Apr; 3(2): 109-18; ISSN:
1053-8119.
UNITED-STATES. In temporal lobe epilepsy (TLE) patients without lesions,
major hippocampal sclerosis, or atrophy on magnetic resonance imaging (MRI),
the localizing power of [11C]flumazenil (FMZ) and 2-[18F]fluoro-2-deoxy-D-
glucose (FDG) was compared using high-resolution positron emission
tomography (PET) studies and individually coregistered MRI scans. Following
complete clinical, neuropsychological, and electrophysiological evaluation,
benzodiazepine receptor density was assessed using the FMZ equilibrium
method. Thirty minutes later, interictal FDG-PET was performed under resting
conditions. PET images were matched to three-dimensionally coregistered, T1-
weighted MRI. Each temporal lobe (TL) was divided into 12 volumes of interest.
The regional FMZ data were normalized with respect to average cortical values.
For each patient the right-left asymmetries of rCMRGlc and normalized FMZ
data were calculated. In 7 to 10 patients, mesial TL structures showed reduced
FMZ binding, with a decrease by at least 10% in the affected TL. Reductions of
10% or more of rCMRGlc usually were more widespread than FMZ reductions
and often involved lateral temporal cortex. The regions of most pronounced
disturbances are not necessarily identical in both methods. Three patients had a
complex correspondence of lateralization with PET, neuropsychological, and EEG
data. In 4 patients, lateralization was less clear from EEG or neuropsychological
results but was still consistent with lateralization by PET. In 3 of 10 patients,
however, major discrepancies were found. These data suggest that the
combination of neuropsychological testing, EEG, and MRI-guided FMZ- and
FDG-PET will help to select patients with clearly defined epileptogenic foci
especially in mesial TLE. Even in cases without MRI lesions, TL epileptic foci
can be lateralized with consistency across the methods; FMZ-PET shows the
pathologic focus more circumscribed than FDG-PET.. 0; 0; 0; 63503-12-8;
78755-81-4.
332. Takanashi, Y.; Yoshikawa, K.; Iwamoto, K.; Yoshida, Y.; Ueda, M.; Tanaka, C.;
Umeda, M.; Ebisu, T.; Fukunaga, M.; Naruse, S.; Sato, H.; Nakajima, K.
Comparison of functional localization in human visual cortices using MEG and
fMRI: a preliminary report. Electroencephalogr-Clin-Neurophysiol-Suppl. 1996;
47: 59-63; ISSN: 0424-8155.
IRELAND.
333. Tanaka, J.; Hayashi, Y.; Shimamune, S.; Nomura, M. Ascending pathways from the
nucleus of the solitary tract to the subfornical organ in the rat. Brain-Res. 1997
Nov 28; 777(1-2): 237-41; ISSN: 0006-8993.
NETHERLANDS. Electrical stimulation of the nucleus of the solitary tract
(NTS) produced orthodromic excitation (n = 28, 15%) and inhibition (n = 6, 4%)
of the activity of neurons in the subfornical organ (SFO) in male rats under
urethane anesthesia. Almost all (n = 26) of the excitatory responses (n = 28) were
blocked by microiontophoretically applied phentolamine, an alpha-adrenergic
antagonist, but not by timolol, a beta-adrenergic antagonist. In contrast, the
inhibitory response of all the neurons (n = 6) tested was not affected by either
phentolamine or timolol. Approximately two-third (n = 19) of SFO neurons that
demonstrated the excitatory response to NTS stimulation exhibited an increase in
neuronal activity in response to hemorrhage (10 ml/kg b.w.t.). Hemorrhage did not
cause any change in the activity of all the neurons that demonstrated the
inhibitory response to NTS stimulation. These results suggest that the excitatory
pathways from the NTS to the SFO may transmit the peripheral baroreceptor
information through alpha-adrenoreceptor mechanisms.. 0; 26839-75-8; 50-60-2;
51-41-2.
334. Tecchio, F.; Rossini, P. M.; Pizzella, V.; Cassetta, E.; Romani, G. L. Spatial
properties and interhemispheric differences of the sensory hand cortical
representation: a neuromagnetic study. Brain-Res. 1997 Aug 29; 767(1): 100-8;
ISSN: 0006-8993.
NETHERLANDS. We performed a neuromagnetic investigation of the sensory
hand cortical representation in the two hemispheres of 20 healthy volunteers. The
localizations within the brain hemispheres of the cortical Equivalent Current
Dipoles (ECDs) activated with the shortest latencies (N20 m and P30 m
components) by separate stimulation of contralateral median nerve, thumb and
little finger were analysed. The ECD spatial coordinates were in agreement with
the known somatotopy of the sensory homunculus: little finger more medial and
posterior, thumb more lateral and anterior, median nerve in-between. By
considering the ECDs to thumb and little finger stimulation the boundaries of the
hand cortical representation in primary sensory cortex, the 'hand extension' was
evaluated as the distance between the two. This parameter was similar on the two
hemispheres, the 'hand extension' being 17 mm and 12 mm for N20 m and P30 m
components, respectively, with a standard deviation of 5 mm. We provide for the
first time the ECDs localization of left and right median nerve, thumb and little
finger, as well as the 'hand extension' values, and their interhemispheric differences
as a normative data set describing the organization of primary sensory cortical
areas reserved to the hand in the healthy population. This approach permits
objective measurements of absolute values, as well as of interhemispheric
differences, of the sensory hand area following a monohemispheric lesion as well
as to non-invasively follow-up its reorganization during clinical recovery.
335. Thomas, W. B.; Adams, W. H.; McGavin, M. D.; Gompf, R. E. Magnetic resonance
imaging appearance of intracranial hemorrhage secondary to cerebral vascular
malformation in a dog. Vet-Radiol-Ultrasound. 1997 Sep; 38(5): 371-5; ISSN:
1058-8183.
UNITED-STATES. A 14-year-old dog developed an acute onset of depression,
disorientation, left hemiparesis,left hemianopia, left facial hypoesthesia, and a
tendency to turn to the right. Based on these findings, a lesion affecting the right
forebrain was suspected. Magnetic resonance imaging showed a mass within the
right cerebral hemisphere resulting in compression of the right lateral ventricle and
shifting the longitudinal fissure to the left. The lesion was hyperintense on T1-
weighted images and hyperintense with focal regions of hypointensity on proton
density-, and T2-weighted images, consistent with a subacute hemorrhage. At
necropsy, there was a hematoma in the parietal portion of the right cerebral
hemisphere. The hemorrhage was surrounded by numerous thin-walled veins,
most likely a venous malformation. Magnetic resonance imaging of intracranial
hemorrhage is reviewed.
336. Thorens, J. B.; Ritz, M.; Reynard, C.; Righetti, A.; Vallotton, M.; Favre, H.; Kyle,
U.; Jolliet, P.; Chevrolet, J. C. Haemodynamic and endocrinological effects of
noninvasive mechanical ventilation in respiratory failure. Eur-Respir-J. 1997 Nov;
10(11): 2553-9; ISSN: 0903-1936.
DENMARK. The aim of this study was to investigate the haemodynamic and
endocrinological effects of noninvasive positive pressure ventilation (NIPPV).
Eleven patients with oedema and recent hypercapnic and hypoxaemic worsening
of a chronic respiratory insufficiency were included. Echocardiography, cardiac
radionuclide assessment, blood catecholamines, salt and water handling hormones
were measured at admission and discharge (long study (LS)). To discriminate
between the action of NIPPV and other treatments, measurements were
performed on the fourth day, for 4 h without NIPPV and 4 h with NIPPV (short
study (SS)). NIPPV entailed a correction of P(a,CO2) and an increase of P(a,O2)
in LS and SS. Oedema disappeared. Body weight decreased (from 85+/-42 to
81+/-40 kg) during LS. Systolic and mean pulmonary arterial pressure decreased in
LS and SS. Right ventricular ejection fraction increased in LS. Left ventricular
ejection fraction did not change. Cardiac index was normal on admission and then
decreased. Natriuretic peptides and catecholamines were increased on admission,
whereas plasma renin activity, aldosterone and vasopressin were normal. We
suggest that in these patients, oedema can occur independently of renin-
angiotensin-aldosterone-vasopressin and with a normal cardiac output.
Noninvasive positive pressure ventilation allowed a correction of blood gases,
associated with the resolution of oedema, a decrease in pulmonary arterial
pressures and an increase in right ventricular ejection fraction.. 0; 0; 114471-18-0;
85637-73-6.
337. Thorin, E.; Nguyen, T. D.; Bouthillier, A. Control of vascular tone by endogenous
endothelin-1 in human pial arteries. Stroke. 1998 Jan; 29(1): 175-80; ISSN: 0039-
2499.
UNITED-STATES. BACKGROUND AND PURPOSE: Endothelin-1 (ET) has
been shown to be involved in human pathological conditions, but its physiological
function remains to be elucidated. The aim of this work was to assess whether
endothelium-derived ET was involved in the overall responsiveness of freshly
isolated human pial arteries. METHODS: Samples of cerebral cortex, otherwise
discarded, were obtained during tumor or epileptic lesion resections (n = 10
donors). Arterial segments were isolated and mounted on a microvessel myograph.
RESULTS: Inhibition of nitric oxide (NO) formation with N omega-nitro-L-
arginine (L-NA, 100 micromol/L) increased basal tone by 7+/-1% Emax (n=5).
This increase in tone was fully abolished in the presence of BQ123 (1 micromol/L;
ET(A) receptor antagonist, P<.05) but potentiated by a subthreshold
concentration of exogenous ET (1 nmol/L; 33+/-8% Emax; P<.05). In the presence
of L-NA, serotonin (10 micromol/L)-induced tone was doubled compared with the
control response (P<.05) but reduced by 90% in the presence of BQ123 (P<.05).
In the absence of L-NA, BQ123 prevented serotonin-induced tone (n=3).
Oxymetazoline, a selective alpha2-adrenergic receptor agonist, induced an
endothelium-dependent relaxation of preconstricted human pial arteries. The
relaxation was partially sensitive to NO synthase inhibition and fully prevented
by the addition of ET, whereas substance P-induced relaxation was preserved.
Glibenclamide (1 micromol/L), an inhibitor of ATP-sensitive K+ channels and
tetraethylammonium (1 mmol/L), an inhibitor of Ca2+-activated K+ channels had
no effect on oxymetazoline-induced relaxation. CONCLUSIONS: The results of
this study suggest first that ET is involved in the tonic response induced by NO
synthase inhibition; second, part of the contractile response induced by serotonin
is endothelium-dependent and sensitive to BQ123; and third, the data suggest that
activation of alpha2-adrenergic receptors generated an endothelium-dependent
relaxation that was selectively inhibited by exogenous ET.. EC 1.14.13.39; 0; 0; 0;
0; 0; 0; 0; 0; 0; 10102-43-9; 10238-21-8; 136553-81-6; 1491-59-4; 33507-63-0;
50-67-9; 50903-99-6; 66-40-0.
338. Thulborn, K. R.; Chang, S. Y.; Shen, G. X.; Voyvodic, J. T. High-resolution echo-
planar fMRI of human visual cortex at 3.0 tesla. NMR-Biomed. 1997 Jun; 10(4-
5): 183-90; ISSN: 0952-3480.
