The following chapters in DeJong's Textbook "Neurological Examination" are recommended readings prior to the module Motor Systems as taught by Prof. Dr. Frederick Robert Carrick.

Chapter 11 Ocular Nerves

Chapter 26 Function of the Motor Systems

Chapter 27 Motor Strength and Power

Chapter 31 Abnormal Movements

The following references were utilized by Prof. Dr. Frederick Carrick in the preperation of his lecture for the Motor System of human kind.

 

1. Ackles, P. K.; Cook, K. G. Stimulus probability and event-related potentials of the

brain in 6-month-old human infants: a parametric study. Int-J-Psychophysiol.

1998 Jul; 29(2): 115-43; ISSN: 0167-8760.

NETHERLANDS. The effects of a priori stimulus probability and local-stimulus

sequences on the Nc, NSW and Pc components of the event-related brain

potentials were studied in six groups of 6-month-old human infants. Predictions

from memory, expectancy and attentional accounts of the Nc, NSW and Pc

components were examined using an infant-control oddball paradigm in which

visual stimuli were presented across groups, at 0.90/0.10, 0.80/0.20, 0.70/0.30,

0.60/0.40, 0.50/0.50 (alternation) and 0.50/0.50 (random) probabilities. The main

results indicated that stimulus probabilities and local-stimulus sequences affected

Nc amplitude and latency, NSW amplitude but not the Pc component. Concurrent

visual fixation performance was also found to be influenced by stimulus

probabilities. The results were discussed in terms of the predictions from

memory, expectancy and attentional accounts of the infant late components.

2. Afanas'ev, S. V.; Tolkunov, B. F.; Orlov, A. A.; Selezneva, E. V. Collective responses

of neostriatal (putamen) neurons during alternative behavior in monkeys.

Neurosci-Behav-Physiol. 1998 May; 28(3): 231-7; ISSN: 0097-0549.

UNITED-STATES. A monkey (Macaca nemestrina) was trained to perform a

behavioral program consisting of the selection and execution of a defined sequence

of actions according to a visual conditioned signal. Discriminant analysis was used

to evaluate the parameters of the collective activity of six simultaneously recorded

putamen neurons. The collective activity of the neurons showed significant

differences associated with execution by the monkey of left- and right-sided tasks.

These differences were seen to be quite consistent in different groups of neurons.

Despite the fact that putamen neurons were involved in the performance of nine

separately analyzed fragments of the program, differences were seen in two of

these: at the moment of taking the decision relating to the direction of movement,

and after its completion when a signal indicating the completed result was

presented, independently of whether the animal selected the side for the action

correctly or incorrectly. In the case of erroneous decisions, the response mosaic

differed from that obtained for correct decisions; however, differences due to

previously taken decisions regarding the side of action were preserved. These

differences were greater at the point of program completion than at the moment of

deciding the direction of movement.

3. Ahonen, J. P.; Jehkonen, M.; Dastidar, P.; Molnar, G.; Hakkinen, V. Cortical silent

period evoked by transcranial magnetic stimulation in ischemic stroke.

Electroencephalogr-Clin-Neurophysiol. 1998 Jun; 109(3): 224-9; ISSN: 0013-

4694.

IRELAND. OBJECTIVES: Transcranial magnetic stimulation (TMS) of the

motor cortex produces motor evoked potentials (MEPs). Besides this excitatory

response, TMS has inhibitory effects. When TMS is performed during voluntary

muscle contraction, the MEP is followed by a pause in electromyographic activity

(cortical silent period, SP). The aim of this study was to evaluate the clinical

usefulness of the SP. METHODS: We studied SP changes in 50 patients with

acute hemispheric brain infarction. A stimulator with a round coil and a fixed

intensity of 90% of maximum was used to evoke MEPs. RESULTS: SP was

elicited on the affected side in 29 of the 50 patients. The mean SP duration was

markedly longer on the affected side in the patient group. There were no

significant differences between left and right sides in the means of the MEP

amplitude ratio (amplitude related to corresponding amplitudes to peripheral

electric stimulation) and MEP latencies in the patient group. Prolonged SP was

found in 25 of the 29 patients (86%) whereas only 4 (14%) had abnormalities in

MEP latency or amplitude ratio. The mean SP duration was significantly

prolonged also in a subgroup of 14 patients with normal hand function.

CONCLUSIONS: The SP measurement is an easily performed and sensitive

method to detect even subclinical disturbances in motor system function in

ischemic stroke.

4. Airapetiants, M. G.; Levshina, I. P.; Nozdracheva, L. V.; Shuikin, N. N. [The action

of the neurotoxin AF64A on the reactions of neuroticized rats]. Deistvie

neirotoksina AF64A na reaktsii nevrotizirovannykh krys. Zh-Vyssh-Nerv-Deiat-

Im-I-P-Pavlova. 1998 May; 48(3): 534-40; ISSN: 0044-4677.

RUSSIA. The effects of intracerebroventricular administration of ethylholine

aziridinum ion (AF64A) were studied in neuroticized male Wistar rats. The

cholinotoxin was bilaterally injected in the dose of 3 nmol. AF64A produced a

significant decrease in arterial pressure and activity of respiratory enzymes

succinate dehydrogenase and NADH-dehydrogenase in hippocampus and motor

cortex. Increase in the local blood flow in the hippocampus and motor cortex had a

compensatory character.. EC 1.3.99.1; EC 1.6.99.3; 0; 0; 62-49-7; 63918-37-6.

5. Anastasopoulos, D.; Haslwanter, T.; Fetter, M.; Dichgans, J. Smooth pursuit eye

movements and otolith-ocular responses are differently impaired in cerebellar

ataxia. Brain. 1998 Aug; 121( Pt 8): 1497-505; ISSN: 0006-8950.

ENGLAND. Horizontal and vertical smooth pursuit was compared with otolith-

ocular responses in 11 patients with cerebellar ataxia and 21 normal subjects using

three-dimensional magnetic search coil eye movement recordings. Otolith-ocular

responses were investigated during off-vertical axis rotation. This stimulus

induces nystagmus consisting of the exponentially decaying canalicular response,

and an eye-velocity modulation and offset which arise from the excitation of the

otoliths by the gravity vector, which lasts as long as the rotation continues.

Otolith-ocular reflexes are intimately interrelated with visual tracking when real

targets are viewed during linear motion. The responses of both the translational

vestibulo-ocular reflex and the pursuit system have been shown to be linearly

dependent on the inverse of the viewing distance, so that a common central

pathway for the two systems has been suggested, probably travelling through the

cerebellum. Thus, the aim of the study was to evaluate to what extent these

reflexes are disturbed in cerebellar disease. The results confirm the earlier notion

that in normal subjects pursuit performance is better for horizontal than for

vertical tracking, and that it is better for upward than for downward tracking. This

pattern is also found in patients. In addition, smooth pursuit performance is

clearly degraded in patients, but the modulation of eye-velocity during off-vertical

axis rotation is enhanced. Since the amount of this enhancement does not correlate

with the amount of pursuit impairment, degradation of smooth pursuit and

pathological enhancement of otolith-ocular responses seem to be independent

effects of cerebellar degeneration. Thus, the increase in the otolith-ocular response

in patients cannot be attributed to adaptational mechanisms trying to overcome

the smooth pursuit deficiency; it is more likely to represent pathological

disinhibition of otolith derived responses. The absence of compensatory eye-

velocity offset during off-vertical axis rotation may reflect the fact that in patients

the otolith signals are not utilized in computations thought to be important for

spatial orientation mechanisms arising from the interaction of vestibular, visual

and somatosensory signals.

6. Anderson, R. W.; Keller, E. L.; Gandhi, N. J.; Das, S. Two-dimensional saccade-

related population activity in superior colliculus in monkey. J-Neurophysiol.

1998 Aug; 80(2): 798-817; ISSN: 0022-3077.

UNITED-STATES. The two-dimensional distribution of population activity in

the superior colliculus (SC) during saccadic eye movements in the monkey was

estimated using radial basis functions. To make these ensemble activity estimates,

cells in the deeper layers of the SC were recorded over much of the rostrocaudal

(caudal to 3.8 mm from the rostral tip), mediolateral extent of this structure. The

dynamic movement field of each cell was determined at 2-ms intervals around the

time of saccades for a wide variety of horizontal and oblique movements.

Collicular neurons were divided into partially overlapping dorsal and ventral cell

layers on the basis of recorded depth in SC. The pattern of presaccadic activity

was used as an additional discriminant to sort the cells in the two layers into

separate burst (dorsal) and buildup (ventral) cell classes. Rostrocaudal and

medioventral cell location on the colliculus was estimated from the optimal target

vector for a cell's visual response rather than from the optimal motor vector. The

former technique was more reliable for locating some buildup neurons because it

produced locations that compared better with the locations suggested by electrical

stimulation. From the movement field data and from the estimates of each cell's

anatomic location, a similar algorithm was used to compute the two-dimensional

population activity in the two layers of the SC during horizontal and oblique

saccades. A subset of the sample of neurons, located near the horizontal meridian

of the SC, first was used to compute one-dimensional dynamic population

activity estimates for horizontal saccades to allow partial comparison to previous

studies. Statistical analyses on the one-dimensional data were limited to saccades

of </=20 degrees. The analyses indicated that while there was a small rostrally

directed shift in the center of gravity of the distributed activity in the buildup cell

layer, there was little support for the theory of a systematic rostrally directed

spread of the leading edge of the activity. The two-dimensional results extend the

previous one-dimensional estimates of collicular activity during saccades.

Discharge in the burst layer was invariant in size for all saccade vectors and

symmetrically arranged about a center of gravity that did not move during

saccades. The size of the active area in the buildup layer grew modestly with

saccade amplitude, whereas the distribution of activity was skewed toward the

rostral end of the SC for saccades larger than 10 degrees. There was a small, but

consistent shift in the center of gravity of the two-dimensional activity that was

directed along the horizontal meridian (for horizontal movements) or an oblique

meridian (for oblique movements) of the SC. However, the spread of activity

during a saccade was as large or larger in the mediolateral direction as it was in the

rostral direction. The results indicate that changes in activity occur in an extended

zone on the SC, and in all directions but caudal, in the buildup layer during

saccades and do not support the idea of a rostrally directed spread of activity as a

dynamic control mechanism for saccades. Our results and those of previous

investigators of collicular population activity may be limited by stationarity

concerns in that the cells used to estimate population activity were recorded in

several monkeys over an extended period of time to obtain a sufficient spatial

sample.

7. Anderson, R. W.; Keller, E. L.; Gandhi, N. J.; Das, S. Two-dimensional saccade-

related population activity in superior colliculus in monkey. J-Neurophysiol.

1998 Aug; 80(2): 798-817; ISSN: 0022-3077.

UNITED-STATES. The two-dimensional distribution of population activity in

the superior colliculus (SC) during saccadic eye movements in the monkey was

estimated using radial basis functions. To make these ensemble activity estimates,

cells in the deeper layers of the SC were recorded over much of the rostrocaudal

(caudal to 3.8 mm from the rostral tip), mediolateral extent of this structure. The

dynamic movement field of each cell was determined at 2-ms intervals around the

time of saccades for a wide variety of horizontal and oblique movements.

Collicular neurons were divided into partially overlapping dorsal and ventral cell

layers on the basis of recorded depth in SC. The pattern of presaccadic activity

was used as an additional discriminant to sort the cells in the two layers into

separate burst (dorsal) and buildup (ventral) cell classes. Rostrocaudal and

medioventral cell location on the colliculus was estimated from the optimal target

vector for a cell's visual response rather than from the optimal motor vector. The

former technique was more reliable for locating some buildup neurons because it

produced locations that compared better with the locations suggested by electrical

stimulation. From the movement field data and from the estimates of each cell's

anatomic location, a similar algorithm was used to compute the two-dimensional

population activity in the two layers of the SC during horizontal and oblique

saccades. A subset of the sample of neurons, located near the horizontal meridian

of the SC, first was used to compute one-dimensional dynamic population

activity estimates for horizontal saccades to allow partial comparison to previous

studies. Statistical analyses on the one-dimensional data were limited to saccades

of </=20 degrees. The analyses indicated that while there was a small rostrally

directed shift in the center of gravity of the distributed activity in the buildup cell

layer, there was little support for the theory of a systematic rostrally directed

spread of the leading edge of the activity. The two-dimensional results extend the

previous one-dimensional estimates of collicular activity during saccades.

Discharge in the burst layer was invariant in size for all saccade vectors and

symmetrically arranged about a center of gravity that did not move during

saccades. The size of the active area in the buildup layer grew modestly with

saccade amplitude, whereas the distribution of activity was skewed toward the

rostral end of the SC for saccades larger than 10 degrees. There was a small, but

consistent shift in the center of gravity of the two-dimensional activity that was

directed along the horizontal meridian (for horizontal movements) or an oblique

meridian (for oblique movements) of the SC. However, the spread of activity

during a saccade was as large or larger in the mediolateral direction as it was in the

rostral direction. The results indicate that changes in activity occur in an extended

zone on the SC, and in all directions but caudal, in the buildup layer during

saccades and do not support the idea of a rostrally directed spread of activity as a

dynamic control mechanism for saccades. Our results and those of previous

investigators of collicular population activity may be limited by stationarity

concerns in that the cells used to estimate population activity were recorded in

several monkeys over an extended period of time to obtain a sufficient spatial

sample.

8. Angelaki, D. E. Three-dimensional organization of otolith-ocular reflexes in rhesus

monkeys. III. Responses To translation. J-Neurophysiol. 1998 Aug; 80(2): 680-

95; ISSN: 0022-3077.

UNITED-STATES. The three-dimensional (3-D) properties of the translational

vestibulo-ocular reflexes (translational VORs) during lateral and fore-aft

oscillations in complete darkness were studied in rhesus monkeys at frequencies

between 0.16 and 25 Hz. In addition, constant velocity off-vertical axis rotations

extended the frequency range to 0.02 Hz. During lateral motion, horizontal

responses were in phase with linear velocity in the frequency range of 2-10 Hz.

At both lower and higher frequencies, phase lags were introduced. Torsional

response phase changed more than 180 degrees in the tested frequency range such

that torsional eye movements, which could be regarded as compensatory to "an

apparent roll tilt" at the lowest frequencies, became anticompensatory at all

frequencies above approximately 1 Hz. These results suggest two functionally

different frequency bandwidths for the translational VORs. In the low-frequency

spectrum (<<0.5 Hz), horizontal responses compensatory to translation are small

and high-pass-filtered whereas torsional response sensitivity is relatively

frequency independent. At higher frequencies however, both horizontal and

torsional response sensitivity and phase exhibit a similar frequency dependence,

suggesting a common role during head translation. During up-down motion,

vertical responses were in phase with translational velocity at 3-5 Hz but phase

leads progressively increased for lower frequencies (>90 degrees at frequencies

<0.2 Hz). No consistent dependence on static head orientation was observed for

the vertical response components during up-down motion and the horizontal and

torsional response components during lateral translation. The frequency response

characteristics of the translational VORs were fitted by "periphery/brain stem"

functions that related the linear acceleration input, transduced by primary otolith

afferents, to the velocity signals providing the input to the velocity-to-position

neural integrator and the oculomotor plant. The lowest-order, best-fit

periphery/brain stem model that approximated the frequency dependence of the

data consisted of a second order transfer function with two alternating poles (at

0.4 and 7.2 Hz) and zeros (at 0.035 and 3.4 Hz). In addition to clearly

differentiator dynamics at low frequencies (less than approximately 0.5 Hz), there

was no frequency bandwidth where the periphery/brain stem function could be

approximated by an integrator, as previously suggested. In this scheme, the

oculomotor plant dynamics are assumed to perform the necessary high-frequency

integration as required by the reflex. The detailed frequency dependence of the

data could only be precisely described by higher order functions with

nonminimum phase characteristics that preclude simple filtering of afferent inputs

and might be suggestive of distributed spatiotemporal processing of otolith signals

in the translational VORs.

9. Annoni, G.; Pegna, A.; Michel, C.; Estade, M.; Landis, T. Motor perseverations: a

function of the side and the site of a cerebral lesion. Eur-Neurol. 1998 Aug; 40(2):

84-90; ISSN: 0014-3022.

SWITZERLAND. Motor perseverations are commonly thought to be a sign of

frontal lobe lesions, although they may also occur following lesions outside the

frontal lobes. Moreover, differences in the type and frequency of motor

perseverations between the two cerebral hemispheres have been suggested.

Recurrent perseverations (repetition of a previous response to a subsequent

stimulus) and continuous perseverations (abnormal prolongation of a current

activity) are two different aspects of motor intentional disorders. The former have

been associated with left hemispheric lesions, and the latter with right hemispheric

lesions. To test this hypothesis, we examined 42 patients with single cerebral

lesions of different locations: 22 right hemispheric (7 frontal and 15 extrafrontal)

and 20 left hemispheric lesions (8 frontal and 12 extrafrontal), and healthy

controls with a graphic task, allowing for analysis of these two types of motor

perseverations. We found that (i) both types of perseverations increased

significantly for all groups of patients compared to normal controls, except for

recurrent perseverations in patients with right posterior lesions, (ii) there was no

significant dissociation between the type of perseverations and the side of lesions,

and (iii) there was a significant interaction between the type of perseveration,

frontal versus extrafrontal location, and the side of a lesion, which is based on the

tendency for recurrent perseverations to be increased in left posterior and right

frontal lesions, and decreased in left frontal and right posterior lesions, as

compared to continuous perseverations. These findings cast doubt about the

predominant role of the frontal lobes for motor perseverations, but support the

idea of hemispheric specialization in motor control which is, however, more

complex than previously thought.

10. Aranyi, Z.; Mathis, J.; Hess, C. W.; Rosler, K. M. Task-dependent facilitation of

motor evoked potentials during dynamic and steady muscle contractions. Muscle-

Nerve. 1998 Oct; 21(10): 1309-16; ISSN: 0148-639X.

UNITED-STATES. Task-dependent differences in the facilitation of motor

evoked potentials (MEPs) following cortex stimulation were studied in a proximal

(deltoid) and a distal muscle (abductor digiti minimi; ADM) in 23 healthy subjects

during both dynamic and steady contractions of the target muscle under isometric

and under nonisometric conditions. In the deltoid, MEP amplitudes were

significantly greater if stimulation was performed during dynamic contractions

than during steady contractions, despite equal background electromyographic

levels just prior to the stimulus. The same task-specific extra facilitation of deltoid

MEP amplitudes was also found with magnetic stimulation of the brain stem

instead of the cortex in 3 subjects. In the ADM, no such task-dependent extra

facilitation of MEPs during dynamic contractions was found. It is concluded that

in the deltoid, during dynamic contractions, a greater proportion of the spinal

motoneurons is close to depolarization threshold (greater "subliminal fringe")

whereas the number of firing motoneurons is similar to that during steady

contraction. The lack of task-dependent extra facilitation of MEPs in the ADM is

explained by the predominant recruitment principle for force gradation in small

hand muscles, which is in contrast to the predominant frequency principle used in

proximal muscles.

11. Atkinson, G.; Speirs, L. Diurnal variation in tennis service. Percept-Mot-Skills. 1998

Jun; 86(3 Pt 2): 1335-8; ISSN: 0031-5125.

UNITED-STATES. With informed consent, 6 competitive tennis players

performed alternate 15 "first" (emphasis-speed) serves and 15 "second"

(emphasis-accuracy) serves at 09:00, 14:00 and 18:00 hours. Serve velocity was

measured by the digitisation of video footage of each serve. The Hewitt Tennis

Achievement Test was employed to measure the accuracy of serve. The amount

of spin imparted on the ball was not measured. First serves were at all times of

day faster than second serves. First serves were faster but least accurate at 18:00

hours, the time of day that body temperature and grip strength were highest. At

09:00 hours, first serves were just as accurate as second serves, even though

velocity of first serves was higher. No effects for time of day were found for the

speed and accuracy of second serves. These results indicate that time of day does

affect the performance of tennis serves in a way that suggest a nonlinear

relationship between velocity and accuracy.

12. Aurora, S. K.; Welch, K. M. Brain excitability in migraine: evidence from transcranial

magnetic stimulation studies. Curr-Opin-Neurol. 1998 Jun; 11(3): 205-9; ISSN:

1350-7540.

UNITED-STATES. Central neuronal hyperexcitability is proposed to be the

putative basis for the physiologic disturbances in migraine. Because there are no

structural disturbances in migraine, only physiologic studies can provide insight

into the underlying mechanisms. Recently, transcranial magnetic stimulation has

been developed as a valuable research tool and can be used to study brain function

noninvasively. This article is a review of the studies done in migraine using

transcranial magnetic stimulation.

13. Aurora, S. K.; Welch, K. M. Brain excitability in migraine: evidence from transcranial

magnetic stimulation studies. Curr-Opin-Neurol. 1998 Jun; 11(3): 205-9; ISSN:

1350-7540.

UNITED-STATES. Central neuronal hyperexcitability is proposed to be the

putative basis for the physiologic disturbances in migraine. Because there are no

structural disturbances in migraine, only physiologic studies can provide insight

into the underlying mechanisms. Recently, transcranial magnetic stimulation has

been developed as a valuable research tool and can be used to study brain function

noninvasively. This article is a review of the studies done in migraine using

transcranial magnetic stimulation.

14. Ay, H.; Buonanno, F. S.; Price, B. H.; Le, D. A.; Koroshetz, W. J. Sensory alien hand

syndrome: case report and review of the literature. J-Neurol-Neurosurg-

Psychiatry. 1998 Sep; 65(3): 366-9; ISSN: 0022-3050.

ENGLAND. An 81 year old right handed woman developed a left alien hand

syndrome characterised by involuntary movements of choking and hitting the

face, neck, and shoulder. The patient showed multiple disorders of primary

sensation, sensory processing, hemispatial attention, and visual association, as

well as a combination of sensory, optic, and cerebellar ataxia (triple ataxia) of the

left arm in the absence of motor neglect or hemiparesis. Imaging studies disclosed

subacute infarction in the right thalamus, hippocampus, inferior temporal lobes,

splenium of corpus callosum, and occipital lobe due to right posterior cerebral

artery occlusion. This rare syndrome should be considered as a "sensory" or

"posterior" form of the alien hand syndrome, to be distinguished from the "motor"

or "anterior" form described more commonly.

15. Bair, W.; O'Keefe, L. P. The influence of fixational eye movements on the response of

neurons in area MT of the macaque. Vis-Neurosci. 1998 Jul; 15(4): 779-86; ISSN:

0952-5238.

ENGLAND. We analyzed the relationship between eye movements and neuronal

responses recorded from area MT in alert monkeys trained to maintain visual

fixation during the presentation of moving patterns. The monkeys made small

saccades which moved the eyes with velocities that spanned the sensitivity range

of MT neurons. The saccades evoked changes in the neuronal response that

depended upon (1) the level of stimulus-evoked activity amidst which the saccade

occurred and (2) the direction of the saccade relative to the preferred direction of

the neuron. Most notably, saccades were able to suppress stimulus-evoked

activity when they caused retinal image flow that opposed the neuron's preference

and were able to elicit a response or enhance weak activity when they caused flow

in the neuron's preferred direction. On average, the disturbance lasted 40 ms

beginning about 40 ms following saccade onset. Using these parameters, we

simulated synthetic spike trains from an imaginary pair of similarly tuned neurons

and determined that the interneuronal correlation due to saccades should be

negligible at all but the lowest ongoing firing rates. This conclusion was supported

from our data by the observation that response variance for single MT spike

trains was not measurably reduced during periods of stable gaze compared to

periods when eye movement exceeded a stability criterion (0.1 deg during 0.5 s).

While the intrusions caused by saccades are too short-lived and infrequent to

account for the variability of MT neuronal response (counter to the finding in V1

of Gur et al., 1997), the clear directional signal that they carry in area MT

suggests that motion perception is not blocked during saccades by suppression at

early stages in the visual pathway.

16. Bair, W.; O'Keefe, L. P. The influence of fixational eye movements on the response of

neurons in area MT of the macaque. Vis-Neurosci. 1998 Jul; 15(4): 779-86; ISSN:

0952-5238.

ENGLAND. We analyzed the relationship between eye movements and neuronal

responses recorded from area MT in alert monkeys trained to maintain visual

fixation during the presentation of moving patterns. The monkeys made small

saccades which moved the eyes with velocities that spanned the sensitivity range

of MT neurons. The saccades evoked changes in the neuronal response that

depended upon (1) the level of stimulus-evoked activity amidst which the saccade

occurred and (2) the direction of the saccade relative to the preferred direction of

the neuron. Most notably, saccades were able to suppress stimulus-evoked

activity when they caused retinal image flow that opposed the neuron's preference

and were able to elicit a response or enhance weak activity when they caused flow

in the neuron's preferred direction. On average, the disturbance lasted 40 ms

beginning about 40 ms following saccade onset. Using these parameters, we

simulated synthetic spike trains from an imaginary pair of similarly tuned neurons

and determined that the interneuronal correlation due to saccades should be

negligible at all but the lowest ongoing firing rates. This conclusion was supported

from our data by the observation that response variance for single MT spike

trains was not measurably reduced during periods of stable gaze compared to

periods when eye movement exceeded a stability criterion (0.1 deg during 0.5 s).

While the intrusions caused by saccades are too short-lived and infrequent to

account for the variability of MT neuronal response (counter to the finding in V1

of Gur et al., 1997), the clear directional signal that they carry in area MT

suggests that motion perception is not blocked during saccades by suppression at

early stages in the visual pathway.

17. Barry, J. C.; Backes, A. [Measuring the effect of eyeglasses on determination of

squint angle with Purkinje reflexes and the prism cover test]. Messungen zum

Einfluss von Brillenglasern auf die Bestimmung des Schielwinkels mit Purkinje-

Reflexen und mit dem Prismenabdecktest. Klin-Monatsbl-Augenheilkd. 1998 Apr;

212(4): 234-9; ISSN: 0023-2165.

GERMANY. BACKGROUND: The alternating prism and cover test is the

conventional test for the measurement of the angle of strabismus. The error

induced by the prismatic effect of glasses is typically about 27-30%/10 D.

Alternatively, the angle of strabismus can be measured with methods based on

Purkinje reflex positions. This study examines the differences between three such

options, taking into account the influence of glasses. MATERIALS AND

METHODS: The studied system comprised the eyes with or without glasses, a

fixation object and a device for recording the eye position: in the case of the

alternate prism and cover test, a prism bar was required; in the case of a Purkinje

reflex based device, light sources for generation of reflexes and a camera for the

documentation of the reflex positions were used. Measurements performed on

model eyes and computer ray traces were used to analyze and compare the

options. RESULTS: When a single corneal reflex is used, the misalignment of the

corneal axis can be measured; the error in this measurement due to the prismatic

effect of glasses was 7.6%/10 D, the smallest found in this study. The individual

Hirschberg ratio can be determined by monocular measurements in three gaze

directions. CONCLUSIONS: The angle of strabismus can be measured with

Purkinje reflex based methods if the fundamental differences between these

methods and the alternate prism and cover test, and if the influence of glasses and

other sources of error are accounted for.

18. Basso, M. A.; Wurtz, R. H. Modulation of neuronal activity in superior colliculus by

changes in target probability. J-Neurosci. 1998 Sep 15; 18(18): 7519-34; ISSN:

0270-6474.

UNITED-STATES. Complex visual scenes require that a target for an impending

saccadic eye movement be selected from a larger number of possible targets. We

investigated whether changing the probability that a visual stimulus would be

selected as the target for a saccade altered activity of monkey superior colliculus

(SC) neurons in two experiments. First, we changed the number of possible

targets on each trial. Second, we kept the visual display constant and presented a

single saccade target repeatedly so that target probability was established over

time. Buildup neurons in the SC, those with delay period activity, showed a

consistent reduction in activity as the probability of the saccade decreased,

independent of the visual stimulus configuration. Other SC neurons, fixation and

burst, were largely unaffected by the changes in saccade target probability.

Because we had monkeys making saccades to many locations within the visual

field, we could examine activity associated with saccades outside of the movement

field of neurons. We found the activity of buildup neurons to be similar across the

SC, before the target was identified, and reduced when the number of possible

targets increased. The results of our experiments are consistent with a role for this

activity in establishing a motor set. We found, consistent with this interpretation,

that the activity of these neurons was predictive of the latency of a saccadic eye

movement and not other saccade parameters such as end point or peak velocity.

19. Basso, M. A.; Wurtz, R. H. Modulation of neuronal activity in superior colliculus by

changes in target probability. J-Neurosci. 1998 Sep 15; 18(18): 7519-34; ISSN:

0270-6474.

UNITED-STATES. Complex visual scenes require that a target for an impending

saccadic eye movement be selected from a larger number of possible targets. We

investigated whether changing the probability that a visual stimulus would be

selected as the target for a saccade altered activity of monkey superior colliculus

(SC) neurons in two experiments. First, we changed the number of possible

targets on each trial. Second, we kept the visual display constant and presented a

single saccade target repeatedly so that target probability was established over

time. Buildup neurons in the SC, those with delay period activity, showed a

consistent reduction in activity as the probability of the saccade decreased,

independent of the visual stimulus configuration. Other SC neurons, fixation and

burst, were largely unaffected by the changes in saccade target probability.

Because we had monkeys making saccades to many locations within the visual

field, we could examine activity associated with saccades outside of the movement

field of neurons. We found the activity of buildup neurons to be similar across the

SC, before the target was identified, and reduced when the number of possible

targets increased. The results of our experiments are consistent with a role for this

activity in establishing a motor set. We found, consistent with this interpretation,

that the activity of these neurons was predictive of the latency of a saccadic eye

movement and not other saccade parameters such as end point or peak velocity.

20. Baunez, C.; Salin, P.; Nieoullon, A.; Amalric, M. Impaired performance in a

conditioned reaction time task after thermocoagulatory lesions of the fronto-

parietal cortex in rats. Cereb-Cortex. 1998 Jun; 8(4): 301-9; ISSN: 1047-3211.

UNITED-STATES. The present study examined whether cortical damage in rats

may disrupt the integrative processes and motor control involved in the

performance of a reaction time (RT) task. To investigate the nature of the deficits

in the conditioned task, rats were subjected, after learning, to a coagulation of pia

brain surface of varying extent, including the frontal and parietal cortical areas.

They were then tested daily for over one month. The behavioural task required

the rats to hold a lever down during a variable and random delay and react quickly

to the onset of a visual cue by releasing the lever within a RT limit for food

reinforcement. Extensive bilateral cortical lesions had no effect on spontaneous

motor activity, but severely impaired RT performance. Latencies to release the

lever after the cue were dramatically increased during the first postoperative

sessions and gradually returned to baseline levels within 3 weeks, whereas less

dramatic but long-lasting increase in premature responding (anticipatory response

before the visual cue) was observed throughout the testing sessions. More

restricted lesions to the frontoparietal cortex produced a similar pattern of

incorrect responding with a faster recovery of delayed responses and a strong

deficit in premature responding. The major effects of lesions confined to the

rostral pole of the frontal cortex were observed on premature responding,

however. The present results demonstrate that the impairment in movement

initiation is rapidly recovered within 2-3 weeks even after extensive

thermocoagulatory lesions of the frontal and parietal areas. This recovery suggests

the involvement of adaptive processes developing progressively and probably

reflecting the remarkable synaptic plasticity of the extrapyramidal motor output.

In contrast, the long-lasting increase in premature responding, supposed to reflect

some attentional deficits, may produce anatomofunctional long-term

disorganization of subcortical structures such as the basal ganglia. Interestingly

enough, these results show that the rat neocortex supports functions very similar

to those of primates and provide a good model for studying these higher functions

in operant motor procedures that require prior associative learning and

appropriate motor coordination.

21. Bernasconi, O.; Borruat, F. X. [Unilateral accommodation spasm: a diagnostic

pitfall!]. Spasme d'accommodation unilateral: un piege diagnostic! Klin-

Monatsbl-Augenheilkd. 1998 May; 212(5): 392-3; ISSN: 0023-2165.

GERMANY. BACKGROUND: Accommodation-convergence spasm (spasm of

the near reflex) is usually bilateral, resulting in increased myopia, convergence, and

miosis. Unilateral spasm of accommodation has rarely been reported. PATIENTS:

We investigated three females (age range 10-19 years) referred for investigations of

retrobulbar optic neuritis (2 cases) and decompensated esophoria (1 case).

RESULTS: They all presented unilateral spasm of accommodation with visual

loss due to increased myopia (-3.5 to -11.75 diopters). Apart from that, results of

neuro-ophthalmological examination were normal. CONCLUSIONS: Unilateral

accommodation spasm is rare and can mimic retrobulbar optic neuritis and

convergent strabismus. The three components of the accommodation-convergence

spasm may not always be present simultaneously. Recognizing such an entity is

important to prevent the patient from useless, costful and potentially harmful

investigations.

22. Bernasconi, O.; Klainguti, G. [Is there a primary and secondary torsion deviation in

paralysis of the grand oblique muscle?]. Peut-on parler de deviation torsionnelle

primaire et secondaire dans la paralysie du grand oblique? Klin-Monatsbl-

Augenheilkd. 1998 May; 212(5): 286-8; ISSN: 0023-2165.

