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,