ENGLAND. Known specialized properties of the human visual cortex have been
used to investigate the role of spatial resolution on fMRI using blood oxygenation
level dependent (BOLD) echo-planar MRI at 3.0 tesla. The magnitude of BOLD
signal changes has been examined at low (3.1 x 3.1 x 3.0 mm3) and high (0.8 x 1.6 x
3.0 mm3) resolution using both gradient-echo and spin-echo EPI. Paradigms were
designed to activate primary visual cortex (V1/V2) and more specialized areas
associated with detection of color (V4) and motion (V5). Sensitivity of activation
maps increased at higher resolution despite the decreased total signal intensity at
the smaller voxel size, presumably from reduced partial volume averaging. The
greater microvascular selectivity of high-resolution spin-echo imaging enabled
distinct activation patterns sensitive to motion to be detected in V1/V2 that were
not apparent with gradient-echo imaging. The spatial resolution at 3.0 tesla was
constrained by the size of physiological head motion relative to the voxel
dimensions rather than SNR or the hemodynamic response of BOLD contrast.
The higher spatial resolution at 3.0 tesla with more selective spin-echo EPI can
further refine functional mapping within the cerebral cortex.. 7782-44-7.
339. Thulborn, K. R.; Chang, S. Y.; Shen, G. X.; Voyvodic, J. T. High-resolution echo-
planar fMRI of human visual cortex at 3.0 tesla. NMR-Biomed. 1997 Jun; 10(4-
5): 183-90; ISSN: 0952-3480.
ENGLAND. Known specialized properties of the human visual cortex have been
used to investigate the role of spatial resolution on fMRI using blood oxygenation
level dependent (BOLD) echo-planar MRI at 3.0 tesla. The magnitude of BOLD
signal changes has been examined at low (3.1 x 3.1 x 3.0 mm3) and high (0.8 x 1.6 x
3.0 mm3) resolution using both gradient-echo and spin-echo EPI. Paradigms were
designed to activate primary visual cortex (V1/V2) and more specialized areas
associated with detection of color (V4) and motion (V5). Sensitivity of activation
maps increased at higher resolution despite the decreased total signal intensity at
the smaller voxel size, presumably from reduced partial volume averaging. The
greater microvascular selectivity of high-resolution spin-echo imaging enabled
distinct activation patterns sensitive to motion to be detected in V1/V2 that were
not apparent with gradient-echo imaging. The spatial resolution at 3.0 tesla was
constrained by the size of physiological head motion relative to the voxel
dimensions rather than SNR or the hemodynamic response of BOLD contrast.
The higher spatial resolution at 3.0 tesla with more selective spin-echo EPI can
further refine functional mapping within the cerebral cortex.. 7782-44-7.
340. Tiihonen, J.; Kuikka, J.; Rasanen, P.; Lepola, U.; Koponen, H.; Liuska, A.;
Lehmusvaara, A.; Vainio, P.; Kononen, M.; Bergstrom, K.; Yu, M.; Kinnunen, I.;
Akerman, K.; Karhu, J. Cerebral benzodiazepine receptor binding and distribution
in generalized anxiety disorder: a fractal analysis. Mol-Psychiatry. 1997 Oct; 2(6):
463-71; ISSN: 1359-4184.
ENGLAND. Data obtained from animal and human brain imaging studies indicate
that frontal cortex and medial temporal lobe are involved in experiencing and
controlling fear and anxiety. We tested the hypothesis that benzodiazepine
receptor binding is decreased in the left temporal pole and increased in the right
prefrontal area among patients suffering from anxiety. We studied 10 drug-naive
female patients with generalized anxiety disorder (GAD) and 10 age- and gender-
matched healthy controls with MRI and with SPET by using a new (123)I-
labelled specific benzodiazepine receptor radioligand, NNC 13-8241. Blindly
analyzed results showed that the benzodiazepine receptor binding of
[(123)I]NNC 13-8241 was significantly decreased in the left temporal pole among
patients with GAD when compared with age- and sex-matched healthy controls.
This hemispheric asymmetry was studied further with a fractal analysis of the
SPET images. The fractal dimension of the left hemispheric benzodiazepine
receptor binding in patients with GAD was significantly higher than that of
controls (1.28 +/- 0.09 and 1.17 +/- 0.07, respectively), whereas the intercept was
decreased by 43 +/- 23% reflecting more homogeneous cerebral benzodiazepine
receptor density distribution in patients with GAD. The finding is analogous to
the decreased heterogeneity of myocardial blood flow observed in patients with
ischemic heart disease. The results are consistent with the general hypothesis that
high regional heterogeneity of perfusion, metabolism and receptor density is
necessary to maintain adaptation ability in the living organism.. 0; 0; 0; 0.
341. Toga, A. W.; Ambach, K. L.; Schluender, S. High-resolution anatomy from in situ
human brain. Neuroimage. 1994 Nov; 1(4): 334-44; ISSN: 1053-8119.
UNITED-STATES. We have generated a spatially accurate, high-resolution
three-dimensional (3D) volume of brain anatomy from cryosectioned whole
human head. The head of a female cadaver was cryosectioned on a heavy duty
cryomacrotome (PMV, Stockholm Sweden) modified for quantitative digital image
capture. Serial images (1024(2), 24-bit) were captured directly from the
cryoplaned specimen blockface in 500-micron intervals and reconstructed to a 3D
data volume. Data were placed into the Talairach coordinate system to create a
volume of brain anatomy for atlas reference. We resampled the volume at 500
microns along the sagittal, coronal, and horizontal planes and enhanced the images
by digitally editing the background. The spatial resolution of the original digitized
images provided sufficient anatomic detail to clearly delineate gray and white
matter and neural structures, including major fiber pathways, subthalamic nuclei,
and laminae. We developed a compact disk and controlling software program to
enable the viewer to select planes of orientation, display, and copy individual to
sections at higher resolution. Animation proved useful in the conveyance of
system anatomy as structures are shown traversing through the neuroaxis.
Postmortem cryosectioning paired with this computerized presentation allowed
the complete 3D volume data to be distributed and shared as an educational,
clinical, and research resource.
342. Tomimoto, H.; Akiguchi, I.; Matsuo, A.; Terai, K.; Wakita, H.; Kimura, J.; McGeer,
P. L.; Budka, H. Encephalitogenic peptide (EP) in human cerebrovascular white
matter lesions. Neuroreport. 1997 Dec 1; 8(17): 3727-30; ISSN: 0959-4965.
ENGLAND. The expression of encephalitogenic peptide (EP), a 68-86 amino
acid sequence of guinea pig myelin basic protein (MBP), was investigated in
autopsied brains with focal cerebral damage or with diffuse white matter (WM)
lesions. EP immunoreactive fibers were distributed in parallel with fibers
immunoreactive for amyloid protein precursor (APP), an indicator of WM
damages. EP was expressed in the periphery of cerebral infarctions and hematoma
in the acute and subacute stages, but was also distributed in diffuse WM lesions
due to heterogeneous causes. These data indicate that EP epitopes are exposed
specifically in ongoing WM damages, and that the destruction of myelin occurs
sporadically in diffuse WM lesions of varying intensity.. 0; 0; 0.
343. Tootell, R. B.; Hadjikhani, N. K.; Vanduffel, W.; Liu, A. K.; Mendola, J. D.; Sereno,
M. I.; Dale, A. M. Functional analysis of primary visual cortex (V1) in humans.
Proc-Natl-Acad-Sci-U-S-A. 1998 Feb 3; 95(3): 811-7; ISSN: 0027-8424.
UNITED-STATES. Human area V1 offers an excellent opportunity to study,
using functional MRI, a range of properties in a specific cortical visual area,
whose borders are defined objectively and convergently by retinotopic criteria.
The retinotopy in V1 (also known as primary visual cortex, striate cortex, or
Brodmann's area 17) was defined in each subject by using both stationary and
phase-encoded polar coordinate stimuli. Data from V1 and neighboring retinotopic
areas were displayed on flattened cortical maps. In additional tests we revealed
the paired cortical representations of the monocular "blind spot." We also
activated area V1 preferentially (relative to other extrastriate areas) by presenting
radial gratings alternating between 6% and 100% contrast. Finally, we showed
evidence for orientation selectivity in V1 by measuring transient functional MRI
increases produced at the change in response to gratings of differing orientations.
By systematically varying the orientations presented, we were able to measure
the bandwidth of the orientation "transients" (45 degrees).
344. Tootell, R. B.; Mendola, J. D.; Hadjikhani, N. K.; Liu, A. K.; Dale, A. M. The
representation of the ipsilateral visual field in human cerebral cortex. Proc-Natl-
Acad-Sci-U-S-A. 1998 Feb 3; 95(3): 818-24; ISSN: 0027-8424.
UNITED-STATES. Previous studies of cortical retinotopy focused on influences
from the contralateral visual field, because ascending inputs to cortex are known to
be crossed. Here, functional magnetic resonance imaging was used to demonstrate
and analyze an ipsilateral representation in human visual cortex. Moving stimuli,
in a range of ipsilateral visual field locations, revealed activity: (i) along the vertical
meridian in retinotopic (presumably lower-tier) areas; and (ii) in two large
branches anterior to that, in presumptive higher-tier areas. One branch shares the
anterior vertical meridian representation in human V3A, extending superiorly
toward parietal cortex. The second branch runs antero-posteriorly along lateral
visual cortex, overlying motion-selective area MT. Ipsilateral stimuli sparing the
region around the vertical meridian representation also produced signal reductions
(perhaps reflecting neural inhibition) in areas showing contralaterally driven
retinotopy. Systematic sampling across a range of ipsilateral visual field extents
revealed significant increases in ipsilateral activation in V3A and V4v, compared
with immediately posterior areas V3 and VP. Finally, comparisons between
ipsilateral stimuli of different types but equal retinotopic extent showed clear
stimulus specificity, consistent with earlier suggestions of a functional segregation
of motion vs. form processing in parietal vs. temporal cortex, respectively.
345. Tranel, D.; Damasio, H.; Damasio, A. R. A neural basis for the retrieval of conceptual
knowledge. Neuropsychologia. 1997 Oct; 35(10): 1319-27; ISSN: 0028-3932.
ENGLAND. Both clinical reports and systematic neuropsychological studies
have shown that patients with damage to selected brain sites develop defects in
the retrieval of conceptual knowledge for various concrete entities, leading to the
hypothesis that the retrieval of knowledge for entities from different conceptual
categories depends on partially segregated large-scale neural systems. To test this
hypothesis, 116 subjects with focal, unilateral lesions to various sectors of the
telencephalon, and 55 matched controls, were studied with a procedure which
required the visual recognition of entities from three categories--unique persons,
non-unique animals and non-unique tools. Defective recognition of persons was
associated with maximal lesion overlap in right temporal polar region; defective
recognition of animals was associated with maximal lesion overlap in right mesial
occipital/ventral temporal region and also in left mesial occipital region; and
defective recognition of tools was associated with maximal lesion overlap in the
occipital-temporal-parietal junction of the left hemisphere. The findings support
the hypothesis that the normal retrieval of knowledge for concrete entities from
different conceptual domains depends on partially segregated neural systems.
These sites may operate as catalysts for the retrieval of the multidimensional
aspects of knowledge which are necessary and sufficient for the mental
representation of a concept of a given entity.
346. Tredici, G.; Di Francesco, A.; Miani, A. Jr; Pizzini, G. Real complete three-
dimensional reconstruction of Golgi-impregnated neurons by means of a confocal
laser scanning microscope. Neuroimage. 1993 Sep; 1(2): 87-93; ISSN: 1053-8119.