GERMANY. BACKGROUND: An extraocular muscle palsy is conventionally

characterized by a deviation of the visual axes, this being greater when measured

with the affected eye fixing. By definition and illustrating Hering's law, this

secondary angle of deviation is greater than the primary one, measured with the

sound eye fixing. We present here a comparative study of the amount of

subjective excyclodeviation measured in patients suffering from IVth nerve palsy,

with the sound or affected eye fixing. METHODS: Two groups of patients were

entered into the study: Group 1 (N = 54) for superior oblique palsies studied

retrospectively and Group 2 (N = 14), for a prospective study of those recently

acquired (post-traumatic) and followed over 6 months. In both groups,

measurements were made at two stages, early (1 to 7 weeks after onset) and late

(4 to 6 months later). RESULTS: In both groups, the majority of cases showed a

greater secondary torsional deviation, the difference between this and the primary

deviation lessening on late stage measurements. CONCLUSION: In both groups,

the difference between primary and secondary torsional deviation was not

statistically significant.

23. Bernhardt, J.; Ellis, P.; Denisenko, S.; Hill, K. Changes in balance and locomotion

measures during rehabilitation following stroke. Physiother-Res-Int. 1998; 3(2):

109-22; ISSN: 1358-2267.

ENGLAND. BACKGROUND AND PURPOSE: This study aimed to examine

the utility of a number of measures of balance and locomotion for the purpose of

measuring change in a group of stroke patients undergoing in-patient

rehabilitation. The aim was to select a core group of measures based on empirical

evidence of usefulness rather than personal preference. METHODS: Twenty-nine

stroke patients undergoing in-patient rehabilitation (mean age 71.8 +/- 10.5 years;

66% male) participated in the study. A prospective design was utilized with

repeated measurement undertaken at four, six and eight weeks post-stroke. Static

standing, the Clinical Test of Sensory Interaction of Balance (CTSIB) (Shumway-

Cook & Horak, 1986), functional reach (FR), repetitive reach (RR), step test

(ST), gait velocity, stride length and the Motor Assessment Scale (Carr et al.,

1985) (walking item) were assessed at each interval. RESULTS: All measures of

dynamic balance showed significant change over the four-week measurement

period (p < 0.0036). Factor analysis identified two factors which grouped tests

into static and dynamic, with a trend towards a third factor incorporating bipedal

dynamic tests. Tests of static balance suffered from ceiling effects, whereas

dynamic tests of balance and gait suffered from floor effects. Dynamic tests were

more responsive (Standardized Response Measure (SRM) > 0.75) to change over

the rehabilitation period than static tests. CONCLUSIONS: The findings suggest

that a clinically useful and responsive balance and mobility test battery should

include one component of the CTSIB (Shumway-Cook & Horak, 1986), RR (step

stance), ST and gait velocity.

24. Birmingham, T. B.; Kramer, J. F.; Inglis, J. T.; Mooney, C. A.; Murray, L. J.; Fowler,

P. J.; Kirkley, S. Effect of a neoprene sleeve on knee joint position sense during

sitting open kinetic chain and supine closed kinetic chain tests. Am-J-Sports-

Med. 1998 Jul; 26(4): 562-6; ISSN: 0363-5465.

UNITED-STATES. The primary objective of the present study was to compare

the effect of a neoprene sleeve on knee joint position sense during a sitting open

kinetic chain test and a supine closed kinetic chain test. Young (24 +/- 2 years

old), healthy subjects (18 men and 18 women) performed knee joint angle

replication tests during open kinetic chain knee extension (sitting) and closed

kinetic chain leg press (supine with an axial load of 15% body weight) before and

after application of a neoprene sleeve over the dominant knee. The improvement

in ability to replicate joint angles after application of the sleeve (sleeve effect) was

significantly less during the supine closed kinetic chain test (0.3 degree +/- 1.4

degrees) than during the sitting open kinetic chain test (1.2 degrees +/- 1.1

degrees). The sleeve effect was inversely related to subjects' performance without

the sleeve during both the sitting open kinetic chain and supine closed kinetic

chain tests, suggesting that some people may derive greater benefit from the sleeve

than others. Although the sleeve effects were small, particularly during the supine

closed kinetic chain test, 72% of subjects felt that the sleeve improved their

overall test performance. Future research is needed to establish the functional

relevance of the small sleeve effects observed and to identify the characteristics of

people who might derive greatest benefit from sleeve use.. 9010-98-4.

25. Bjorklund, D. F.; Brown, R. D. Physical play and cognitive development: integrating

activity, cognition, and education [comment]. Child-Dev. 1998 Jun; 69(3): 604-6;

ISSN: 0009-3920.

Note: Comment on: Child Dev 1998 Jun;69(3):577-98.

UNITED-STATES. We propose that humans may have evolved a special

sensitivity to certain types of social information during rough-and-tumble play

that facilitates social cognition. The cognitive benefits of physical play are

described as providing a break from demanding intellectual tasks, and are

hypothesized to be related to gender differences in spatial cognition.

26. Blakemore, S. J.; Goodbody, S. J.; Wolpert, D. M. Predicting the consequences of our

own actions: the role of sensorimotor context estimation. J-Neurosci. 1998 Sep

15; 18(18): 7511-8; ISSN: 0270-6474.

UNITED-STATES. During self-generated movement it is postulated that an

efference copy of the descending motor command, in conjunction with an internal

model of both the motor system and environment, enables us to predict the

consequences of our own actions (von Helmholtz, 1867; Sperry, 1950; von Holst,

1954; Wolpert, 1997). Such a prediction is evident in the precise anticipatory

modulation of grip force seen when one hand pushes on an object gripped in the

other hand (Johansson and Westling, 1984; Flanagan and Wing, 1933). Here we

show that self-generation is not in itself sufficient for such a prediction. We used

two robots to simulate virtual objects held in one hand and acted on by the other.

Precise predictive grip force modulation of the restraining hand was highly

dependent on the sensory feedback to the hand producing the load. The results

show that predictive modulation requires not only that the movement is self-

generated, but also that the efference copy and sensory feedback are consistent

with a specific context; in this case, the manipulation of a single object. We

propose a novel computational mechanism whereby the CNS uses multiple

internal models, each corresponding to a different sensorimotor context, to

estimate the probability that the motor system is acting within each context.

27. Blekher, T.; Christian, J. C.; Abel, L. A.; Yee, R. D. Influences of chorion type on

saccadic eye movements in twins. Invest-Ophthalmol-Vis-Sci. 1998 Oct; 39(11):

2186-90; ISSN: 0146-0404.

UNITED-STATES. PURPOSE: The influence of genetic and prenatal

environmental factors on characteristics of saccadic performance were evaluated in

young monozygotic (MZ) twins (8-19 years old) of known chorion type.

METHODS: Saccadic eye movements were recorded using an infrared system.

Saccadic latency, accuracy, and parameters of amplitude-peak velocity

exponential equation (main sequence) were quantified. RESULTS: Intraclass

correlations of saccadic parameters differed significantly from zero for

monochorionic and dichorionic MZ twins. The within-pair mean squares were

significantly less, and intraclass correlations were significantly higher in

monochorionic than in dichorionic twins for latency and were similar for other

saccadic parameters (accuracy, slope of main sequence, and peak velocity for 15

degrees saccades). CONCLUSIONS: These findings confirmed previous reports

that saccadic parameters of MZ twins are significantly correlated and indicated

that similarity of these parameters seen in MZ twins may be driven both by

genetic and by prenatal environmental factors.

28. Bohning, D. E.; Shastri, A.; Nahas, Z.; Lorberbaum, J. P.; Andersen, S. W.; Dannels,

W. R.; Haxthausen, E. U.; Vincent, D. J.; George, M. S. Echoplanar BOLD fMRI

of brain activation induced by concurrent transcranial magnetic stimulation.

Invest-Radiol. 1998 Jun; 33(6): 336-40; ISSN: 0020-9996.

UNITED-STATES. RATIONALE AND OBJECTIVES: The authors

demonstrate the feasibility of combining transcranial magnetic stimulation (TMS)

and functional magnetic resonance imaging (fMRI) inside an MR scanner to

noninvasively stimulate and image regional brain activity. METHODS:

Echoplanar blood oxygen level dependent (BOLD)-based fMRI studies of TMS

response were performed on three human volunteers inside a standard 1.5 T MR

scanner using independent computer control to interleave echoplanar image

acquisition and stimulation of right thumb primary motor cortex with a

nonferromagnetic TMS coil. RESULTS: Significant (P< 0.001) response was

observed in motor cortex under the TMS coil during stimulation compared to rest,

as well in auditory cortex, the latter presumably due to the loud "snap" when the

coil was pulsed. CONCLUSIONS: Concurrent TMS stimulation and echoplanar

BOLD fMRI imaging is possible. This method has potential for tracing neural

circuits with brain imaging, as well as investigating the effects of TMS.

29. Bondestam, M.; Amcoff, B. [Child health centers do not catch all preschool children

with problems. Child health services should co-operate with school health

services more closely]. BVC fangar inte alla forskolebarn med problem.

Barnhalsovard och skolhalsovard borde samarbeta tatare. Lakartidningen. 1998

Sep 16; 95(38): 4103-5; ISSN: 0023-7205.

SWEDEN.

30. Borruat, F. X.; Gianoli, F.; Maeder, P.; Bogousslavsky, J. [Skew deviation]. Skew

deviation. Klin-Monatsbl-Augenheilkd. 1998 May; 212(5): 289-90; ISSN: 0023-

2165.

GERMANY. BACKGROUND: Skew deviation is a vertical ocular misalignment

of prenuclear origin. Although well described in the literature, it is still probably

underdiagnosed. Natural history of skew deviation is not well described in the

literature. PURPOSE: To describe the clinical presentations, etiologies and follow-

up of skew deviation. METHODS: Retrospective study of 29 patients diagnosed

with skew deviation between 1993 and 1996. RESULTS: The commonest cause

was cerebrovascular accident (12/29) and the commonest localisation was

mesencephalic (9/29). Other causes included surgery (7/29), tumor (4/29), trauma

(3/29), degeneration (3/29), inflammatory (2/29), increased intracranial pressure

(1/29). Other localisations included cerebellum (5/29), ponto-mesencephalic

(3/29), and medulla (2/29). Vertical diplopia was always accompanied by other

neuro-ophthalmologic abnormalities. 69.2% (18/26) patients were totally

asymptomatic after 7.5 months. 30.8% (8/26) were still symptomatic (diplopia).

One patient required surgery, three patients were relieved with prisms, one

patient needed monocular occlusion. One patient died during follow-up and

precise data were lacking in two symptomatic patients. CONCLUSION: Skew

deviation is not so rare, 10% of the cases referred to us for diplopia in 3 years.

The diagnosis of skew deviation should be entertained when vertical diplopia

cannot be explained by pathology of extraocular muscles, peripheral or central

cranial nerve III or IV palsies, myasthenia, or orbital pathology. Prognosis for

recovery in patients with skew deviation is good. 70% will recover, after a median

time of 7.5 months. Surgery should be postponed at least for 12 months.

31. Bremmer, F.; Pouget, A.; Hoffmann, K. P. Eye position encoding in the macaque

posterior parietal cortex. Eur-J-Neurosci. 1998 Jan; 10(1): 153-60; ISSN: 0953-

816X.

FRANCE. In two previous studies, we had demonstrated the influence of eye

position on neuronal discharges in the middle temporal area, medial superior

temporal area, lateral intraparietal area and area 7A of the awake monkey

(Bremmer et al., 1997a,b). Eye position effects also have been found in visual

cortical areas V3A and V6 and even in the premotor cortex and the supplementary

eye field. These effects are generally discussed in light of a coordinate

transformation of visual signals into a non-retinocentric frame of reference. Neural

network studies dealing with the eye position effect succeeded in constructing

such non-retinocentric representations by using model neurones whose response

characteristics resembled those of 'real' neurones. However, to our knowledge,

response properties of real neurones never acted as input into these neural

networks. In the present study, we thus investigated whether, theoretically, eye

position could be estimated from the population discharge of the (previously)

recorded neurones and, if so, we intended to develop an encoding algorithm for the

position of the eyes in the orbit. The optimal linear estimator proved the

capability of the ensemble activity for determining correctly eye position. We

then developed the so-called subpopulation encoding of eye position. This

algorithm is based on the partition of the ensemble of neurones into two pairs of

subpopulations. Eye position is represented by the differences of activity levels

within each pair of subpopulations. Considering this result, encoding of the

location of an object relative to the head could easily be accomplished by

combining eye position information with the intrinsic knowledge about the retinal

location of a visual stimulus. Taken together, these results show that throughout

the monkey's visual cortical system information is available which can be used in a

fairly simple manner in order to generate a non-retinocentric representation of

visual information.

32. Breton, P.; Bizot, J. C.; Buee, J.; De, La Manche I. Brain neurotoxicity of Penitrem

A: electrophysiological, behavioral and histopathological study. Toxicon. 1998

Apr; 36(4): 645-55; ISSN: 0041-0101.

ENGLAND. The neurotoxicity of Penitrem A (PA) in rats was assessed against

neurophysiological, behavioral and histopathological parameters. Animals were

acutely given intracerebroventricular (22-45 mg) or intraperitoneal injections (0.5-

1.5 mg/kg) of PA. A typical trembling syndrome associated with PA was always

noted. Depending on the dose administered, animals may convulse and eventually

die (1-1.5 mg/kg). PA-induced transient alterations of the EEG involving an

increase in the frequency and voltage of electrical activity recorded from the

cerebral cortex. Hippocampal activity was not modified and some pathologic

activities may be recorded at the thalamus. Generally these EEG alterations

disappeared at d 3 after the injection and the animals progressively recovered.

However in the most severe cases, neuromotor disturbances were maintained at d

7 (rotarod test). Coronal sections of the brain at the striatal, thalamic,

hippocampal and pons levels mainly revealed that PA was able to induce dose

related injuries in the cerebellum with massive degeneration of Purkinje cells and a

significant vacuolization within the molecular layer. The neurotoxic mechanism

remains unclear. Action of the mycotoxin on the cerebello-thalamo-cortical tract is

discussed.. 0; 37203-49-9.

33. Brooke Wavell, K.; Athersmith, L. E.; Jones, P. R.; Masud, T. Brisk walking and

postural stability: A cross-sectional study in postmenopausal women.

Gerontology. 1998; 44(5): 288-92; ISSN: 0304-324X.

SWITZERLAND. This study compared body sway, a measure of postural

stability, between regular brisk walkers and control subjects. Furthermore, the

relationship between body sway and physical activity duration in

postmenopausal women was examined. Subjects were 31 healthy postmenopausal

women, aged 61-71 years. They were recruited from a randomized controlled

study of the influence of brisk walking on bone: 16 women had been completing

20 min d-1 brisk walking, whilst 15 controls had been completing habitual

activities only. Body sway was measured using a swaymeter that measured

displacement at the waist whilst subjects stood on a compliant surface, with eyes

closed, for 1 min. The activity was measured using activity monitors which were

worn at the waist for 3 consecutive days. Body sway (eyes closed, standing on a

compliant surface) was lower in walkers than in controls: 2,958 +/- (SE) 270

versus 5,225+/-371 mm2 min-1, respectively (p < 0.05). A negative correlation

was found between body sway and minutes of physical activity (r = -0.47, p <

0.01). Analysis of variance revealed that body sway differed significantly (p <

0.05) between groups of differing physical activity participation, being 4,839 +/-

499, 4,167 +/- 516, and 2,877 +/- 362 mm2 min-1, respectively, in women

completing <20, 20-40, and >40 min d-1 of physical activity. Body sway was

significantly lower in the most active group than in the least active (p < 0.01).

These data suggest that postural stability is better in regular walkers than in

control subjects. Furthermore, a dose-response relationship was observed

between physical activity and postural stability in postmenopausal women.

These findings provide a preliminary indication that brisk walking, a low-cost and

acceptable form of physical activity for the elderly, could be incorporated into

strategies for improving balance in the elderly.

34. Brown, D. A.; Effgen, S. K.; Palisano, R. J. Performance following ability-focused

physical therapy intervention in individuals with severely limited physical and

cognitive abilities. Phys-Ther. 1998 Sep; 78(9): 934-47; discussion 948-50; ISSN:

0031-9023.

UNITED-STATES. BACKGROUND AND PURPOSE: Do individuals with

severely limited physical and cognitive abilities improve their gross motor abilities

when given physical therapy intervention, and does improvement transfer to

nontreatment settings? SUBJECTS: The subjects were 24 individuals (10 female,

14 male), aged 3 to 30 years (X = 20.1, SD = 8.1), who were nonambulatory and

had limited adaptive behavior. METHODS: Change in gross motor ability during

18 weeks of twice-weekly therapy was measured using goal attainment scaling

(GAS). Three gross motor goals were developed for each subject based on

individual or caregiver needs, with one goal randomly selected as a control.

Physical impairments were treated, and behavioral management principles, low-

level communication approaches, high-repetition practice of goals, and a

progressive reduction of both physical assistance and multisensory cues were

used. An independent rater scored goal level from randomly ordered videotapes

recorded during therapy and in recess and home settings. RESULTS: Mean GAS

T scores were higher for treatment goals (X = 45.6, SD = 10.5) compared with

control goals (X = 34.6, SD = 11.8). When the expected goal level (50) was met

during therapy, mean GAS T scores in recess settings ( X = 35.9, SD = 11.5) and

home settings (X = 42.2, SD = 12.2) were lower. At the conclusion of therapy,

there were no differences in goal levels between treatment and control goals in

both the recess and home settings. CONCLUSION AND DISCUSSION: The

subjects demonstrated improvement of gross motor abilities practiced during

therapy. Level of ability during therapy, however, did not consistently transfer to

the recess of home settings. [Brown DA, Effgen SK, Palisano RJ. Performance

following ability-focused physical therapy intervention in individuals with

severely limited physical and cognitive abilities.

35. Bruder, G.; Kayser, J.; Tenke, C.; Rabinowicz, E.; Friedman, M.; Amador, X.; Sharif,

Z.; Gorman, J. The time course of visuospatial processing deficits in

schizophrenia: an event-related brain potential study. J-Abnorm-Psychol. 1998

Aug; 107(3): 399-411; ISSN: 0021-843X.

UNITED-STATES. Event-related brain potentials (ERPs) were recorded during a

dot enumeration task so as to investigate electrophysiologic correlates of early

visuospatial processing in schizophrenia. Twenty-eight patients having a

diagnosis of schizophrenia (n = 19) or schizoaffective disorder (n = 9) and 28

controls were tested. Patients showed poorer dot enumeration than did controls

and also had markedly reduced early negative ERPs, which began about 150 ms

after stimulus onset at the peak of the N1 potential and reached its maximum

about 275 ms at the N2 peak. The N1 reduction in patients was greatest over left

parietal sites for stimuli in the right visual field. The marked N1 and N2

reductions in patients are supportive of models postulating deficits in early

visuospatial attention and allocation of conceptual resources in schizophrenia.

36. Bussmann, H. B.; Reuvekamp, P. J.; Veltink, P. H.; Martens, W. L.; Stam, H. J.

Validity and reliability of measurements obtained with an "activity monitor" in

people with and without a transtibial amputation. Phys-Ther. 1998 Sep; 78(9):

989-98; ISSN: 0031-9023.

UNITED-STATES. BACKGROUND AND PURPOSE: In this study, the

validity and reliability of measurements obtained with an "Activity Monitor"

(AM) were examined. The instrument is designed to monitor ambulatory activity

by use of accelerometer signals, and it detects several activities associated with

mobility (standing, sitting, lying, transitions, movement-related activities).

SUBJECTS: Four men with a transtibial amputation and 4 men without a

transtibial amputation participated. METHODS: The subjects performed normal

daily activities, during which accelerations were measured and videotape recording

were made (reference method). Validity was assessed by calculating agreement

scores between the AM output and the videotape recordings and by comparing

the number of transitions and the duration of activities determined by both

methods. RESULTS: The overall agreement between the AM output and the

videotape recordings was 90%. Other agreement scores, in addition to the

determination of the number of transitions and the duration of activities, were

generally within a range of error of 0% to 10%. CONCLUSION AND

DISCUSSION: The reliability and validity of the AM measurements appeared to

be good, which supports its potential use in rehabilitation and physical therapy.

[Bussmann HBJ, Reuvekamp PJ, Veltink PH, et al. Validity and reliability of

measurements obtained with an "Activity Monitor" in people with and without a

transtibial amputation.

37. Bussmann, J. B.; Tulen, J. H.; van Herel, E. C.; Stam, H. J. Quantification of physical

activities by means of ambulatory accelerometry: a validation study.

Psychophysiology. 1998 Sep; 35(5): 488-96; ISSN: 0048-5772.

UNITED-STATES. The objective of the study was to assess the validity of an

activity monitor (AM) within a psychophysiological study. The AM was based

on four body-fixed accelerometers and discriminated postures, transitions, and

dynamic activities. Three subjects participated in each of two 4-hr sessions.

During each session, consisting of two protocols, ambulatory accelerometer and

heart rate measurements were made. The output of the AM was compared with

simultaneously recorded video tapes. An overall agreement between AM and

video of 88 and 96% was found. The number of transitions and dynamic periods,

and the duration of activities were well determined. Posture-related heart rate

changes were demonstrated. A three-sensor configuration hardly influenced the

validity scores. The AM appeared to be a valid instrument to quantify aspects of

physical activity, and offers new possibilities for ambulatory

psychophysiological research.. 0; 28981-97-7; 846-49-1.

38. Candau, R.; Belli, A.; Millet, G. Y.; Georges, D.; Barbier, B.; Rouillon, J. D. Energy

cost and running mechanics during a treadmill run to voluntary exhaustion in

humans. Eur-J-Appl-Physiol. 1998 May; 77(6): 479-85; ISSN: 0301-5548.

GERMANY. The aim of the present study was to examine the physiological and

mechanical factors which may be concerned in the increase in energy cost during

running in a fatigued state. A group of 15 trained triathletes ran on a treadmill at

velocities corresponding to their personal records over 3000m [mean 4.53 (SD

0.28) m x s(-1)] until they felt exhausted. The energy cost of running (CR) was

quantified from the net O2 uptake and the elevation of blood lactate

concentration. Gas exchange was measured over 1 min firstly during the 3rd-4th

min and secondly during the last minute of the run. Blood samples were collected

before and after the completion of the run. Mechanical changes of the centre of

mass were quantified using a kinematic arm. A significant mean increase [6.9 (SD

3.5)%, P < 0.001] in CR from a mean of 4.4 (SD 0.4) J x kg(-1) x m(-1) to a mean

of 4.7 (SD 0.4) J x kg(-1) x m(-1) was observed. The increase in the O2 demand of

the respiratory muscles estimated from the increase in ventilation accounted for a

considerable proportion [mean 25.2 (SD 10.4)%] of the increase in CR. A mean

increase [17.0 (SD 26.0)%, P < 0.05] in the mechanical cost (CM) from a mean of

2.36 (SD 0.23) J x kg m(-1) to a mean of 2.74 (SD 0.55) J x kg(-1) x m(-1) was

also noted. A significant correlation was found between CR and CM in the non-

fatigued state (r=0.68, P < 0.01), but not in the fatigued state (r=0.25, NS).

Furthermore, no correlations were found between the changes (from non-fatigued

to fatigued state) in CR and the changes in CM suggesting that the increase in CR

is not solely dependent on the external work done per unit of distance. Since step

frequency decreased slightly in the fatigued state, the internal work would have

tended to decrease slightly which would not be compatible with an increase in CR.

A stepwise regressions showed that the changes in CR were linked (r=0.77, P <

0.01) to the changes in the variability of step frequency and in the variability of

potential cost suggesting that a large proportion of the increase in CR was due to

an increase in the step variability. The underlying mechanisms of the relationship

between CR and step variability remains unclear.. 7782-44-7.

39. Carpenter, M. G.; Bellos, A.; Patla, A. E. Is backward stepping over obstacles

achieved through a simple temporal reversal of forward stepping? Int-J-Neurosci.

1998 Apr; 93(3-4): 189-96; ISSN: 0020-7454.

ENGLAND. The main purpose of the study was to examine whether backward

stepping over obstacles was a simple temporal reversal of kinematic and muscle

activation patterns found in forward obstacle avoidance. Obstacle avoidance was

used as a probe to represent one aspect of walking over variable terrain.

Kinematics, trajectories and muscle activation profiles for forward versus

backward stepping over obstacles revealed that the simple reversal of locomotor

patterns observed for level walking cannot be applied to obstacle avoidance.

However, key kinematic data and limb trajectories for backward leading limb

stepping were found to be similar to existing forward trailing limb data. Therefore,

it appears that stepping over obstacles requires a complex upper level

reorganization of the basic locomotor pattern based on biomechanical and sensory

feedback.

40. Casazza, B. A.; Young, J. L.; Press, J. P.; Heinemann, A. W. Suprascapular nerve

conduction: a comparative analysis in normal subjects. Electromyogr-Clin-

Neurophysiol. 1998 Apr; 38(3): 153-60; ISSN: 0301-150X.

BELGIUM. An electromyographic examination is often utilized to confirm the

diagnosis of suprascapular neuropathy in patients with shoulder pain and

dysfunction. The purpose of this study was to compare three compound motor

action potential (CMAP) recording methods (surface electrode, monopolar needle,

concentric needle) for evaluating suprascapular nerve conduction. Twenty-two

normal, healthy subjects were tested with each method. Differences between the

recording methods were noted for CMAP latencies and amplitudes with the

monopolar needle recordings having the shortest mean latency and greatest mean

amplitude. The monopolar needle recordings also appeared to give a more

reproducible measurement of CMAP latency and evoked amplitude to the

supraspinatus and infraspinatus. Therefore, it may be more accurate to use a

monopolar needle to record suprascapular nerve conduction and determine

abnormalities with a side-to-side latency difference of 0.4 ms being acceptable.

Considering the diverse branching of the suprascapular nerve, and the monopolar

needle's relatively small sampling area of motor fibers, it may be prudent to test

conduction to multiple sites within these muscles for the most accurate

assessment.

41. Cauquil, A. S.; Bessou, M.; Dupui, P.; Bessou, P. Lateral dynamic balance reactions

to circular translation of the visual field. C-R-Acad-Sci-III. 1998 Apr; 321(4):

289-94; ISSN: 0764-4469.

FRANCE. Lateral sway of subjects in spontaneous dynamic balance conditions

on a seesaw platform was measured during a visual stimulation monocularly

produced by a rotating glass covered with a prism membrane. Prism rotation

induced the perception of a circular translation of the whole visual field and an

ocular pursuit movement. Therefore, the retinal slip that occurs in normal pursuit

was cancelled. Strong stereotyped postural reactions were observed in a direction

that depended upon both the vertical visual field deviation and the eye stimulated:

upper position of the right visual field induced a leftward sway resulting from an

extension of the right hemibody; symmetrical reactions occurred for the left

stimulation. The results suggest that the postural reactions recorded depend on

the isolated oculomotor activity and, in addition, on retinal afferences

corresponding to the temporal crescent of the stimulated side, which orientates

the postural reaction on the homolateral lower limb muscles.

42. Censi, L.; Toti, E.; Pastore, G.; Ferro Luzzi, A. The basal metabolic rate and energy

cost of standardised walking of short and tall men. Eur-J-Clin-Nutr. 1998 Jun;

52(6): 441-6; ISSN: 0954-3007.

ENGLAND. OBJECTIVES: To assess the influence of stature on the basal

metabolic rate (BMR) and on the energy cost of standardised walking. A second

objective was assess the accuracy of the FAO/UNU/WHO (1985) equations to

predict BMR. DESIGN/SUBJECTS: Forty-six young men were selected on the

basis of their stature and assigned to the group of short, S (n = 25, mean stature =

1.65 +/- 0.03 m) or of tall, T (n = 21, mean stature = 1.87 +/- 0.04 m). SETTING:

Rome, Italy. INTERVENTIONS: Body composition was assessed by underwater

weighing. BMR and energy cost walking at 5 km/h was measured by the Douglas

bag. RESULTS: Body fat % was similar in the two groups (15.2 +/- 4.3 for S;

17.4 +/- 5.3 for T; ns). The BMR of T was 20% higher than that of S, but 12%

and 10% lower when standardised respectively for body weight (BW) and fat free

mass (FFM). However these differences were removed when BMR was covaried

for BW or FFM, or normalised by BW0.62 or FFM0.64. Measured BMR was

7% for T and 6% for S lower than that predicted by the FAO/WHO/UNU (1985)

equation; the inclusion of stature did not reduce the overestimation. The energy

cost of walking was 27% higher in T than in S, but 9% and 5% lower when

standardised respectively for BW and FFM. The differences disappeared when

expressing the energy cost of walking as net cost per kg FFM. CONCLUSIONS:

Tall people have lower BMR per unit of BW or FFM than short people, and it is

necessary to control for the diverse body mass by the appropriate method.

However, qualitative differences in the composition of FFM are plausible, due to

the diverse proportion of metabolically active internal organs in people of

different height, which might be reflected in the higher BMR/kg FFM of the

shorter subjects. The sex- and age-specific FAO/WHO/UNU (1985) equation

significantly overestimates the BMR of both short and tall people, but there is no

simple explanation of this observation. The energy cost of walking is not affected

by stature when expressed as net cost per kg FFM.

43. Chapillon, P.; Lalonde, R.; Jones, N.; Caston, J. Early development of synchronized

walking on the rotorod in rats. Effects of training and handling. Behav-Brain-Res.

1998 Jun; 93(1-2): 77-81; ISSN: 0166-4328.

NETHERLANDS. There is considerable improvement of motor coordination on

the rotorod during the first 3 weeks of development in rats. The purpose of the

present study was to determine some factors implicated in this improvement.

From days 15-22 of age, rats were: (1) extensively trained on the rotorod; (2)

minimally trained on the rotorod; (3) handled daily but not trained on the rotorod;

and (4) neither handled nor trained. All animals were tested on the rotorod on day

23, with separate groups of the naive rats also being tested on days, 19, 20, 21 or

22. Latencies before falling and the percentage of time spent walking in time to the

movement of the rotating rod were recorded. There was a close correspondence

between these two scores during ontogeny. The percentage of time spent walking

was similar among extensively trained, minimally trained, and handled rats and

significantly higher than that measured in rats tested only on 1 day. These results

indicate that the emergence of this postural sensorimotor skill is more dependent

on the maturation of sensorimotor brain region than on previous training on the

apparatus.

44. Chaturvedi, V.; Gisbergen, J. A. Shared target selection for combined version-vergence

eye movements. J-Neurophysiol. 1998 Aug; 80(2): 849-62; ISSN: 0022-3077.

UNITED-STATES. Primates frequently make rapid binocular eye movements to

reorient gaze in both direction and depth. To explain the unequal movements made

by the two eyes, it often is assumed that they result from the combined action of

a conjugate saccadic system and a vergence contribution. Clearly such a scheme

can only yield coordinated binocular movements if both systems are guided by a

shared or coupled target selection mechanism. To investigate the degree of

cooperation at this level, we studied binocular refixations to target-nontarget

double-stimuli in three-dimensional (3-D) space. Binocular eye movements were

recorded in seven subjects using the scleral coil technique. In the experiments,

20% of trials were composed of a green target and a red nontarget, presented at

the same time, but at different locations in 3-D space. These were alternated

randomly with single-target trials (80%) in which the green stimulus was

presented randomly at one of eight possible positions in 3-D space. Instructions

to the subject emphasized either the speed or accuracy of response. Our findings

show that typical features of the saccadic response to double-stimuli (bistability,

averaging, and a speed-accuracy trade-off), as found in earlier two-dimensional

studies, are also prevalent for initial binocular refixations to double stimuli in 3-D

space. When the first saccadic response is directed to one of the two stimuli, the

vergence system almost invariably makes the same choice. Likewise, when the

saccadic system makes a short-latency averaging response, the vergence system

shows a similar compromise. Statistical analysis shows a high correlation between

saccadic and vergence target selection, strongly suggesting that the amplitude

computation process of both subsystems is due to a common target selection

stage that has access to information about stimulus location in 3-D space.

45. Chaturvedi, V.; Gisbergen, J. A. Shared target selection for combined version-vergence

eye movements. J-Neurophysiol. 1998 Aug; 80(2): 849-62; ISSN: 0022-3077.

UNITED-STATES. Primates frequently make rapid binocular eye movements to

reorient gaze in both direction and depth. To explain the unequal movements made

by the two eyes, it often is assumed that they result from the combined action of

a conjugate saccadic system and a vergence contribution. Clearly such a scheme

can only yield coordinated binocular movements if both systems are guided by a

shared or coupled target selection mechanism. To investigate the degree of

cooperation at this level, we studied binocular refixations to target-nontarget

double-stimuli in three-dimensional (3-D) space. Binocular eye movements were

recorded in seven subjects using the scleral coil technique. In the experiments,

20% of trials were composed of a green target and a red nontarget, presented at

the same time, but at different locations in 3-D space. These were alternated

randomly with single-target trials (80%) in which the green stimulus was

presented randomly at one of eight possible positions in 3-D space. Instructions

to the subject emphasized either the speed or accuracy of response. Our findings

show that typical features of the saccadic response to double-stimuli (bistability,

averaging, and a speed-accuracy trade-off), as found in earlier two-dimensional

studies, are also prevalent for initial binocular refixations to double stimuli in 3-D

space. When the first saccadic response is directed to one of the two stimuli, the

vergence system almost invariably makes the same choice. Likewise, when the

saccadic system makes a short-latency averaging response, the vergence system

shows a similar compromise. Statistical analysis shows a high correlation between

saccadic and vergence target selection, strongly suggesting that the amplitude

computation process of both subsystems is due to a common target selection

stage that has access to information about stimulus location in 3-D space.

46. Chen, R.; Yaseen, Z.; Cohen, L. G.; Hallett, M. Time course of corticospinal

excitability in reaction time and self-paced movements. Ann-Neurol. 1998 Sep;

44(3): 317-25; ISSN: 0364-5134.