UNITED-STATES. Golgi-impregnated neurons of the human or animal central
nervous system were studied with a confocal laser scanning microscope (CLSM).
The scanning properties (optical sectioning of the specimen) offered by the
CLSM and the capacity of metal granules to reflect the laser beam allow a three-
dimensional reconstruction of the impregnated neurons. The volume scanned can
be depicted in three different ways: (a) extended focus, i.e., a bidimensional image
that contains information from all the optical sections, as if there were an
extensive depth of focus; (b) a topographic representation in which the intensity
of every pixel is proportional to the calculated z value (as a result, the closer the
object section is to the surface, the greater the color intensity becomes); and (c)
shadow representation, i.e., a pseudo-three-dimensional image. In addition, a true
and complete three-dimensional reconstruction of neurons can be obtained using
an extended RAM and quick elaboration (fast CPU) combined with the rotation of
the reconstructed image in the different planes. High-magnification, high-
numerical-aperture (NA) oil immersion objective lenses with reduced working
distance may present some problems in the three-dimensional reconstruction of
large neurons with extensive and spreading dendritic branches. This limitation may
be overcome by using a low-magnification (10 x) oil immersion lens.
347. Turetsky, B.; Colbath, E. A.; Gur, R. E. P300 subcomponent abnormalities in
schizophrenia: II. Longitudinal stability and relationship to symptom change.
Biol-Psychiatry. 1998 Jan 1; 43(1): 31-9; ISSN: 0006-3223.
UNITED-STATES. BACKGROUND: Reduced amplitude of the P300 event-
related brain potential (ERP) is a robust finding in schizophrenia. It remains
unclear whether this represents a state or trait abnormality. We previously
reported reductions of specific subcomponents of the auditory oddball P300 that
were independent of acute symptomatology and were differentially associated
with gender and deficit/nondeficit subtype. To clarify the state vs. trait nature of
these abnormalities, we reassessed a subset of these patients after a minimum
interval of 1 year following initial study. METHODS: Auditory P300 ERPs were
obtained from 18 patients at two time points and compared to baseline normative
data recorded from 48 controls. Five P300 subcomponents were identified using
current source density measures: frontal (P3f), bilateral parietal (P3pL, P3pR),
and bilateral temporal (P3tL, P3tR). RESULTS: Patients exhibited reduced P300
amplitudes at baseline, including specific reductions of left temporal and right
parietal subcomponents. There were no significant changes in P300 amplitudes
over time, despite significant improvement in symptomatology, and the parietal
subcomponent exhibited persistent impairment. There was, however, a trend
toward normalization of the left temporal subcomponent that correlated with
change in Brief Psychiatric Rating Scale. There was also a highly significant
inverse relationship between changes in frontal P300 subcomponent amplitude
and severity of auditory hallucinations (r = -.76). CONCLUSIONS: The findings
support the overall longitudinal stability of P300 deficits in schizophrenia, though
there is some state-dependent modulation of these deficits. The relationship
between the frontal P300 and hallucinations is consistent with both the cognitive
orienting function of this subcomponent and the role of the anterior cingulate as a
hypothesized generator of this ERP activity.
348. Turjanski, N.; Pentland, B.; Lees, A. J.; Brooks, D. J. Parkinsonism associated with
acute intracranial hematomas: an [18F]dopa positron-emission tomography study.
Mov-Disord. 1997 Nov; 12(6): 1035-8; ISSN: 0885-3185.
UNITED-STATES. We present the case of a 36-year-old woman with a right
temporal hematoma and an overlying subdural hematoma following rupture of a
right middle cerebral artery aneurysm. Three weeks after recovering
consciousness, she developed a levodopa-responsive parkinsonian syndrome
involving the right limbs. A year after the vascular event, she reported subjective
improvement in her parkinsonism, which has remained stable since. 18F-dopa
positron-emission tomography showed a marked reduction of uptake in the left
putamen, raising the possibility that the intracranial hemorrhage unmasked latent
Parkinson's disease. To the best of our knowledge, this is the first case of
parkinsonism associated with spontaneous acute intracerebral and subdural
hematomas.. 0; 0; 0.
349. Tzourio, N.; Massioui, F. E.; Crivello, F.; Joliot, M.; Renault, B.; Mazoyer, B.
Functional anatomy of human auditory attention studied with PET. Neuroimage.
1997 Jan; 5(1): 63-77; ISSN: 1053-8119.
UNITED-STATES. Positron emission tomography was used to investigate the
functional anatomy of selective auditory attention in 17 right-handed male
volunteers who submitted to different tasks: silent rest (REST) listening to
frequent low- or rare high-pitched tones (LIS) delivered randomly to the right or
the left ear, selective auditory attention where subjects had to attend to deviants
in one ear, right (ATTR) or left (ATTL). Six subjects had the series REST, LIS,
ATTR twice, eight subjects the series REST, LIS, ATTL, and the last three
subjects the sereis REST, ATTR, ATTL. Event-related potentials were
simultaneously recorded with PET and showed significant task and electrode site
effects on the N100 amplitude. When compared to REST, LIS elicited bilateral
temporal activations of the Heschl's gyri and the planum temporale, with a
significant rightward asymmetry, and of the posterior part of the superior
temporal gyrus. Significant right precentral and anterior cingulate gyri normalized
regional cerebral blood flow increases were observed in the frontal lobe. Both the
ATTR and the ATTL conditions, compared to LIS, activated the supplementary
motor area, bilateral precentral, and left postcentral cortices without any temporal
cortex activation. In addition, the ATTL condition resulted in a right prefrontal
cortex activation. Pooling the 14 subjects revealed an asymmetry in the superior
temporal gyrus favoring the cortex contralateral to the attended ear. Two major
networks seem thus to be involved during selective auditory attention: (1) a local
temporal network, on which selective attention produces a modulation of the
functional lateralization, and (2) a frontal network that could mediate the temporal
cortex modulation by attention.
350. Tzourio, N.; Massioui, F. E.; Crivello, F.; Joliot, M.; Renault, B.; Mazoyer, B.
Functional anatomy of human auditory attention studied with PET. Neuroimage.
1997 Jan; 5(1): 63-77; ISSN: 1053-8119.
UNITED-STATES. Positron emission tomography was used to investigate the
functional anatomy of selective auditory attention in 17 right-handed male
volunteers who submitted to different tasks: silent rest (REST) listening to
frequent low- or rare high-pitched tones (LIS) delivered randomly to the right or
the left ear, selective auditory attention where subjects had to attend to deviants
in one ear, right (ATTR) or left (ATTL). Six subjects had the series REST, LIS,
ATTR twice, eight subjects the series REST, LIS, ATTL, and the last three
subjects the sereis REST, ATTR, ATTL. Event-related potentials were
simultaneously recorded with PET and showed significant task and electrode site
effects on the N100 amplitude. When compared to REST, LIS elicited bilateral
temporal activations of the Heschl's gyri and the planum temporale, with a
significant rightward asymmetry, and of the posterior part of the superior
temporal gyrus. Significant right precentral and anterior cingulate gyri normalized
regional cerebral blood flow increases were observed in the frontal lobe. Both the
ATTR and the ATTL conditions, compared to LIS, activated the supplementary
motor area, bilateral precentral, and left postcentral cortices without any temporal
cortex activation. In addition, the ATTL condition resulted in a right prefrontal
cortex activation. Pooling the 14 subjects revealed an asymmetry in the superior
temporal gyrus favoring the cortex contralateral to the attended ear. Two major
networks seem thus to be involved during selective auditory attention: (1) a local
temporal network, on which selective attention produces a modulation of the
functional lateralization, and (2) a frontal network that could mediate the temporal
cortex modulation by attention.
351. Undar, A.; Lodge, A. J.; Daggett, C. W.; Runge, T. M.; Ungerleider, R. M.; Calhoon,
J. H. Error associated with the choice of an aortic cannula in measuring regional
cerebral blood flow with microspheres during pulsatile CPB in a neonatal piglet
model. ASAIO-J. 1997 Sep; 43(5): M482-6; ISSN: 1058-2916.
UNITED-STATES. The effectiveness of an infant pulsatile cardiopulmonary
bypass (CPB) system on maintaining regional cerebral blood flow (CBF) using
two different types of aortic cannulae in 3 kg piglets has been investigated. The
University of Texas Neonatal Pulsatile Pump was used with either a DLP (Group
I, n = 6) or an Elecath (Group II, n = 7) 10Fr aortic cannula. In all the subjects,
nasopharyngeal temperature was reduced to 18 degrees C, followed by 1 hr of
deep hypothermic circulatory arrest (DHCA), then 45 min of rewarming. During
cooling and rewarming, alpha-stat blood gas management was used. The
radionuclide labeled microsphere technique was used to determine blood flows in
the cerebellum, basal ganglia, brainstem, right and left hemispheres, as well as
global CBF (ml/100 g/min). When the DLP aortic cannula was used, regional and
global CBF appeared to be higher pre- and post DHCA. In both groups regional
CBF was significantly decreased following DHCA. Although better pulsatile flow
was attained using the DLP cannula and this may have resulted in higher regional
CBF, these results must be interpreted in light of the large standard deviations
noted when this cannula was chosen for the studies. These results demonstrate
the importance of choosing an appropriate aortic cannula for measuring regional
CBF with a pulsatile neonate-infant CPB system.
352. Ungerleider, L. G.; Courtney, S. M.; Haxby, J. V. A neural system for human visual
working memory. Proc-Natl-Acad-Sci-U-S-A. 1998 Feb 3; 95(3): 883-90; ISSN:
0027-8424.
UNITED-STATES. Working memory is the process of actively maintaining a
representation of information for a brief period of time so that it is available for
use. In monkeys, visual working memory involves the concerted activity of a
distributed neural system, including posterior areas in visual cortex and anterior
areas in prefrontal cortex. Within visual cortex, ventral stream areas are selectively
involved in object vision, whereas dorsal stream areas are selectively involved in
spatial vision. This domain specificity appears to extend forward into prefrontal
cortex, with ventrolateral areas involved mainly in working memory for objects
and dorsolateral areas involved mainly in working memory for spatial locations.
The organization of this distributed neural system for working memory in
monkeys appears to be conserved in humans, though some differences between
the two species exist. In humans, as compared with monkeys, areas specialized
for object vision in the ventral stream have a more inferior location in temporal
cortex, whereas areas specialized for spatial vision in the dorsal stream have a
more superior location in parietal cortex. Displacement of both sets of visual areas
away from the posterior perisylvian cortex may be related to the emergence of
language over the course of brain evolution. Whereas areas specialized for object
working memory in humans and monkeys are similarly located in ventrolateral
prefrontal cortex, those specialized for spatial working memory occupy a more
superior and posterior location within dorsal prefrontal cortex in humans than in
monkeys. As in posterior cortex, this displacement in frontal cortex also may be
related to the emergence of new areas to serve distinctively human cognitive
abilities.
353. Unterberg, A. W.; Stroop, R.; Thomale, U. W.; Kiening, K. L.; Pauser, S.; Vollmann,
W. Characterisation of brain edema following "controlled cortical impact injury" in
rats. Acta-Neurochir-Suppl-Wien. 1997; 70: 106-8; ISSN: 0065-1419.