UNITED-STATES. We used transcranial magnetic stimulation (TMS) to study

the time course of corticospinal excitability before and after brisk thumb

abduction movements, either in a simple reaction time (RT) paradigm or self-

paced. Premovement increase in corticospinal excitability began about 20 msec

earlier for self-paced compared with simple RT movements. For both simple RT

and self-paced movements after electromyographic (EMG) offset, there was a

first period of increased excitability from 0 to 100 msec, followed by a second

period from 100 to 160 msec. Corticospinal excitability was decreased from about

500 to 1,000 msec after EMG offset for both types of movements. Our results

show that motor preparation that begins 1.5 to 2 seconds before self-paced

movement is not associated with increased corticospinal excitability. The first

phase of increased corticospinal excitability after EMG offset may be due to

activity of motor cortex neuron subthreshold for activating spinal motor neurons,

and the second phase may reflect a subthreshold second agonist burst. The period

of decreased corticospinal excitability after movement corresponds to the onset of

event-related synchronization (ERS) of electroencephalographic signals in the 20-

Hz band, and supports the hypothesis that ERS may be related to an inactive,

idling state of the motor cortex.

47. Cohen, H.; Friedman, E. M.; Lai, D.; Pellicer, M.; Duncan, N.; Sulek, M. Balance in

children with otitis media with effusion. Int-J-Pediatr-Otorhinolaryngol. 1997 Dec

10; 42(2): 107-15; ISSN: 0165-5876.

IRELAND. To determine the presence of balance disorders in young children

who had otitis media with effusion (OME), 25 subjects, aged 13-57 months,

diagnosed by pediatric otolaryngologists, were tested on the gross motor subtest

of the Peabody Developmental Motor Scales, a standardized test of motor

development with established norms. Parents also filled out questionnaires about

their children's balance skills. Subjects with unilateral disease did not differ

significantly from normals. Subjects with bilateral disease, however, were

significantly impaired compared to normals on balance, locomotion and total score

and they were significantly impaired compared to unilateral subjects on all scores.

Parental perceptions of their children's balance correlated poorly with the test

results. These data suggest that young children with bilateral otitis media with

effusion are delayed in developing motor skills that require dynamic balance.

Therefore, in spite of a negative history for balance problems physicians should

consider balance performance when developing a treatment plan. Children with

balance impairments might benefit from more aggressive intervention.

48. Cohen, H.; Friedman, E. M.; Lai, D.; Pellicer, M.; Duncan, N.; Sulek, M. Balance in

children with otitis media with effusion. Int-J-Pediatr-Otorhinolaryngol. 1997 Dec

10; 42(2): 107-15; ISSN: 0165-5876.

IRELAND. To determine the presence of balance disorders in young children

who had otitis media with effusion (OME), 25 subjects, aged 13-57 months,

diagnosed by pediatric otolaryngologists, were tested on the gross motor subtest

of the Peabody Developmental Motor Scales, a standardized test of motor

development with established norms. Parents also filled out questionnaires about

their children's balance skills. Subjects with unilateral disease did not differ

significantly from normals. Subjects with bilateral disease, however, were

significantly impaired compared to normals on balance, locomotion and total score

and they were significantly impaired compared to unilateral subjects on all scores.

Parental perceptions of their children's balance correlated poorly with the test

results. These data suggest that young children with bilateral otitis media with

effusion are delayed in developing motor skills that require dynamic balance.

Therefore, in spite of a negative history for balance problems physicians should

consider balance performance when developing a treatment plan. Children with

balance impairments might benefit from more aggressive intervention.

49. Courage, M. L.; Howe, M. L. The ebb and flow of infant attentional preferences:

evidence for long-term recognition memory in 3-month-olds. J-Exp-Child-

Psychol. 1998 Jul; 70(1): 26-53; ISSN: 0022-0965.

UNITED-STATES. Using paired-comparisons, 3-month-olds' (n = 148)

recognition of dynamic visual events was investigated after retention intervals of 1

minute, 1 day, and 1 and 3 months (Experiment 1) and 1 minute, 1 day, and 1

week (Experiment 2). Participants were either tested at each retention interval

(Multiple Tests) or tested at one interval (Single Test). The proportion of total

looking time to the novel event and the length of the longest look to novel and

familiar events in the first 15 s of the retention test revealed significant novelty

preferences at 1 minute and 1 day and a null preference at 1 week for Multiple-

and Single-Test groups. At 1 month, Multiple- (Proportion of Total Looking

Time and Longest Look) and Single-Test groups (Longest Look only) preferred

the familiar event. The 3-month test revealed a familiarity preference (both

measures) for Single- and a null preference for Multiple-Tests groups. This

changing pattern of attentional preferences is consistent with models of infant

recognition memory in which novelty, familiarity, and null preferences are

considered conjointly and hypothesized to reflect the accessibility of novel and

familiar event representations in memory. Copyright 1998 Academic Press.

50. Crego, F.; Galindo, J.; Quesada, P.; Naches, S.; Pinas, J.; Vila, J.; Pollan, C.; Raguer,

N. [Recurrent peripheral facial paralysis. Our case load from 1995]. Paralisis

facial periferica recidivante. Nuestra casuistica del ano 1995. Acta-

Otorrinolaringol-Esp. 1998 May; 49(4): 280-2; ISSN: 0001-6519.

SPAIN. Of 117 cases of peripheral facial palsy seen in our emergency room in

1995, 10 (8.5%) were relapses. Seven were males and 3, females. Mean age at the

first appearance was 23.6 years. The mean interval between the first facial palsy

and the first recurrence was 10.1 years, and between the first and second

recurrence, 4.6 years. Five of the 10 patients (50%) had a second recurrence. Two

of the 10 patients (20%) had a family history of facial palsy. Only 1 (10%) was

diabetic. Seven of 10 patients achieved a complete functional recovery and 3 had

sequelae. Computed tomography was normal in every patient. In our series, a

family history of facial palsy and low ENoG results were related with a poorer

prognosis. ENoG scan was used as a prognostic and follow-up factor.

51. Cruz Martinez, A.; Munoz, J.; Palacios, F. The muscle inhibitory period by

transcranial magnetic stimulation. Study in stroke patients. Electromyogr-Clin-

Neurophysiol. 1998 Apr; 38(3): 189-92; ISSN: 0301-150X.

BELGIUM. Motor evoked potentials (MEPs) elicited over hand muscles by

transcranial magnetic stimulation (TMS) were studied in healthy individuals and,

bilaterally, in patients with cerebral infarction. Conduction time of the central

motor pathways (CMCT), threshold intensity, and amplitude of the MEPs were

correlated with recovery motor hand function after stroke. Following MEPs by

TMS during tonic muscle contraction, there is a transient suppression of muscle

action. This inhibitory period (IP) was significantly shorter in the upper paretic

limb of stroke patients with spasticity than in normal limb of the patients and

healthy individuals. Shortening of the IP duration was correlated to degree of

upper limb spasticity (Ashworth scale) and may be due to supraspinal level

reduction of the inhibitory function. The IP study contributes to a better

quantification of the hand function in stroke patients.

52. Cruz Martinez, A.; Munoz, J.; Palacios, F. The muscle inhibitory period by

transcranial magnetic stimulation. Study in stroke patients. Electromyogr-Clin-

Neurophysiol. 1998 Apr; 38(3): 189-92; ISSN: 0301-150X.

BELGIUM. Motor evoked potentials (MEPs) elicited over hand muscles by

transcranial magnetic stimulation (TMS) were studied in healthy individuals and,

bilaterally, in patients with cerebral infarction. Conduction time of the central

motor pathways (CMCT), threshold intensity, and amplitude of the MEPs were

correlated with recovery motor hand function after stroke. Following MEPs by

TMS during tonic muscle contraction, there is a transient suppression of muscle

action. This inhibitory period (IP) was significantly shorter in the upper paretic

limb of stroke patients with spasticity than in normal limb of the patients and

healthy individuals. Shortening of the IP duration was correlated to degree of

upper limb spasticity (Ashworth scale) and may be due to supraspinal level

reduction of the inhibitory function. The IP study contributes to a better

quantification of the hand function in stroke patients.

53. Csibra, G.; Tucker, L. A.; Johnson, M. H. Neural correlates of saccade planning in

infants: a high-density ERP study. Int-J-Psychophysiol. 1998 Jul; 29(2): 201-15;

ISSN: 0167-8760.

NETHERLANDS. Neural correlates of saccade planning in 6-month-old infants

were investigated by high-density event-related potentials. Subjects made

saccades to a target stimulus following a time gap from fixation stimulus offset

(gap trials) or with the fixation stimulus still present (overlap trials). Like adults,

infants were slower to make a saccade to the target when the fixation stimulus was

still present. Strikingly, infants did not show clear evidence of the pre-saccadic

components observed in adults which are thought to reflect cortical saccade

planning processes. They did, however, show a left frontal positivity, which we

suggest reflects cortical disinhibition of the colliculus initiated by fixation stimulus

offset, and clear post-saccadic lambda waves. These results indicate that the

frontal cortex already plays a role in action control by 6 months of age, while

other aspects of cortical action planning may not yet be present in certain task

situations.

54. Csibra, G.; Tucker, L. A.; Johnson, M. H. Neural correlates of saccade planning in

infants: a high-density ERP study. Int-J-Psychophysiol. 1998 Jul; 29(2): 201-15;

ISSN: 0167-8760.

NETHERLANDS. Neural correlates of saccade planning in 6-month-old infants

were investigated by high-density event-related potentials. Subjects made

saccades to a target stimulus following a time gap from fixation stimulus offset

(gap trials) or with the fixation stimulus still present (overlap trials). Like adults,

infants were slower to make a saccade to the target when the fixation stimulus was

still present. Strikingly, infants did not show clear evidence of the pre-saccadic

components observed in adults which are thought to reflect cortical saccade

planning processes. They did, however, show a left frontal positivity, which we

suggest reflects cortical disinhibition of the colliculus initiated by fixation stimulus

offset, and clear post-saccadic lambda waves. These results indicate that the

frontal cortex already plays a role in action control by 6 months of age, while

other aspects of cortical action planning may not yet be present in certain task

situations.

55. Davey, N. J.; Rawlinson, S. R.; Maskill, D. W.; Ellaway, P. H. Facilitation of a hand

muscle response to stimulation of the motor cortex preceding a simple reaction

task. Motor-Control. 1998 Jul; 2(3): 241-50; ISSN: 1087-1640.

UNITED-STATES. Transcranial magnetic stimulation (TMS) of the motor

cortex was used to produce compound motor evoked potentials (cMEPs) in the

first dorsal interosseus (FDI) muscle. The size of cMEPs was measured as an

index of corticospinal excitability before and after initiation of a simple reaction

task (SRT). The SRT, consisting of an abduction of the right index finger against a

vertical support in response to a 1 kHz cueing tone, was performed in 6 healthy

male subjects. cMEPs were facilitated when timed to occur just before the fastest

simple reaction time (fSRT). When the cMEP was placed 15.5 +/- 1.5 ms before

the fSRT, its amplitude increased to 176 +/- 36% of the control response seen in

the relaxed state (no SRTs). Facilitation of the cMEP increased to 382 +/- 43% of

the control when it was placed 11.9 +/- 1.5 ms after the fSRT. The facilitation of

cMEP responses prior to the SRT is discussed with particular reference to the

premovement potential that may be recorded over the cortex prior to a voluntary

movement.

56. David, T.; Smye, S.; Dabbs, T.; James, T. A model for the fluid motion of vitreous

humour of the human eye during saccadic movement. Phys-Med-Biol. 1998 Jun;

43(6): 1385-99; ISSN: 0031-9155.

ENGLAND. During saccadic motion the eyewall moves in a manner similar to a

sinusoid or at least can be represented by a sine Fourier series. Motion of the

vitreous is induced by the saccade and the vitreo-retinal interface is subjected to a

time-dependent shear. This force may be a significant factor for retinal tearing in

the neighbourhood of small retinal holes or tears. An analytical viscoelastic model

and a numerical, Newtonian model of the motion of the vitreous are presented and

compared. Under sinusoidal boundary motion the analytical model shows that a

viscous wave propagates inward toward the axis of rotation and the characteristic

length of this wave is a function of the Womersley number. The numerical

solution indicates that the vitreous moves similarly to the analytical result with

small secondary motion; however, this motion allows complete recirculation of

the vitreous over large timescales. Excellent agreement is found between the

analytical and numerical models. The time-dependent fluid shear is evaluated and

from the analytical solution the maximum value of this is found to be proportional

to R0 square root of v(omega)3, where R0 is the eye radius, v the modified

complex viscosity and omega the sinusoidal frequency. This indicates that

myopes have a larger shear force exerted on them by virtue of the larger eye size.

Further work is directed toward a model which links the stress found in the sclera

to that exerted on the vitreo-retinal interface by the vitreous fluid motion.

57. David, T.; Smye, S.; Dabbs, T.; James, T. A model for the fluid motion of vitreous

humour of the human eye during saccadic movement. Phys-Med-Biol. 1998 Jun;

43(6): 1385-99; ISSN: 0031-9155.

ENGLAND. During saccadic motion the eyewall moves in a manner similar to a

sinusoid or at least can be represented by a sine Fourier series. Motion of the

vitreous is induced by the saccade and the vitreo-retinal interface is subjected to a

time-dependent shear. This force may be a significant factor for retinal tearing in

the neighbourhood of small retinal holes or tears. An analytical viscoelastic model

and a numerical, Newtonian model of the motion of the vitreous are presented and

compared. Under sinusoidal boundary motion the analytical model shows that a

viscous wave propagates inward toward the axis of rotation and the characteristic

length of this wave is a function of the Womersley number. The numerical

solution indicates that the vitreous moves similarly to the analytical result with

small secondary motion; however, this motion allows complete recirculation of

the vitreous over large timescales. Excellent agreement is found between the

analytical and numerical models. The time-dependent fluid shear is evaluated and

from the analytical solution the maximum value of this is found to be proportional

to R0 square root of v(omega)3, where R0 is the eye radius, v the modified

complex viscosity and omega the sinusoidal frequency. This indicates that

myopes have a larger shear force exerted on them by virtue of the larger eye size.

Further work is directed toward a model which links the stress found in the sclera

to that exerted on the vitreo-retinal interface by the vitreous fluid motion.

58. Davids, J. R.; Bagley, A. M.; Bryan, M. Kinematic and kinetic analysis of running in

children with cerebral palsy. Dev-Med-Child-Neurol. 1998 Aug; 40(8): 528-35;

ISSN: 0012-1622.

ENGLAND. Computer-based analysis of gait was used to study walking and

running in 19 children with spastic-diplegic cerebral palsy (CP) and 15 healthy

control children. Temporospatial parameters, kinematic and kinetic data were

compared and contrasted between groups for both types of gait. The majority of

children with diplegic CP, who are independent ambulators, are able to run. These

children increase their velocity by increasing their cadence, a mechanism that is

distinct (and presumably less energy efficient) from that used by healthy children.

Sagittal-plane kinematic and kinetic profiles at the ankle in children with CP were

more similar to normal profiles in running than in walking, suggesting that the

primary deviations at the ankle associated with CP are better tolerated at greater

velocities. Relative power analysis showed that, like healthy children, those with

CP depend more upon the proximal musculature about the hip for power

generation as the velocity of gait increases. Children with CP achieve energy

transfer between adjacent joints during walking and running in a manner

comparable to unaffected children. Running is an important activity for children

and should be considered in the functional assessment of those with CP.

59. de Zeeuw, C. I.; van Alphen, A. M.; Koekkoek, S. K.; Buharin, E.; Coesmans, M. P.;

Morpurgo, M. M.; van, den Burg J. Recording eye movements in mice: a new

approach to investigate the molecular basis of cerebellar control of motor learning

and motor timing. Otolaryngol-Head-Neck-Surg. 1998 Sep; 119(3): 193-203;

ISSN: 0194-5998.

UNITED-STATES. The vestibulocerebellum is involved in the control of

compensatory eye movements. To investigate its role in learning and timing of

motor behavior, we investigated compensatory eye movements in mice with the

use of search coils. Wild-type mice showed the ability to increase the gain of their

vestibulo-ocular reflex by visuovestibular training. This adaptation did not occur

in lurcher mice, a natural mouse mutant that completely lacks Purkinje cells.

During the optokinetic reflex the phase of the eye movements of lurcher mice in

reference to the stimulus lagged behind that of wild-type littermates, whereas

during the vestibulo-ocular reflex it led that of the wild-type mice. During

combined optokinetic and vestibular stimulation, the phase of the lurcher mice

lagged behind that of the wild-type mice at the low stimulus frequencies, whereas

it led the phase of the wild-type mice at the high frequencies. In addition, the

optokinetic response of the lurcher mice showed a significantly longer latency

during constant-velocity step stimulation than that of the wild-type mice. We

conclude that Purkinje cells are necessary for both learning and timing of

compensatory eye movements in mice. The present description of gain adaptation

and phase dynamics provides the basis for studies in which the molecular

mechanisms of cerebellar control of compensatory eye movements are

investigated with the use of genetically manipulated mice.

60. Dejardin, S.; Dubois, S.; Bodart, J. M.; Schiltz, C.; Delinte, A.; Michel, C.; Roucoux,

A.; Crommelinck, M. PET study of human voluntary saccadic eye movements in

darkness: effect of task repetition on the activation pattern. Eur-J-Neurosci. 1998

Jul; 10(7): 2328-36; ISSN: 0953-816X.

FRANCE. Using H2(15)O 3D Positron Emission Tomography (PET), regional

cerebral blood flow (rCBF) was measured in six human subjects under two

different conditions: at rest and while performing self-paced horizontal saccadic

eye movements in darkness. These two conditions were repeated four times each.

First, the comparison between the four saccadic and four resting conditions was

investigated in a group and a single subject analysis. Saccades elicited bilateral

rCBF increases in the medial part of the superior frontal gyrus (supplementary

eye field), precentral gyrus (frontal eye field), superior parietal lobule, anterior

medial part of the occipital lobe involving striate and extrastriate cortex (lingual

gyrus and cuneus), and in the right inferior parietal lobule. At the subcortical level,

activations were found in the left putamen. These results mainly replicate

previous PET findings on saccadic control. Second, the interaction between the

experimental conditions and their repetition was examined. When activations

throughout repetition of the same saccadic task are compared, the supplementary

eye fields show a progressive increase of activation. On the contrary, the

activation in the cerebellum, left superior parietal lobule and left occipital cortex

progressively decreases during the scanning session. Given the existence of such

an interaction, the pattern of activations must be interpreted as a function of task

repetition. This may be a factor explaining some apparent mismatch between

different studies.

61. Dejardin, S.; Dubois, S.; Bodart, J. M.; Schiltz, C.; Delinte, A.; Michel, C.; Roucoux,

A.; Crommelinck, M. PET study of human voluntary saccadic eye movements in

darkness: effect of task repetition on the activation pattern. Eur-J-Neurosci. 1998

Jul; 10(7): 2328-36; ISSN: 0953-816X.

FRANCE. Using H2(15)O 3D Positron Emission Tomography (PET), regional

cerebral blood flow (rCBF) was measured in six human subjects under two

different conditions: at rest and while performing self-paced horizontal saccadic

eye movements in darkness. These two conditions were repeated four times each.

First, the comparison between the four saccadic and four resting conditions was

investigated in a group and a single subject analysis. Saccades elicited bilateral

rCBF increases in the medial part of the superior frontal gyrus (supplementary

eye field), precentral gyrus (frontal eye field), superior parietal lobule, anterior

medial part of the occipital lobe involving striate and extrastriate cortex (lingual

gyrus and cuneus), and in the right inferior parietal lobule. At the subcortical level,

activations were found in the left putamen. These results mainly replicate

previous PET findings on saccadic control. Second, the interaction between the

experimental conditions and their repetition was examined. When activations

throughout repetition of the same saccadic task are compared, the supplementary

eye fields show a progressive increase of activation. On the contrary, the

activation in the cerebellum, left superior parietal lobule and left occipital cortex

progressively decreases during the scanning session. Given the existence of such

an interaction, the pattern of activations must be interpreted as a function of task

repetition. This may be a factor explaining some apparent mismatch between

different studies.

62. Delgado Garcia, J. M. Output-to-input approach to neural plasticity in vestibular

pathways. Otolaryngol-Head-Neck-Surg. 1998 Sep; 119(3): 221-30; ISSN: 0194-

5998.

UNITED-STATES. Some thoughts on current interpretations of available data

regarding vestibular compensation at functional, network, and neural levels are

presented. Basic concepts related to neural plasticity (or elasticity) underlying

motor learning and regeneration also are discussed briefly. Modifiability in

vestibular pathways, at both the functional and structural levels, after peripheral

and central axotomy, and subsequent to transient or permanent chemical target

removal, is presented as an experimental ground to explain similarities and

differences between regenerative, compensatory, and adaptive mechanisms in the

mammal central nervous system.. 0.

63. Dell'Osso, L. F.; Williams, R. W.; Jacobs, J. B.; Erchul, D. M. The congenital and see-

saw nystagmus in the prototypical achiasma of canines: comparison to the human

achiasmatic prototype. Vision-Res. 1998 Jun; 38(11): 1629-41; ISSN: 0042-6989.

ENGLAND. We applied new methods for canine eye-movement recording to the

study of achiasmatic mutant Belgian Sheepdogs, documenting their nystagmus

waveforms and comparing them to humans with either congenital nystagmus (CN)

alone or in conjunction with achiasma. A sling apparatus with head restraints and

infrared reflection with either earth- or head-mounted sensors were used. Data

were digitized for later evaluation. The horizontal nystagmus (1-6 Hz) was similar

to that of human CN. Uniocular and disconjugate nystagmus and saccades were

recorded. See-saw nystagmus (SSN), not normally seen with human CN, was

present in all mutants (0.5-6 Hz) and in the one human achiasmat studied thus far.

This pedigree is an animal model of CN and the SSN caused by achiasma or

uniocular decussation. Given the finding of SSN in all mutant dogs and in a human,

achiasma may be sufficient for the development of congenital SSN and, in human

infants, SSN should alert the clinician to the possibility of either achiasma or

uniocular decussation. Finally, the interplay of conjugacy and disconjugacy

suggests independent ocular motor control of each eye with variable yoking in the

dog.

64. Dewey, C.; Fleming, P.; Golding, J. Does the supine sleeping position have any

adverse effects on the child? II. Development in the first 18 months.ALSPAC

Study Team. Pediatrics. 1998 Jan; 101(1): E5; ISSN: 1098-4275.

UNITED-STATES. OBJECTIVE: To assess whether the recommendations that

infants sleep supine could have adverse consequences on their motor and mental

development. DESIGN: A prospective study of infants, delivered before, during,

and after the Back to Sleep Campaign in the United Kingdom, followed to 18

months of age. SUBJECTS: The children were participants of the Avon

Longitudinal Study of Pregnancy and Childhood born to mothers resident in the

three former Bristol-based health districts of Avon, with expected date of delivery

from April 1, 1991 to December 31, 1992. Questionnaires were completed on

sleeping position at 4 to 6 weeks of age and sets of standardized questions on

development at 6 and 18 months. MAIN OUTCOME MEASURES: Social,

communication, fine and gross motor, and total developmental scales based on the

Denver Developmental Screening Test at 6 and 18 months. RESULTS: After

adjustment for 27 factors using multiple regression, 3 of the 10 scales and

subscales significantly distinguished between front and back sleeping position. At

6 months of age, infants put to sleep on their front had a mean score 0.38 SD

(95% confidence interval [CI]: 0.28, 0.49) higher on the gross motor scale, 0.11

SD (95% CI: 0.00, 0.23) higher in the social skills scale, and a total development

score 0.20 SD (95% CI: 0.10, 0.30) higher than those on their backs. These

differences were no longer apparent at 18 months. CONCLUSIONS: There is

some evidence that putting infants to sleep in the supine position results in a

reduced developmental score at 6 months of age, but this disadvantage appears to

be transient. Weighing this against the adverse health effects demonstrated with

the prone sleeping position, these results should not change the message of the

Back to Sleep Campaign.

65. Dieterich, M.; Bucher, S. F.; Seelos, K. C.; Brandt, T. Horizontal or vertical

optokinetic stimulation activates visual motion-sensitive, ocular motor and

vestibular cortex areas with right hemispheric dominance. An fMRI study. Brain.

1998 Aug; 121( Pt 8): 1479-95; ISSN: 0006-8950.

ENGLAND. The differential effects of optokinetic stimulation with and without

fixation suppression were analysed in an fMRI study in 10 right-handed healthy

subjects. Horizontal and vertical small-field optokinetic stimulation activated the

same multiple visual, ocular motor and vestibular cortical and subcortical areas in

both hemispheres. The extent of activation in each hemisphere was independent

of the stimulus direction. All activated areas representing cortical

(occipitotemporal cortex, posterior parietal cortex, precentral and posterior

median frontal gyrus, prefrontal cortex, medial part of the superior frontal gyrus)

and subcortical (caudate nucleus, putamen, globus pallidus and paramedian

thalamus) ocular motor structures were activated during optokinetic stimulation as

well as during fixation suppression of optokinetic nystagmus. However, the

activation was significantly stronger with optokinetc nystagmus compared with

fixation suppression. The only relatively increased activity during fixation

suppression was seen in the medial part of the superior frontal gyrus

(supplementary eye field) and the anterior cingulate gyrus. The anterior insula and

the posterior insula (human homologue of the parieto-insular vestibular cortex)

were activated during optokinetic nystagmus but not during fixation suppression.

A significant right hemispheric predominance (regardless of stimulus direction)

was found under both conditions in the visual motion-sensitive and ocular motor

areas of the cortex, except the supplementary eye field and anterior cingulate

gyrus. This was most prominent in the occipitotemporal cortex, but did not occur

in the primary visual cortex and in subcortical ocular motor structures (putamen,

globus pallidus and caudate nucleus). Thus, cortical and subcortical activation

patterns did not differ for horizontal and vertical optokinetic stimulation, and

there was distinct right-hemisphere dominance for visual motion-sensitive and

cortical ocular motor areas and the thalamus. Fixation suppression of optokinetic

nystagmus yielded four different results: (i) increased activation in the

supplementary eye field and anterior cingulate gyrus; (ii) unchanged activation in

the visual cortex; (iii) decreased activation in most of the ocular motor areas; and

(iv) suppressed activation in the anterior and posterior insula and the thalamus.

Activation of the parieto-insular vestibular cortex may be related to ocular motor

function rather than self-motion perception.

66. Dietz, V.; Wirz, M.; Colombo, G.; Curt, A. Locomotor capacity and recovery of

spinal cord function in paraplegic patients: a clinical and electrophysiological

evaluation. Electroencephalogr-Clin-Neurophysiol. 1998 Apr; 109(2): 140-53;

ISSN: 0013-4694.

IRELAND. Recent studies have shown that a locomotor pattern can be induced

and trained into paraplegic patients under conditions of body unloading using a

moving treadmill. The present study investigated the behaviour of the locomotor

pattern and also the relationship of its development to the spontaneous recovery

of spinal cord function assessed by clinical and electrophysiological (tibial nerve

somatosensory evoked potentials and motor evoked potentials) examinations. The

earliest time that spinal locomotor activity could be induced was when signs of

spinal shock had disappeared. This activity was distinct from spinal stretch reflex

activity. In complete and incomplete paraplegic patients an increase of

gastrocnemius electromyographic activity occurred during the stance phase of a

step cycle with daily locomotor training over the whole training period of 12

weeks. This was coincident with a significant decrease in body unloading. In

contrast to this, neither clinical nor electrophysiological examination scores

improved after the onset of training in both patient groups. Only in incomplete

paraplegic patients was there an insignificant increase in sensory and motor scores

obtained in the neurological examination during the time period before onset of

training. An improvement of locomotor function by training was also seen in

patients with paraplegia due to a cauda lesion. Therefore, in patients with a spinal

cord lesion training effects on muscles and tendons are present in addition to those

on the spinal locomotor centres. The findings of this study may be relevant for

future clinical treatment of paraplegic patients.

67. Dietz, V.; Wirz, M.; Curt, A.; Colombo, G. Locomotor pattern in paraplegic patients:

training effects and recovery of spinal cord function. Spinal-Cord. 1998 Jun;

36(6): 380-90; ISSN: 1362-4393.

ENGLAND. Recent studies have shown that a locomotor pattern can be induced

and utilized by paraplegic patients under conditions of body unloading using a

moving treadmill. The present study investigated the behaviour of the locomotor

pattern and also the relationship of its development to the spontaneous recovery

of spinal cord function assessed by clinical and electrophysiological (tibial nerve

somatosensory evoked potentials and motor evoked potentials) examinations. The

earliest time that spinal locomotor activity could be induced was when signs of

spinal shock had disappeared. This activity was distinct from spinal stretch reflex

activity. In complete paraplegic patients the locomotor pattern improved

spontaneously without training. This was coincident with both an increase of

gastrocnemius electromyographic activity during the stance phase of gait and a

decrease of body unloading. These effects reached a plateau after about 5 weeks.

In complete and incomplete paraplegic patients a near linear increase of

gastrocnemius electromyographic activity occurred during the stance phase of a

step cycle with daily locomotor training over the whole training period of 12

weeks. This was also coincident with a significant decrease of body unloading. In

contrast to this, neither clinical nor electrophysiological examination scores

improved after the onset of training in both patient groups. Only in incomplete

paraplegic patients was there recovery, albeit statistically insignificant, of spinal

cord function according to the sensory and motor scores obtained in the

neurological examination during the time period before onset of training. An

improvement of locomotor function by training was also seen in patients with

paraplegia due to a cauda lesion. Such training effects on muscles and tendons

could be separated from those on the spinal locomotor centres. The findings of

this study may be relevant for the future clinical treatment of paraplegic patients.

68. Donchin, O.; Gribova, A.; Steinberg, O.; Bergman, H.; Vaadia, E. Primary motor

cortex is involved in bimanual coordination. Nature. 1998 Sep 17; 395(6699): 274-

8; ISSN: 0028-0836.

ENGLAND. Many voluntary movements involve coordination between the

limbs. However, there have been very few attempts to study the neuronal

mechanisms that mediate this coordination. Here we have studied the activity of

cortical neurons while monkeys performed tasks that required coordination

between the two arms. We found that most neurons in the primary motor cortex

(MI) show activity specific to bimanual movements (bimanual-related activity),

which is strikingly different from the activity of the same neurons during

unimanual movements. Moreover, units in the supplementary motor area (SMA;

the area of cortex most often associated with bimanual coordination) showed no

more bimanual-related activity than units in MI. Our results challenge the classic

view that MI controls the contralateral (opposite) side of the body and that SMA

is responsible for the coordination of the arms. Rather, our data suggest that both

cortical areas share the control of bilateral coordination.

69. Dorfman, L.; Robinson, L. Ab-normative data [letter]. Muscle-Nerve. 1998 Sep;

21(9): 1233-5; ISSN: 0148-639X.

UNITED-STATES.

70. Dorris, M. C.; Munoz, D. P. Saccadic probability influences motor preparation

signals and time to saccadic initiation. J-Neurosci. 1998 Sep 1; 18(17): 7015-26;

ISSN: 0270-6474.

UNITED-STATES. One must be prudent when selecting potential saccadic

targets because the eyes can only move to one location at a time, yet movements

must occur quickly enough to permit interaction with a rapidly changing world.

This process of efficiently acquiring relevant targets may be aided by advanced

planning of a movement toward an upcoming target whose location is gathered via

environmental cues or situational experience. We studied how saccadic reaction

times (SRTs) and early pretarget neuronal activity covaried as a function of

saccadic probability. Monkeys performed a saccadic task in which the probability

of the required saccade being directed into the response field of a neuron varied

systematically between blocks of trials. We recorded simultaneously the early

pretarget activity of saccade-related neurons in the intermediate layers of the

superior colliculus. We found that, as the likelihood of the saccade being generated

into the response field of the neuron increased, the level of neuronal activity

preceding target presentation also increased. Our data suggest that this early

activity codes motor preparation because its activity was related to not only the

metrics but also the timing of the saccade, with 94% (29/31) of the neurons tested

having significant negative correlations between discharge rate and SRT. This view

is supported by cases in which exceptionally high levels of pretarget activity were

associated with anticipatory saccades into the response field of a neuron that

occurred in advance of the target being presented. This study demonstrates how

situational experience can expedite motor behavior via the advanced preparation of

motor programs.

71. Dorris, M. C.; Munoz, D. P. Saccadic probability influences motor preparation

signals and time to saccadic initiation. J-Neurosci. 1998 Sep 1; 18(17): 7015-26;

ISSN: 0270-6474.

UNITED-STATES. One must be prudent when selecting potential saccadic

targets because the eyes can only move to one location at a time, yet movements

must occur quickly enough to permit interaction with a rapidly changing world.

This process of efficiently acquiring relevant targets may be aided by advanced

planning of a movement toward an upcoming target whose location is gathered via

environmental cues or situational experience. We studied how saccadic reaction

times (SRTs) and early pretarget neuronal activity covaried as a function of

saccadic probability. Monkeys performed a saccadic task in which the probability

of the required saccade being directed into the response field of a neuron varied

systematically between blocks of trials. We recorded simultaneously the early

pretarget activity of saccade-related neurons in the intermediate layers of the

superior colliculus. We found that, as the likelihood of the saccade being generated

into the response field of the neuron increased, the level of neuronal activity

preceding target presentation also increased. Our data suggest that this early

activity codes motor preparation because its activity was related to not only the

metrics but also the timing of the saccade, with 94% (29/31) of the neurons tested

having significant negative correlations between discharge rate and SRT. This view

is supported by cases in which exceptionally high levels of pretarget activity were

associated with anticipatory saccades into the response field of a neuron that

occurred in advance of the target being presented. This study demonstrates how

situational experience can expedite motor behavior via the advanced preparation of

motor programs.

72. Dubowitz, L.; Mercuri, E.; Dubowitz, V. An optimality score for the neurologic

examination of the term newborn. J-Pediatr. 1998 Sep; 133(3): 406-16; ISSN:

0022-3476.

UNITED-STATES. We describe the application of a revised version of the

Dubowitz neurologic examination of the newborn in 224 low-risk, term newborn

infants. The method has been updated by eliminating less useful items and

including new items evaluating general movements and patterns of distribution of

tone. An optimality score is included to make the evaluation more quantitative

and for comparison with sequential examinations with neurophysiologic and

imaging findings. The score is based on the distribution of the scores for each item

in the population of low-risk term infants. We defined not only the most common

pattern for each item but also the variability of the findings by using 10th and 5th

centiles. Because most of the items assessing tone and the Moro reflex varied with

gestational age between 37 and 42 weeks, the changes were incorporated in the

scoring system. The total optimality score was the sum of the optimality scores

of individual items. Although the association of 4 or more deviant scores was

found in less than 10% of our infants, deviant results on 1 or 2 single items could

be observed in a third of this normal population, suggesting that isolated deviant

signs have little diagnostic value. In contrast, an abnormal distribution of tone

patterns, which we have commonly observed in infants with brain lesions, was

not found in this cohort.

73. Dumitru, D.; King, J. C. Concentric needle recording characteristics related to depth

of tissue penetration. Electroencephalogr-Clin-Neurophysiol. 1998 Apr; 109(2):

124-34; ISSN: 0013-4694.

IRELAND. This study investigates the influence of tissue penetration depth as it

relates to a concentric needle electrode, particularly delineating regions where the

cannula potential predominates over the core potential. The regions of cannula

predominance is studied by means of a standard and 20 times enlarged physical

model of an electromyographic concentric needle electrode in a homogeneous

volume conductor by delineating the zero isopotential which partitions where the

core potential predominates versus where the cannula potential predominates.

Clinical studies in muscle tissue are used to test and confirm results from the

enlarged physical model. At shallow electrode insertions equivalent to 4 mm, the

concentric needle model records a net negative potential, which is a region where

the cannula predominates, from a distant positive dipole at the same depth

compared with a net positive potential for penetration depths exceeding 4 mm.

The clinical portion of this study verifies the bipolar nature of the concentric

needle electrode in detecting motor unit action potentials (MUAPs) with

primarily an initial positive onset irrespective of recording depth. Refinements to

the conceptualization of the nature and detection of MUAPs are discussed which

are consistent with all the findings of the clinical and model study.

74. Eckstein, A. K.; Fischer, M.; Esser, J. [Normal accommodative convergence excess--

long-term follow-up of conservative therapy with bifocal eyeglasses].

Normakkommodativer Konvergenzexzess--Langzeitverlauf bei konservativer

Therapie mit Bifokalbrille. Klin-Monatsbl-Augenheilkd. 1998 Apr; 212(4): 218-

25; ISSN: 0023-2165.

GERMANY. BACKGROUND: In patients with normaccommodative

convergence excess it is possible to reduce or eliminate the excess of

accommodative convergence by adding plus lenses. The resulting reduction of near

deviation can lead to an improvement in the quality of binocular vision at near,

and also to a better compensation of an esophoria at near. The aim of the paper

was to study long term results in patients with small angle esotropia and

esophoria and accommodative convergence excess treated by bifocals.

METHODS: Clinical data of 91 patients were analysed retrospectively. Among

them were 13 patients with esophoria, 32 patients with microesotropia and 46

with microesotropia and a phoric component. An orthoptic status was performed

every three months and at every examination it was tried to reduce the added plus

lenses. The mean follow up was 5.6 +/- 2.4 years (range: 1.1-13.2). RESULTS:

The mean onset of strabismus was similar in all groups: i.e. 2.5 (+/- 1.7) years.

The patients received their first bifocals on average 3.4 (+/- 1.9) years later. In 40

of the 91 patients the near addition could be stopped because of sufficient

decrease of accommodative convergence excess during the follow-up period. The

convergence excess decreased continuously in all patients with esophoria and

microesotropia and the additional plus lenses could be stopped on average after

6.4 (3.5-8.4) years (esophoria) and 5.0 (2.6-8.1) years (microesotropia)

respectively. In patients with microesotropia and an additional phoric deviation

bifocals were only partly successful to reduce the convergence excess. The basic

angle decompensated in more than half of the patients (27 out of 46) and was

operated in 14 cases by unilateral resection/recession procedure. After the

operation the convergence excess decreased rapidly and the bifocals could be

stopped after 4.4 (3.4-7.4) years. In the remaining 19 cases it was possible to

reduced the convergence excess with bifocals in 8 patients after about 8.1 (4.1-9.3)

years and in some of the remaining 11 cases a Fadenoperation has been suggested.

CONCLUSION: While wearing bifocals the accommodative convergence excess

decreased completely in patients with esophoria and microesotropia. In the

condition with markedly reduced binocular vision and a large phoric component at

far and near, the convergence excess decreased only in some of the patients while

wearing bifocals. Conventional strabismus surgery to reduce the basic angle has a

positive influence. A Fadenoperation is only necessary in a few cases.

75. Eliasson, A. C.; Ekholm, C.; Carlstedt, T. Hand function in children with cerebral

palsy after upper-limb tendon transfer and muscle release. Dev-Med-Child-

Neurol. 1998 Sep; 40(9): 612-21; ISSN: 0012-1622.

ENGLAND. Thirty-two children with hand dysfunction due to cerebral palsy

were examined before tendon transfer and muscle release, and 9 months

postoperatively. All children improved their performance regardless of the degree

of impaired hand function. The main advantage of surgery was a more functional

position of the hand with increased wrist extension and forearm supination. There

were also increased functionality of handgrips, grip strength, and dexterity.

Impaired sensibility before surgery did not influence the outcome. Individual goals

were set preoperatively. Individual functional goals outlined before surgery were

met by most children. Children identified as having mild impairments gained new

functional skills related to everyday activity (self-care and leisure), while children

with severely impaired hand function demonstrated enhanced grasping ability, as

well as a better cosmetic appearance.

76. Ellaway, P. H.; Davey, N. J.; Maskill, D. W.; Rawlinson, S. R.; Lewis, H. S.;

Anissimova, N. P. Variability in the amplitude of skeletal muscle responses to

magnetic stimulation of the motor cortex in man. Electroencephalogr-Clin-

Neurophysiol. 1998 Apr; 109(2): 104-13; ISSN: 0013-4694.

IRELAND. We have investigated variability in the amplitude of compound motor

evoked potentials (cMEPs) in right and left thenar and wrist extensor muscles in

response to synchronous bilateral transcranial magnetic stimulation (TMS) of the

motor cortices using two figure-of-eight stimulating coils. Trials of 50 stimuli

revealed a wide range of variability in cMEP amplitudes in relaxed muscles

(coefficient of variation, range 0.22-1.12). The amplitudes of the cMEPs in one

muscle correlated positively with those in the others. The r2 values (mean +/-

SEM) were 0.27 +/- 0.06 for muscles on the same side of the body and 0.19 +/-

0.04 for muscles on opposite sides. Employing the ECG to trigger TMS, clamping

the coil relative to the head or altering the orientation of the coil all failed to affect

the variability of cMEPs. We conclude that fluctuations in excitability of the

corticospinal pathway give rise to the variability in the response to TMS, that

they are wide-ranging with respect to the muscles affected, and include a bilateral

component. We argue that the variability reveals fluctuations in excitability

mainly at the cortical rather than the spinal level. We suggest that measures of

variability might provide an indication of cortical activity in conditions where

consciousness and voluntary movement are compromised.

77. Escudero, J. V.; Sancho, J.; Bautista, D.; Escudero, M.; Lopez Trigo, J. Prognostic

value of motor evoked potential obtained by transcranial magnetic brain

stimulation in motor function recovery in patients with acute ischemic stroke.

Stroke. 1998 Sep; 29(9): 1854-9; ISSN: 0039-2499.

UNITED-STATES. BACKGROUND AND PURPOSE: The early prognostic

application of transcranial magnetic brain stimulation (TMS) for assessing motor

and functional recovery in ischemic stroke patients has yielded contradictory

results. We performed a prospective study of patients with acute ischemic stroke

and motor deficit to evaluate the early prognostic value of TMS in motor and

functional recovery. METHODS: Fifty patients with different degrees of

hemiparesis were studied in the first week after ischemic stroke and evaluated by

clinical scales (Medical Research Council Scale, Canadian Neurological Scale,

Barthel Index), with clinical follow-up over 6 months. TMS (Magstim 200) was

performed at the same time, recording the motor evoked potential (MEP) in the

thenar eminence muscles, with facilitation by voluntary contraction. RESULTS:

Of the total group of 50 patients, MEP was absent in 20 and present in 30 (17

with normal and 13 with delayed central conduction time [CCT]). The patients

with MEP showed better motor and functional recovery than those without. The

MEP provided information on patient recovery, regardless of the initial strength

and/or Barthel values. The degree of recovery was better in those patients with

normal CCT than in those with delayed CCT. CONCLUSIONS: MEP obtained

by TMS in patients with hemiparesis after acute ischemic stroke is useful as an

early prognostic indicator of motor and functional recovery. This technique would

allow the early identification of those patients who will have a good recovery,

particularly among those with severe initial paresis.

78. Etnier, J. L.; Landers, D. M. Motor performance and motor learning as a function of

age and fitness. Res-Q-Exerc-Sport. 1998 Jun; 69(2): 136-46; ISSN: 0270-1367.

UNITED-STATES. Past studies have shown that electroencephalographic alpha

activity increases as people learn to perform a novel motor task. Additionally, it

has been suggested that motor performance and learning decline as people age

beyond 60 years, and it has been hypothesized that physical fitness may

attenuate this decline through its impact on the cerebral environment. This study

was designed to replicate past research by assessing changes in alpha activity as a

function of learning and to extend past research by examining differences in motor

performance, motor learning, and alpha activity as a function of age and fitness.

VO2max was assessed in 41 older (ages 60-80 years) and 42 younger (ages 20-30

years) participants. Participants were randomly assigned to experimental or

control conditions, which differed in the amount of practice received. Participants

performed trials on the mirror star trace on both an acquisition and a retention

day. Results indicated that younger participants performed better and had greater

learning than older participants. Fitness was not found to impact either

performance or learning. Participants in the experimental group improved more

than those in the control group and maintained this difference at retention, which

suggests that learning occurred. Associated with these improvements in

performance capabilities was an increase in alpha power.

79. Etnyre, B. R. Accuracy characteristics of throwing as a result of maximum force

effort. Percept-Mot-Skills. 1998 Jun; 86(3 Pt 2): 1211-7; ISSN: 0031-5125.

UNITED-STATES. Fitts' law predicts the accuracy of movement to a target

decreases as the velocity of the movement increases. This speed-accuracy tradeoff

has been examined under numerous conditions. During some tasks, however,

increased force to nearly maximal level decreases the variability of the movement

(Sherwood & Schmidt, 1980). This condition apparently produced results

different from what would be predicted by Fitts' law. The purpose of the present

study was to examine the effects of maximal force on dart throwing accuracy and

variability. 54 subject were categorized into groups based upon their experience

with dart throwing: Advanced, Intermediate, or Beginners. Each subject performed

two sessions of 15 trials. Subjects were instructed to "throw normally" for one

session and "throw as hard as you can" for the other session Distances from the

target (triple-20 area) on the regulation dart board were measured and recorded

after each of three darts was thrown. Average Error and Variable Error were

calculated for each condition for each subject. The Average Error and Variable

Error were greatest for the Beginner group and least for the Advanced group. For

all three experience categories both Average Error and Variable Error were

significantly greater when subjects performed with maximal force. The greater

average error for the maximal force for all subjects suggested that the speed-

accuracy tradeoff applied to this aiming task. The greater variability in accuracy

with maximal force suggested a ceiling effect, which reduced variability in previous

studies, was not achieved.

80. Fellows, S. J.; Noth, J.; Schwarz, M. Precision grip and Parkinson's disease. Brain.

1998 Sep; 121( Pt 9): 1771-84; ISSN: 0006-8950.

ENGLAND. In order to investigate sensorimotor processing and force

development in Parkinson's disease, 16 patients, four patients with

hemiparkinsonism and 12 age-matched normal subjects were assessed during

lifting and holding of an object in a precision grip between thumb and forefinger,

or holding the object in this grip at a fixed height above a table. In the former case,

object loading could be changed between lifts without warning. In the latter case,

unexpected step load changes to the object were applied to the object with a

torque motor. All procedures could be applied with or without visual control of

the hand and the object. Normal subjects lifted an unpredictable load employing

the grip force parameters used in the preceding lift. If a load change was

encountered, the parameters became adapted to the new conditions during the lift,

modulating grip forces to match the loading. Parkinsonian patients retained this

strategy and the ability to regulate grip forces according to load. Under all

conditions, however, parkinsonian subjects developed abnormally high grip forces

in both the lift and the hold phase, although the ratio of these forces remained

normal. Lifting height was normal in parkinsonian subjects, but the duration of the

lifting task was significantly prolonged, due to a marked slowing in the rate of grip

force development in the lead-up to object lift-off and to prolongation of the

movement phase. Forewarning of object loading, with or without visual control,

did not reduce timing deficits or improve the rate of grip force development.

However, it did allow parkinsonian subjects to reduce the safety margin

significantly. Responses to step load changes imposed during holding without

visual control showed minor abnormalities in the parkinsonian patients: onset

latencies and EMG activity in the first dorsal interosseus and thenar muscles were

normal up to 140 ms after displacement. Subsequent EMG activity in the first

dorsal interosseus remained largely normal, but activity later in the slip response

(140-210 ms), subject to voluntary influence, was reduced in the thenar muscle.

Differences were less marked under visual conditions, but remained significant.

We concluded that the internal parameter set for lifting an object in a precision

grip and the automatic processes adapting precision grip to actual conditions are

intact in Parkinson's disease. However, parkinsonian subjects generate abnormally

high grip forces and require longer than normal subjects to complete a lift,

particularly with lighter loads. This deterioration in performance reflects both

reduced effectiveness of sensorimotor processing and impairment in the rate of

force development in Parkinson's disease.

81. Fern, K. D.; Manny, R. E.; Garza, R. Screening for anisometropia in preschool

children. Optom-Vis-Sci. 1998 Jun; 75(6): 407-23; ISSN: 1040-5488.

UNITED-STATES. PURPOSE: A preschool vision screening program was

reviewed to evaluate eccentric photoscreening (EP), visual acuity, and stereopsis

in identifying anisometropia. METHODS: Patients referred by the screening were

examined to assess efficacy of the three screening techniques in a population of

preschool children. Testability and comparison of screening results to the

classification of anisometropia (> or = 1 D) by retinoscopy obtained during a

complete examination were evaluated. RESULTS: Although EP identified 94.5%

of the anisometropic children as abnormal, only 27.8% were classified as

anisometropic by EP. Of the anisometropic children, 36.1% failed acuity, but

only 19.4% failed based on a 2 line or greater interocular acuity difference.

Stereopsis correctly identified only 7.3% of anisometropes as abnormal.

CONCLUSIONS: The sensitivity of EP in identifying anisometropic children as

abnormal was superior to acuity and stereopsis, yet its ability to identify

anisometropia specifically was poor. Anisometropia of low magnitude or that

masked by the dead zone of the EP system was frequently classified as

isometropic. Altering the EP referral criterion and/or taking photographs through

adequate power plus lenses may improve the sensitivity for specifically

identifying anisometropia. However, caution must be exercised when using EP to

examine the prevalence of anisometropia in a population or if used to screen for

only amblyogenic refractive errors (i.e., anisometropia), because many

anisometropes will be missed, resulting in inaccurate prevalence data and

significant underreferrals.

82. Fischer, B.; Weber, H. Effects of pre-cues on voluntary and reflexive saccade

generation. I. Anti-cues for pro-saccades. Exp-Brain-Res. 1998 Jun; 120(4): 403-

16; ISSN: 0014-4819.

GERMANY. Experiments on visual attention have employed both physical cues

and verbal instructions to enable subjects to allocate attention at a location that

becomes relevant within a perceptual or motor task some time later (cue lead time,

CLT). In this study we have used valid visual peripheral cues (CLT between 100

and 700 ms) to indicate the direction and location of the next saccade. A cue is

considered valid or invalid if its meaning with respect to the next saccade is correct

or incorrect. A cue is called an anti- or pro-cue if the side of its presentation is

opposite to or the same as the direction of the saccade required on a given trial.

Correspondingly, a saccade is called an anti- or pro-saccade if it is directed to the

side opposite to or the same as the stimulus presentation. A condition in which

the cue and the stimulus are presented on opposite sides provides a simple way

of dissociating voluntary attention allocation from automatic orienting. This paper

considers the anti-cue pro-saccade task: the subjects were instructed to use the

cue to direct attention to the opposite side, i.e. the location, where on valid trials

the saccade target would occur. In the companion paper we have used the same

physical condition, but we have reversed the instructions as to saccade direction

and we have reversed the meaning of the cue, i.e. we designed a pro-cue anti-

saccade task. In this first paper, the saccadic reaction times (SRTs) of pro-

saccades of five adult subjects were measured in the gap paradigm (fixation point

offset precedes target onset by 200 ms). With a CLT of 100 ms, valid anti-cues

reduced the number of express saccades (i.e. saccades with SRTs in the range 80-

120 ms) significantly compared with the control values (no cues). Valid anti-cues

with increasingly long CLTs (100-700 ms) resulted in an increasing incidence of

anticipatory saccades and saccades with longer SRTs (more than 120 ms), while

the frequency of express saccades remained below the control value. When cue

and saccade target were dissociated in location or in both location and direction,

the effects of the cueing revealed a much lower spatial selectivity as compared to

the effects that have been described for voluntary attention allocation by means of

central cues. The results suggest that voluntary allocation of attention and cue-

induced automatic orienting not only have different time courses but also have

opposite effects on the generation of express saccades, and different spatial

selectivities. A possible neuronal basis of these results is discussed considering

related findings from electrophysiological studies in monkeys.

83. Fischer, B.; Weber, H. Effects of pre-cues on voluntary and reflexive saccade

generation. I. Anti-cues for pro-saccades. Exp-Brain-Res. 1998 Jun; 120(4): 403-

16; ISSN: 0014-4819.

GERMANY. Experiments on visual attention have employed both physical cues

and verbal instructions to enable subjects to allocate attention at a location that

becomes relevant within a perceptual or motor task some time later (cue lead time,

CLT). In this study we have used valid visual peripheral cues (CLT between 100

and 700 ms) to indicate the direction and location of the next saccade. A cue is

considered valid or invalid if its meaning with respect to the next saccade is correct

or incorrect. A cue is called an anti- or pro-cue if the side of its presentation is

opposite to or the same as the direction of the saccade required on a given trial.

Correspondingly, a saccade is called an anti- or pro-saccade if it is directed to the

side opposite to or the same as the stimulus presentation. A condition in which

the cue and the stimulus are presented on opposite sides provides a simple way

of dissociating voluntary attention allocation from automatic orienting. This paper

considers the anti-cue pro-saccade task: the subjects were instructed to use the

cue to direct attention to the opposite side, i.e. the location, where on valid trials

the saccade target would occur. In the companion paper we have used the same

physical condition, but we have reversed the instructions as to saccade direction

and we have reversed the meaning of the cue, i.e. we designed a pro-cue anti-

saccade task. In this first paper, the saccadic reaction times (SRTs) of pro-

saccades of five adult subjects were measured in the gap paradigm (fixation point

offset precedes target onset by 200 ms). With a CLT of 100 ms, valid anti-cues

reduced the number of express saccades (i.e. saccades with SRTs in the range 80-

120 ms) significantly compared with the control values (no cues). Valid anti-cues

with increasingly long CLTs (100-700 ms) resulted in an increasing incidence of

anticipatory saccades and saccades with longer SRTs (more than 120 ms), while

the frequency of express saccades remained below the control value. When cue

and saccade target were dissociated in location or in both location and direction,

the effects of the cueing revealed a much lower spatial selectivity as compared to

the effects that have been described for voluntary attention allocation by means of

central cues. The results suggest that voluntary allocation of attention and cue-

induced automatic orienting not only have different time courses but also have

opposite effects on the generation of express saccades, and different spatial

selectivities. A possible neuronal basis of these results is discussed considering

related findings from electrophysiological studies in monkeys.

84. Forster, J.; Strack, F. Motor actions in retrieval of valenced information: II. Boundary

conditions for motor congruence effects. Percept-Mot-Skills. 1998 Jun; 86(3 Pt

2): 1423-6; ISSN: 0031-5125.

UNITED-STATES. We report an experiment on the influence of arm positions

on the generation of valenced information. Participants were induced to perform

either approach (arm flexion) or avoidance (arm extension) behavior while

generating names of persons. One half of the participants had to indicate whether

they had positive, negative or neutral attitudes towards these persons during

retrieval (evaluation group), the other half had to indicate their attitudes after

retrieval (nonevaluation group). Participants retrieved significantly more negative

than positive names under arm extension but more positive than negative names

under arm flexion. This motor congruence effect, however, was only obtained for

the evaluation group. The data show that an evaluative context is necessary to

produce the effect in retrieval.

85. Fotiou, F.; Goulas, A.; Fountoulakis, K.; Koutlas, E.; Hamlatzis, P.;

Papakostopoulos, D. Changes in psychophysiological processing of vision in

myasthenia gravis. Int-J-Psychophysiol. 1998 Aug; 29(3): 303-10; ISSN: 0167-

8760.

NETHERLANDS. OBJECTIVE: To investigate the possibility of impaired

central nervous system (CNS) cholinergic transmission in myasthenia gravis

(MG), and the effect of eye movements and particularly of micromovements in

the psychophysiology of vision. MATERIALS AND METHODS: Fourteen

patients with clinical manifestations of external ophthalmoplegia due to different

causes (nine patients with myasthenia gravis and five with ocular myopathy)

were examined. Simultaneous recording of eye movements (optical method) and

pattern reversal-visual evoked potentials (PR-VEPs) were performed. RESULTS:

Eye micromovements during fixation were impaired in both groups. A statistically

significant difference (P < 0.01) was found in the amplitude of P100 of PR-VEPs

before and after treatment in MG patients, and also between normal controls and

MG patients before (P < 0.001) and after treatment (P < 0.01). P100 latency of

the PR-VEPs in MG patients before and after treatment was delayed compared to

normal controls, while there were no differences between ocular myopathy

patients and normal controls. CONCLUSION: The eye movement impairment

observed in MG patients is not sufficient to explain abnormal PR-VEPs detected

in these patients. These results provide neurophysiological evidence of impaired

cholinergic transmission in the central nervous system in patients with MG and

suggest that PR-VEPs offer an easily applicable non-invasive method to study the

central effects of MG.

86. Franch, J.; Madsen, K.; Djurhuus, M. S.; Pedersen, P. K. Improved running economy

following intensified training correlates with reduced ventilatory demands. Med-

Sci-Sports-Exerc. 1998 Aug; 30(8): 1250-6; ISSN: 0195-9131.

UNITED-STATES. PURPOSE: To compare the effects of three types of

intensive run training on running economy (RE) during exhaustive running and to

establish possible relationships with changes in ventilatory function and/or muscle

fiber type distribution. METHODS: Thirty-six male recreational runners were

divided into three groups and assigned to either exhaustive distance training (DT),

long-interval training (LIT), or short-interval training (SIT) three times 20-30

minxwk(-1) for 6 wk. VO(2 max) and RE were measured during treadmill running

before and after training. Muscle fiber type distribution of the vastus lateralis

muscle was established from biopsy material. RESULTS: VO(2max) (Lxmin(-1)

increased by 5.9% (P < 0.0001), 6.0% (P < 0.0001), and 3.6% (P < 0.01) in DT,

LIT, and SIT, respectively, and running speed at VO(2max) by 9% (P < 0.0001),

10% (P < 0.0001), and 4% (P < 0.05), respectively. Time-to-exhaustion at 87% of

pretraining VO(2max) (mean 3.83) mxs(-1) increased by 94% in DT (P < 0.0001),

67% in LIT (P < 0.0001). Running economy improved by 3.1% in DT (P < 0.05),

3.0% in LIT (P < 0.01), and 0.9% SIT (NS): pulmonary ventilation (VE) was on

average 11 Lxmin(-1) lower following training (P < 0.0001). The individual

decrements in VE correlated with improvements in RE (r = 0.77; P < 0.0001) and

may account for 25-70% of the decrease in aerobic demand. Muscle fiber

composition, and respiratory exchange ratio, stride length, and stride frequency

during running were unaltered with training. CONCLUSIONS: Recreational

runners can improve RE and aerobic run performance by exchanging parts of their

conventional aerobic distance training with intensive distance or long-interval

running, whereas short-interval running is less efficient. The improvement in RE

may relate to reduced ventilatory demands. Muscle fiber type distribution was

unaltered with training and showed no associations with RE.. 50-21-5.

87. Frens, M. A.; Van Opstal, A. J. Visual-auditory interactions modulate saccade-related

activity in monkey superior colliculus. Brain-Res-Bull. 1998 Jun; 46(3): 211-24;

ISSN: 0361-9230.

UNITED-STATES. This paper reports on single-unit activity of saccade-related

burst neurons (SRBNs) in the intermediate and deep layers of the monkey

superior colliculus (SC), evoked by bimodal sensory stimulation. Monkeys were

trained to generate saccadic eye movements towards visual stimuli, in either a

unimodal visual saccade task, or in a bimodal visual-auditory task. In the latter

task, the monkeys were required to make an accurate saccade towards a visual

target, while ignoring an auditory stimulus. The presentation of an auditory

stimulus in temporal and spatial proximity of the visual target influenced neither

the accuracy nor the kinematic properties of the evoked saccades. However, it had

a significant effect on the activity of 90% (45/50) of the SRBNs. The motor-

related burst increased significantly in some neurons, but was suppressed in

others. In visual-movement cells, comparable bimodal interactions were observed

in both the visually evoked burst and the movement-related burst. The large

differences observed in the movement-related activity of SRBNs for identical

saccades under different sensory conditions do not support the hypothesis that

such cells encode dynamic motor error. The only behavioral parameter that was

affected by the presentation of the auditory stimulus was saccade latency.

Auditory stimulation caused saccade latency changes in the majority of the

experiments. Meanwhile, the timing of peak collicular motor activity and saccade

onset remained tightly coupled for all stimulus configurations. In addition, saccade

latency varied as function of the distance between the stimuli in 36% of the

recordings. Interestingly, the occurrence of a spatial latency effect covaried

significantly with a similar spatial influence on the SRBNs firing rate. These cells

were always most active in the bimodal task when both stimuli were in spatial

register, but activity decreased with increasing stimulus separation.

88. Frens, M. A.; Van Opstal, A. J. Visual-auditory interactions modulate saccade-related

activity in monkey superior colliculus. Brain-Res-Bull. 1998 Jun; 46(3): 211-24;

ISSN: 0361-9230.

UNITED-STATES. This paper reports on single-unit activity of saccade-related

burst neurons (SRBNs) in the intermediate and deep layers of the monkey

superior colliculus (SC), evoked by bimodal sensory stimulation. Monkeys were

trained to generate saccadic eye movements towards visual stimuli, in either a

unimodal visual saccade task, or in a bimodal visual-auditory task. In the latter

task, the monkeys were required to make an accurate saccade towards a visual

target, while ignoring an auditory stimulus. The presentation of an auditory

stimulus in temporal and spatial proximity of the visual target influenced neither

the accuracy nor the kinematic properties of the evoked saccades. However, it had

a significant effect on the activity of 90% (45/50) of the SRBNs. The motor-

related burst increased significantly in some neurons, but was suppressed in

others. In visual-movement cells, comparable bimodal interactions were observed

in both the visually evoked burst and the movement-related burst. The large

differences observed in the movement-related activity of SRBNs for identical

saccades under different sensory conditions do not support the hypothesis that

such cells encode dynamic motor error. The only behavioral parameter that was

affected by the presentation of the auditory stimulus was saccade latency.

Auditory stimulation caused saccade latency changes in the majority of the

experiments. Meanwhile, the timing of peak collicular motor activity and saccade

onset remained tightly coupled for all stimulus configurations. In addition, saccade

latency varied as function of the distance between the stimuli in 36% of the

recordings. Interestingly, the occurrence of a spatial latency effect covaried

significantly with a similar spatial influence on the SRBNs firing rate. These cells

were always most active in the bimodal task when both stimuli were in spatial

register, but activity decreased with increasing stimulus separation.

89. Frolov, A. G.; Pavlova, O. G. [The formation of instrumental escape reactions based

on movements induced by stimulation of the motor cortex in dogs]. Formirovanie

instrumental'nykh reaktsii izbavleniia na osnove dvizhenii, vyzyvaemykh

stimuliatsiei motornoi kory u sobak. Zh-Vyssh-Nerv-Deiat-Im-I-P-Pavlova. 1998

May; 48(3): 422-30; ISSN: 0044-4677.

RUSSIA. The purpose of the study was to find out the possibility of

instrumentalization of movements induced by stimulation of the motor cortex

(MI) in dogs. The scheme of conditioning was as follows. The electrical shock

applied to the right forepaw was used for a weak painful stimulation. In 3 s, the

stimulation of the MI was added, which elicited the right hind limb flexion. The

shock was switched off at the moment of the hind limb lifting. After several trials,

the shock began to elicit the hind limb flexion before the cortical stimulation. The

scheme of conditioning excluded the possibility of instrumentalization of

irrelevant chance movements. Prolonging the shock by 2 s after the cortical

stimulation led to extinction of acquired responses. Renewal of reinforcement of

the hind limb movements by immediate switching off the shock led to recovery of

conditioned reactions. Thus, the instrumental nature of the responses has been

proved. The obtained results are of particular interest in connection with the

findings that similar acquisition of instrumental reaction on the basis of food

reinforcement is impossible. The results support the assumption that the

"instrumental" conditioned connection can be addressed directly to the motor

cortex.

90. Fujihara, K.; Miyoshi, T. The effects of 4-aminopyridine on motor evoked potentials

in multiple sclerosis. J-Neurol-Sci. 1998 Jul 15; 159(1): 102-6; ISSN: 0022-510X.

NETHERLANDS. In order to study the effects of 4-aminopyridine (4-AP) on

impulse conduction in multiple sclerosis (MS), we studied motor-evoked

potentials (MEPs) in the upper (U/E) and lower extremities (L/E) of six MS

patients with stable spastic paraparesis before and after intravenous

administration of 4-AP. As a result, we found a significant increase in mean

amplitudes in U/E and L/E (P = 0.008) and a significant decrease in the variability

of onset latencies in L/E (P = 0.017) without any significant changes in mean and

shortest onset latencies. In four limbs of three patients in whom there were no

detectable MEP responses before 4-AP administration, definite responses were

elicited after 4-AP administration. 4-AP seems to have its therapeutic effects by

improving impulse conductivity in demyelinated nerve fibers or by enhancing

central or peripheral synaptic transmission, which thus results in coordinated

contractions of more muscle fibers in MS.. 504-24-5.

91. Fujii, N.; Mushiake, H.; Tanji, J. An oculomotor representation area within the

ventral premotor cortex. Proc-Natl-Acad-Sci-U-S-A. 1998 Sep 29; 95(20): 12034-

7; ISSN: 0027-8424.

UNITED-STATES. We explored the ventral part of the premotor cortex (PMV)

with intracortical microstimulation (ICMS) while monkeys performed a visual

fixation task, to see whether the PMV is involved in oculomotor control. ICMS

evoked saccades from a small-restricted region in the PMV, without evoking

movements in the limbs, neck, or body. We found the saccade-evoking site in the

PMV in a total of three hemispheres in two monkeys. Quantitative analysis of the

effects of eye position on saccades evoked by microstimulation of the PMV

characterized the evoked saccades as goal directed. The nature of the saccades

evoked in the PMV contrasted with the fixed vector nature of saccades evoked by

ICMS of the frontal eye field. We also found that neurons in this restricted area of

the PMV were active while the animals were performing a saccade task that

required them to make saccades toward targets without arm movements. These

data provide evidence for the presence of an oculomotor-specific subregion within

the PMV. This subregion and the surrounding skeletomotor-representing regions

of the PMV seem to coordinate oculomotor and skeletomotor control in

performing goal-directed motor tasks.

92. Fujii, N.; Mushiake, H.; Tanji, J. An oculomotor representation area within the

ventral premotor cortex. Proc-Natl-Acad-Sci-U-S-A. 1998 Sep 29; 95(20): 12034-

7; ISSN: 0027-8424.

UNITED-STATES. We explored the ventral part of the premotor cortex (PMV)

with intracortical microstimulation (ICMS) while monkeys performed a visual

fixation task, to see whether the PMV is involved in oculomotor control. ICMS

evoked saccades from a small-restricted region in the PMV, without evoking

movements in the limbs, neck, or body. We found the saccade-evoking site in the

PMV in a total of three hemispheres in two monkeys. Quantitative analysis of the

effects of eye position on saccades evoked by microstimulation of the PMV

characterized the evoked saccades as goal directed. The nature of the saccades

evoked in the PMV contrasted with the fixed vector nature of saccades evoked by

ICMS of the frontal eye field. We also found that neurons in this restricted area of

the PMV were active while the animals were performing a saccade task that

required them to make saccades toward targets without arm movements. These

data provide evidence for the presence of an oculomotor-specific subregion within

the PMV. This subregion and the surrounding skeletomotor-representing regions

of the PMV seem to coordinate oculomotor and skeletomotor control in

performing goal-directed motor tasks.