AUSTRIA. Significance, origin and nature of posttraumatic brain edema are still
being debated. Recently, a "controlled cortical impact injury" (CCII) was
introduced to model traumatic brain injury. Purpose of this study was to
investigate the development and nature of brain edema following CCII. Traumatic
brain injury was applied to the intact dura of the left hemisphere in Sprague-
Dawley rats (n = 52, 250-350 g b.w.). Ketamine/xylazine-anesthesia or inhalation-
anesthesia were used. A pneumatic impactor with a diameter of 5 mm contused
the temporo-parietal cortex with a velocity of 7 m/s and an impact depth of 2 mm.
24 hours post injury the brains were removed. Posttraumatic hemispheric swelling
and water content were determined gravimetrically, Evans blue extravasation
spectrophotometrically, area and volume of ischemia by staining with TTC. MRI
studies were performed with T1-,T2- and diffusion-weighted sequences.
Posttraumatic swelling following CCII was 14.3 +/- 3.1%. Brain water content
increased to 82.5 +/- 0.5% in lesioned hemisphere compared to 79.9 +/- 0.2% in
control hemisphere. Following TTC staining, the average ischemic tissue volume
was 56.7 +/- 19.2 mm3. There was a moderate uptake of Evans blue into the
lesioned hemisphere. MRI studies demonstrated edema in 35.4 +/- 9.5 mm3 of the
lesioned hemisphere. Gd-DTPA was taken up early after trauma only. A
significantly decreased ADC (apparent diffusion coefficient) indicates the
cytotoxic (ischemic) component of edema in this model. In conclusion, CCII
produces significant posttraumatic brain swelling and edema which is both, of
vasogenic and cytotoxic nature. Thus, the CCII models the human cortical
contusion more appropriately and opens new avenues for therapeutical studies
focussing on cortical contusions.
354. Uusitalo, M. A.; Virsu, V.; Salenius, S.; Nasanen, R.; Hari, R. Activation of human V5
complex and rolandic regions in association with moving visual stimuli.
Neuroimage. 1997 May; 5(4 Pt 1): 241-50; ISSN: 1053-8119.
UNITED-STATES. We recorded magnetoencephalographic responses from
seven healthy humans during the presentation of stationary and rotating radial
gratings. Rotations lasting 1 s evoked movement-specific sustained activity in the
parieto-occipitotemporal border area, in agreement with the activation of the V5
complex specialized for the analysis of movement. The source areas of the
movement-specific sustained fields were transiently active 100-130 ms after the
onsets of both rotating and stationary stimuli, suggesting that movement-related
cortical areas respond to any transient changes in the visual environment.
Transients were evoked also in other brain areas 60-200 ms after onsets of both
stimuli. Four subjects displayed additional motion-related sustained activity in the
rolandic region. Sustained activity continued after the stimulus movement in
several subjects during perception of the movement aftereffect. The transient
activity may evoke visual attention while sustained activity of the V5 complex
may be related to the conscious perception of movement.
355. Vajtai, I.; Varga, Z. [Teratoid/rhabdoid tumor of the central nervous system]. A
kozponti idegrendszer teratoid/rhabdoid tumora. Orv-Hetil. 1998 Jan 4; 139(1):
29-34; ISSN: 0030-6002.
HUNGARY. Teratoid/rhabdoid tumor is a recently introduced infantile brain
neoplasm of uncertain origin clinically characterized by a most aggressive course.
We describe the case of a 2-year-old boy and a 7-year-old girl, the former
presenting with central fever and hemiparesis, while vomiting and headache were
symptoms in the latter. A brain tumor in the right fronto-parieto-occipital and the
left fronto-medial parenchyma, respectively, were found and removed by surgery.
On histology, both lesions consisted of sheets of ovoid cells with prominent
cytoplasm, vesicular nuclei and macronucleoli. In the second case, a spindle-cell
component and bone metaplasia were also noted. Ultrastructurally, tumor cells
contained whorls of intermediate filaments. Immunohistochemistry revealed a
polyphenotypic expression profile including positivity for epithelial membrane
antigen, vimentin and a-actin. There was no evidence of a germ-cell origin.
Chromosomal translocation involving 22q11 was established cytogenetically in
the first case. The teratoid/rhabdoid tumor shares many common traits with renal
rhabdoid tumors and primitive neuroectodermal tumors as well as germ cell
neoplasms; therefore its being an entity is debated.
356. Vallar, G. Spatial frames of reference and somatosensory processing: a
neuropsychological perspective. Philos-Trans-R-Soc-Lond-B-Biol-Sci. 1997 Oct
29; 352(1360): 1401-9; ISSN: 0962-8436.
ENGLAND. In patients with lesions in the right hemisphere, frequently
involving the posterior parietal regions, left-sided somatosensory (and visual and
motor) deficits not only reflect a disorder of primary sensory processes, but also
have a higher-order component related to a defective spatial representation of the
body. This additional factor, related to right brain damage, is clinically relevant:
contralesional hemianaesthesia (and hemianopia and hemiplegia) is more frequent
in right brain-damaged patients than in patients with damage to the left side of the
brain. Three main lines of investigation suggest the existence of this higher-order
pathological factor. (i) Right brain-damaged patients with left hemineglect may
show physiological evidence of preserved processing of somatosensory stimuli, of
which they are not aware. Similar results have been obtained in the visual domain.
(ii) Direction-specific vestibular, visual optokinetic and somatosensory or
proprioceptive stimulations may displace spatial frames of reference in right
brain-damaged patients with left hemineglect, reducing or increasing the extent of
the patients' ipsilesional rightward directional error, and bring about similar
directional effects in normal subjects. These stimulations, which may improve or
worsen a number of manifestations of the neglect syndrome (such as extrapersonal
and personal hemineglect), have similar effects on the severity of left
somatosensory deficits (defective detection of tactile stimuli, position sense
disorders). However, visuospatial hemineglect and the somatosensory deficits
improved by these stimulations are independent, albeit related, disorders. (iii) The
severity of left somatosensory deficits is affected by the spatial position of body
segments, with reference to the midsagittal plane of the trunk. A general
implication of these observations is that spatial (non-somatotopic) levels of
representation contribute to corporeal awareness. The neural basis of these spatial
frames includes the posterior parietal and the premotor frontal regions. These
spatial representations could provide perceptual-premotor interfaces for the
organization of movements (e.g. pointing, locomotion) directed towards targets in
personal and extrapersonal space. In line with this view, there is evidence that the
sensory stimulations that modulate left somatosensory deficits affect left motor
disorders in a similar, direction-specific, fashion.
357. Vallar, G.; Guariglia, C.; Magnotti, L.; Pizzamiglio, L. Dissociation between position
sense and visual-spatial components of hemineglect through a specific
rehabilitation treatment. J-Clin-Exp-Neuropsychol. 1997 Oct; 19(5): 763-71;
ISSN: 1380-3395.
NETHERLANDS. Current evidence suggests an association between
contralesional extra-personal hemineglect, and deficits of arm position sense in
patients with damage to the right cerebral hemisphere. A unitary deficit may
produce both disorders, or this association may reflect the anatomical contiguity
of relevant brain structures. A rehabilitation treatment, devised for visual-spatial
hemineglect, was used to investigate these hypotheses in 8 patients with damage
to the right cerebral hemisphere. The treatment improved hemineglect, but not the
position sense deficit. The severity of the latter was however transiently reduced
by optokinetic stimulation, with effects similar to those found in visual-spatial
hemineglect. These effects of rehabilitation suggest that extra-personal hemineglect
and the neglect-related component of the position sense disorder of the left
forearm are independent, though frequently associated, deficits. Implications for
the design of rehabilitation programs are discussed.
358. Vallar, G.; Guariglia, C.; Nico, D.; Pizzamiglio, L. Motor deficits and optokinetic
stimulation in patients with left hemineglect. Neurology. 1997 Nov; 49(5): 1364-
70; ISSN: 0028-3878.
UNITED-STATES. Optokinetic stimulation with left direction of the movement
of luminous dots temporarily improved motor weakness of the left hand in two
right-brain-damaged patients with left spatial hemineglect. Stimulation to the right
had no effect. In two left-brain-damaged patients, optokinetic stimulation did not
affect the right motor weakness, regardless of direction of the movement of the
optokinetic stimuli. We suggest that in patients with left hemineglect,
contralesional motor deficits have a neglect-related component, which, as other
aspects of the neglect syndrome, may be improved by optokinetic stimulation.
The mechanisms may include a temporary restoration of the spatial coordinates of
bodily representations, pathologically distorted towards the side of the lesion.
359. Vallar, G.; Rusconi, M. L.; Bernardini, B. Modulation of neglect hemianesthesia by
transcutaneous electrical stimulation. J-Int-Neuropsychol-Soc. 1996 Sep; 2(5):
452-9; ISSN: 1355-6177.
ENGLAND. The effects of transcutaneous electrical stimulation on deficits of
tactile perception contralateral to a hemispheric lesion were investigated in 10
right brain-damaged patients and in four left brain-damaged patients. The
somatosensory deficit recovered, transiently and in part, after stimulation of the
side of the neck contralateral to the side of the lesion, in all 10 patients with
lesions in the right hemisphere, both with (six cases) and without (four cases) left
visuo-spatial hemineglect, and in one left brain-damaged patient with right
hemineglect. In three left brain-damaged patients without hemineglect, the
treatment had no detectable effects. In one right brain-damaged patient, the
stimulation of the side of the neck ipsilateral to the side of the lesion temporarily
worsened the somatosensory deficit. These effects of transcutaneous electrical
stimulation are similar to those of vestibular stimulation. The suggestion is made
that these treatments modulate, through afferent sensory pathways, higher-order
spatial representations of the body, which are pathologically distorted toward the
side of the lesion. The modulatory effect is direction-specific: the defective
internal representation of the contralesional side may be either partly restored,
improving the disorder of tactile perception, or further impoverished, worsening
the deficit. The possible neural basis of this modulation is discussed.
360. van, der Kallen BF; Morris, G. L.; Yetkin, F. Z.; van Erning, L. J.; Thijssen, H. O.;
Haughton, V. M. Hemispheric language dominance studied with functional MR:
preliminary study in healthy volunteers and patients with epilepsy. AJNR-Am-J-
Neuroradiol. 1998 Jan; 19(1): 73-7; ISSN: 0195-6108.
UNITED-STATES. PURPOSE: We used functional MR imaging to compare
hemispheric language dominance in healthy volunteers and in patients with
epilepsy. METHODS: We retrospectively reviewed the functional MR images of
23 healthy volunteers and 16 patients with epilepsy obtained by using an echo-
planar technique designed for whole-brain imaging. The activation paradigm used
was a silent word generation task. Hemispheric language dominance was assessed
as the percentage of activated pixels in the left hemisphere minus the percentage
of activated pixels in the right hemisphere x 100. RESULTS: We found no
significant difference in language lateralization between right-handed male and
right-handed female volunteers. However, a statistically significant difference in
language distribution was found between left- and right-handed female volunteers.
The left-handed female volunteers showed a more bilateral hemispheric language
lateralization. Language lateralization in right-handed male epilepsy patients with
early age at seizure onset and seizure locus in the left temporal lobe was not
significantly different from that of healthy right-handed male volunteers.
Similarly, we found no difference in language lateralization between right-handed
female volunteers and right-handed female epilepsy patients with late age at
seizure onset and seizures in the left temporal lobe. CONCLUSION: Handedness
has a significant influence on hemispheric language dominance in healthy
volunteers. Sex has no influence on hemispheric language dominance, regardless of
the task used to assess such dominance, nor does age at seizure onset influence
language lateralization in patients with left temporal lobe epilepsy. Therefore,
hemispheric language dominance can be assessed and compared effectively with
functional MR imaging.
361. Van Essen, D. C.; Drury, H. A.; Joshi, S.; Miller, M. I. Functional and structural
mapping of human cerebral cortex: solutions are in the surfaces. Proc-Natl-Acad-
Sci-U-S-A. 1998 Feb 3; 95(3): 788-95; ISSN: 0027-8424.
UNITED-STATES. The human cerebral cortex is notorious for the depth and
irregularity of its convolutions and for its variability from one individual to the
next. These complexities of cortical geography have been a chronic impediment to
studies of functional specialization in the cortex. In this report, we discuss ways
to compensate for the convolutions by using a combination of strategies whose
common denominator involves explicit reconstructions of the cortical surface.
Surface-based visualization involves reconstructing cortical surfaces and
displaying them, along with associated experimental data, in various
complementary formats (including three-dimensional native configurations, two-
dimensional slices, extensively smoothed surfaces, ellipsoidal representations, and
cortical flat maps). Generating these representations for the cortex of the Visible
Man leads to a surface-based atlas that has important advantages over
conventional stereotaxic atlases as a substrate for displaying and analyzing large
amounts of experimental data. We illustrate this by showing the relationship
between functionally specialized regions and topographically organized areas in
human visual cortex. Surface-based warping allows data to be mapped from
individual hemispheres to a surface-based atlas while respecting surface topology,
improving registration of identifiable landmarks, and minimizing unwanted
distortions. Surface-based warping also can aid in comparisons between species,
which we illustrate by warping a macaque flat map to match the shape of a human
flat map. Collectively, these approaches will allow more refined analyses of
commonalities as well as individual differences in the functional organization of
primate cerebral cortex.
362. Van Oostende, S.; Sunaert, S.; Van Hecke, P.; Marchal, G.; Orban, G. A. The kinetic
occipital (KO) region in man: an fMRI study. Cereb-Cortex. 1997 Oct; 7(7): 690-
701; ISSN: 1047-3211.
UNITED-STATES. We used functional magnetic resonance imaging to explore, in
individual subjects, the properties of the kinetic occipital (KO) region, which
previous position emission tomography studies have shown to be involved in the
processing of kinetic boundaries. The KO region was significantly activated in
23/25 subjects tested in the subtraction of uniform motion from kinetic gratings.
The KO region is genuinely specialized for processing kinetic boundaries since it
is significantly more activated by kinetic gratings than by luminance-defined
gratings, uniform motion or transparent motion. This leaves only the kinetic
boundaries, created by discontinuities in motion direction, as the specific stimulus
aspect, activating the KO region. The KO region is anatomically and functionally
distinct from areas MT/V5, V3 and V3A. It also has minimal overlap with the
lateral occipital (LO) region. The selective activation of the KO region is robust
and relatively immune to changes in stimulus size, spatial frequency and type of
kinetic boundary. These results strongly argue for the view that the KO region is a
new, separate, functional region in human occipital cortex.
363. Vandenberghe, R.; Dupont, P.; Bormans, G.; Mortelmans, L.; Orban, G. Blood flow
in human anterior temporal cortex decreases with stimulus familiarity.
Neuroimage. 1995 Dec; 2(4): 306-13; ISSN: 1053-8119.
UNITED-STATES. In this positron emission tomography investigation of
human nonverbal visual memory, we determined the anatomical distribution of
changes in regional cerebral blood flow (rCBF) reflecting familiarity of visual
shapes. All stimuli consisted of relatively simple, abstract outlines generated by
Fourier expansions. Subjects performed the same task twice, once using unfamiliar
and once using familiar stimuli. The task was a modified version of delayed
nonmatching-to-sample, consisting of one sample presentation prior to tracer
injection and a sequence of test trials during which images were acquired. When
this task was performed with familiar instead of unfamiliar stimuli, only decreases
in rCBF were observed, which were localized to the left lateral anterior temporal
neocortex, the left medial temporal pole, and the rostral anterior cingulate. The
correlates of familiarity measured in this human brain mapping experiment may
correspond with what has been measured in single neurons in monkeys. This
correspondence holds both for the type and for the localization of changes.
364. Veselis, R. A.; Reinsel, R. A.; Beattie, B. J.; Mawlawi, O. R.; Feshchenko, V. A.;
DiResta, G. R.; Larson, S. M.; Blasberg, R. G. Midazolam changes cerebral blood
flow in discrete brain regions: an H2(15)O positron emission tomography study.
Anesthesiology. 1997 Nov; 87(5): 1106-17; ISSN: 0003-3022.
UNITED-STATES. BACKGROUND: Changes in regional cerebral blood flow
(rCBF) determined with H2(15)O positron emission tomographic imaging can
identify neural circuits affected by centrally acting drugs. METHODS: Fourteen
volunteers received one of two midazolam infusions adjusted according to
electroencephalographic response. Low or high midazolam effects were identified
using post-hoc spectral analysis of the electroencephalographic response obtained
during positron emission tomographic imaging based on the absence or presence of
14-Hz spindle activity. The absolute change in global CBF was calculated, and
relative changes in rCBF were determined using statistical parametric mapping
with localization to standard stereotactic coordinates. RESULTS: The low-effect
group received 7.5 +/- 1.7 mg midazolam (serum concentrations, 74 +/- 24 ng/ml),
and the high-effect group received 9.7 +/- 1.3 mg midazolam (serum
concentrations, 129 +/- 48 ng/ml). Midazolam decreased global CBF by 12% from
39.2 +/- 4.1 to 34.4 +/- 6.1 ml x 100 g(-1) x min(-1) (P < 0.02 at a partial pressure
of carbon dioxide of 40 mmHg). The rCBF changes in the low-effect group were a
subset of the high-effect group. Decreased rCBF (P < 0.001) occurred in the
insula, the cingulate gyrus, multiple areas in the prefrontal cortex, the thalamus,
and parietal and temporal association areas. Asymmetric changes occurred,
particularly in the low-effect group, and were more significant in the left frontal
cortex and thalamus and the right insula. Relative rCBF was increased in the
occipital areas. CONCLUSION: Midazolam causes dose-related changes in rCBF
in brain regions associated with the normal functioning of arousal, attention, and
memory.. 0; 0; 59467-70-8.
365. Vicari, S.; Stiles, J.; Stern, C.; Resca, A. Spatial grouping activity in children with
early cortical and subcortical lesions. Dev-Med-Child-Neurol. 1998 Feb; 40(2):
90-4; ISSN: 0012-1622.
ENGLAND. Spatial construction skills were examined in 3- to 5-year-old
children with prenatal or perinatal focal brain injury. In earlier work, a dissociation
was reported between children with injury to the right hemisphere and the left
hemisphere, right-hemisphere injury resulting in significantly lower levels of
performance. In the current paper, the effect of isolated unilateral subcortical
injury was explored. Thirty-four children with early focal brain injury were tested
in a task which required them to copy a series of simple block constructions.
There were approximately equal numbers of children with right-hemisphere and
left-hemisphere injury; within each of these groups approximately half of the
children had injury involving only subcortical regions. Consistent with the earlier
work, children with right-hemisphere injury performed significantly below
children with left-hemisphere injury and the normal controls. Importantly, no
differences were observed between the children with isolated subcortical injury
and children with injury involving both cortical and subcortical brain areas.
366. Villringer, A.; Chance, B. Non-invasive optical spectroscopy and imaging of human
brain function. Trends-Neurosci. 1997 Oct; 20(10): 435-42; ISSN: 0166-2236.
ENGLAND. Brain activity is associated with changes in optical properties of
brain tissue. Optical measurements during brain activation can assess haemoglobin
oxygenation, cytochrome-c-oxidase redox state, and two types of changes in light
scattering reflecting either membrane potential (fast signal) or cell swelling (slow
signal), respectively. In previous studies of exposed brain tissue, optical imaging
of brain activity has been achieved at high temporal and microscopical spatial
resolution. Now, using near-infrared light that can penetrate biological tissue
reasonably well, it has become possible to assess brain activity in human subjects
through the intact skull non-invasively. After early studies employing single-site
near-infrared spectroscopy, first near-infrared imaging devices are being applied
successfully for low-resolution functional brain imaging. Advantages of the optical
methods include biochemical specificity, a temporal resolution in the millisecond
range, the potential of measuring intracellular and intravascular events
simultaneously and the portability of the devices enabling bedside examinations.
367. Virgintino, D.; Monaghan, P.; Robertson, D.; Errede, M.; Bertossi, M.; Ambrosi, G.;
Roncali, L. An immunohistochemical and morphometric study on astrocytes and
microvasculature in the human cerebral cortex. Histochem-J. 1997 Sep; 29(9):
655-60; ISSN: 0018-2214.
ENGLAND. In this study, astrocytes and microvessels of the human cerebral
cortex were analysed morphometrically with the aim of acquiring quantitative
information on the glio-vascular relationships, considered to be of great
importance in the formation and functioning of the blood-brain barrier.
Immunohistochemistry for the astrocytic marker, glial fibrillary acidic protein,
was used with a computerized image analysis system. The brain tissue was
embedded using the progressive lowering of temperature method, and the image
analyser was applied to semithin sections subjected to immunogold-silver staining
and viewed by epipolarization microscopy. The results show that, in the human
cerebral cortex, astrocytes cover 11.4% of the cortex area and that their
perivascular processes are nearly as extensive as the vascular bed (0.8% versus
1.72% of the cortex area). These processes form a virtually continuous sheath
around the vascular walls, only 11% of the vessel perimeter lacking this astrocytic
glia covering. The present results, compared with previous unpublished data
obtained by conventional immunocytochemical procedures on wax sections,
indicate that low-temperature methods combined with gold-silver immunolabelling
on semithin sections significantly improve the detection of immunoreactivity and
the performance of the image analyser.. 0.
368. Vitouch, O.; Bauer, H.; Gittler, G.; Leodolter, M.; Leodolter, U. Cortical activity of
good and poor spatial test performers during spatial and verbal processing studied
with Slow Potential Topography. Int-J-Psychophysiol. 1997 Dec; 27(3): 183-99;
ISSN: 0167-8760.
NETHERLANDS. Whether essential processing of spatial information is
lateralized asymmetrically in the human cortex is still a matter of debate. In this
study, items of an Item Response Theory calibrated test for spatial ability were
used to ensure stimulus homogeneity and validity. Subjects were preselected as
extreme groups of good and poor spatializers. Mapping of true DC-recorded slow
potential shifts (SPSs) resulted in distinctly discriminable topographies with
spatial and verbal-analytic material as well as with spatial performance groups
within the spatial block. Left fronto-central negativity maxima in the verbal
condition clearly contrasted with occipito-parietal peak activity in the spatial
condition. Poor spatializers showed higher amplitudes as well as a tendency to
asymmetric activity in right parietal (parieto-temporal) areas, whereas in good
spatializers the activity was localized symmetrically in occipital and occipito-
parietal regions. The findings emphasize the importance of the right posterior
cortex for spatial processing (negativity maxima at occipital and right parietal
sites) and suggest a task-specific lower cortical efficiency or, seen from a
processing perspective, a higher Investment of Cortical Effort (ICE) on the part of
poor spatializers.