93. Fujii, N.; Mushiake, H.; Tanji, J. An oculomotor representation area within the

ventral premotor cortex. Proc-Natl-Acad-Sci-U-S-A. 1998 Sep 29; 95(20): 12034-

7; ISSN: 0027-8424.

UNITED-STATES. We explored the ventral part of the premotor cortex (PMV)

with intracortical microstimulation (ICMS) while monkeys performed a visual

fixation task, to see whether the PMV is involved in oculomotor control. ICMS

evoked saccades from a small-restricted region in the PMV, without evoking

movements in the limbs, neck, or body. We found the saccade-evoking site in the

PMV in a total of three hemispheres in two monkeys. Quantitative analysis of the

effects of eye position on saccades evoked by microstimulation of the PMV

characterized the evoked saccades as goal directed. The nature of the saccades

evoked in the PMV contrasted with the fixed vector nature of saccades evoked by

ICMS of the frontal eye field. We also found that neurons in this restricted area of

the PMV were active while the animals were performing a saccade task that

required them to make saccades toward targets without arm movements. These

data provide evidence for the presence of an oculomotor-specific subregion within

the PMV. This subregion and the surrounding skeletomotor-representing regions

of the PMV seem to coordinate oculomotor and skeletomotor control in

performing goal-directed motor tasks.

94. Gallant, J. L.; Connor, C. E.; Van Essen, D. C. Neural activity in areas V1, V2 and V4

during free viewing of natural scenes compared to controlled viewing [corrected

and republished article originally printed in Neuroreport 1998 Jan 5;9(1):85-90].

Neuroreport. 1998 Jun 22; 9(9): 2153-8; ISSN: 0959-4965.

ENGLAND. Under natural viewing conditions primates make frequent

exploratory eye movements across complex scenes. We recorded neural activity of

62 cells in visual areas V1, V2 and V4 in an awake behaving monkey that freely

viewed natural images. About half of the cells studied showed a modulation in

firing rate following some of the eye movements made during free viewing, though

the proportions showing a discernible modulation varied across areas. These cells

were also examined under controlled viewing conditions in which gratings or

natural image patches were flashed in and around the classical receptive field while

the animal performed a fixation task. Activity rates were generally highest with

flashed gratings and lowest during free viewing. Flashed natural image patches

evoked responses between these two extremes, and the responses were higher

when the patches were confined to the classical receptive field than when they

extended into the non-classical surround. Thus the reduction of activity during

free viewing relative to that obtained with flashed gratings is partly attributable to

natural images being less effective stimuli and partly to suppressive spatio-

temporal neural mechanisms that are important during natural vision.

95. Garcia Coll, C.; Buckner, J. C.; Brooks, M. G.; Weinreb, L. F.; Bassuk, E. L. The

developmental status and adaptive behavior of homeless and low-income housed

infants and toddlers. Am-J-Public-Health. 1998 Sep; 88(9): 1371-4; ISSN: 0090-

0036.

UNITED-STATES. OBJECTIVES: This study describes the development status

of 127 homeless and 91 low-income housed infants and toddlers. METHODS:

The Bayley Scales of Infant Development and the Vineland Screener were used to

gather data. RESULTS: There were no differences between homeless and low-

income housed children. However, younger children in both groups performed

better than the older children on most summary scores. CONCLUSIONS:

Homeless and low-income housed children did not differ in their cognitive and

motor skills. However, older children scored lower than younger children on most

measures of development status, suggesting that the cumulative effects of poverty

may increase with time.

96. Gentil, M.; Tournier, C. L. Differences in fine control of forces generated by the

tongue, lips and fingers in humans. Arch-Oral-Biol. 1998 Jul; 43(7): 517-23; ISSN:

0003-9969.

ENGLAND. This study compared the fine control of forces generated by the

tongue, lips and fingers in middle-aged adults. The aims were to determine

whether (1) the articulatory organs (tongue, lips) and fingers differed in the

manner of motor control, (2) force control of the various articulatory organs was

similar, and (3) control of forces generated by males was different from that of

forces generated by females. The relation among several variables of the ramp-and-

hold force contraction and target force level was quantified for the articulatory

organs and the fingers in 14 normal individuals (7 males and 7 females). Using

visual feedback, participants produced ramp-and-hold compression forces as

rapidly and accurately as possible to targets ranging from 0.25 to 2 N. The results

showed differences in the profiles of forces generated by the articulatory organs

and fingers. In particular, the forefingers were characterized by a greater accuracy

of force control and precision of movement, a greater stability of the hold phase,

but by slower velocities than the articulatory organs. Motor control of the lower

lip differed from that of the upper lip and tongue. Mostly, the lower lip was

characterized by a greater precision of contraction, faster development of the

force, and greater stability of the hold phase than the upper lip and tongue.

Gender was a distinguishing factor in the force task; males were able to produce

forces with higher velocities and greater precision than females.

97. Gentilucci, M.; Gangitano, M. Influence of automatic word reading on motor control.

Eur-J-Neurosci. 1998 Feb; 10(2): 752-6; ISSN: 0953-816X.

FRANCE. We investigated the possible influence of automatic word reading on

processes of visuo-motor transformation. Six subjects were required to reach and

grasp a rod on whose visible face the word 'long' or 'short' was printed. Word

reading was not explicitly required. In order to induce subjects to visually analyse

the object trial by trial, object position and size were randomly varied during the

experimental session. The kinematics of the reaching component was affected by

word presentation. Peak acceleration, peak velocity, and peak deceleration of arm

were higher for the word 'long' with respect to the word 'short'. That is, during the

initial movement phase subjects automatically associated the meaning of the word

with the distance to be covered and activated a motor program for a farther and/or

nearer object position. During the final movement phase, subjects modified the

braking forces (deceleration) in order to correct the initial error. No effect of the

words on the grasp component was observed. These results suggest a possible

influence of cognitive functions on motor control and seem to contrast with the

notion that the analyses executed in the ventral and dorsal cortical visual streams

are different and independent.

98. Gerling, J.; Ball, M.; Bomer, T.; Bach, M.; Kommerell, G. [Fixation disparity with

the Pola pointing test: not representative for eye position under natural viewing

conditions]. Fixationsdisparation am Pola-Zeigertest: nicht reprasentativ fur die

Augenstellung unter naturlichen Sehbedingungen. Klin-Monatsbl-Augenheilkd.

1998 Apr; 212(4): 226-33; ISSN: 0023-2165.

GERMANY. BACKGROUND: According to certain findings obtained with the

Zeiss Polatest, H.J. Haase defined a "Fixation Disparity Type One". In this

diagnosis, the "Zeigertest" is particularly important. The Zeigertest consists of a

central ring presented to both eyes for fixation, a vertical clock hand presented to

the right eye and two markings at the six and twelve o'clock positions presented

to the left eye. All parts are surrounded by a binocularly visible frame. Subjects

with a "Fixation Disparity Type One" see a misalignment between the clock hand

and the peripheral markings. We investigated (1) whether the perceived

misalignment correlated with an objective deviation of the eyes from

orthovergence and (2) whether subjects with a "Fixation Disparity Type One"

had a deviation of the eyes from orthovergence when looking at a natural, i.e.,

fully fusionable object. SUBJECTS AND METHODS: Out of 303 medical

students, 10 subjects with a "Fixation Disparity Type One" were selected and

asked to indicate the perceived alignment or misalignment in the Zeigertest with a

laser pointer. Two subjects without fixation disparity served as controls. The

position of both eyes was recorded using the search coil technique. One of the 10

subjects with "Fixation Disparity Type One" had to be excluded due to excessive

blinking. Experiment 1: In the beginning all parts of the Zeigertest were presented

to both eyes (natural viewing condition). Then, the object for one of the eyes was

switched off leaving the frame as the only fusional stimulus. The outcome variable

was a refixation movement of the other eye. This experiment is similar to the

unilateral cover test. Experiment 2: In the beginning all parts of the Zeigertest

were presented to both eyes (natural viewing condition). Then, the original

Zeigertest was switched on (clock hand presented only to the right eye, peripheral

markings only to the left eye). The outcome variable was a change of vergence.

RESULTS: Experiment 1: A significant refixation movement did not occur in any

of the subjects. Experiment 2. In all 9 subjects with "Fixation Disparity Type

One" the vergence changed significantly between 2.4 and 14.9 arcmin. The change

of vergence correlated significantly with the angle of the perceived misalignment

between clock hand and peripheral markings. CONCLUSION: A fixation

disparity ascertained at the Zeigertest does not indicate a fixation disparity under

natural viewing conditions.

99. Gerloff, C.; Cohen, L. G.; Floeter, M. K.; Chen, R.; Corwell, B.; Hallett, M.

Inhibitory influence of the ipsilateral motor cortex on responses to stimulation of

the human cortex and pyramidal tract. J-Physiol-Lond. 1998 Jul 1; 510( Pt 1):

249-59; ISSN: 0022-3751.

ENGLAND. 1. The ability of the primary motor cortex (M1) to modulate motor

responses in ipsilateral hand muscles seems to be important for normal motor

control and potentially also for recovery after brain lesions. It is not clear which

pathways mediate this ipsilateral modulation. Transcallosal connections have been

proposed, but are known to be sparse between cortical hand motor

representations in primates. The present study was performed to determine

whether descending ipsilateral modulation of motor responses might also be

mediated below the cortical level in humans. 2. A paired-pulse protocol was used,

in which motor-evoked potentials (MEPs) were produced by cortical transcranial

magnetic stimulation (cTMS) or by electrical stimulation of the pyramidal tract at

the level of the pyramidal decussation (pdTES), in both preactivated and relaxed

hand muscles. Paired stimuli were applied at various interstimulus intervals (ISIs)

between 2 and 100 ms. The conditioning stimulus (CS) was always magnetic, and

delivered to the M1 ipsilateral to the target hand, prior to the test stimulus (TS).

The magnetic TS was delivered to the M1 contralateral to the target hand; the

electrical TS was applied through electrodes placed over the mastoid process

bilaterally. Further experiments included cortical electrical stimulation and H-

reflexes. The MEP amplitudes were averaged separately for each ISI and the

control condition (no CS), and expressed as a percentage of the unconditioned

response. 3. Conditioning stimulation of the ipsilateral M1 resulted in significant

inhibition of magnetically evoked MEPs, and also of MEPs produced by pdTES.

Inhibition occurred at ISIs between 6 and 50 ms, and was observed in preactivated

and relaxed muscles. Higher CS intensities caused greater inhibition of both

cTMS- and pdTES-evoked MEPs. 4. While the conditioning effects on

magnetically evoked muscle responses could be explained by a transcallosal

mechanism, the effects on pdTES-evoked MEPs cannot, because they are elicited

subcortically and are therefore not susceptible to inhibitory mechanisms

transmitted at the cortico-cortical level. 5. In conclusion, the present results

provide novel evidence that the inhibitory influence of the human M1 on

ipsilateral hand muscles is to a significant extent mediated below the cortical level,

and not only through cortico-cortical transcallosal connections. They point to a

concept of inhibitory interaction between the two primary motor cortices that is

relayed at multiple levels along the neuroaxis, thus perhaps providing a

structurally redundant system which may become important in case of lesions.

100. Gerloff, C.; Cohen, L. G.; Floeter, M. K.; Chen, R.; Corwell, B.; Hallett, M.

Inhibitory influence of the ipsilateral motor cortex on responses to stimulation of

the human cortex and pyramidal tract. J-Physiol-Lond. 1998 Jul 1; 510( Pt 1):

249-59; ISSN: 0022-3751.

ENGLAND. 1. The ability of the primary motor cortex (M1) to modulate motor

responses in ipsilateral hand muscles seems to be important for normal motor

control and potentially also for recovery after brain lesions. It is not clear which

pathways mediate this ipsilateral modulation. Transcallosal connections have been

proposed, but are known to be sparse between cortical hand motor

representations in primates. The present study was performed to determine

whether descending ipsilateral modulation of motor responses might also be

mediated below the cortical level in humans. 2. A paired-pulse protocol was used,

in which motor-evoked potentials (MEPs) were produced by cortical transcranial

magnetic stimulation (cTMS) or by electrical stimulation of the pyramidal tract at

the level of the pyramidal decussation (pdTES), in both preactivated and relaxed

hand muscles. Paired stimuli were applied at various interstimulus intervals (ISIs)

between 2 and 100 ms. The conditioning stimulus (CS) was always magnetic, and

delivered to the M1 ipsilateral to the target hand, prior to the test stimulus (TS).

The magnetic TS was delivered to the M1 contralateral to the target hand; the

electrical TS was applied through electrodes placed over the mastoid process

bilaterally. Further experiments included cortical electrical stimulation and H-

reflexes. The MEP amplitudes were averaged separately for each ISI and the

control condition (no CS), and expressed as a percentage of the unconditioned

response. 3. Conditioning stimulation of the ipsilateral M1 resulted in significant

inhibition of magnetically evoked MEPs, and also of MEPs produced by pdTES.

Inhibition occurred at ISIs between 6 and 50 ms, and was observed in preactivated

and relaxed muscles. Higher CS intensities caused greater inhibition of both

cTMS- and pdTES-evoked MEPs. 4. While the conditioning effects on

magnetically evoked muscle responses could be explained by a transcallosal

mechanism, the effects on pdTES-evoked MEPs cannot, because they are elicited

subcortically and are therefore not susceptible to inhibitory mechanisms

transmitted at the cortico-cortical level. 5. In conclusion, the present results

provide novel evidence that the inhibitory influence of the human M1 on

ipsilateral hand muscles is to a significant extent mediated below the cortical level,

and not only through cortico-cortical transcallosal connections. They point to a

concept of inhibitory interaction between the two primary motor cortices that is

relayed at multiple levels along the neuroaxis, thus perhaps providing a

structurally redundant system which may become important in case of lesions.

101. Gerloff, C.; Corwell, B.; Chen, R.; Hallett, M.; Cohen, L. G. The role of the human

motor cortex in the control of complex and simple finger movement sequences.

Brain. 1998 Sep; 121( Pt 9): 1695-709; ISSN: 0006-8950.

ENGLAND. We evaluated the effects of high-frequency repetitive transcranial

magnetic stimulation (rTMS) over the primary motor cortex (M1) at different

stimulus intensities on finger sequences of varying complexity. Eighteen subjects

played unimanual finger sequences of different complexity on an electronic piano.

For each finger sequence, 16 notes were played to the 2 Hz beat of a metronome.

After the first four notes, rTMS was applied to the scalp location overlying the

hand motor representation for approximately 2 s. Accuracy and timing errors

were analysed. Stimulation over the M1 had a differential effect on sequences of

different complexity. Stimulus intensities capable of disrupting the performance

of a complex sequence did not affect simple sequences. To disrupt simple

sequences, the stimulus strength had to be augmented. This effect was

characteristic of the contralateral M1 position (five other scalp locations were also

stimulated). It is argued that the differential effect of rTMS on simple and

complex sequences is probably due to interference with M1 function. Interference

with the lateral premotor cortex (PMC) may play an additional role. The

particular relevance of the M1 is supported by results in a patient with PMC

stroke. The present findings suggest that the human M1 plays a greater role in the

performance of complex than of simple finger movement sequences. One possible

explanation could be that the human M1 is not only an executive motor area but

can also contribute to movement sequence organization.

102. Gerloff, C.; Richard, J.; Hadley, J.; Schulman, A. E.; Honda, M.; Hallett, M.

Functional coupling and regional activation of human cortical motor areas during

simple, internally paced and externally paced finger movements. Brain. 1998 Aug;

121( Pt 8): 1513-31; ISSN: 0006-8950.

ENGLAND. We studied the activation and interaction of cortical motor regions

during simple, internally paced and externally paced right-hand finger extensions

in healthy volunteers. We recorded EEGs from 28 scalp electrodes and analysed

task-related coherence, task-related power and movement-related cortical

potentials. Task-related coherence reflects inter-regional functional coupling of

oscillatory neuronal activity, task-related power reflects regional oscillatory

activity of neuronal assemblies and movement-related cortical potentials reflect

summated potentials of apical dendrites of pyramidal cells. A combination of

these three analytical techniques allows comprehensive evaluation of different

aspects of information processing in neuronal assemblies. For both externally and

internally paced finger extensions, movement-related regional activation was

predominant over the contralateral premotor and primary sensorimotor cortex,

and functional coupling occurred between the primary sensorimotor cortex of both

hemispheres and between the primary sensorimotor cortex and the mesial

premotor areas, probably including the supplementary motor area. The main

difference between the different types of movement pacing was enhanced

functional coupling of central motor areas during internally paced finger

extensions, particularly inter-hemispherically between the left and right primary

sensorimotor cortexes and between the contralateral primary sensorimotor cortex

and the mesial premotor areas. Internally paced finger extensions were also

associated with additional regional (premovement) activation over the mesial

premotor areas. The maximal task-related coherence differences between internally

and externally paced finger extensions occurred in the frequency range of 20-22

Hz rather than in the range of maximal task-related power differences (9-11 Hz).

This suggests that important aspects of information processing in the human

motor system could be based on network-like oscillatory cortical activity and

might be modulated on at least two levels, which to some extent can operate

independently from each other: (i) regional activation (task-related power) and (ii)

inter-regional functional coupling. We propose that internal pacing of movement

poses higher demands on the motor system than external pacing, and that the

motor system responds not only by increasing regional activation of the mesial

premotor system, including the supplementary motor area, but also by enhancing

information flow between lateral and mesial premotor and sensorimotor areas of

both hemispheres, even if the movements are simple and unimanual.

103. Gerloff, C.; Richard, J.; Hadley, J.; Schulman, A. E.; Honda, M.; Hallett, M.

Functional coupling and regional activation of human cortical motor areas during

simple, internally paced and externally paced finger movements. Brain. 1998 Aug;

121( Pt 8): 1513-31; ISSN: 0006-8950.

ENGLAND. We studied the activation and interaction of cortical motor regions

during simple, internally paced and externally paced right-hand finger extensions

in healthy volunteers. We recorded EEGs from 28 scalp electrodes and analysed

task-related coherence, task-related power and movement-related cortical

potentials. Task-related coherence reflects inter-regional functional coupling of

oscillatory neuronal activity, task-related power reflects regional oscillatory

activity of neuronal assemblies and movement-related cortical potentials reflect

summated potentials of apical dendrites of pyramidal cells. A combination of

these three analytical techniques allows comprehensive evaluation of different

aspects of information processing in neuronal assemblies. For both externally and

internally paced finger extensions, movement-related regional activation was

predominant over the contralateral premotor and primary sensorimotor cortex,

and functional coupling occurred between the primary sensorimotor cortex of both

hemispheres and between the primary sensorimotor cortex and the mesial

premotor areas, probably including the supplementary motor area. The main

difference between the different types of movement pacing was enhanced

functional coupling of central motor areas during internally paced finger

extensions, particularly inter-hemispherically between the left and right primary

sensorimotor cortexes and between the contralateral primary sensorimotor cortex

and the mesial premotor areas. Internally paced finger extensions were also

associated with additional regional (premovement) activation over the mesial

premotor areas. The maximal task-related coherence differences between internally

and externally paced finger extensions occurred in the frequency range of 20-22

Hz rather than in the range of maximal task-related power differences (9-11 Hz).

This suggests that important aspects of information processing in the human

motor system could be based on network-like oscillatory cortical activity and

might be modulated on at least two levels, which to some extent can operate

independently from each other: (i) regional activation (task-related power) and (ii)

inter-regional functional coupling. We propose that internal pacing of movement

poses higher demands on the motor system than external pacing, and that the

motor system responds not only by increasing regional activation of the mesial

premotor system, including the supplementary motor area, but also by enhancing

information flow between lateral and mesial premotor and sensorimotor areas of

both hemispheres, even if the movements are simple and unimanual.

104. Geyer, S.; Matelli, M.; Luppino, G.; Schleicher, A.; Jansen, Y.; Palomero Gallagher,

N.; Zilles, K. Receptor autoradiographic mapping of the mesial motor and

premotor cortex of the macaque monkey. J-Comp-Neurol. 1998 Jul 27; 397(2):

231-50; ISSN: 0021-9967.

UNITED-STATES. This study analyzes regional and laminar distribution

patterns of neurotransmitter binding sites in the motor areas of the macaque

mesial frontal cortex. Differences in distribution patterns are compared with the

cytoarchitectonic parcellation. Binding sites were analyzed with quantitative in

vitro receptor autoradiography in unfixed brains of five macaque monkeys. Alpha-

amino-3-hydroxy-5-methyl-4-isoxalone propionic acid (AMPA), kainate, and N-

methyl-D-aspartate (NMDA) binding sites were labeled with [3H]AMPA,

[3H]kainate, and [3H]MK-801, respectively, muscarinic binding sites with

[3H]pirenzepine or [3H]oxotremorine-M, noradrenergic binding sites with

[3H]prazosin or [3H]UK-14304, gamma-aminobutyric acid (GABA)A binding

sites with [3H]muscimol, and serotoninergic binding sites with [3H]ketanserine.

Adjacent sections were stained with a modified Nissl method for

cytoarchitectonic analysis. In the motor areas F1, F3, and F6, [3H]AMPA,

[3H]pirenzepine, and [3H]oxotremorine-M binding was maximal in layers II, III,

and V, and [3H]kainate binding was maximal in layers V and VI. Clear-cut changes

in laminar distribution patterns of [3H]AMPA, [3H]kainate, and

[3H]oxotremorine-M binding sites very closely matched corresponding

cytoarchitectonic borders. Mean areal binding densities of all ligands to F1, F3,

and F6 were plotted as polar plots for each area. A polygon was obtained for each

area ("neurochemical fingerprint") when all the density values belonging to one

area were connected with each other. The "neurochemical fingerprints" of F1, F3,

and F6 were virtually identical in shape but increased in size from F1 to F6. This

result reflects the functional similarity of these motor-related areas and possibly

correlates with their differential involvement in motor control. Areas F1, F3, and

F6 can thus be grouped into one "neurochemical family" of areas.

105. Ghezzi, A.; Baldini, S. A simple method for recording motor evoked potentials of

lingual muscles to transcranial magnetic and peripheral electrical stimulation.

Electroencephalogr-Clin-Neurophysiol. 1998 Apr; 109(2): 114-8; ISSN: 0013-

4694.

IRELAND. Motor evoked potentials were recorded from lingual muscles by

means of clip electrodes applied on the lateral side of the tongue, following

transcranial magnetic stimulation and peripheral electrical stimulation of the 12th

cranial nerve at the mandible jaw. Using a circular coil, the stimulation of the

cerebral cortex elicited a response of about 8 ms: its amplitude was higher in the

right tongue placing the coil over the contralateral hemisphere, 4 cm from the

vertex, with coil currents flowing counterclockwise. Coil position and current flow

direction did not significantly modify the characteristics of responses recorded

from the left side. The separate stimulation of either hemisphere was better

obtained using an 8-shaped coil. The latency of the motor response measured 7.7-

8.0 ms, the amplitude was greater on stimulation of the contralateral than the

ipsilateral hemisphere and was larger recording from the right (3.3 +/- 1.1 mV)

than from the left (1.2 +/- 0.7 mV) side. Positioning the circular coil over the

parieto-occipital skull, a response of 4.1 +/- 0.3 ms was obtained, reflecting the

intracranial activation of the hypoglossal nerve. The peripheral stimulation at the

mandible elicited a response of 3.2 +/- 0.5 ms. The method described appears

simple and reliable, potentially helpful in clinical practice.

106. Glenberg, A. M.; Schroeder, J. L.; Robertson, D. A. Averting the gaze disengages the

environment and facilitates remembering. Mem-Cognit. 1998 Jul; 26(4): 651-8;

ISSN: 0090-502X.

UNITED-STATES. When people are asked moderately difficult questions, they

often avert their gazes. We report five experiments in which we documented this

phenomenon. They demonstrate that (1) the frequency of gaze aversion is related

to the difficulty of cognitive processing, (2) this behavior cannot be due solely to

demand characteristics or embarrassment, and (3) the behavior is functional:

Averting the gaze improves performance. We speculate that averting the gaze

helps people to disengage from environmental stimulation and thereby enhances

the efficiency of cognitive processing directed by nonenvironmental stimulation.

107. Gomi, H.; Shidara, M.; Takemura, A.; Inoue, Y.; Kawano, K.; Kawato, M. Temporal

firing patterns of Purkinje cells in the cerebellar ventral paraflocculus during ocular

following responses in monkeys I. Simple spikes. J-Neurophysiol. 1998 Aug;

80(2): 818-31; ISSN: 0022-3077.

UNITED-STATES. The simple-spike firing frequency of 30 Purkinje cells (P

cells) in the ventral paraflocculus (VPFL) of alert monkeys was studied in relation

to vertical slow eye movements, termed ocular following response (OFR), induced

by large-field visual motions of different velocities and durations. To

quantitatively analyze the relationship between eye movement and firing

frequency, an inverse dynamics representation of the eye movement was used for

reconstructing the temporal waveform of firing. Coefficients of eye-acceleration,

velocity, and position, bias, and time lag between firing and eye movement were

estimated by least-square error method. In the regression analyses for each

stimulus condition, 86% (146/170) of the well-modulated temporal firing patterns

taken from those 30 P cells were reconstructed successfully from eye movement.

The model with acceleration, velocity, and position terms, which we used, was

shown as the best among several potential models by Cp statistics, consistent

with t-test of significance of each term. Reliable coefficients were obtained from

75% (109/146) of the well-reconstructed firing patterns of 28 cells among 30. The

estimated coefficients were larger (statistically significant) for slow stimuli than

for fast stimuli, suggesting changes in sensitivities under different conditions.

However, firing patterns of each cell under several different conditions were

frequently well reconstructed by an inverse dynamics representation with a single

set of coefficients (13 cells among 21). This indicates that the relationships

between P cell firing and OFR are roughly linear in those stimulus ranges. The

estimated coefficients for acceleration and velocity suggested that the VPFL P

cells properly encode the dynamic components of the motor command during

vertical OFR. As for the positional component, however, these P cells are

correlated with eye movement in the opposite direction. In the regression analysis

without positional component, remarkable differences between observed and

reconstructed firing patterns were noted especially in the initial phase of the

movements, indicating that the negative positional component was not negligible

during OFR. Thus we conclude that, during OFR, the VPFL P cells cannot

provide the necessary final motor command, and other brain regions, downstream

neural structures, or other types of P cells must provide lacking position-

dependent motor commands. This finding about the negative correlation with the

position is in the opposite sign with previous studies obtained from the fixation

and the smooth pursuit movement. From these comparisons, how the VPFL

contributes to a part of the final motor command or how other brain regions

complement the VPFL is suggested to be different for early and late phases of the

movements.

108. Graf, M. [Objective assessment of minimum visual acuity by suppression of

optokinetic nystagmus]. Objektive Schatzung der Mindestsehscharfe durch

Suppression des optokinetischen Nystagmus. Klin-Monatsbl-Augenheilkd. 1998

Apr; 212(4): 196-202; ISSN: 0023-2165.

GERMANY. PURPOSE: To develop and to validate an objective method which

allows an estimation of the visual acuity (VA) of adults. METHODS: A

horizontal optokinetic nystagmus (OKN) was elicited by a vertical rectangular

grating presented on a PC-screen and was recorded by an infrared reflection

method. Superimposition of three stationary black detection stimuli was used to

suppress the OKN. The size of these stimuli was increased every two seconds, in

ten steps. Suppression of the OKN was taken as an indication that the stimuli

were detected. The relation between the smallest effective stimulus and logVA

was evaluated in 65 healthy volunteers (130 eyes) with artificially reduced VA

and 425 cooperative patients (842 eyes) whose VA was reduced due to different

etiologies. The tolerance intervals of logVA related to the discrete detection

stimuli were calculated. RESULTS: The method allows an estimation of the least

expectable VA in steps of 0.8, 0.32, 0.25, 0.12, 0.1, 0.06, 0.03 und 0.025 due to

the smallest value of three trials. The least VA of strabismic amblyopic eyes can

only be estimated in steps of 0.16, 0.06, and 0.02. A VA > 0.02 can be proven

with high reliability. CONCLUSION: The method allows a clinically useful,

objective estimation of the least VA without observer bias in non-amblyopic eyes.

109. Graupe, D.; Kohn, K. H. Functional neuromuscular stimulator for short-distance

ambulation by certain thoracic-level spinal-cord-injured paraplegics. Surg-Neurol.

1998 Sep; 50(3): 202-7; ISSN: 0090-3019.

UNITED-STATES. BACKGROUND: Functional Neuromuscular Stimulation

(FNS) for unbraced short-distance ambulation by traumatic complete/near-

complete T4 to T12 paraplegics is based on work by Graupe et al (1982), Kralj et

al (1980), Liberson et al (1961), and others. This paper discusses methodology,

performance, training, admissibility criteria, and medical observations for FNS-

ambulation using the Parastep-I system, which is the first and only such system

to have received FDA approval (1994) and which emanated from these previous

works. METHOD: The Parastep system is a transcutaneous non-invasive and

microcomputerized electrical stimulation system built into a Walkman-size unit

powered by eight AA batteries that is controlled by finger-touch buttons located

on a walker's handbars for manual selection of stimulation menus. The

microcomputer shapes, controls, and distributes trains of stimulation signals that

trigger action potentials in selected peripheral nerves. Walker support is used for

balance. The patient can don the system in under 10 minutes. At least 32 training

sessions are required. RESULTS: Approximately 400 patients have used the

Parastep system, essentially all achieving standing and at least 30 feet of

ambulation, with a few reaching as much as 1 mile at a time. Recent literature

presents data on the medical benefits of using the Parastep system-beyond the

exercise benefits of short distance ambulation at will-such as increased blood flow

to the lower extremities, lower HR at subpeak work intensities, increased peak

work capability, reduced spasticity, and psychological benefits.

CONCLUSIONS: We believe that the Parastep FNS system, which is presently

commercially available by prescription, is easily usable for independent short-

distance ambulation. We believe that its exercise benefits and its other medical and

psychological benefits, as discussed, make it an important option for thoracic-

level traumatic paraplegics.

110. Gray, M. S.; Pouget, A.; Zemel, R. S.; Nowlan, S. J.; Sejnowski, T. J. Reliable

disparity estimation through selective integration. Vis-Neurosci. 1998 May;

15(3): 511-28; ISSN: 0952-5238.

ENGLAND. A network model of disparity estimation was developed based on

disparity-selective neurons, such as those found in the early stages of processing

in the visual cortex. The model accurately estimated multiple disparities in

regions, which may be caused by transparency or occlusion. The selective

integration of reliable local estimates enabled the network to generate accurate

disparity estimates on normal and transparent random-dot stereograms. The

model was consistent with human psychophysical results on the effects of

spatial-frequency filtering on disparity sensitivity. The responses of neurons in

macaque area V2 to random-dot stereograms are consistent with the prediction of

the model that a subset of neurons responsible for disparity selection should be

sensitive to disparity gradients.

111. Graziano, M. S.; Gross, C. G. Spatial maps for the control of movement. Curr-Opin-

Neurobiol. 1998 Apr; 8(2): 195-201; ISSN: 0959-4388.

ENGLAND. Neurons in the ventral premotor cortex of the monkey encode the

locations of visual, tactile, auditory and remembered stimuli. Some of these

neurons encode the locations of stimuli with respect to the arm, and may be useful

for guiding movements of the arm. Others encode the locations of stimuli with

respect to the head, and may be useful for guiding movements of the head. We

suggest that a general principle of sensory-motor integration is that the space

surrounding the body is represented in body-part-centered coordinates. That is,

there are multiple coordinate systems used to guide movement, each one attached

to a different part of the body. This and other recent evidence from both monkeys

and humans suggest that the formation of spatial maps in the brain and the

guidance of limb and body movements do not proceed in separate stages but are

closely integrated in both the parietal and frontal lobes.

112. Grisaru, N.; Amir, M.; Cohen, H.; Kaplan, Z. Effect of transcranial magnetic

stimulation in posttraumatic stress disorder: a preliminary study. Biol-

Psychiatry. 1998 Jul 1; 44(1): 52-5; ISSN: 0006-3223.

UNITED-STATES. BACKGROUND: Transcranial magnetic stimulation (TMS)

has become, over the last few years, a promising avenue for new research in

affective disorders. In this study we have evaluated the clinical effect of slow

TMS on posttraumatic stress disorder (PTSD) symptoms. METHODS: Ten

PTSD patients were given one session of slow TMS with 30 pulses of 1 m/sec

each, 15 to each side of the motor cortex. RESULTS: Symptoms of PTSD were

assessed by using three psychological assessment scales, at four different time

points. In this first, pilot, open study, TMS was found to be effective in lowering

the core symptoms of PTSD: avoidance (as measured by the Impact of Event

Scale), anxiety, and somatization (as measured by the Symptom Check List-90).

A general clinical improvement was found (as measured by the Clinical Global

Impression scale); however, the effect was rather short and transient.

CONCLUSIONS: The present study showed TMS to be a safe and tolerable

intervention with possibly indications of therapeutic efficacy for PTSD patients.

113. Gustave, Dit Duflo S.; Borel, L.; Harlay, F.; Leonard, J.; Lacour, M. Short-term

changes in neck muscle and eye movement responses following unilateral

vestibular neurectomy in the cat. Exp-Brain-Res. 1998 Jun; 120(4): 439-49; ISSN:

0014-4819.