369. Volk, S. A.; Kaendler, S. H.; Hertel, A.; Maul, F. D.; Manoocheri, R.; Weber, R.;
Georgi, K.; Pflug, B.; Hor, G. Can response to partial sleep deprivation in
depressed patients be predicted by regional changes of cerebral blood flow?
Psychiatry-Res. 1997 Sep 29; 75(2): 67-74; ISSN: 0165-1781.
IRELAND. The possible predictive value of regional cerebral perfusion patterns
with respect to the response to partial sleep deprivation (PSD) was evaluated in
15 major depressive patients (mean age = 54.9 years, mean Hamilton depression
score = 21.6). Patients were studied with single photon emission computed
tomography with technetium-99 m-D,L-hexamethyl-propylene amine oxime.
Scans were performed on the morning before and after (at 08.00 h) PSD.
Responders to PSD had significantly higher perfusion in the right orbitofrontal
cortex than did non-responders before PSD. Multiple regression analysis indicated
that right orbitofrontal/basal cingulate perfusion (r = -0.77, P < 0.001) before
PSD, and left inferior temporal perfusion (r = 0.59, P = 0.01) after PSD, were
fairly accurate predictors of change in Hamilton depression scores. Thus, it
appears that the orbitofrontal cortex and the cingulate are involved in PSD and
may serve as predictors of therapeutic response.
370. Vuilleumier, P.; Reverdin, A.; Landis, T. Four legs. Illusory reduplication of the lower
limbs after bilateral parietal lobe damage. Arch-Neurol. 1997 Dec; 54(12): 1543-7;
ISSN: 0003-9942.
UNITED-STATES. OBJECTIVE: To report an unusual disorder of body schema
and its neurologic and neuropsychological correlates. DESIGN AND METHODS:
We describe a patient with a reduplicative phantom illusion of her lower limbs.
Motor and sensory functions, as well as mental representation of body and space,
were studied during the reduplication experience until its resolution. SETTING:
Clinical neurology department in a primary care hospital. PATIENT: A 64-year-
old, left-handed woman who experienced the uncontrollable and distressing feeling
of having 4 legs, without delusional belief, after surgical removal of a right-
predominant parasagittal parietal meningioma. This phenomenon spontaneously
resolved after 2 weeks. INTERVENTION: None. MAIN OUTCOME
MEASURES: Clinical neurologic examinations and standardized
neuropsychological tests, with emphasis on tests assessing orientation to body
parts, right-left discrimination, and mental orientation in space. RESULTS: The
patient had severe weakness and proprioceptive sensory loss in both lower limbs.
She had no disturbances of body schema knowledge but a striking impairment in
tasks requiring mental orientation in space, particularly for right-left laterality
discrimination. Resolution of the reduplication experience correlated with
improvement in the affected spatial abilities, while motor, sensory, and other
cognitive functioning did not significantly change. CONCLUSION: This patient's
reduplicative phantom illusion might be related to the combination of the severe
somatosensory loss with an underlying impaired mental representation of relative
positions in space.
371. Wang, S. Traumatic stress and attachment. Acta-Physiol-Scand-Suppl. 1997; 640:
164-9; ISSN: 0302-2994.
ENGLAND. Traumatic stress in the normal individual results in activation of the
sympatho-adrenal system causing a rise in noradrenaline and adrenaline,
stimulation of the thyroid system causing increased secretion of thyroid hormones
and activation of the hypothalamic-pituitary-adrenocortical (HPA) system
resulting in elevated levels of cortisol. Studies in animals and in humans with
posttraumatic stress disorder indicate that chronic traumatic stress can result in
dissociation of the sympatho-adrenal medullary and the HPA system resulting in
sustained elevations of the former system but suppressed or altered ACTH-
corticoid responsivity. As reviewed by Henry, self preservative behavior with its
emphasis on power and control, is associated with catecholamines, thyroid
hormones and left hemispheric functioning while species preservative behavior,
with its emphasis on attachment, familiarity, reverence and synchronicity, is
associated with cortisol, oxytocin and right hemispheric functioning. Traumatic
stress seems to disturb this hemispheric balance which is reflected in the
suppression of cortisol and loss of attachment behavior and other species
preservative right hemispheric functions.
372. Wassermann, E. M.; Wang, B.; Zeffiro, T. A.; Sadato, N.; Pascual Leone, A.; Toro,
C.; Hallett, M. Locating the motor cortex on the MRI with transcranial magnetic
stimulation and PET. Neuroimage. 1996 Feb; 3(1): 1-9; ISSN: 1053-8119.
UNITED-STATES. Transcranial magnetic stimulation with a focal coil was used
to map the cortical representation of a hand muscle in four healthy subjects. In
each subject, the three-dimensional locations of the magnetic stimulation positions
and about 400 positions on the surface of the head were digitized. The amplitude-
weighted center of gravity of each subject's map was found, and a line
perpendicular to the local head surface was projected inward. The digitized heads
were registered with the subjects' MRIs using the scalp contours. The coordinate
transformations yielded by this process were used to map the stimulation
positions and the perpendicular line into the MRIs. Brain areas imaged with
positron emission tomography (PET) and 15O-labeled water, activated by
movement of the same muscle, were registered with the MRIs using the brain
contours. In all cases, the magnetic stimulation lines encountered the surface of the
brain at the anterior lip of the central sulcus and ran along the precentral gyrus a
few millimeters anterior to the central sulcus, coming within 5-22 mm of all the
PET activation maxima. This technique demonstrates the accuracy of transcranial
magnetic stimulation for locating the primary motor area.
373. Wentzlaff, K. A.; Cooper, M. E.; Yang, P.; Aston, C. P.; Liu, Y. E.; Melnick, M.;
Marazita, M. L. Association between non-right-handedness and cleft lip with or
without cleft palate in a Chinese population. J-Craniofac-Genet-Dev-Biol. 1997
Jul; 17(3): 141-7; ISSN: 0270-4145.
DENMARK. The etiology of non-syndromic cleft lip with or without cleft
palate (CL +/- P) is unclear, although both familial and environmental factors are
implicated. Because CL +/- P occurs at approximately the time of brain
lateralization and is most often unilateral, developmental asymmetry effects have
been postulated in CL +/- P etiology. Handedness is frequently used as an
indicator of brain lateralization; therefore, several studies have examined the
relationship between cleft laterality and handedness. However, these studies have
had conflicting results. The present study investigated handedness in a Chinese
sample of 211 non-syndromic CL +/- P surgical probands (ascertained in Shanghai
for family studies of CL +/- P), 221 population-based but unmatched controls,
and 272 first-degree relatives of the probands. Handedness was assessed by
means of laterality quotients (LQ) calculated from questionnaire data. Mean LQ's
were compared, as were various arbitrary definitions of handedness based on the
LQ, for cases versus controls, males versus females, right-sided versus left-sided
clefts, and cleft lip alone versus cleft lip plus cleft palate. CL +/- P cases had a
significantly higher proportion of non-right-handedness (NRH) than controls,
regardless of the definition of NRH (P values < or = .001). There were no
statistically significant differences for any of the other comparisons. Familiarity
of NRH was tested by comparing first-degree relatives of cases to controls; first-
degree relatives were found to have a significantly higher proportion of NRH than
controls, supporting familial effects in NRH. These results support the concept
of a common etiology and/or developmental pathway for CL +/- P and
handedness.
374. Wienbruch, C.; Eulitz, C.; Lehnertz, K.; Brockhaus, A.; Elger, C. E.; Elbert, T.; Hoke,
M. Methohexital-induced changes in spectral power of neuromagnetic signals:
beta augmentation is smaller over the hemisphere containing the epileptogenic
focus. Brain-Topogr. 1997 Sep; 10(1): 41-7; ISSN: 0896-0267.
UNITED-STATES. Previous research has suggested that methohexital, a short-
term barbiturate, alters activity in the primary epileptogenic area. It can be
assumed that drug-induced activation of the epileptogenic focus provides a rapid
and safe method to obtain a sufficient amount of information relevant for the
lateralization and localisation of the primary epileptogenic area. This study shows
that methohexital changes spectral power in the beta band derived from
magnetoencephalographic (MEG) signals over the hemisphere ipsilateral to the
primary epileptogenic area. This effect was demonstrated for 10/13 of the
investigated patients suffering from unilateral temporal lobe epilepsy (TLE). The
side and location of the primary epileptogenic area of these patients (5 left TLE, 8
right TEL) was determined invasively during presurgical evaluation. During a 1-2
minute interval after intravenous bolus injection of 100 mg methohexital a clear
lateralization effect in the beta band was observed, which differed marginally
between fronto-central, fronto-temporal and temporo-parietal brain regions. In
addition, bilateral spectral power changes were obtained in the theta, alpha and
gamma bands that differed between brain regions. Analyses of simultaneously
recorded scalp electroencephalographic (EEG) data revealed effects consistent
with those of the MEG analysis. The reduced enhancement of beta band spectral
power of MEG recordings provides a potential application for the non-invasive
lateralization of the primary epileptogenic area.. 18652-93-2.
375. Wigal, S. B.; Swanson, J. M.; Potkin, S. G. Lateralized attentional deficits in drug-free
and medicated schizophrenic patients. Neuropsychologia. 1997 Dec; 35(12):
1519-25; ISSN: 0028-3932.
ENGLAND. Performance on a cued reaction time (RT) task, theoretically linked
to posterior and anterior neuroanatomical systems in the brain (Posner, M. I. et
al., Science, 1988, 210, 1627-1631; Archives of General Psychiatry, 1988, 15,
811-821), was used to assess sensory orienting and maintenance of attention. In
schizophrenic patients, Posner et al. found a lateralized abnormality in RT (longer
RTs to uncued targets in the right visual field than in the left visual field), as did
Maruff et al. (Neuropsychologia, 1995, 33, 1205-1223), but Strauss et al. (Journal
of Psychiatric Research, 1991, 37, 139-146), among others, did not replicate this
effect. However, the subjects in these studies differed in the percentage of
schizophrenic patients taking neuroleptic medication at the time of testing and in
the chronicity of the illness. In the present study, we used two groups of
schizophrenic subjects to control for the use of neuroleptic medication. The
lateralized abnormality in RT was observed in the drug-free group of
schizophrenic subjects, but not in the group of drug-treated schizophrenic
subjects.. 0.
376. Wikstrom, H.; Roine, R. O.; Salonen, O.; Aronen, H. J.; Virtanen, J.; Ilmoniemi, R. J.;
Huttunen, J. Somatosensory evoked magnetic fields to median nerve stimulation:
interhemispheric differences in a normal population. Electroencephalogr-Clin-
Neurophysiol. 1997 Nov; 104(6): 480-7; ISSN: 0013-4694.
IRELAND. The objective of the present study was to evaluate the normal
interhemispheric variability of the locations and activation strengths of the
somatosensory cortices. Somatosensory evoked magnetic fields (SEFs) were
recorded with a 122-channel magnetometer in 23 healthy subjects (mean age 57
years) to stimulation of left and right median nerves. Equivalent current dipole
(ECD) strengths and locations were determined for the main SEF deflections at
the contralateral primary sensorimotor (SMI) and secondary somatosensory
(SIIc) cortices. In a Cartesian co-ordinate system, defined by the preauricular
points and the nasion, the SMI sources were slightly but significantly more
laterally and anteriorly located in the right than in the left hemisphere. No
systematic co-ordinate asymmetries were found for the SIIc sources. In individual
subjects, the interhemispheric differences in the ECD co-ordinates averaged less
than 6 mm at both SMI and SIIc. The group means of the source strengths did not
differ between the hemispheres, but individual differences were on average 20%
for the SMI and 65% for the SIIc sources. We conclude that at the individual level,
the median nerve SEFs from SMI can be used to detect abnormally large
interhemispheric asymmetries of source locations in the centimetre scale.