GERMANY. The purpose of this study was to investigate changes in neck

muscle and eye movement responses during the early stages of vestibular

compensation (first 3 weeks after unilateral vestibular neurectomy, UVN).

Electromyographic (EMG) activity from antagonist neck extensor (splenius

capitis) and flexor (longus capitis) muscles and eye movements were recorded

during sinusoidal visual and/or otolith vertical linear stimulations in the 0.05-1 Hz

frequency range (corresponding acceleration range 0.003-1.16 g) in the head-fixed

alert cat. Preoperative EMG activity from the splenius and longus capitis muscles

showed a pattern of alternate activation of the antagonist neck muscles in all the

cats. After UVN, two motor strategies were observed. For three of the seven cats,

the temporal activation of the individual neck muscles was the same as that

recorded before UVN. For the other four cats, UVN resulted in a pattern of

coactivation of the flexor and extensor neck muscles because of a phase change of

the splenius capitis. In both subgroups, the response patterns of the antagonist

neck muscles were consistent for each cat independently of the experimental

conditions, throughout the 3 weeks of testing. Cats displaying alternate activation

of antagonist neck muscles showed an enhanced gain of the visually induced neck

responses, particularly in the high range of stimulus frequency, and a gain decrease

in the otolith-induced neck responses at the lowest frequency (0.25 Hz) only. By

contrast, for cats with neck muscle coactivation, the gain of the visually induced

neck responses was basically unaffected relative to preoperative values, whereas

otolith-induced neck responses were considerably decreased in the whole range of

stimulation. As concerns oculomotor responses, results in the two subgroups of

cats were similar. The optokinetic responses were not affected by the vestibular

lesion. On the contrary, otolith-induced eye responses showed a gain reduction

and a phase lead. Deficits and short-term changes after UVN of otolith- and

semicircular canal-evoked collic and ocular responses are compared.

114. Gustave, Dit Duflo S.; Borel, L.; Harlay, F.; Leonard, J.; Lacour, M. Short-term

changes in neck muscle and eye movement responses following unilateral

vestibular neurectomy in the cat. Exp-Brain-Res. 1998 Jun; 120(4): 439-49; ISSN:

0014-4819.

GERMANY. The purpose of this study was to investigate changes in neck

muscle and eye movement responses during the early stages of vestibular

compensation (first 3 weeks after unilateral vestibular neurectomy, UVN).

Electromyographic (EMG) activity from antagonist neck extensor (splenius

capitis) and flexor (longus capitis) muscles and eye movements were recorded

during sinusoidal visual and/or otolith vertical linear stimulations in the 0.05-1 Hz

frequency range (corresponding acceleration range 0.003-1.16 g) in the head-fixed

alert cat. Preoperative EMG activity from the splenius and longus capitis muscles

showed a pattern of alternate activation of the antagonist neck muscles in all the

cats. After UVN, two motor strategies were observed. For three of the seven cats,

the temporal activation of the individual neck muscles was the same as that

recorded before UVN. For the other four cats, UVN resulted in a pattern of

coactivation of the flexor and extensor neck muscles because of a phase change of

the splenius capitis. In both subgroups, the response patterns of the antagonist

neck muscles were consistent for each cat independently of the experimental

conditions, throughout the 3 weeks of testing. Cats displaying alternate activation

of antagonist neck muscles showed an enhanced gain of the visually induced neck

responses, particularly in the high range of stimulus frequency, and a gain decrease

in the otolith-induced neck responses at the lowest frequency (0.25 Hz) only. By

contrast, for cats with neck muscle coactivation, the gain of the visually induced

neck responses was basically unaffected relative to preoperative values, whereas

otolith-induced neck responses were considerably decreased in the whole range of

stimulation. As concerns oculomotor responses, results in the two subgroups of

cats were similar. The optokinetic responses were not affected by the vestibular

lesion. On the contrary, otolith-induced eye responses showed a gain reduction

and a phase lead. Deficits and short-term changes after UVN of otolith- and

semicircular canal-evoked collic and ocular responses are compared.

115. Gutgesell, M. E.; Timmerman, M. G. Alcohol use and behaviors in women long-

distance race participants reporting a history of bulimia and/or anorexia nervosa.

J-Sports-Med-Phys-Fitness. 1998 Jun; 38(2): 142-8; ISSN: 0022-4707.

ITALY. OBJECTIVE: To describe the relationship between a reported a history

of an eating disorder, a history of problem alcohol behavior and current alcohol

consumption in women long-distance runners. DESIGN: Survey. SETTING:

General community. PARTICIPANTS: Women participating in a 20-mile road

race (n = 398) and age-matched non-exercising women enrolled in a family practice

health maintenance organization (n = 121) (mean age, 37.1 +/- 9.4 years).

INTERVENTION: Not applicable. MEASURES: Responses to questions relating

to 1) a past history of an eating disorder; 2) weight; 3) running and exercise habits;

4) drinking behaviors using alcoholism screening tests; 5) quantity-frequency data

of the previous two week alcohol consumption. RESULTS: Ten percent of racers

and 4.1% of controls reported a history of an eating disorder. Those racers

reporting a history of bulimia nervosa without anorexia were more likely to report

feeling guilty about their drinking, drunk-driving arrests, an elevated score on an

alcoholism screening test (suggestive of problem drinking), alcoholism, and seeking

help for problem drinking than other racers or the control population without a

history of an eating disorder. However, bulimic racers did not report either

increased current alcohol consumption or occasions of drinking, including binge

drinking (five or more drinks in one episode). CONCLUSIONS: Women racers

reporting a history of bulimia nervosa are more likely to report a history of

problem behaviors with alcohol but not differences in current alcohol

consumptions from that reported by other women racers or women without a

history of an eating disorder from the control population.

116. Haarmeier, T.; Thier, P. An electrophysiological correlate of visual motion awareness

in man. J-Cogn-Neurosci. 1998 Jul; 10(4): 464-71; ISSN: 0898-929X.

UNITED-STATES. It is usually held that perceptual spatial stability, despite

smooth pursuit eye movements, is accomplished by comparing a signal reflecting

retinal image slip with an internal reference signal, encoding the eye movement.

The important consequence of this concept is that our subjective percept of visual

motion reflects the outcome of this comparison rather than retinal image slip. In

an attempt to localize the cortical networks underlying this comparison and

therefore our subjective percept of visual motion, we exploited an imperfection

inherent in it, which results in a movement illusion. If smooth pursuit is carried

out across a stationary background, we perceive a tiny degree of illusionary

background motion (Filehne illusion, or FI), rather than experiencing the

ecologically optimal percept of stationarity. We have recently shown that this

illusion can be modified substantially and predictably under laboratory conditions

by visual motion unrelated to the eye movement. By making use of this finding,

we were able to compare cortical potentials evoked by pursuit-induced retinal

image slip under two conditions, which differed perceptually, while being identical

physically. This approach allowed us to discern a pair of potentials, a parieto-

occipital negativity (N300) followed by a frontal positivity (P300), whose

amplitudes were solely determined by the subjective perception of visual motion

irrespective of the physical attributes of the situation. This finding strongly

suggests that subjective awareness of visual motion depends on neuronal activity

in a parieto-occipito-frontal network, which excludes the early stages of visual

processing.

117. Han, Y.; Lennerstrand, G. Effects of neck muscle proprioceptive activation on the

dynamics of monocularly driven horizontal vergence movements. Acta-

Ophthalmol-Scand. 1998 Jun; 76(3): 283-8; ISSN: 1395-3907.

DENMARK. PURPOSE: The dynamics of accommodative vergence responses

were studied to accommodative stimuli combined with the activation of neck

muscle proprioception. METHODS: Accommodative stimulation was done with

a LED bar. The stimuli were presented monocularly in a stepwise and a sinusoidal

mode to either the dominant or the non-dominant eye with the other eye covered.

The neck proprioceptors were activated by vibration on the neck muscles which

turn the head horizontally. Eye movements were recorded with an infra-red

reflection system in both eyes. RESULTS: Vibration of the neck muscles

shortened the time constant of the accommodative vergence movement in the

covered eye to square wave stimulation when the non-dominant eye was fixating

the targets. The gain factor to sine wave stimulation was higher when the non-

dominant eye was fixating. CONCLUSION: Extraretinal signals from neck

proprioception influenced not only the static eye position, but also the dynamics

of monocularly driven accommodative vergence movements, when the non-

dominant eye was the viewing eye.

118. Harris, C. M.; Wolpert, D. M. Signal-dependent noise determines motor planning [see

comments]. Nature. 1998 Aug 20; 394(6695): 780-4; ISSN: 0028-0836.

Note: Comment in: Nature 1998 Aug 20;394(6695):725-6.

ENGLAND. When we make saccadic eye movements or goal-directed arm

movements, there is an infinite number of possible trajectories that the eye or arm

could take to reach the target. However, humans show highly stereotyped

trajectories in which velocity profiles of both the eye and hand are smooth and

symmetric for brief movements. Here we present a unifying theory of eye and

arm movements based on the single physiological assumption that the neural

control signals are corrupted by noise whose variance increases with the size of

the control signal. We propose that in the presence of such signal-dependent

noise, the shape of a trajectory is selected to minimize the variance of the final eye

or arm position. This minimum-variance theory accurately predicts the

trajectories of both saccades and arm movements and the speed-accuracy trade-off

described by Fitt's law. These profiles are robust to changes in the dynamics of

the eye or arm, as found empirically. Moreover, the relation between path

curvature and hand velocity during drawing movements reproduces the empirical

'two-thirds power law. This theory provides a simple and powerful unifying

perspective for both eye and arm movement control.

119. Harris, C. M.; Wolpert, D. M. Signal-dependent noise determines motor planning [see

comments]. Nature. 1998 Aug 20; 394(6695): 780-4; ISSN: 0028-0836.

Note: Comment in: Nature 1998 Aug 20;394(6695):725-6.

ENGLAND. When we make saccadic eye movements or goal-directed arm

movements, there is an infinite number of possible trajectories that the eye or arm

could take to reach the target. However, humans show highly stereotyped

trajectories in which velocity profiles of both the eye and hand are smooth and

symmetric for brief movements. Here we present a unifying theory of eye and

arm movements based on the single physiological assumption that the neural

control signals are corrupted by noise whose variance increases with the size of

the control signal. We propose that in the presence of such signal-dependent

noise, the shape of a trajectory is selected to minimize the variance of the final eye

or arm position. This minimum-variance theory accurately predicts the

trajectories of both saccades and arm movements and the speed-accuracy trade-off

described by Fitt's law. These profiles are robust to changes in the dynamics of

the eye or arm, as found empirically. Moreover, the relation between path

curvature and hand velocity during drawing movements reproduces the empirical

'two-thirds power law. This theory provides a simple and powerful unifying

perspective for both eye and arm movement control.

120. Hart, S.; Gabbard, C. Examining the mobilizing feature of footedness. Percept-Mot-

Skills. 1998 Jun; 86(3 Pt 2): 1339-42; ISSN: 0031-5125.

UNITED-STATES. This study examined the mobilizing feature of footedness in

a unilateral and a bilateral context. Analysis for 47 right- and 32 left-footed

undergraduates indicated a strong relationship between preferred limbs in both

conditions, with right footer showing the strongest concordance. Theoretical

explanations for the origin of behavior and differences in right versus left

concordance are discussed. Based on selected previous reports and present

findings, it seems reasonable that for most persons the right foot may be preferred

for mobilizing activities regardless of behavioral context.

121. Hartwig, W. C.; Doneski, K. Evolution of the hominid hand and tool making behavior.

Am-J-Phys-Anthropol. 1998 Jul; 106(3): 401-2; discussion 402-4; ISSN: 0002-

9483.

UNITED-STATES.

122. Harwerth, R. S.; Moeller, M. C.; Wensveen, J. M. Effects of cue context on the

perception of depth from combined disparity and perspective cues. Optom-Vis-

Sci. 1998 Jun; 75(6): 433-44; ISSN: 1040-5488.

UNITED-STATES. PURPOSE: In normal vision, stereoscopic cues are

combined with perspective cues to provide veridical depth perception. The

relative strengths of these depth cues, however, may be dependent upon context

effects. We investigated the role of stimulus context on the interactions of

binocular disparity, contrast, and size. METHODS: The subjects, four observers

with normal stereoacuity and one stereo-amblyope, discriminated far vs. near

perceived depth of Gabor patches; feedback was based on the sign of binocular

disparity. Depth discrimination functions were measured under conditions in

which depth cues were consonant or in conflict. Three stimulus contexts were

used: (1) variable disparity with fixed spatial frequency and contrast; (2) variable

contrast with fixed spatial frequency and disparity; and (3) variable spatial

frequency with fixed contrast and disparity. The effects of stimulus context were

derived from comparisons of discrimination rates for identical stimuli across the

three sets of conditions. RESULTS: In subjects with normal stereopsis, for

disparities less than 2 arcmin, depth perception was dominated by contrast in

contrast-varying sessions, or by size in spatial frequency-varying sessions. With

larger disparities, depth perception became dependent on disparity, regardless of

the contrast or spatial frequency of the test stimulus. The results for the stereo-

amblyope showed much greater dependence on perspective cues and, in most

cases, the transition from perspective- to disparity-based depth perception did

not occur. CONCLUSIONS: These investigations demonstrate strong stimulus

context effects and have important implications for the combination rules of

stereoscopic and perspective cues in depth perception of normal and stereo-

deficient subjects.

123. Hauber, W.; Lutz, S.; Munkle, M. The effects of globus pallidus lesions on

dopamine-dependent motor behaviour in rats. Neuroscience. 1998 Sep; 86(1):

147-57; ISSN: 0306-4522.

UNITED-STATES. Motor effects of bilateral lesions of the globus pallidus

induced by quinolinic acid (30 and 60 nmol in 0.5 microl) were investigated in rats.

Globus pallidus lesions with 60 nmol quinolinic acid produced a significant

reduction of spontaneous motor activity measured by a reduced locomotor

activity in an open field and by a reduced sniffing activity in an experimental

chamber. In addition, D-amphetamine (1 mg/kg, i.p.)-induced hyperlocomotion

and D-amphetamine (3 mg/kg, i.p.)-induced stereotyped sniffing were

significantly reduced in animals with quinolinic acid lesions (60 nmol). Globus

pallidus lesions with 60 nmol quinolinic acid potently reversed catalepsy induced

by systemic administration of the dopamine D1 receptor antagonist SCH23390

(0.75 and 1 mg/kg, i.p.) or the dopamine D2 receptor antagonist raclopride (1.25

and 5 mg/kg, i.p.), while lesions with 30 nmol quinolinic acid exerted anti-

cataleptic effects which were only partly significant. In line with current models

of basal ganglia functions, these findings indicate that inactivation of the globus

pallidus reduced spontaneous motor activity and motor hyperactivity after

dopamine receptor stimulation. However, the present data also demonstrate that

inactivation of the globus pallidus reversed motor hypoactivity induced by a

blockade of dopamine D1 and D2 receptors. Therefore, a more complex functional

model of the globus pallidus is required to account for the opposite effects on

motor behaviour observed after lesions of this basal ganglia nucleus.. 0; 0; 0; 0;

51-61-6; 51-64-9; 84225-95-6; 87075-17-0; 89-00-9.

124. Heeg, M.; Broughton, N. S.; Menelaus, M. B. Bilateral dislocation of the hip in spina

bifida: a long-term follow-up study. J-Pediatr-Orthop. 1998 Jul; 18(4): 434-6;

ISSN: 0271-6798.

UNITED-STATES. Nineteen patients with spina bifida and bilateral dislocation

of the hips were studied with a minimal follow-up of 10 years. The average age at

review was 21 years (range, 10-31). Ten patients had an upper neurologic level

(thoracic to L3), and nine had a low lesion (L4 to sacrum). Three patients had no

hip surgery. A closed or open reduction was performed in 12 hips, supplemented

by one or more surgical procedures. Of these, 10 remained enlocated, and two had

redislocated. In all other hips, several surgical procedures were performed, aimed

at improvement of hip-flexion deformity or stability. At follow-up, one patient

had occasional pain in one hip, which was dysplastic. Of the 10 patients with a

high lesion, only two were walkers, but both had bilateral dislocation of the hips

at follow-up. In contrast, all nine patients were walkers, but four of these had

bilateral dislocation at follow-up. We found that a level pelvis and good range of

motion of the hips are more important for ambulation than is reduction of bilateral

hip dislocation.

125. Heikkila, H. V.; Wenngren, B. I. Cervicocephalic kinesthetic sensibility, active range

of cervical motion, and oculomotor function in patients with whiplash injury.

Arch-Phys-Med-Rehabil. 1998 Sep; 79(9): 1089-94; ISSN: 0003-9993.

UNITED-STATES. OBJECTIVE: To investigate cervicocephalic kinesthetic

sensibility, active range of cervical motion, and oculomotor function in patients

with whiplash injury. DESIGN: A 2-year review of consecutive patients admitted

to the emergency unit after whiplash injury. SETTING: An otorhinolaryngology

department. PATIENTS AND SUBJECTS: Twenty-seven consecutive patients

with diagnosed whiplash injury (14 men and 13 women, mean age, 33.8yrs [range,

18 to 66yrs]). The controls were healthy subjects without a history of whiplash

injury. MAIN OUTCOME MEASURES: Oculomotor function was tested at 2

months and at 2 years after whiplash injury. The ability to appreciate both

movement and head position was studied. Active range of cervical motion was

measured. Subjective intensity of neck pain and major medical symptoms were

recorded. RESULTS: Active head repositioning was significantly less precise in

the whiplash subjects than in the control group. Failures in oculomotor functions

were observed in 62% of subjects. Significant correlations occurred between

smooth pursuit tests and active cervical range of motion. Correlations also were

established between the oculomotor test and the kinesthetic sensibility test.

CONCLUSION: The results suggest that restricted cervical movements and

changes in the quality of proprioceptive information from the cervical spine region

affect voluntary eye movements. A flexion/extension injury to the neck may result

in dysfunction of the proprioceptive system. Oculomotor dysfunction after neck

trauma might be related to cervical afferent input disturbances.

126. Heinze, H. J.; Hinrichs, H.; Scholz, M.; Burchert, W.; Mangun, G. R. Neural

mechanisms of global and local processing. A combined PET and ERP study. J-

Cogn-Neurosci. 1998 Jul; 10(4): 485-98; ISSN: 0898-929X.

UNITED-STATES. The neural mechanisms of hierarchical stimulus processing

were investigated using a combined event-related potentials (ERPs) and positron

emission tomography (PET) approach. Healthy subjects were tested under two

conditions that involved selective or divided attention between local and global

levels of hierarchical letter stimuli in order to determine whether and where

hemispheric differences might exist in the processing of local versus global

information. When attention was divided between global and local levels, the N2

component of the ERPs (260- to 360-msec latency) elicited by the target stimuli

showed asymmetries in amplitude over the two hemispheres. The N2 to local

targets was larger over the left hemisphere, but the N2 to global targets tended to

be slightly larger over the right hemisphere. However, the shorter-latency,

sensory-evoked P1 component (90- to 150-msec latency) was not different for

global versus local targets under conditions of divided attention. In contrast,

during selective attention to either global or local targets, asymmetries in the N2

component were not observed. But under selective attention conditions, the

sensory-evoked P1 components in the extrastriate cortex were enlarged for global

versus local attention. Increased regional cerebral blood flow in the posterior

fusiform gyrus bilaterally was observed in the PET data during selective attention

to either global or local targets, but neither these nor the P1 component showed

any tendency toward hemispheric difference for global versus local attention.

Neither were there any activations observed in the parietal lobe during selective

attention to global versus local targets. Together these data indicate that early

sensory inputs are not modulated to gate global versus local information

differentially into the two hemispheres. Rather, later stages of processing that

may be asymmetrically organized in the left and right hemispheres operate in

parallel to process global and local aspects of complex stimuli (i.e., the N2 effect

of the ERPs). This pattern of results supports models proposing that spatial

frequency analysis is only asymmetric at higher stages of perceptual processing

and not at the earliest stages of visual cortical analysis.

127. Heitkamp, H. C.; Schulz, H.; Rocker, K.; Dickhuth, H. H. Endurance training in

females: changes in beta-endorphin and ACTH. Int-J-Sports-Med. 1998 May;

19(4): 260-4; ISSN: 0172-4622.

GERMANY. Previous results from endurance training in women have been

discrepant in regard to influences on basal and maximum adrenocorticotropin

(ACTH) and beta-endorphin (beta-EP) concentrations before and after exhaustive

exercise. A group of 23 untrained young women ran 3 times a week for 30 min at

an individual specific intensity corresponding to their respective anaerobic

threshold, derived from the lactate performance curve obtained from prior

treadmill testing. ACTH and beta-EP were measured at rest, as well as 5 and 30

min after exhaustive progressive spiroergometric treadmill running, both before

and after the 8 week endurance training program. Basal beta-EP did not change

after training, but less elevated concentrations were measured both 5 (p < 0.05)

and 30 min (p < 0.05) after exercise, after the training program. In contrast, the

resting concentration of ACTH increased significantly; the respective maximum

concentration was less elevated after 5 min and much less elevated 30 min after

the exercise (p < 0.05). Positive correlations were found after the exhaustive

exercise between beta-EP and ACTH, as well as between maximum lactate and

ACTH. Training was associated with significant changes in maximum running

speed (p < 0.01), maximum oxygen uptake (p < 0.01) and the running speed at the

anaerobic threshold (p < 0.05). Maximum lactate and the level of perceived

exertion remained unchanged, showing a similar level of exhaustion. Our results

indicate that endurance training modulates the hormonal responses of beta-EP and

ACTH to comparable workloads of high intensity. After the training program the

maximum concentrations are significantly lower during the recovery period. The

tendency to elevated basal ACTH, and thus elevated cortisol, might be a new

factor to consider in evaluation of endurance training induced hormonal

disturbances in women.. 0; 60617-12-1; 9002-60-2.

128. Helmstaedter, C.; Gleibner, U.; Zentner, J.; Elger, C. E. Neuropsychological

consequences of epilepsy surgery in frontal lobe epilepsy. Neuropsychologia.

1998 Apr; 36(4): 333-41; ISSN: 0028-3932.

ENGLAND. The present study investigated the effect of frontal lobe surgery on

"cognitive functions", which have previously been shown to be discriminative in

the evaluation of non-resected patients with frontal lobe epilepsy (FLE). The

cognitive outcome was evaluated with particular consideration of the side

(left/right), the site (lateral, orbital, mesial, premotor/SMA), the type of surgery

(resections vs. resections plus multiple subpial transections; MST), and seizure

outcome. The evaluation is based on 33 patients with left (n = 17) or right (n =

16) frontal surgery. Forty-five patients who underwent successful left (n = 21) or

right (n = 24) temporal lobectomy served as controls. The neuropsychological

examination covered speed/attention, motor sequencing/coordination, response

maintenance/inhibition, short-term memory, and language. With the exception of

short-term memory, the chosen tests were discriminative in determining

preoperative frontal lobe dysfunctions but they did not differentiate patients with

a different lateralization or localization of the frontal focus. At the 3 month

follow-up examination, patients with temporal lobectomy had improved frontal

functions, whereas patients with frontal lobe surgery showed a mild deterioration.

Within the frontally resected group, completely seizure-free patients had

significantly improved short-term memory. Further consideration of the side, site

and the type of the frontal resection indicated that patients with premotor/SMA

surgery and patients with precentral/central MST had additional impairment after

surgery. Premotor/SMA resections led to a deterioration in response

maintenance/inhibition and if performed left sided also to deteriorated language

functions. The latter impairment could be clearly related to transient aphasia

directly after surgery. Irrespective of pareses observed immediately after surgery,

patients with MSTs of the precentral/central areas displayed additional problems

in motor coordination at the follow-up examination. In this group the seizure

outcome was also less favourable. In summing up, frontal lobe surgery does not

cause any considerable additional impairment in the short-term follow-up.

However, caution is recommended when surgery or MST affect functional

relevant cortex (here the prefrontal/SMA and precentral/central area). Finally, a

release of functions associated with frontal areas not affected by surgery is

suggested, when seizures are successfully controlled by surgery.

129. Hershey, T.; Black, K. J.; Stambuk, M. K.; Carl, J. L.; McGee Minnich, L. A.;

Perlmutter, J. S. Altered thalamic response to levodopa in Parkinson's patients

with dopa-induced dyskinesias. Proc-Natl-Acad-Sci-U-S-A. 1998 Sep 29; 95(20):

12016-21; ISSN: 0027-8424.

UNITED-STATES. Parkinson's disease (PD) is a progressive neurologic

condition characterized by tremor, slowness, stiffness, and unstable posture.

Degeneration of dopamine-producing neurons in the substantia nigra causes PD.

Treatment with levodopa, a precursor of dopamine, initially ameliorates the

clinical manifestations of PD. However, chronic levodopa treatment can produce

severe involuntary movements (so-called dopa-induced dyskinesias or DID),

limiting treatment. Pallidotomy, placement of a surgical lesion in the internal

segment of the globus pallidus, reduces DID. Because this result is inconsistent

with current theories of both basal ganglia function and DID, it prompted us to

investigate the brain's response to levodopa. We measured regional cerebral blood

flow response to levodopa with positron-emission tomography in 6 PD patients

with DID, 10 chronically treated PD patients without DID, 17 dopa-naive PD

patients, and 11 normals. The dose of levodopa was chosen to produce clinical

benefit without inducing DID. This strategy allowed us to examine the brain

response to levodopa across groups without the confounding effect of differences

in motor behavior. We found that the DID group had a significantly greater

response in ventrolateral thalamus than the other groups. This was associated

with decreased activity in primary motor cortex. These findings are consistent

with increased inhibitory output from the internal segment of the globus pallidus

to thalamus after levodopa administration. They provide a physiological

explanation for the clinical efficacy of pallidotomy and new insights into the

physiology of the basal ganglia.. 0; 38821-49-7.

130. Highstein, S. M. Role of the flocculus of the cerebellum in motor learning of the

vestibulo-ocular reflex. Otolaryngol-Head-Neck-Surg. 1998 Sep; 119(3): 212-20;

ISSN: 0194-5998.

UNITED-STATES. Structure-function studies at the systems level are an

effective method for understanding the relationship of the central nervous system

to behavior. Motor learning or adaptation of the vestibulo-ocular reflex is a clear

example wherein this approach has been productive. During a vestibulo-ocular

reflex the brain converts a head velocity signal, transduced through the vestibular

semicircular canals, into an eye movement command delivered to the extraocular

muscles. If the viewed target remains on the fovea of the retina, the reflex is

compensatory, and its gain, eye velocity/head velocity, is one. When the image of

the viewed object slips across the retina, visual acuity decreases, and the gain of

the reflex, which is no longer one, is plastically adapted or adjusted until retinal

stability is restored. The anatomic substrate for this plasticity thus involves brain

structures in which visual-vestibular interaction can potentially occur, as well as

vestibular and visual sensory and oculomotor motor structures. Further, it has

been known for many years that removal of the flocculus of the cerebellum

permanently precludes further vestibulo-ocular reflex adaptation, demonstrating

the involvement of the cerebellum in this behavior. Maekawa and Simpson (J

Neurophysiol 1973;36: 649-66) discovered that one visual input to the flocculus

involved the accessory optic system and the inferior olive. Ensuing work has

demonstrated that the visual signals used to adapt the vestibulo-ocular reflex are

transmitted by this accessory optic system to the flocculus and subsequently to

brain stem structures involved in vestibulo-ocular reflex plasticity. Presently the

inclusive list of anatomic sites involved in vestibulo-ocular reflex circuitry and its

adaptive plasticity is small. Our laboratory continues to believe that this behavior

should be caused by interactions within this small class of neurons. By studying

each class of identified neuron and its interactions with others within the list, we

hope to ultimately understand the mechanisms used by the brain in the expression

of this behavior.

131. Highstein, S. M. Role of the flocculus of the cerebellum in motor learning of the

vestibulo-ocular reflex. Otolaryngol-Head-Neck-Surg. 1998 Sep; 119(3): 212-20;

ISSN: 0194-5998.

UNITED-STATES. Structure-function studies at the systems level are an

effective method for understanding the relationship of the central nervous system

to behavior. Motor learning or adaptation of the vestibulo-ocular reflex is a clear

example wherein this approach has been productive. During a vestibulo-ocular

reflex the brain converts a head velocity signal, transduced through the vestibular

semicircular canals, into an eye movement command delivered to the extraocular

muscles. If the viewed target remains on the fovea of the retina, the reflex is

compensatory, and its gain, eye velocity/head velocity, is one. When the image of

the viewed object slips across the retina, visual acuity decreases, and the gain of

the reflex, which is no longer one, is plastically adapted or adjusted until retinal

stability is restored. The anatomic substrate for this plasticity thus involves brain

structures in which visual-vestibular interaction can potentially occur, as well as

vestibular and visual sensory and oculomotor motor structures. Further, it has

been known for many years that removal of the flocculus of the cerebellum

permanently precludes further vestibulo-ocular reflex adaptation, demonstrating

the involvement of the cerebellum in this behavior. Maekawa and Simpson (J

Neurophysiol 1973;36: 649-66) discovered that one visual input to the flocculus

involved the accessory optic system and the inferior olive. Ensuing work has

demonstrated that the visual signals used to adapt the vestibulo-ocular reflex are

transmitted by this accessory optic system to the flocculus and subsequently to

brain stem structures involved in vestibulo-ocular reflex plasticity. Presently the

inclusive list of anatomic sites involved in vestibulo-ocular reflex circuitry and its

adaptive plasticity is small. Our laboratory continues to believe that this behavior

should be caused by interactions within this small class of neurons. By studying

each class of identified neuron and its interactions with others within the list, we

hope to ultimately understand the mechanisms used by the brain in the expression

of this behavior.

132. Hiroshige, Y. The effects of time constant on electrooculographic recording of slow

eye movements during the wake-sleep transition. Psychiatry-Clin-Neurosci. 1998

Apr; 52(2): 163-4; ISSN: 1323-1316.

AUSTRALIA. This study examines distortions in electrooculogram (EOG) wave

form of slow eye movements (SEM) during the wake-sleep transition. Distortions

in AC-coupled EOG, which were evaluated by computing Pearson's product-

moment correlation coefficient between DC- and AC-coupled EOG, decreased as

a function of time constants (0.3, 3 and 6 s) and showed SEM-dependent changes.

Time constants of longer than 3.0 s should be chosen to reliably recognize SEM.

133. Hoffmann, K. P.; Distler, C.; Grusser, O. J. Optokinetic reflex in squirrel monkeys

after long-term monocular deprivation. Eur-J-Neurosci. 1998 Mar; 10(3): 1136-

44; ISSN: 0953-816X.

FRANCE. Horizontal optokinetic nystagmus (OKN) as well as neuronal

response properties in the nucleus of the optic tract and the dorsal terminal

nucleus of the accessory optic system (NOT-DTN) were investigated in three

monocularly deprived squirrel monkeys. In two monkeys occlusion of one eye

was performed at birth (early) and in the third after 7 weeks (late). In adulthood,

in early deprived monkeys monocular horizontal OKN tested through the non-

deprived eye was symmetrical and in no way different from normal, i.e.

stimulation in the temporonasal and nasotemporal direction elicited equal and

robust responses. OKN through the early occluded eye, however, was grossly

abnormal with low gain and great variability in the consistency of nasotemporal

and temporonasal slow phase eye movements. When in the late deprived monkey

the non-deprived eye was occluded a strong spontaneous nystagmus developed

despite the deprived eye viewing a stationary pattern. The slow phases were

directed from nasal to temporal for the deprived eye. When tested through the

non-deprived eye all neuronal responses of the NOT-DTN were normal. The

deprived eye's influence on NOT-DTN neurons was extremely weak. No neuron

with a moderate or even dominant input from the deprived eye was found after

early deprivation. In the late deprived case the deficit was not as severe but still

the non-deprived eye was clearly dominating the responses in all neurons tested.

Velocity tuning of neurons tested through the non-deprived eye was normal and

qualitatively corresponded well to slow phase eye velocity in response to

equivalent retinal slip during OKN. Through the early deprived eye, however,

velocity tuning was extremely poor. It was somewhat better through the late

deprived eye. We suggest that the dramatic deterioration in the optokinetic reflex

found after long-term monocular deprivation for the amblyopic eye is probably

caused by the almost complete loss of retinal and cortical input driven by that eye

to the NOT-DTN. These results are discussed in relation to our previous results

in cats and reports in the literature for humans with occlusion amblyopia.

134. Hogg, S.; Moser, P. C.; Sanger, D. J. Mild traumatic lesion of the right parietal cortex

of the rat: selective behavioural deficits in the absence of neurological impairment.

Behav-Brain-Res. 1998 Jun; 93(1-2): 143-55; ISSN: 0166-4328.

NETHERLANDS. Fluid impact models are widely used to study the histological

and neurochemical consequences of traumatic brain injury and although

behavioural consequences have also been studied, behavioural changes are often

confounded by non-specific neurological deficits. In the present study we

investigated behavioural effects of a unilateral mild traumatic lesion of the right

lateral parietal cortex. This region is implicated in a number of basic and complex

behaviors, and we therefore analyzed the performance of rats in a diverse range of

behavioural procedures. The lesion had no effects on general neurological function,

motor activity (activity boxes, rota-rod and paw reaching tests), habituation to a

novel environment (holeboard), spatial learning ability (Morris water maze) or

anxiety (elevated plus-maze). However, the lesioned animals demonstrated lower

levels of exploration than the control group when novel objects were placed

beneath some of the holes in the holeboard. Lesioned animals also differed from

controls in their performance in passive and active avoidance procedures. In a

step-through passive avoidance test the lesioned rats performed worse than the

sham-operated controls, i.e. they had significantly lower entry latencies on the

2nd day. In contrast, in the active avoidance task the lesioned animals performed

better than sham-operated rats, demonstrating a better ability to learn to avoid and

escape from the shock. These diverse results in different tests of learning and

memory, in particular the impairment in passive avoidance and the improvement

in active avoidance behavior, are difficult to reconcile with a simple effect of the

lesion on cognitive performance per se. The complete absence of general

neurological deficits following the mild traumatic injury rules out the possibility

that the observed behavioural changes reflect a non-specific impairment. These

results demonstrate that mild traumatic lesion of the right parietal cortex can

induce relatively selective behavioural changes that may serve to study functional

recovery after trauma. However further work is required to establish the

underlying deficit(s) that has led to the behavioural effects described here.

135. Hogg, S.; Sanger, D. J.; Moser, P. C. Mild traumatic lesion of the right parietal cortex

in the rat: characterisation of a conditioned freezing deficit and its reversal by

dizocilpine. Behav-Brain-Res. 1998 Jun; 93(1-2): 157-65; ISSN: 0166-4328.

NETHERLANDS. We have previously demonstrated that traumatic injury of the

lateral aspect of the right parietal cortex results in reduced acquisition of the

passive avoidance task but enhanced learning in an active avoidance procedure. In

order to try to explain the apparent dichotomy between these findings a series of

experiments examined the effect of fluid percussion-induced traumatic brain injury

(FP-TBI) on the conditioned freezing response to a context previously paired

with an aversive stimulus. Rats subjected to FP-TBI displayed less conditioned

freezing than the sham-operated controls. This effect was particularly marked

when the delay between context exposure and footshock was short (< or = 30 s)

and was no longer significant when this delay was 3 min, indicating that the

injured animals did not have an impaired freezing response per se. This

phenomenon was enduring such that it could still be observed 2 months following

the surgery. There was no significant freezing deficit after FP-TBI of the motor

cortex, demonstrating that the site of injury is important and that the freezing

deficit is not a general response to CNS trauma. The NMDA receptor antagonist

dizocilpine (MK-801, 1 mg/kg i.v.) significantly reduced the trauma-induced

freezing deficit when administered as a single bolus 15 min prior to the surgery, or

as three repeated treatments (3 x 0.33 mg/kg) 15 min, and 6 and 24 h following

lesion. The trauma-induced deficit in conditioned freezing can explain the

differences in active and passive avoidance behaviours and appears to be specific

to lesion of the lateral parietal cortex. In addition, the behavioural deficit can be

attenuated using the neuroprotective agent dizocilpine, suggesting that it may

prove useful as a sensitive and specific measure of cortical damage following

traumatic injury.. 0; 77086-22-7.

136. Hollerman, J. R.; Tremblay, L.; Schultz, W. Influence of reward expectation on

behavior-related neuronal activity in primate striatum. J-Neurophysiol. 1998 Aug;

80(2): 947-63; ISSN: 0022-3077.

UNITED-STATES. Rewards constitute important goals for voluntary behavior.

This study aimed to investigate how expected rewards influence behavior-related

neuronal activity in the anterior striatum. In a delayed go-nogo task, monkeys

executed or withheld a reaching movement and obtained liquid or sound as

reinforcement. An initial instruction picture indicated the behavioral reaction to be

performed and the reinforcer to be obtained after a subsequent trigger stimulus.

Movements varied according to the reinforcers predicted by the instructions,

suggesting that animals differentially expected the two outcomes. About 250 of

nearly 1,500 neurons in anterior parts of caudate nucleus, putamen, and ventral

striatum showed typical task-related activations that reflected the expectation of

instructions and trigger, and the preparation, initiation, and execution of behavioral

reactions. Strikingly, most task-related activations occurred only when liquid

reward was delivered at trial end, rather than the reinforcing sound. Activations

close to the time of reward showed similar preferences for liquid reward over the

reinforcing sound, suggesting a relationship to the expectation or detection of the

motivational outcome of the trial rather than to a "correct" or "end-of-trial" signal.

By contrast, relatively few activations in the present task occurred irrespective of

the type of reinforcement. In conclusion, many of the behavior-related neurons

investigated in the anterior striatum were influenced by an upcoming primary

liquid reward and did not appear to code behavioral acts in a motivationally

neutral manner. Rather, these neurons incorporated information about the

expected outcome into their behavior-related activity. The activations influenced

by reward several seconds before its occurrence may constitute a neuronal basis

for the retrograde effects of rewards on behavioral reactions.

137. Honrubia, V.; Greenfield, A. A novel psychophysical illusion resulting from

interaction between horizontal vestibular and vertical pursuit stimulation. Am-J-

Otol. 1998 Jul; 19(4): 513-20; ISSN: 0192-9763.

UNITED-STATES. HYPOTHESIS: The hypothesis was tested that the

perception of an object's motion is made in relation to an internal reference center

(IRC), which is under the influence of vestibular receptors. Experiments were

designed to evaluate whether induced vestibular self-motion will interact linearly

with the perception of a visual target (VT). BACKGROUND: The major

complaint of vestibular patients is vertigo, an illusion of motion. However, there

is as yet no objective method to measure this illusion, which is produced by

vestibular stimulation. METHODS: Six subjects were instructed to track a

vertically moving VT while sinusoidally rotating (0.2 Hz) in the yaw plane at 14,

28, and 42 degrees/s. Eye movements were monitored by electro-oculographic

electrodes. RESULTS: During visual-vestibular interaction, all subjects perceived

a VT moving obliquely while the eyes moved in the vertical plane. The subject

then tilted the VT trajectory until vertical was perceived. At this time, the eye had

an oblique vectorial trajectory. Interactive horizontal eye velocities, both vertical

and horizontal components, were compared with those from rotation in the dark,

showing a strong positive linear relationship (slope = 0.96, r = 0.84, n = 18).

CONCLUSIONS: Results support the hypothesis of an egocentric sense of

orientation whereby velocity of external objects is evaluated in relation to an IRC

that is dependent on the status of the vestibular system. These methods may lead

to new techniques for clinical evaluation of vestibular patients.

138. Husain, S.; Mishra, B.; Prakash, V.; Malaviya, G. N. Results of surgical

decompression of ulnar nerve in leprosy. Acta-Leprol. 1998; 11(1): 17-20; ISSN:

0001-5938.

SWITZERLAND. Ulnar neurolysis in 279 cases of leprosy was performed with

objectives of relief in neuritic pain and impending/ existing sensory motor loss of

varying extent. Of the above, 193 could be followed between 3-10 years. Neuritic

pain was first to disappear. 48.7% of the 193 cases showed sensory recovery.

Motor power gain and/or further fall in muscle power was prevented as a result of

preventive neurolysis in 173 (89.6%) cases. In this series benefits of appropriate

and timely surgical intervention have been observed.

139. Hutton, S. B.; Crawford, T. J.; Puri, B. K.; Duncan, L. J.; Chapman, M.; Kennard, C.;

Barnes, T. R.; Joyce, E. M. Smooth pursuit and saccadic abnormalities in first-

episode schizophrenia. Psychol-Med. 1998 May; 28(3): 685-92; ISSN: 0033-

2917.

ENGLAND. BACKGROUND: Previous studies of oculomotor dysfunction in

schizophrenia have tended to concentrate on abnormalities of smooth pursuit eye

tracking in chronic medicated patients. We report the results of a study of smooth

pursuit, reflexive and antisaccade performance in drug naive and antipsychotic

treated first-episode schizophrenic patients. METHODS: Smooth pursuit and

saccadic eye movements were recorded in 36 first-episode schizophrenic patients

and 36 controls matched for age and estimated IQ. The schizophrenic patients

were divided into drug-naive (N = 17) and antipsychotic treated groups (N = 19).

RESULTS: Smooth pursuit velocity gain was significantly lower than controls

only in the drug-naive patients. The treated patients did not differ significantly

from either the controls or the untreated group. In an antisaccade paradigm both

treated and drug-naive schizophrenic patients demonstrated an increased number

of errors, but only drug-naive patients also demonstrated an increased latency in

initiating correct antisaccades. CONCLUSIONS: These impairments are unlikely

to be due to a generalized deficit in oculomotor function in the schizophrenic

groups, as there were no differences between the groups in saccadic metrics on a

reflexive saccade task. The results show that both smooth pursuit and saccadic

abnormalities are present at the onset of schizophrenia and are integral to the

disorder.. 0.

140. Hutton, S. B.; Crawford, T. J.; Puri, B. K.; Duncan, L. J.; Chapman, M.; Kennard, C.;

Barnes, T. R.; Joyce, E. M. Smooth pursuit and saccadic abnormalities in first-

episode schizophrenia. Psychol-Med. 1998 May; 28(3): 685-92; ISSN: 0033-

2917.

ENGLAND. BACKGROUND: Previous studies of oculomotor dysfunction in

schizophrenia have tended to concentrate on abnormalities of smooth pursuit eye

tracking in chronic medicated patients. We report the results of a study of smooth

pursuit, reflexive and antisaccade performance in drug naive and antipsychotic

treated first-episode schizophrenic patients. METHODS: Smooth pursuit and

saccadic eye movements were recorded in 36 first-episode schizophrenic patients

and 36 controls matched for age and estimated IQ. The schizophrenic patients

were divided into drug-naive (N = 17) and antipsychotic treated groups (N = 19).

RESULTS: Smooth pursuit velocity gain was significantly lower than controls

only in the drug-naive patients. The treated patients did not differ significantly

from either the controls or the untreated group. In an antisaccade paradigm both

treated and drug-naive schizophrenic patients demonstrated an increased number

of errors, but only drug-naive patients also demonstrated an increased latency in

initiating correct antisaccades. CONCLUSIONS: These impairments are unlikely

to be due to a generalized deficit in oculomotor function in the schizophrenic

groups, as there were no differences between the groups in saccadic metrics on a

reflexive saccade task. The results show that both smooth pursuit and saccadic

abnormalities are present at the onset of schizophrenia and are integral to the

disorder.. 0.

141. Hyoki, K.; Shigeta, M.; Tsuno, N.; Kawamuro, Y.; Kinoshita, T. Quantitative electro-

oculography and electroencephalography as indices of alertness.

Electroencephalogr-Clin-Neurophysiol. 1998 Mar; 106(3): 213-9; ISSN: 0013-

4694.

IRELAND. Even though both electro-oculography (EOG) and EEG have been

widely used for assessing alertness, the relationship between these two measures

has not yet been clarified at various alertness levels. We estimated the frequencies

of eye movements faster than 15 degrees/s (NoEM15) and EEG power at every

0.5 Hz step frequency point, quantitatively as well as continuously from alert to

very light sleep (Stage 1) in 14 healthy adults. We devised a new EOG derivation

for a computerized analysis, because conventional EOG recordings suffer from

EEG contamination and have been analyzed manually. EOG electrodes were

attached to the left orbitale in this study. The eye movements were detected as

peaks in differentiated EOG signals. Significant correlations were found between

NoEM15 and EEG powers at several frequency points, mainly in the alpha and

beta bands. Though fluctuating EEG components in close correspondence to the

frequency of the eye movements varied depending on the individual, EEG power

at the peak frequency of the awake state was most closely associated with the eye

movements. A broad band power that centers at the peak frequency may be a

better measure for alertness assessment than powers in fixed bands.

142. Inui, N.; Ichihara, T.; Minami, T.; Matsui, A. Interactions: timing and force control of

finger-tapping sequences. Percept-Mot-Skills. 1998 Jun; 86(3 Pt 2): 1395-401;

ISSN: 0031-5125.

UNITED-STATES. This study examined effects of combinations of intertap

interval and muscle force on interactions between two factors in sequences of

equally paced finger taps. 12 male college students tapped a force plate connected

to strain gauges. Subjects firstly tapped the plate at a preferred pace and force for

12 sec. Next, subjects tapped the plate by half or double the preferred pace. A

series of finger-tapping tasks the consisted of nine combinations of pace and

force. Analysis showed that, although variations in intertap interval were

considerably accurately controlled across conditions, those in peak forces were

not. Movement timing of tapping sequences hence appeared to be independent of

force control. For six of 12 subjects, on the other hand, positive correlations

between spontaneous variations in intertap interval and in forces were noted.

Then, although motor timing was independent of force control in controls of low

pace and weak forces, there were strong interactions between the two factors

under high pace conditions.

143. Inui, N.; Ichihara, T.; Minami, T.; Matsui, A. Interactions: timing and force control of

finger-tapping sequences. Percept-Mot-Skills. 1998 Jun; 86(3 Pt 2): 1395-401;

ISSN: 0031-5125.

UNITED-STATES. This study examined effects of combinations of intertap

interval and muscle force on interactions between two factors in sequences of

equally paced finger taps. 12 male college students tapped a force plate connected

to strain gauges. Subjects firstly tapped the plate at a preferred pace and force for

12 sec. Next, subjects tapped the plate by half or double the preferred pace. A

series of finger-tapping tasks the consisted of nine combinations of pace and

force. Analysis showed that, although variations in intertap interval were

considerably accurately controlled across conditions, those in peak forces were

not. Movement timing of tapping sequences hence appeared to be independent of

force control. For six of 12 subjects, on the other hand, positive correlations

between spontaneous variations in intertap interval and in forces were noted.

Then, although motor timing was independent of force control in controls of low

pace and weak forces, there were strong interactions between the two factors

under high pace conditions.

144. Irwin, D. E. Lexical processing during saccadic eye movements. Cognit-Psychol. 1998

Jun; 36(1): 1-27; ISSN: 0010-0285.

UNITED-STATES. Three experiments examined whether processes devoted to

word recognition and word identification are suppressed during saccades, as most

eye movement and reading researchers implicitly assume. In the first two

experiments, subjects made short or long saccades while performing lexical

decisions; lexical decision latency and accuracy were unaffected by saccade

distance, and post-saccadic processing time was reduced when a long as opposed

to a short saccade was made. Experiment 3 showed that word identification is

more accurate when a long as opposed to a short saccade separates the

presentation of a word and the presentation of a mask. These results demonstrate

that lexical processing is not suppressed during saccades, so saccade durations

should be taken into account in eye movement studies of reading. The

implications of the results for current theories of cognitive suppression during

saccades are discussed.

145. Irwin, D. E. Lexical processing during saccadic eye movements. Cognit-Psychol. 1998

Jun; 36(1): 1-27; ISSN: 0010-0285.

UNITED-STATES. Three experiments examined whether processes devoted to

word recognition and word identification are suppressed during saccades, as most

eye movement and reading researchers implicitly assume. In the first two

experiments, subjects made short or long saccades while performing lexical

decisions; lexical decision latency and accuracy were unaffected by saccade

distance, and post-saccadic processing time was reduced when a long as opposed

to a short saccade was made. Experiment 3 showed that word identification is

more accurate when a long as opposed to a short saccade separates the

presentation of a word and the presentation of a mask. These results demonstrate

that lexical processing is not suppressed during saccades, so saccade durations

should be taken into account in eye movement studies of reading. The

implications of the results for current theories of cognitive suppression during

saccades are discussed.

146. Ishijima, T.; Hirai, T.; Koshino, H.; Konishi, Y.; Yokoyama, Y. The relationship

between occlusal support and physical exercise ability. J-Oral-Rehabil. 1998 Jun;

25(6): 468-71; ISSN: 0305-182X.

ENGLAND. This study was conducted to elucidate the relationship between the

presence of occlusal support in edentulous subjects and their ability for physical

exercise. Ten complete denture wearers were selected and instructed to jump

vertically while standing on a force plate with and without occlusal support (i.e.

dentures). On the curve recorded by the force plate (1) reaction time (latency) (2)

jump elevation time and (3) maximum kicking force were analysed. The reaction

time, which is an index of physical quickness, was significantly prolonged when

the subjects lost their occlusal support. This result suggests that reconstruction of

occlusal support at a desirable mandibular position has significance not only for

the restoration of masticatory function but also for the maintenance of physical

exercise.

147. Ivliev, D. A. [The effect of a microinjection of atropine into the rat motor cortex on

the acquisition of a motor skill]. Vliianie mikroin''ektsii atropina v motornuiu koru

krysy na vyrabotku dvigatel'nogo navyka. Zh-Vyssh-Nerv-Deiat-Im-I-P-Pavlova.

1998 May; 48(3): 478-84; ISSN: 0044-4677.

RUSSIA. Atropine is known to impede the acquisition of conditioned responses

by neurons of the motor cortex. Does atropine exert influence (and of what kind)

on acquisition of local movements controlled by neurons of the motor cortex? In

the present study we examined the influence of atropine microinjections on

acquisition of reaching movement in freely moving rats. The intracortical pressure

injections of atropine (5 mcg and 15 mcg/0,6 mcl/40 s) were made unilaterally into

the forearm area of the motor cortex in adult mongrel rats. Hungry rats learned to

reach sunflower seeds form a horizontal tube by using the forelimb contralateral to

the injected site. Atropine exerted dose-dependent influence of the acquisition of

the motor skill. All the tested doses depressed the inhibition of concurrent

movements during learning. In addition, the higher dose of atropine inhibited the

initiation of the reaching movements. A hypothesis was proposed to explain these

differences.. 0; 51-55-8.

148. James, D. V.; Doust, J. H. Oxygen uptake during moderate intensity running:

response following a single bout of interval training. Eur-J-Appl-Physiol. 1998

May; 77(6): 551-5; ISSN: 0301-5548.

GERMANY. Eight male endurance runners [mean+/-(SD): age 25 (6) years;

height 1.79 (0.06) m; body mass 70.5 (6.0) kg; % body fat 12.5 (3.2); maximal

oxygen consumption (VO2max 62.9 (1.7) ml x kg(-1) x min(-1)] performed an

interval training session, preceded immediately by test 1, followed after 1 h by

test 2, and after 72 h by test 3. The training session was six 800-m intervals at 1

km x h(-1) below the velocity achieved at VO2max with 3 min of recovery

between each interval. Tests 1, 2 and 3 were identical, and included collection of

expired gas, measurement of ventilatory frequency (fr), heart rate (Fc)r rate of

perceived exertion (RPE), and blood lactate concentration ([La-]B) during the final

5 min of 15 min of running at 50% of the velocity achieved at V02max (50% v-

VO2max). Oxygen uptake (VO2), ventilation (VE), and respiratory exchange ratio

(R) were subsequently determined from duplicate expired gas collections. Body

mass and plasma volume changes were measured preceding and immediately

following the training session, and before tests 1-3. Subjects ingested water

immediately following the training session, the volume of which was determined

from the loss of body mass during the session. Repeated measures analysis of

variance with multiple comparison (Tukey) was used to test differences between

results. No significant differences in body mass or plasma volume existed between

the three test stages, indicating that the differences recorded for the measured

parameters could not be attributed to changes in body mass or plasma volume

between tests, and that rehydration after the interval training session was

successful. A significant (P < 0.05) increase was found from test 1 to test 2 [mean

(SD)] for VO2 [2.128 (0.147) to 2.200 (0.140) l x min(-1)], fc [125 (17) to 132

(16) beats x min(-1)], and RPE [9 (2) to 11 (2)]. A significant (P < 0.05) decrease

was found for submaximal R [0.89 (0.03) to 0.85 (0.04)]. These results suggest

that alterations in VO2 during moderate-intensity, constant-velocity running do

occur following heavy-intensity endurance running training, and that this is due to

factors in addition to changed substrate metabolism towards greater fat utilisation,

which could explain only 31% of the increase in VO2.. 50-21-5; 7782-44-7.

149. Jentsch, J. D.; Tran, A.; Taylor, J. R.; Roth, R. H. Prefrontal cortical involvement in

phencyclidine-induced activation of the mesolimbic dopamine system: behavioral

and neurochemical evidence. Psychopharmacology-Berl. 1998 Jul; 138(1): 89-95;

ISSN: 0033-3158.

GERMANY. Acute administration of phencyclidine to rats potently activates

mesocorticolimbic dopaminergic neurons. The activation of dopamine release and

utilization in the prefrontal cortex and nucleus accumbens are associated with

profound cognitive impairment and hyperlocomotion, respectively. This

dopaminergic activation by phencyclidine is not mediated by direct effects on the

cell body regions of the dopamine neurons; however, phencyclidine augments

dopamine release locally in the terminal fields. In the present study, the possible

involvement of the prefrontal cortex in mediating activation of the mesolimbic

dopamine system by phencyclidine was examined. Ibotenic acid lesions of the

prefrontal cortex attenuated the biochemical activation of the mesolimbic

dopamine neurons by PCP, and prefrontal lesions sharply blunted phencyclidine-,

but not amphetamine- or novelty-, induced hyperlocomotion. In addition,

injection of phencyclidine directly into the prefrontal cortex increased dopamine

utilization in the nucleus accumbens and induced hyperlocomotion. In summary,

these studies show that phencyclidine activates the mesolimbic pathway through

a mechanism in the prefrontal cortex, possibly by disinhibiting the cortical circuit

and activating corticofugal glutamatergic release in the ventral tegmental area.. 0;

0; 0; 51-61-6; 77-10-1.

150. Kanaya, K.; Takahashi, M. Long-term rail stance training in healthy young adult

women. Eur-Arch-Otorhinolaryngol. 1998; 255(5): 229-34; ISSN: 0937-4477.

GERMANY. Daily rail stance training was performed for no longer than 3

months on 12 healthy Japanese women volunteers with eyes open and closed.

Rail width conditions were varied, during which time rail stance was repeated 30

times every day until volunteers could stand for 60 s in at least half the trials.

Prolongation of stance time and retention of training effects were investigated. The

rate of progress depended on the difficulty of the stance and was determined by

rail width and visual conditions. However, marked differences were seen among

subjects even under the same training conditions. The faster the progress, the

better preserved was the training effect during the post-training period. There was

no obvious difference in the learning curve between narrow rails with eyes open

and wide rails with eyes closed. We concluded that the retention of the training

effect parallels the rate of progress, and this is determined by the difficulty of

action relative to the inherent ability of the subjects.

151. Kansaku, K.; Kitazawa, S.; Kawano, K. Sequential hemodynamic activation of motor

areas and the draining veins during finger movements revealed by cross-correlation

between signals from fMRI. Neuroreport. 1998 Jun 22; 9(9): 1969-74; ISSN:

0959-4965.

ENGLAND. Activity in the human supplementary motor area (SMA), primary

motor cortex (M1), and the draining vein of the motor cortex during a visually

triggered finger opposition task was measured by functional magnetic resonance

imaging with a repetition time of 1 s. Sequential hemodynamic activation in these

areas was revealed by cross-correlating a signal sequence in M1 directly with

signal sequences from SMA and the draining vein, and applying polynomial fitting

with the aid of Akaike's information criterion. We succeeded in detecting a time

delay of approximately 0.5 s between the activations of SMA and M1, and a

delay of nearly 1.3 s between the activations of M1 and its draining vein. The new

combination of fMRI and data analysis techniques has attained a time resolution

comparable to those in preceding studies that used shorter fMRI repetition times

of 100-200 ms.

152. Karrer, J. H.; Karrer, R.; Bloom, D.; Chaney, L.; Davis, R. Event-related brain

potentials during an extended visual recognition memory task depict delayed

development of cerebral inhibitory processes among 6-month-old infants with

Down syndrome. Int-J-Psychophysiol. 1998 Jul; 29(2): 167-200; ISSN: 0167-

8760.

NETHERLANDS. Development of cerebral inhibitory processes among

individuals with Down syndrome (DS) may be delayed at an early age. In support

of this hypothesis, sensory-evoked potentials (EPs) and event-related brain

potentials (ERPs) have previously delineated altered habituation to stimuli among

infants with DS. The purpose of the current study was to provide extended

experience with visual stimuli among 6-month-old infants with and without DS

(nDS) to determine if altered ERP and behavioral response decrements would be

evident even after repeated presentations of stimuli. An 80/20% oddball paradigm

was employed. Infants with DS and nDS were matched according to age and

gender. Infants with DS demonstrated significantly larger Nc areas, Nc peak

amplitudes, Nc2 areas and, inversely, significantly smaller peak Pb amplitudes

when compared to infants nDS. Contrasts of the two study groups were most

robust within ERP measures from frontal (Fz) and parietal (Pz) recording sites.

Infants with DS also demonstrated a significantly slower decrement of most ERP

components with repetitive stimulus experience. Most noteworthy was the

observation of little or no decrement of ERP components at Fz among infants

with DS. Both infants with DS and nDS demonstrated significantly larger Nc peak

amplitudes, Nc areas, Nc2 areas, Pb peak amplitudes and NSW areas to rare

stimuli. While significant probability and experiential trends were observed in

visual fixation measures across both study groups, there were no significant

differences of visual attention between infants with DS or nDS. These data

demonstrate the value of ERPs within the study of atypical cognitive

development during infancy and support the concept of altered inhibitory

processes in the brain of infants with DS.

153. Katayama, Y.; Fukaya, C.; Yamamoto, T. Poststroke pain control by chronic motor

cortex stimulation: neurological characteristics predicting a favorable response. J-

Neurosurg. 1998 Oct; 89(4): 585-91; ISSN: 0022-3085.

UNITED-STATES. OBJECT: The goal of this study was to identify the

neurological characteristics of patients with poststroke pain who show a favorable

response to motor cortex (MC) stimulation used to control their pain.

METHODS: The neurological characteristics of 31 patients treated by MC

stimulation were analyzed. In 15 patients (48%), excellent or good pain control

(pain reduction > 60%) was achieved for follow-up periods of more than 2 years

by using MC stimulation at intensities below the threshold for muscle

contraction. Satisfactory pain control was achieved in 13 (73%) of 18 patients in

whom motor weakness in the painful area was virtually absent or mild, but in

only two (15%) of the 13 patients who demonstrated moderate or severe

weakness in the painful area (p < 0.01). Muscle contraction was inducible in the

painful area in 20 patients when stimulated at a higher intensity. No such muscle

response was inducible in the remaining 11 patients, no matter how extensively

the authors attempted to determine appropriate stimulation sites. Satisfactory

pain control was achieved in 14 (70%) of the 20 patients in whom muscle

contraction was inducible, but in only one (9%) of the 11 patients in whom

muscle contraction was not inducible (p < 0.01). No significant relationship was

observed between pain control and various sensory symptoms, including the

presence of hypesthesia, spontaneous dysesthesia, hyperpathia, and allodynia, or

the disappearance of the N20 component of the median nerve-evoked

somatosensory scalp potential. No significant relationship existed between the

effect of MC stimulation on the pain and stimulation-induced phenomena,

including paresthesia, improvement in motor performance, and attenuation of

involuntary movements. CONCLUSION: These findings suggest that the pain

control afforded by MC stimulation requires neuronal circuits that are maintained

by the presence of intact corticospinal tract neurons originating from the MC.

Preoperative evaluation of motor weakness of the painful area appears to be

useful for predicting a favorable response to MC stimulation in the control of

poststroke pain.

154. Katayama, Y.; Fukaya, C.; Yamamoto, T. Poststroke pain control by chronic motor

cortex stimulation: neurological characteristics predicting a favorable response. J-

Neurosurg. 1998 Oct; 89(4): 585-91; ISSN: 0022-3085.

UNITED-STATES. OBJECT: The goal of this study was to identify the

neurological characteristics of patients with poststroke pain who show a favorable

response to motor cortex (MC) stimulation used to control their pain.

METHODS: The neurological characteristics of 31 patients treated by MC

stimulation were analyzed. In 15 patients (48%), excellent or good pain control

(pain reduction > 60%) was achieved for follow-up periods of more than 2 years

by using MC stimulation at intensities below the threshold for muscle

contraction. Satisfactory pain control was achieved in 13 (73%) of 18 patients in

whom motor weakness in the painful area was virtually absent or mild, but in

only two (15%) of the 13 patients who demonstrated moderate or severe

weakness in the painful area (p < 0.01). Muscle contraction was inducible in the

painful area in 20 patients when stimulated at a higher intensity. No such muscle

response was inducible in the remaining 11 patients, no matter how extensively

the authors attempted to determine appropriate stimulation sites. Satisfactory

pain control was achieved in 14 (70%) of the 20 patients in whom muscle

contraction was inducible, but in only one (9%) of the 11 patients in whom

muscle contraction was not inducible (p < 0.01). No significant relationship was

observed between pain control and various sensory symptoms, including the

presence of hypesthesia, spontaneous dysesthesia, hyperpathia, and allodynia, or

the disappearance of the N20 component of the median nerve-evoked

somatosensory scalp potential. No significant relationship existed between the

effect of MC stimulation on the pain and stimulation-induced phenomena,

including paresthesia, improvement in motor performance, and attenuation of

involuntary movements. CONCLUSION: These findings suggest that the pain

control afforded by MC stimulation requires neuronal circuits that are maintained

by the presence of intact corticospinal tract neurons originating from the MC.

Preoperative evaluation of motor weakness of the painful area appears to be

useful for predicting a favorable response to MC stimulation in the control of

poststroke pain.

155. Kawaguchi, M.; Inoue, S.; Kakimoto, M.; Kitaguchi, K.; Furuya, H.; Morimoto, T.;

Sakaki, T. The effect of sevoflurane on myogenic motor-evoked potentials

induced by single and paired transcranial electrical stimulation of the motor cortex

during nitrous oxide/ketamine/fentanyl anesthesia. J-Neurosurg-Anesthesiol. 1998

Jul; 10(3): 131-6; ISSN: 0898-4921.

UNITED-STATES. To overcome anesthetic-induced depression of myogenic

motor-evoked potentials (MEPs), several techniques of stimulation using paired

pulses or trains of pulses are used. This study investigated the effect of

sevoflurane on myogenic MEPs induced by single and paired transcranial electrical

stimulation of the motor cortex. Nine patients undergoing elective spinal surgery

were anesthetized with fentanyl-N2O-ketamine. Partial neuromuscular blockade

(single-twitch height 15% of baseline) was maintained with vecuronium. Single

and paired (interstimulus interval 2 milliseconds) electrical stimuli were delivered

to the scalp, and compound muscle action potentials were recorded from the left

and right tibialis anterior muscles. In all patients, baseline MEPs were recorded

from both the left and right anterior tibialis muscles (in a total of 18 legs). During

the administration of 0.25 MAC and 0.5 MAC sevoflurane, MEPs induced by

stimulation with a single pulse could be recorded in 12 of 18 and 4 of 18 legs,

respectively, and MEP amplitude was significantly reduced to 48% and 4% of the

control value, respectively. During the administration of 0.75 MAC sevoflurane,

MEPs following single-pulse stimulation could not be recorded in any legs. The

success rate of MEP recording during the administration of sevoflurane was

greater after paired stimulation than after single stimulation, and percentage MEP

amplitude (percentage of the control value after single stimulation but before

sevoflurane) after paired stimulation was significantly higher than after single

stimulation before and during the administration of 0.25 MAC and 0.5 MAC

sevoflurane. The success rate of MEP recording and MEP amplitude after paired

stimulation decreased in a dose-dependent manner during the administration of

sevoflurane. These results suggest that although facilitation by the second

stimulus was considerable, paired stimuli are still not sufficient to overcome the

depressant effects of sevoflurane in clinically used concentrations.. 0; 0; 0; 0; 0;

10024-97-2; 28523-86-6; 437-38-7; 50700-72-6; 6740-88-1.

156. Kawaguchi, M.; Inoue, S.; Kakimoto, M.; Kitaguchi, K.; Furuya, H.; Morimoto, T.;

Sakaki, T. The effect of sevoflurane on myogenic motor-evoked potentials

induced by single and paired transcranial electrical stimulation of the motor cortex

during nitrous oxide/ketamine/fentanyl anesthesia. J-Neurosurg-Anesthesiol. 1998

Jul; 10(3): 131-6; ISSN: 0898-4921.

UNITED-STATES. To overcome anesthetic-induced depression of myogenic

motor-evoked potentials (MEPs), several techniques of stimulation using paired

pulses or trains of pulses are used. This study investigated the effect of

sevoflurane on myogenic MEPs induced by single and paired transcranial electrical

stimulation of the motor cortex. Nine patients undergoing elective spinal surgery

were anesthetized with fentanyl-N2O-ketamine. Partial neuromuscular blockade

(single-twitch height 15% of baseline) was maintained with vecuronium. Single

and paired (interstimulus interval 2 milliseconds) electrical stimuli were delivered

to the scalp, and compound muscle action potentials were recorded from the left

and right tibialis anterior muscles. In all patients, baseline MEPs were recorded

from both the left and right anterior tibialis muscles (in a total of 18 legs). During

the administration of 0.25 MAC and 0.5 MAC sevoflurane, MEPs induced by

stimulation with a single pulse could be recorded in 12 of 18 and 4 of 18 legs,

respectively, and MEP amplitude was significantly reduced to 48% and 4% of the

control value, respectively. During the administration of 0.75 MAC sevoflurane,

MEPs following single-pulse stimulation could not be recorded in any legs. The

success rate of MEP recording during the administration of sevoflurane was

greater after paired stimulation than after single stimulation, and percentage MEP

amplitude (percentage of the control value after single stimulation but before

sevoflurane) after paired stimulation was significantly higher than after single

stimulation before and during the administration of 0.25 MAC and 0.5 MAC

sevoflurane. The success rate of MEP recording and MEP amplitude after paired

stimulation decreased in a dose-dependent manner during the administration of

sevoflurane. These results suggest that although facilitation by the second

stimulus was considerable, paired stimuli are still not sufficient to overcome the

depressant effects of sevoflurane in clinically used concentrations.. 0; 0; 0; 0; 0;

10024-97-2; 28523-86-6; 437-38-7; 50700-72-6; 6740-88-1.