377. Woodruff, P. W.; Wright, I. C.; Shuriquie, N.; Russouw, H.; Rushe, T.; Howard, R. J.;
Graves, M.; Bullmore, E. T.; Murray, R. M. Structural brain abnormalities in male
schizophrenics reflect fronto-temporal dissociation. Psychol-Med. 1997 Nov;
27(6): 1257-66; ISSN: 0033-2917.
ENGLAND. BACKGROUND: Many studies have separately reported
abnormalities of frontal and temporal lobe structures in schizophrenia, but little is
known of structural fronto-temporal associations in this condition. We
investigated whether male patients with chronic schizophrenia would show
abnormal patterns of correlation between regional brain volumes. METHODS:
Structural magnetic resonance images of the brain in 42 patients were compared
with 43 matched unaffected controls. We explored the pattern of association
between regional brain volumes by correlational analyses, and non-parametrically
tested for significance of between-group differences by randomization. RESULTS:
The schizophrenics demonstrated significant volume deficits in several brain
regions (left temporal lobe and hippocampus, right dorsolateral prefrontal cortex),
and significant volume increases in the ventricular system (third ventricle and left
temporal horn of the lateral ventricle). Controls demonstrated large positive
correlations (r > 0.4) between prefrontal and temporal lobe regions. By contrast,
inter-regional correlations significantly reduced in schizophrenics included those
between prefrontal, anterior cingulate and temporal regions, and between posterior
cingulate and hippocampus (P < 0.05). The most salient abnormality in patients
was a dissociation between prefrontal and superior temporal gyrus volumes (P <
0.01). CONCLUSIONS: These results support the existence of a relative 'fronto-
temporal dissociation' in schizophrenia which we suggest may be due to lack of
mutually trophic influences during frontal and temporal lobe development.
378. Yamaguchi, K.; Goto, N. Three-dimensional structure of the human cerebellar dentate
nucleus: a computerized reconstruction study. Anat-Embryol-Berl. 1997 Oct;
196(4): 343-8; ISSN: 0340-2061.
GERMANY. To explore the regional differences in neuronal cytoarchitecture of
human dentate nucleus, we examined first the three-dimensional structure of this
nucleus with a computerized reconstruction technique, after making serial sections
of the brain in seven fetuses aged from 20 to 39 weeks of gestation (WG), an
infant (1-month-old) and two adults (22- and 85-year-old). The surface was
broadly smooth at 20-22 weeks, but primary gyri or fissures were noticed in the
rostral half of the lateral surface, earliest in its dorsal region. A small cavity (the
hilus nuclei dentati) was situated in the middle of the medial surface, with four
distinct margins. A great progress in gyration was noted after 22 weeks: gyri were
observed over the entire surface by 28-29 weeks. Gyri were thicker in the caudal
half than the rostral half both in the lateral and the medial surfaces. At this stage,
the rostral margin of the hilus was partially cut off and the hilus was elongated
toward the rostral tip, but its relative size appeared to be grossly equal to that at
22 weeks. The hilus began to open wider and wider after 30 weeks. Subdivision of
the human dentate nucleus into two different parts (the smaller microgyric rostral
part and the larger macrogyric caudal part) was accomplished by 35 weeks. We
have previously, using morphometric approaches, reported that a vulnerable (or
critical) period may exist during 20-30 weeks in the fetal development of the
dentate nucleus. It is possible that this special ten weeks of mid-gestation may be
coincident with the time of extensive growth in gyration for this nucleus. It will be
necessary to sample the neurons independently from at least two different parts,
as described above, to design further microscopic studies on the regional
differences or on other cytological investigations.
379. Yamamoto, M.; Ban, S.; Ide, M.; Jimbo, M. A diffuse white matter ischemic lesion
appearing 7 years after stereotactic radiosurgery for cerebral arteriovenous
malformations: case report. Neurosurgery. 1997 Dec; 41(6): 1405-9; ISSN: 0148-
396X.
UNITED-STATES. OBJECTIVE AND IMPORTANCE: Little information is
available about radiation-induced complications occurring more than 5 years after
radiosurgical treatment for arteriovenous malformations. CLINICAL
PRESENTATION: We present a patient with arteriovenous malformations who
experienced hemimotor weakness caused by a diffuse white matter necrotic lesion
developing 7 years after gamma knife radiosurgery. The original nidus had been
too large (24.1 cm3) to be totally covered and irradiated with a peripheral dose of
20 to 25 Gy. Therefore, the lower half of the nidus, which was adjacent to the
major feeding artery, had been partially covered with a 30% isodose volume using
two target points with an 18-mm collimator. A central dose of 70 Gy was used to
obtain 21 Gy at the periphery. Complete nidus obliteration was angiographically
confirmed 38 months after radiosurgery. After a 6-year uncomplicated period, this
patient experienced a convulsive seizure and then mild right hemiparesis.
INTERVENTION: Computed tomography demonstrated a diffuse hypodense
area in the left white matter, which had not been revealed by the previous
examination. With steroid treatment, this patient achieved clinical improvement,
although there was no significant improvement in the computed tomography-
demonstrated white matter lesion. CONCLUSION: Although the evaluation of
this patient may not be sufficient and further examinations may be necessary, we
tentatively conclude that the computed tomography-demonstrated hypodense
lesion in this patient is a radiation-related necrotic lesion. Long-term follow-up is
crucial, even after the "treatment goal" has been achieved.
380. Yanagawa, Y.; Kiyozumi, T.; Terai, C.; Sakamoto, T.; Okada, Y. [A case of traumatic
hematoma in the basal ganglia: successful drainage with ultrasound-guided
aspiration surgery via burr hole]. No-Shinkei-Geka. 1997 Dec; 25(12): 1105-8;
ISSN: 0301-2603.
JAPAN. A case was reported of massive traumatic hematoma of the basal ganglia
which was treated successfully by ultrasound-guided aspiration surgery. A 8-
year-old girl was transferred to our hospital 20 minutes after a traffic accident. She
was in stupor and had right hemiplegia. A skull x-rays showed right temporal
linear fracture and a head CT disclosed left massive putaminal hematoma.
Ultrasound-guided aspiration surgery via a burr hole was performed under general
anesthesia and 30 ml of hematoma was successfully evacuated. Her symptoms
and signs improved gradually and she was discharged on foot 3 weeks after the
accident. The clinical feature and mechanism of development of the hematoma in
this lesion, and usefulness of ultrasound-guided aspiration surgery were also
discussed.
381. Yasui, T.; Sakamoto, H.; Kishi, H.; Komiyama, M.; Iwai, Y.; Yamanaka, K.;
Nishikawa, M. Bilateral dissecting aneurysms of the vertebral arteries resulting in
subarachnoid hemorrhage: case report. Neurosurgery. 1998 Jan; 42(1): 162-4;
discussion 165; ISSN: 0148-396X.
UNITED-STATES. OBJECTIVE AND IMPORTANCE: We present the case
of a patient with bilateral dissecting aneurysms of the vertebral arteries resulting
in subarachnoid hemorrhage. CLINICAL PRESENTATION: A 44-year-old man
suffered a sudden onset of severe occipital headache and nausea and then
dysphasia caused by subarachnoid hemorrhage. A computed tomographic scan
demonstrated right side dominant subarachnoid hemorrhage mainly in the
posterior fossa. Angiography revealed bilateral, vertebral dissecting aneurysms.
The right aneurysm was larger and had a bleb-like protrusion, which strongly
suggested a causative lesion of the subarachnoid hemorrhage. Six months later, the
patient was referred to our hospital for further evaluation and treatment.
INTERVENTION: The ruptured right aneurysm was trapped surgically through a
lateral suboccipital approach. The patient's postoperative course was
unremarkable, and he was discharged on the 14th day after surgery. However,
postoperative angiography demonstrated slight enlargement of the left
nonruptured aneurysm. Four months after surgery, the patient developed brain
stem ischemic symptoms. The angiography conducted at that time showed further
enlargement of the left aneurysm. Five months after surgery, fatal rupture of the
left aneurysm occurred. CONCLUSION: These results indicate that sacrifice of
the unilateral vertebral artery may result in an enlargement of the contralateral
nonruptured aneurysm and may thus be dangerous in the case of a patient with
bilateral dissecting aneurysms.
382. Yazawa, K.; Fukaya, Y.; Nakano, H.; Kuroda, H.; Nishimura, K.; Amano, J. [A case
of a successfully treated subclavian aneurysm complicated by a brachiocephalic
aneurysm, and the left vertebral artery occlusion]. Nippon-Kyobu-Geka-Gakkai-
Zasshi. 1997 Nov; 45(11): 1854-7; ISSN: 0369-4739.
JAPAN. The patient was a 67-year-old male. Preoperative DSA study revealed a
right subclavian aneurysm, a brachiocephalic aneurysm, stenosis of the left
common carotid artery and the left subclavian artery, and occlusion of the left
vertebral artery. An intraoperative occlusion test of the right vertebral artery
showed a decline of the brainstem auditory evoked responses (BAER) seven
minutes after the start of the procedure. Cardiopulmonary bypass was established
by femoral arterial and bicaval cannulation. Under selective cerebral perfusion by
cannulation of both common caroid arteries, a partial aortic arch replacement was
performed using a graft patch with 3 branches. These three branches were
connected to the right subclavian artery and to both common carotid arteries,
respectively. Under deep hypothermia the right vertebral artery was
reconstructed with the saphenous vein graft. Proximal anastomosis between the
saphenous vein graft and the right caroid graft was done perfusion from a branch
of the saphenous vein graft in order to shorten ischemic time of basilar arterial
region. The patient was weaned from bypass without problems. After weaning
the BAER test was again performed and found to be normal. The postoperative
course was uneventful. Postoperative DSA examination showed good blood flow
in all the reconstructed vessels. This study suggests that deep hypothermia and
shortening of ischemic time of the basilar arterial region are effective in preventing
ischemic injury of the brain stem and the cerebellum.
383. Yoshikawa, K.; Iwamoto, K.; Sugimoto, E.; Takanashi, Y.; Nakajima, K. [A case of
porencephaly with mirror movements: pathophysiological investigation by using
long-latency long-loop reflex and dipole tracing method]. Rinsho-Shinkeigaku.
1997 Jun; 37(6): 500-5; ISSN: 0009-918X.
JAPAN. We report a 42-year-old left-handed woman with congenital right
hemiparesis and bilateral mirror movements in the hands. She had a porencephaly
of the left hemisphere and the brain MRI demonstrated cortical and subcortical
defect of the left hemisphere from Brodmann's area 6 to 40 including the left
motor cortex. By electrical stimulation of the left median nerve at the wrist, N20
of the somatosensory evoked potential was recorded in the right postcentral gyrus
by using the dipole tracing method. Long-loop reflexes from the bilateral thenar
muscles were recorded and their latencies were almost the same. The stimulation
of the right median nerve did not evoke N20, nor long-loop reflex. These
electrophysiological findings suggest that the reorganization of the motor system
made the right motor cortex to innervate bilateral hands, and caused bilateral
mirror movements. In other words, the mirror movements managed to relieve the
paralysis of the right hand though the damage of the left motor cortex was
present. In the previous literature we are able to find hypotheses regarding the
mechanism of mirror movements in congenital hemiparesis. Here we discussed
about the reorganization of the motor system in the damaged brain.
384. Young, Su P.; Shimomura, T.; Okumura, Y. [A case of tension pneumocephalus due
to scalp-ventricle fistula following trepanation after a 9-year interval]. No-
Shinkei-Geka. 1997 Nov; 25(11): 1043-7; ISSN: 0301-2603.
JAPAN. We report a case of tension pneumocephalus due to scalp-ventricle
fistula following trepanation surgery after a 9-year interval. A 68-year-old man
had a past history of subarachnoid hemorrhage (unknown etiology) in 1987. At
that time, he underwent an operation for ventriculoperitoneal (V.P) shunt and
subduroperitoneal (S.P) shunt following ventricular drainage for hydrocephalus.
He was admitted to our hospital with generalized convulsions on Feb. 26, 1996.
On admission, he presented with disoriented consciousness and mild left
hemiparesis. The skull films and CT showed abundant air collection in the
bifrontal lobe mainly in the bilateral anterior horns of the lateral ventricle. We
initially suspected air entry from frontal skull base fracture. However, a dimple
was found on the right frontal scalp and connection between the dimple and the
intracranial space was detected by fistulography. Scalp-ventricle fistula following
trepanation was proved to be the air entry and it brought about tension
pneumocephalus. On Mar. 6, closure of the fistula with a rotation skin flap was
achieved. The collected air was completely absorbed, but a low-density area in the
right frontal lobe remained on CT examination. We surmised that irreversible brain
damage had been caused by longtime air exposure injury.
385. Yune, M. J.; Lee, J. D.; Ryu, Y. H.; Kim, D. I.; Lee, B. I.; Kim, S. J. Ipsilateral
thalamic hypoperfusion on interictal SPECT in temporal lobe epilepsy. J-Nucl-
Med. 1998 Feb; 39(2): 281-5; ISSN: 0161-5505.
UNITED-STATES. Interictal brain SPECT is useful for the localization of a
seizure focus. Concomitant hypoperfusion of the ipsilateral thalamus on interictal
SPECT has been noted for temporal lobe epilepsy. In this study, we aimed to
evaluate the prevalence of thalamic hypoperfusion ipsilateral to temporal
hypoperfusion (ipsilateral thalamic hypoperfusion) and to assess the usefulness
of this finding for the lateralization of epileptic foci on interictal SPECT for
temporal lobe epilepsy patients. METHODS: Forty-six patients with refractory
temporal lobe epilepsy underwent interictal brain SPECT after intravenous
injection of 555-740 MBq of 99mTc-ECD. Perfusion impairments in the brain,
especially the temporal lobe and thalamus, were evaluated. The localization of
seizure foci was determined in conjunction with scalp, ictal and cortical
electroencephalography, MRI and clinical outcomes. Ictal SPECT was performed
for 5 of the 12 patients. RESULTS: Concomitant decreased perfusion in both the
temporal lobe and the ipsilateral thalamus was observed for 12 (26%) of 46
temporal lobe epilepsy patients on interictal brain SPECT. Seven patients showed
hypoperfusion in the left temporal lobe and ipsilateral thalamus. Five patients
showed hypoperfusion in the right temporal lobe and ipsilateral thalamus. In
addition, hypoperfusion in the ipsilateral basal ganglia (ten patients) or
contralateral cerebellum (four patients) was observed. CONCLUSION: Ipsilateral
thalamic hypoperfusion is not uncommon in temporal lobe epilepsy. The exact
mechanism causing ipsilateral thalamic hypoperfusion is uncertain; however,
corticothalamic diaschisis may be an important factor. This finding may aid in the
lateralization of seizure foci on interictal brain SPECT.. 0; 0; 0; 4371-52-2.
386. Zach, O.; Bauer, H. C.; Richter, K.; Webersinke, G.; Tontsch, S.; Bauer, H.
Expression of a chemotactic cytokine (MCP-1) in cerebral capillary endothelial
cells in vitro. Endothelium. 1997; 5(3): 143-53; ISSN: 1062-3329.
SWITZERLAND. A full-length cDNA encoding the porcine monocyte
chemoattractant protein-1 (pMCPC-1) was isolated from growth-stimulated
porcine cerebral capillary endothelial cells (cEC); the pMCP-1 cDNA showed
89% identity to human MCP-1 and was isolated by use of subtractive
hybridization and differential screening of two phenotypically different sub-
populations of cloned cEC. pMCP-1 was abundantly expressed in cEC grown in
the presence of FCS, ECGF and heparin whereas lower expression was observed
in cEC kept in FCS-supplemented medium only. As shown by Northern blot
analysis, no pMCP-1 transcripts were present in total RNA derived from freshly
isolated brain capillaries, large brain vessels or whole brain homogenate. MCP/JE
expression was also demonstrated in ECGF/heparin-treated murine cEC.
Astrocytes and smooth muscle cells grown in FCS-supplemented medium did not
show MCP-1 expression. Treatment of porcine cEC with TNF-alpha increased
pMCP-1 mRNA levels in a dose-dependent manner. These data further support
the notion that cerebral capillary endothelial cells actively participate in processes
of CNS host defense.. 0; 0; 0; 0; 0; 0; 0; 9005-49-6.
387. Zeffiro, T. Clinical functional image analysis: artifact detection and reduction.
Neuroimage. 1996 Dec; 4(3 Pt 3): S95-100; ISSN: 1053-8119.
UNITED-STATES. Rapid improvements in functional magnetic resonance
neuroimaging technology have resulted in impressive advances in our
understanding of structure/function relationships in the human brain. The
application of this new technology to the understanding of human brain disease is
currently limited by difficulties in extracting task-related signal change from signal
intensity time series that have been contaminated by artifacts arising from various
intrinsic and extrinsic sources. Effects induced by interscan head motion are a
major source of these artifacts. The correction of these artifacts by registration of
pairs of reconstructed images has been a focus of research for the past few years
and there are now a number of effective means to compensate for this source of
noise. This paper discusses issues concerning the prevention and correction of
interscan head motion as well as other sources of error variation in fMRI time
series.
388. Zhang, H. F.; Ong, W. Y.; Leong, S. K.; Laperche, Y. Species differences in the
localisation of gamma-glutamyl transpeptidase immunopositive cells at the blood-
brain interface. J-Hirnforsch. 1997; 38(3): 323-30; ISSN: 0021-8359.
GERMANY. The expression of gamma-glutamyl transpeptidase (GGT) has been
associated with the emergence of a functional blood-brain barrier. We have
undertaken a precise localisation of this enzyme in the cerebral cortical vessels of
different species, by immunocytochemistry using a polyclonal antibody and light
and electron microscopy. GGT immunoreaction product was present on the
luminal surface of endothelial cells in 1-day-old to 3-month-old rats, whereas in
the mouse, monkey and human cortex, this protein was present in astrocytic
endfeet around the vessels. No labelling was observed in the other cellular
components of the vessel walls, such as pericytes, fibroblasts, smooth muscle
cells and perivascular cells. The localisation of GGT in astrocytes in mice,
monkeys and humans suggests that these cells could play a role in the detoxication
of lipophilic xenobiotic substances that cross the endothelial barrier. In these
species, astrocytes can be viewed as a second line of defense against xenobiotics,
beyond the capillary endothelium.. EC 2.3.2.2.
389. Zhu, B. S.; Blessing, W. W.; Gibbins, I. L. Parasympathetic innervation of cephalic
arteries in rabbits: comparison with sympathetic and sensory innervation. J-
Comp-Neurol. 1997 Dec 22; 389(3): 484-95; ISSN: 0021-9967.
UNITED-STATES. We investigated the distribution of parasympathetic,
sympathetic, and sensory perivascular nerve fibers in rabbit cephalic arteries
supplying the brain, exocrine glands, nasal mucosa, masseter muscles, tongue, and
skin in the face and also examined cranial autonomic and sensory ganglia. NADPH
diaphorase (NADPHd)-positive and vasoactive intestinal peptide-like
immunoreactive (VIP-LI) neurons were located in the cranial parasympathetic
ganglia. Neuropeptide Y (NPY)-LI neurons occurred mainly, and dopamine beta-
hydroxylase (DBH)-LI neurons occurred exclusively, in the superior cervical
(sympathetic) ganglion. Substance P (SP)-LI and calcitonin gene-related peptide
(CGRP)-LI neurons occurred only in the trigeminal (sensory) ganglion. Therefore,
it was assumed that NADPHd-positive and VIP-LI perivascular nerve fibers in
cephalic arteries were parasympathetic, all DBH-LI and most NPY-LI fibers were
sympathetic, and SP-LI and CGRP-LI fibers were sensory in nature. In the
cerebral arteries, NADPHd-positive and VIP-LI varicose fibers were more
numerous in the rostral than in the caudal half of the Circle of Willis. In the
extracranial arteries, NADPHd-positive and VIP-LI fibers were most abundant in
the lingual, lacrimal, and supraorbital arteries; sparse in the parotid and
submandibular arteries; and absent in the ear artery. There was an obvious
proximal-to-distal density gradient along individual cephalic arterial trees. In
contrast, DBH-LI, NPY-LI, SP-LI, and CGRP-LI varicose nerve fibers were
similar in density in all cephalic arteries and their branches. These neuroanatomical
findings suggest that differential parasympathetic innervation in cephalic arteries
may play a role in the partitioning of blood flow between different cephalic
tissues.. EC 1.6.99.1; 0; 0.
390. Zorrilla, L. T.; Cannon, T. D.; Kronenberg, S.; Mednick, S. A.; Schulsinger, F.;
Parnas, J.; Praestholm, J.; Vestergaard, A. Structural brain abnormalities in
schizophrenia: a family study. Biol-Psychiatry. 1997 Dec 15; 42(12): 1080-6;
ISSN: 0006-3223.
UNITED-STATES. Structural brain abnormalities such as ventricular
enlargement are robust correlates of schizophrenia, but the degree of difference
compared with unrelated normal controls is only moderate (< 1 standard
deviation), and only 40% of patients have values on these measures that fall
outside of the normal distribution. Family studies can help to clarify the meaning
of this overlap by controlling for some of the non-schizophrenia-related genetic
variation in neuroanatomical traits. Computerized tomographic scans of the brain
were used to measure ventricular and sulcal cerebrospinal fluid (CSF) to brain
ratios (VBR and SBR) for each hemisphere in 16 pairs of discordant siblings from
the Copenhagen Schizophrenia High-Risk Project. Schizophrenics' values for VBR
and SBR exceeded those of their nonschizophrenic siblings in 75% of the pairs; on
average, patients' values on these measures were 1 and 5 standard deviations
larger, respectively, than those of their nonschizophrenic siblings. Sulcal and left
hemisphere effects were significantly more pronounced than ventricular and right
hemisphere effects. After controlling for between-family variation, structural brain
abnormalities appear to be more prevalent and more pronounced in schizophrenia
than has previously been assumed, with relatively greater deviation observed for
cortical and left hemisphere measures of CSF space enlargement.