157. Kawashima, R.; Matsumura, M.; Sadato, N.; Naito, E.; Waki, A.; Nakamura, S.;

Matsunami, K.; Fukuda, H.; Yonekura, Y. Regional cerebral blood flow changes in

human brain related to ipsilateral and contralateral complex hand movements--a

PET study. Eur-J-Neurosci. 1998 Jul; 10(7): 2254-60; ISSN: 0953-816X.

FRANCE. The purpose of this study was to investigate the cortical motor areas

activated in relation to unilateral complex hand movements of either hand, and the

motor area related to motor skill learning. Regional cerebral blood flow (rCBF)

was measured in eight right-handed healthy male volunteers using positron

emission tomography during a two-ball-rotation task using the right hand, the

same task using the left hand and two control tasks. In the two-ball-rotation tasks,

subjects were required to rotate the same two iron balls either with the right or left

hand. In the control task, they were required to hold two balls in each hand

without movement. The primary motor area, premotor area and cerebellum were

activated bilaterally with each unilateral hand movement. In contrast, the

supplementary motor area proper was activated only by contralateral hand

movements. In addition, we found a positive correlation between the rCBF to the

premotor area and the degree of improvement in skill during motor task training.

The results indicate that complex hand movements are organized bilaterally in the

primary motor areas, premotor areas and cerebellum, that functional asymmetry

in the motor cortices is not evident during complex finger movements, and that the

premotor area may play an important role in motor skill learning.

158. Kendrick, F.; Wilson, S.; Coury, D. L.; Preisch, J. W. Comparison of temperaments

of children with and without baby bottle tooth decay. ASDC-J-Dent-Child. 1998

May; 65(3): 198-203; ISSN: 0022-0353.

UNITED-STATES. Several demographic studies have been done to identify

children at risk for Baby Bottle Tooth Decay (BBTD). Discussions have

described these children with Baby Bottle Tooth Decay as strong tempered,

cranky, restless, and fussy. The parents of these children have acknowledged

these behaviors. To determine whether there were differences in temperament,

children with Baby Bottle Tooth Decay were compared with children without

Baby Bottle Tooth Decay by assessing the nine temperament components

described by the Toddler Temperament Scale (TTS) questionnaire. Parents

completed the temperament questionnaire and ninety-two children between

twelve and thirty-six months old were studied. Scores for the nine temperament

components were tabulated and temperament difficulty was determined as defined

by the authors of the toddler Temperament Scale. At-test comparison between

the two groups revealed no significant difference for the nine temperament

components. There was also no difference when comparing clusters of the nine

components. The conclusion is that there is no difference in the temperaments

between the group of children with Baby Bottle Tooth Decay and the comparison

group of children without Baby Bottle Tooth Decay.

159. Kerschan, K.; Alacamlioglu, Y.; Kollmitzer, J.; Wober, C.; Kaider, A.; Hartard, M.;

Ghanem, A. H.; Preisinger, E. Functional impact of unvarying exercise program in

women after menopause. Am-J-Phys-Med-Rehabil. 1998 Jul; 77(4): 326-32;

ISSN: 0894-9115.

UNITED-STATES. Low bone mass, functional impairment, low muscle strength,

and postural instability are predictors of the risk of fracture in an elderly person.

The purpose of this study was to investigate the functional impact of an

unvarying long-term exercise program to be carried out at home. The exercises had

been shown to delay bone loss in an elderly population. At the Department of

Physical Medicine and Rehabilitation, University of Vienna, postmenopausal

women who had been stratified into exercise or control groups 5 to 10 yr ago were

called in for a follow-up examination. Frequency of training, habits, and pain

causing disability in activities of daily living were recorded. Walking velocity,

muscle strength, and postural stability were measured. Functional assessment,

blood analysis, and x-rays of the spine were performed additionally. One hundred

twenty-four women aged 68.3 +/- 6.8 yr (mean +/- SD) underwent a follow-up

investigation at the outpatient clinic. After 7.7 +/- 1.1 yr the compliance of the

training group was still 36%. Self-chosen gait velocity was slightly higher in the

regular exercisers than in the controls. No intergroup differences were found for

pain induced disability, muscle strength, body sway, and fracture rate. The pain

disability index was significantly associated with corrected self-chosen gait

velocity. The results suggest that an unvarying home-based exercise program may

support general agility but does not yield enough force to improve muscle

strength and postural stability in healthy, nondisabled, postmenopausal women

who start exercising at the age of 60 yr. Further studies are needed to define more

appropriate exercise programs for a comprehensive improvement of functional

outcome in a population at high risk for osteoporosis.

160. Kirkby, R. E.; Ker, J. A. Exercise-induced asthma in a group of South African

schoolchildren during physical education classes. S-Afr-Med-J. 1998 Feb; 88(2):

136-8; ISSN: 0038-2469.

SOUTH-AFRICA. OBJECTIVES: The study was conducted to ascertain

whether physical education teachers, using a peak flow meter, could reliably

screen for exercise-induced asthma (EIA) in children during free running. DESIGN,

SETTING AND SUBJECTS: The study was conducted using a convenience

sample of male pupils between the ages of 12 and 18 years. They were tested

with a peak flow meter for peak expiratory flow rate (PEFR) and with a flow-

volume curve for forced expiratory flow in 1 second (FEV1) before and 10

minutes after a self-paced free running test during physical education classes.

Testing was undertaken by teachers using the peak flow meter and by a medical

doctor using a flow-volume curve. RESULTS: Using a 10% decrease in flow

parameters (PEFR and FEV1), teachers detected EIA in 14.9% of pupils and the

doctor detected EIA in 21.7% of pupils. CONCLUSION: We conclude that EIA

is common and that teachers using a peak flow meter can detect EIA and thus

screen for it; they do, however, underestimate the true magnitude of the problem.

161. Klainguti, G.; Strickler, J.; Presset, C. [Surgical treatment of accommodative

convergence access esotropia. Study of 50 operated cases]. Traitement chirurgical

de l'exces de convergence accommodative. Etude de 50 cas operes. Klin-Monatsbl-

Augenheilkd. 1998 May; 212(5): 291-3; ISSN: 0023-2165.

GERMANY. BACKGROUND: Convergence excess esotropia (EC) can be an

additional component in all forms of strabismus. The most favourable prognosis is

found in those cases where EC is associated with microtropia or bifoveal fusion,

due to a better binocular potential. METHODS: 50 non selected cases were

entered into the study and divided into two groups (Group A: EC with

microtropia; Group B: EC with bifoveal fusion). All the patients were followed at

the Lausanne Strabismus Unit and all cases underwent a bilateral medial rectus

posterior fixation (Cuppers' Faden operation) placed at 13 mm from the original

insertion. RESULTS: In Group A, the average reduction of angle of strabismus

was 25 delta for near fixation, 20 delta in Group B. In both groups, the average

decrease in angle for distance fixation was 6 delta. In Group A, 75% of cases

gained some binocularity post-operatively, not only for distance but also for near

fixation. In Group B, all the patients showed a normal response on the Lang

stereotest post-operatively. CONCLUSIONS: In both groups of this study, a

bilateral medial rectus retroequatorial myopexy was a satisfactory alternative for

those patients who refused to wear bifocal glasses.

162. Kleim, J. A.; Swain, R. A.; Armstrong, K. A.; Napper, R. M.; Jones, T. A.;

Greenough, W. T. Selective synaptic plasticity within the cerebellar cortex

following complex motor skill learning. Neurobiol-Learn-Mem. 1998 May; 69(3):

274-89; ISSN: 1074-7427.

UNITED-STATES. Complex motor skill learning, but not mere motor activity,

leads to an increase in synapse number within the cerebellar cortex. The present

experiment used quantitative electron microscopy to determine which synapse

types were altered in number. Adult female rats were allocated to either an

acrobatic condition (AC), a voluntary exercise condition (VX), or an inactive

condition (IC). AC animals were trained to traverse an elevated obstacle course

requiring substantial motor coordination to complete. VX animals were housed

with unlimited access to running wheels and IC animals received no motor training

but were handled briefly each day. Results showed the AC animals to have

significantly more parallel fiber to Purkinje cell synapses than both the VX and IC

animals. No other synapse type was significantly altered. Thus, the learning-

dependent increase in synapse number observed within the cerebellar cortex is

accomplished primarily through the addition of parallel fiber synapses. Copyright

1998 Academic Press.

163. Klintsova, A. Y.; Cowell, R. M.; Swain, R. A.; Napper, R. M.; Goodlett, C. R.;

Greenough, W. T. Therapeutic effects of complex motor training on motor

performance deficits induced by neonatal binge-like alcohol exposure in rats . I.

Behavioral results. Brain-Res. 1998 Jul 27; 800(1): 48-61; ISSN: 0006-8993.

NETHERLANDS. The effects of complex motor task learning on subsequent

motor performance of adult rats exposed to alcohol on postnatal days 4 through 9

were studied. Male and female Long-Evans rats were assigned to one of three

treatments: (1) alcohol exposure (AE) via artificial rearing to 4.5.g kg-1 day-1 of

ethanol in a binge-like manner (two consecutive feedings), (2) gastrostomy control

(GC) fed isocaloric milk formula via artificial rearing, and (3) suckling control

(SC), where pups remained with lactating dams. After completion of the

treatments, the pups were fostered back to lactating dams, and after weaning they

were raised in standard cages (two-three animals per cage) until they were 6

months old. Rats from each of the postnatal treatments then spent 20 days in one

of three conditions: (1) inactive condition (IC), (2) motor control condition (MC)

(running on a flat oval track), or (3) rehabilitation condition (RC) (learning to

traverse a set of 10 elevated obstacles). After that all the animals were tested on

three tasks, sensitive to balance and coordination deficits (parallel bars, rope

climbing and traversing a rotating rod). On parallel bars, both male and female rats

demonstrated the same pattern of outcomes: AE-IC rats made significantly more

mistakes (slips and falls) than IC rats from both control groups. After 20 days of

training in the RC condition, there were no differences between AE and both SC

and GC animals in their ability to perform on the parallel bars test. On rope

climbing, female animals showed a similar pattern of abilities: AE-IC rats were the

worst group; exercising did not significantly improve the AE rats' ability to climb,

whereas the RC groups (SC, GC and AE) all performed near asymptote and there

were no significant differences among three neonatal treatment groups. There was

a substantial effect of the male rats' heavier body weight on climbing ability, and

this may have prevented the deficits in AE rats behavior from being detected.

Nevertheless, male animals from all three postnatal treatments (SC, GC and AE)

were significantly better on this task after RC. Female and male rats from all three

postnatal groups demonstrated significantly better performance on the rotarod

task after 20 days of 'rehabilitation'. These results suggest that complex motor

skill learning improves some of the motor performance deficits produced by

postnatal exposure to alcohol and can potentially serve as a model for

rehabilitative intervention. Copyright 1998 Elsevier Science B.V. All rights

reserved.. 64-17-5.

164. Kobayashi, Y.; Kawano, K.; Takemura, A.; Inoue, Y.; Kitama, T.; Gomi, H.; Kawato,

M. Temporal firing patterns of Purkinje cells in the cerebellar ventral

paraflocculus during ocular following responses in monkeys II. Complex spikes.

J-Neurophysiol. 1998 Aug; 80(2): 832-48; ISSN: 0022-3077.

UNITED-STATES. Many theories of cerebellar motor learning propose that

complex spikes (CS) provide essential error signals for learning and modulate

parallel fiber inputs that generate simple spikes (SS). These theories, however, do

not satisfactorily specify what modality is represented by CS or how information

is conveyed by the ultra-low CS firing rate (1 Hz). To further examine the

function of CS and the relationship between CS and SS in the cerebellum, CS and

SS were recorded in the ventral paraflocculus (VPFL) of awake monkeys during

ocular following responses (OFR). In addition, a new statistical method using a

generalized linear model of firing probability based on a binomial distribution of

the spike count was developed for analysis of the ultra-low CS firing rate. The

results of the present study showed that the spatial coordinates of CS were

aligned with those of SS and the speed-tuning properties of CS and SS were more

linear for eye movement than retinal slip velocity, indicating that CS contain a

motor component in addition to the sensory component identified in previous

studies. The generalized linear model to reproduce firing probability confirmed

these results, demonstrating that CS conveyed high-frequency information with

its ultra-low firing frequency and conveyed both sensory and motor information.

Although the temporal patterns of the CS were similar to those of the SS when

the sign was reversed and magnitude was amplified approximately 50 times, the

velocity/acceleration coefficient ratio of the eye movement model, an aspect of the

CS temporal firing profile, was less than that of the SS, suggesting that CS were

more sensory in nature than SS. A cross-correlation analysis of SS that are

triggered by CS revealed that short-term modulation, that is, the brief pause in SS

caused by CS, does not account for the reciprocal modulation of SS and CS. The

results also showed that three major aspects of the CS and SS individual cell firing

characteristics were negatively correlated on a cell-to-cell basis: the preferred

direction of stimulus motion, the mean percent change in firing rate induced by

upward stimulus motion, and patterns of temporal firing probability. These

results suggest that CS may contribute to long-term interactions between parallel

and climbing fiber inputs, such as long-term depression and/or potentiation.

165. Kral, K. Spatial vision in the course of an insect's life. Brain-Behav-Evol. 1998; 52(1):

1-6; ISSN: 0006-8977.

SWITZERLAND. Praying mantises are considered to be phylogenetically ancient

insects with their roots in the palaeozoic Protoblattoidea. They have evolved two

mechanisms for spatial vision: (a) estimating the distance to moving prey objects

with the use of binocular disparity [Rossel, 1983] and (b) estimating the distance

to stationary target objects with motion parallax produced by head movements

[Poteser and Kral, 1995]. There is no doubt that the ability to use both visual cues

is congenital, but the degree to which either mechanism is developed and its

significance to the individual depends to some extent upon the animal's age and

exposure to prey species and environmental cues. Experience and learning play an

important role. It appears that young mantises can perform both binocular and

monocular calculations of distance but they grow to depend more on the binocular

mechanism. Motion parallax plays an important role in movement strategy

throughout the course of a mantis's life, but this mechanism appears to be

particularly in early life.

166. Krings, T.; Naujokat, C.; von Keyserlingk, D. G. Representation of cortical motor

function as revealed by stereotactic transcranial magnetic stimulation.

Electroencephalogr-Clin-Neurophysiol. 1998 Apr; 109(2): 85-93; ISSN: 0013-

4694.

IRELAND. Cortical motor representation of 12 muscles of the trunk and the

upper and lower extremity was investigated in 18 healthy subjects using focal

transcranial magnetic stimulation (TMS) in conjunction with a frameless

stereotactic system (FSS). This combination allowed us to orientate stimulation

sites to the individual central sulcus rather than to bony landmarks. Distinct but

overlapping areas of muscle representation were identified and the 3-dimensional

representation of those 12 muscles along the course of the central sulcus was

obtained. With increasing stimulus intensity, the cortical output maps changed in

that more muscles became excitable, motor evoked potential (MEP) amplitude and

size of the responsive area increased and latency of the MEP decreased. These

effects were more pronounced for proximal than for distal muscles, indicating a

more widespread organization of corticospinal motor projection related to

proximal muscles. The combination of TMS and FSS represents a method with

which functional information can be directly related to underlying cortical

anatomy. This correlation will be useful in the assessment of higher brain

functions with TMS.

167. Krings, T.; Reul, J.; Spetzger, U.; Klusmann, A.; Roessler, F.; Gilsbach, J. M.; Thron,

A. Functional magnetic resonance mapping of sensory motor cortex for image-

guided neurosurgical intervention. Acta-Neurochir-Wien. 1998; 140(3): 215-22;

ISSN: 0001-6268.

AUSTRIA. PURPOSE: This paper describes the potentials of functional

magnetic resonance imaging (fMRI) to map sensory motor cortex in patients with

mass lesions near primary motor cortex and to guide neurosurgical procedures

located close to eloquent brain regions. MATERIAL AND METHODS: 7

patients with mass lesions near the central sulcus and 10 healthy volunteers were

studied using a blood oxygenation level dependent 2D multislice multishot T2*

weighted gradient echo EPI sequence on a 1.5T Phillips Gyroscan during

alternating epochs of rest and motor activation of hand, foot and tongue. Sites of

neuronal activation were identified by statistical analysis of the signal time course

using Kolmogorov Smirnov statistics. RESULTS: Neuronal activation following

motor tasks consistently localised to the contralateral precentral gyrus and the

supplementary motor area, even in the presence of local brain pathology.

Additionally we could observe activation in primary sensory areas (post-central

gyrus) and supplementary motor area (SMA) in some cases. CONCLUSION:

fMRI is capable of mapping sensory motor cortex even in the presence of

distorting brain lesions. Since this information will provide valuable information to

the neurosurgeon during pre-operative planning, we consider this method for

neurosurgical navigation a valuable tool in the routine diagnostic of intracerebral

interventions.

168. Krommenhoek, K. P.; Wiegerinck, W. A. A neural network study of precollicular

saccadic averaging. Biol-Cybern. 1998 Jun; 78(6): 465-77; ISSN: 0340-1200.

GERMANY. Saccadic averaging is the phenomenon that two simultaneously

presented retinal inputs result in a saccade with an endpoint located on an

intermediate position between the two stimuli. Recordings from neurons in the

deeper layers of the superior colliculus have revealed neural correlates of saccade

averaging, indicating that it takes place at this level or upstream. Recently, we

proposed a neural network for internal feedback in saccades. This neural network

model is different from other models in that it suggests the possibility that

averaging takes place in a stage upstream of the colliculus. The network consists

of output units representing the neural map of the deeper layers of the superior

colliculus and hidden layers imitating areas in the posterior parietal cortex. The

deeper layers of the superior colliculus represent the motor error of a desired

saccade, e.g. an eye movement to a visual target. In this article we show that

averaging is an emergent property of the proposed network. When two retinal

targets with different intensities are simultaneously presented to the network, the

activity in the output layer represents a single motor error with a weighted

average value. Our goal is to understand the mechanism of weighted averaging in

this neural network. It appears that averaging in the model is caused by the linear

dependence of the net input, received by the hidden units, on retinal error,

independent of its retinal coding format. For nonnormalized retinal error inputs,

also the nonlinearity between the net input and the activity of the hidden units

plays a role in the averaging process. The averaging properties of the model are in

agreement with physiological experiments if the hypothetical retinal error input

map is normalized. The neural network predicts that if this normalization is

overruled by electrical stimulation, averaging still takes place. However, in this

case--as a consequence of the feedback task--the location of the resulting saccade

depends on the initial eye position and the total intensity/current applied at the

two locations. This could be a way to verify the neural network model. If the

assumptions for the model are valid, a physiological implication of this paper is

that averaging of saccades takes place upstream of the superior colliculus.

169. Kurokawa, K.; Tanaka, E.; Yamashita, H.; Kohriyama, T.; Mimori, Y.; Nakamura, S.

Ratios of nerve conduction parameters in proximal to distal limbs remain constant

through the second to the eighth decades. Electromyogr-Clin-Neurophysiol. 1998

Apr; 38(3): 169-76; ISSN: 0301-150X.

BELGIUM. We investigated the effect of age on nerve conduction parameters to

establish a diagnostic validity in demyelinating neuropathies of the aged. We

evaluated 257 subjects (age 10-76 years old) with no history or signs of peripheral

neuropathies. The CMAP amplitude ratio (proximal CMAP/distal CMAP),

duration ratio, and area ratio were almost the same throughout the second to

eighth decades. The respective lower limits of the normal CMAP amplitude ratio

(mean-3 SD) were 0.79 (median nerve), 0.75 (ulnar nerve), 0.57 (peroneal nerve),

and 0.45 (tibial nerve). The upper limits of the normal CMAP duration ratio

(mean +3 SD) were 1.21 (median nerve), 1.22 (ulnar nerve), 1.37 (peroneal nerve),

and 1.35 (tibial nerve). The lower limits of the normal CMAP area ratio (mean-3

SD) were 0.81 (median nerve), 0.78 (ulnar nerve), 0.60 (peroneal nerve), and 0.57

(tibial nerve). No age-related changes were observed in the amplitude ratio or

duration ratio SNAP, although the standard deviation increased with age. Since the

amplitude, duration and area ratios are easily calculated and age-independent, they

can provide useful and reliable information on aged patients with demyelinating

neuropathies by conventional nerve conduction studies.

170. Lagueny, A.; Le Masson, G.; Burbeaud, P.; Deliac, P. Single fibre electromyography

in multifocal motor neuropathy with persistent conduction blocks. J-Neurol-

Neurosurg-Psychiatry. 1998 Sep; 65(3): 357-61; ISSN: 0022-3050.

ENGLAND. OBJECTIVE: To study the process of denervation-reinnervation in

multifocal motor neuropathy with persistent conduction blocks in clinically

affected and unaffected muscles. METHOD: Volitional single fibre

electromyography (SFEMG) was performed in the extensor digitorum communis

(EDC) of seven patients. The jitter, the fibre density, and the mean interpotential

interval were determined. The results before and after treatment with intravenous

immunoglobulin (IVIg) between the unaffected EDC and affected EDC examined

during the same SFEMG session were also compared. In addition the values of

jitter, fibre density, and mean interpotential interval were analysed for correlation

with the strength score on the MRC scale, the duration of the neuropathy, the

number of IVIg treatment periods, and the radial nerve conduction block values.

RESULTS: Mean jitter, percentage of jitters >60 micros, and impulse blocking

percentage, were higher than normal in both the affected EDCs and to a lesser

degree in unaffected EDCs. Jitter decreased significantly after IVIg and correlated

only with the MRC score. Fibre density and mean interpotential interval were

higher than normal equally in the affected EDC and unaffected EDCs, but no

correlation was found with strength, duration of the neuropathy, number of

treatment periods, and conduction block values. CONCLUSION: The major

finding is the presence of SFEMG abnormalities in clinically unaffected EDCs.

This shows a process of denervation-reinnervation even in the absence of clinical

symptoms, probably more frequent than commonly supposed in this neuropathy.

The rapid clinical improvement after IVIg infusions could be due to remyelination

after demyelination and to an interference of IVIg with the blocking effect of

antibodies on the Na+ channels at the motor nerve endings.

171. Lange Kuttner, C. Pressure, velocity, and time in speeded drawing of basic graphic

patterns by young children. Percept-Mot-Skills. 1998 Jun; 86(3 Pt 2): 1299-310;

ISSN: 0031-5125.

UNITED-STATES. Bender Gestalt cards of Pascal and Suttel, simplified by the

author, and basic graphic patterns used in neuropsychological assessment by Mai

and Marquardt were used in a speeded copying task. Children between 4 and 6

years were drawing with a wireless pen on a pressure-sensitive graphic tablet

linked to a computer. Hand pressure, velocity of hand movements, drawing time

and penlifts were measured by a CS handwriting analyses software package.

Planned comparisons were carried out between developmentally earlier emerging

graphic forms and patterns that are mastered later in development. It was shown

that for 6-yr.-olds pressure was increased which might indicate a generally higher

tension when drawing. Specifically, angular forms were copied with more

pressure, but needed less drawing time than round forms. Moreover, children

needed more time for penlifts to adjust for a starting point that changed from left

to right when drawing vertical lines than horizontal ones. Reduced speed of

drawing was more important when copying open forms than closed shapes. In

denotation of spatial position no differences were found. It is concluded that the

analysis of psychophysical measures of drawing gives important clues about the

specific problems produced by relatively basic graphic patterns.

172. Laufer, Y.; Hocherman, S. Visual and kinesthetic control of goal-directed movements

to visually and kinesthetically presented targets. Percept-Mot-Skills. 1998 Jun;

86(3 Pt 2): 1375-91; ISSN: 0031-5125.

UNITED-STATES. The study investigated the contribution of kinesthetic and

visual input to the performance of reaching movements and identified rules

governing the transformation of information between these two sensory

modalities. The study examined the accuracy by which 39 subjects reproduced

locations of five targets in a horizontal plane. Mode of target presentation and

feedback during reproduction of a target's location was either visual, kinesthetic or

a combination of both modalities. Thus, it was possible to examine performance

when target presentation and reproduction involved feedback from the same

sensory modality (intramodal) as well as from different sensory modalities

(intermodal). Errors in target reproduction were calculated in terms of distance and

systematic biases in movement extent. The major findings of the study are (1)

Intramodal reproduction of a target's location on the basis of kinesthetic feedback

is somewhat less accurate than intramodal reproduction on the basis of visual

feedback (2) Intermodal performance is significantly less accurate than intramodal

performance. (3) Accuracy of performance does not depend on the direction of

information transfer between sensory modalities. (4) Intermodal performance is

characterized by systematic biases in extent of movement which are dependent on

the direction of information transfer between modalities. (5) When presentation of

the target's location is bimodal, reproduction is adversely affected by the

conflicting input. The results suggest that transformation rules, used to combine

input from various sensory modalities, depend on environmental conditions and

attention.

173. Lax, P.; Zamora, S.; Madrid, J. A. Coupling effect of locomotor activity on the rat's

circadian system. Am-J-Physiol. 1998 Aug; 275(2 Pt 2): R580-7; ISSN: 0002-

9513.

UNITED-STATES. Exercise is recognized to affect circadian rhythmicity in a

variety of ways. It masks the expression of other behavioral and physiological

rhythms, entrains the master pacemaker, and influences the free-running period of

other rhythms. In this paper we study the influence of exercise on the

organization of the timing system by analyzing the effect of voluntary locomotor

activity on the circadian feeding behavior of rats subjected to different lighting

conditions. The availability of wheel running prevented loss of feeding circadian

rhythmicity under constant bright light (LL) but did not elicit any circadian

pattern in rats showing a previous arrhythmic pattern. Under dim red light (DR),

the rhythm was more pronounced in exercising than in sedentary rats, while

wheel-running availability accelerated the emergence of circadian rhythmicity in

arrhythmic animals that were moved from LL to DR. These results can be

explained by the existence of a positive feedback loop between physical exercise

and its pacemaker and also suggest that exercise changes the functioning of the

circadian system to facilitate the emergence of circadian rhythms in previously

arrhythmic animals.

174. Layne, J. E. Retinal location is the key to identifying predators in fiddler crabs (Uca

pugilator). J-Exp-Biol. 1998 Aug; 201( Pt 15): 2253-61; ISSN: 0022-0949.

ENGLAND. Fiddler crabs (Uca pugilator Bosc; Crustacea, Decapoda) feed and

court in open, flat spaces. Their visual system has several putative adaptations to

their flat habitat, including the tendency to keep the vertical axis of their eyes

perpendicular to the plane of the substratum. It is hypothesized that one of the

functions of this behavior is to distinguish accurately predators from conspecifics

by aligning the region of the eye sensitive to predators with the region in space in

which predators occur. To test this hypothesis, a crab was placed in a glass dish,

and a moving stimulus was presented between 20 degrees above and below eye

level (horizontal). Stimuli below the crab's horizon hardly ever evoked escape

responses, while identical stimuli above the horizon produced escape responses

whose frequency varied with the angular size, not the absolute size, of the

stimulus. Experiments with artificial horizons showed that it is the position of the

stimulus relative to the eye that is important, rather than its position relative to

external cues such as the visible horizon, the vertical light gradient or the

gravitational horizon. It is concluded that a crab responds to stimuli according to

their position relative to its retinal equator. This conclusion is discussed in light of

the crabs' natural behavior with respect to supra-horizontal stimuli.

175. Lehmann, A.; Tritten, J. J.; Hamel, M. [Asthenopic symptoms in cervical vertebrae

syndrome]. Troubles asthenopiques au cours du syndrome vertebral cervical

(SVC). Klin-Monatsbl-Augenheilkd. 1998 May; 212(5): 294-5; ISSN: 0023-2165.

GERMANY. The vertebral cervical syndrome is a clinical entity defined as a

dysfunction of the cranio-cervical junction of traumatic or non traumatic cause.

The authors report on asthenopic disorders occurring in such a syndrome. The

fusion amplitude and the accommodation power were reduced in all patients and

were a cause of delayed job recurrence. The treatment of fusion was long, painful

and, in some cases, not successful. A depressive status associated with a

prolonged job interruption were bad prognosis factors. A differential diagnosis has

to be made with the so-called insurance neurotic reaction.

176. Leis, A. A. Cutaneous silent period [editorial; comment]. Muscle-Nerve. 1998 Oct;

21(10): 1243-5; ISSN: 0148-639X.

Note: Comment on: Muscle Nerve 1998 Oct;21(10):1256-64.

UNITED-STATES.

177. Lengyel, D.; Weinacht, S.; Charlier, J.; Gottlob, I. The development of visual pursuit

during the first months of life. Graefes-Arch-Clin-Exp-Ophthalmol. 1998 Jun;

236(6): 440-4; ISSN: 0721-832X.

GERMANY. BACKGROUND: There are few previous investigations of

smooth pursuit in infants. The aim of our study was to quantify visual pursuit in

infants between 1 day and 16 weeks of age. METHODS: Eye movements of 97

healthy infants between 1 day and 16 weeks of age were recorded one to seven

times with infrared photo-oculography. For stimulation of visual pursuit a square

of 9.4 deg of visual angle with vertical gratings moved horizontally at a constant

velocity of 7.5 deg/s. RESULTS: In the first 2 weeks of life, segments of smooth

pursuit were measured with a maximum velocity of 7.93 deg/s, with a maximum

gain of 1.06 and a maximal duration of 3.16 s. In sequential recordings no

significant increases of velocity, gain or duration were found. However, the total

time the subjects followed the stimulus with smooth plus saccadic pursuit

increased significantly with age (from a median of 39.0% to a median of 61.5% of

examination time). CONCLUSION: This study clearly demonstrates that smooth

pursuit is already present in the first week of life. We found no significant

increase in velocity, gain and duration of smooth pursuit segments in the first 16

weeks of life with our recording technique. However, the total pursuit time,

reflecting attention, increased with age. The ocular machinery to drive pursuit

appears to be in place at birth and seems not to be influenced by increased

attention in the first months of life.

178. Lengyel, D.; Weinacht, S.; Charlier, J.; Gottlob, I. The development of visual pursuit

during the first months of life. Graefes-Arch-Clin-Exp-Ophthalmol. 1998 Jun;

236(6): 440-4; ISSN: 0721-832X.

GERMANY. BACKGROUND: There are few previous investigations of

smooth pursuit in infants. The aim of our study was to quantify visual pursuit in

infants between 1 day and 16 weeks of age. METHODS: Eye movements of 97

healthy infants between 1 day and 16 weeks of age were recorded one to seven

times with infrared photo-oculography. For stimulation of visual pursuit a square

of 9.4 deg of visual angle with vertical gratings moved horizontally at a constant

velocity of 7.5 deg/s. RESULTS: In the first 2 weeks of life, segments of smooth

pursuit were measured with a maximum velocity of 7.93 deg/s, with a maximum

gain of 1.06 and a maximal duration of 3.16 s. In sequential recordings no

significant increases of velocity, gain or duration were found. However, the total

time the subjects followed the stimulus with smooth plus saccadic pursuit

increased significantly with age (from a median of 39.0% to a median of 61.5% of

examination time). CONCLUSION: This study clearly demonstrates that smooth

pursuit is already present in the first week of life. We found no significant

increase in velocity, gain and duration of smooth pursuit segments in the first 16

weeks of life with our recording technique. However, the total pursuit time,

reflecting attention, increased with age. The ocular machinery to drive pursuit

appears to be in place at birth and seems not to be influenced by increased

attention in the first months of life.

179. Leung, P. W.; Connolly, K. J. Do hyperactive children have motor organization and/or

execution deficits? Dev-Med-Child-Neurol. 1998 Sep; 40(9): 600-7; ISSN: 0012-

1622.

ENGLAND. Hyperactive children have been described as motorically clumsy.

To explore the validity of this assertion, an experiment using the additive factor

method was designed to examine motor organization and execution in hyperactive

children. Four groups of boys aged 7 to 8 years took part in the study: (1) a pure

hyperactive (HA) group, N=20; (2) a pure conduct-disordered (CD) group, N=18;

(3) a mixed hyperactive/conduct-disordered (HA+CD) group, N=12; (4) a normal

(N) control group, N=22. While the small sample size precluded a definitive

conclusion, the results indicated that neither HA nor CD children showed any

motor organization or execution deficit in a simple sequential key-tapping task.

Given previous findings indicating that hyperactive children show deficits in more

complex motor coordination skills, the generalizability of our negative results

needs to be examined on other more complex tasks.

180. Leung, P. W.; Connolly, K. J. Do hyperactive children have motor organization and/or

execution deficits? Dev-Med-Child-Neurol. 1998 Sep; 40(9): 600-7; ISSN: 0012-

1622.

ENGLAND. Hyperactive children have been described as motorically clumsy.

To explore the validity of this assertion, an experiment using the additive factor

method was designed to examine motor organization and execution in hyperactive

children. Four groups of boys aged 7 to 8 years took part in the study: (1) a pure

hyperactive (HA) group, N=20; (2) a pure conduct-disordered (CD) group, N=18;

(3) a mixed hyperactive/conduct-disordered (HA+CD) group, N=12; (4) a normal

(N) control group, N=22. While the small sample size precluded a definitive

conclusion, the results indicated that neither HA nor CD children showed any

motor organization or execution deficit in a simple sequential key-tapping task.

Given previous findings indicating that hyperactive children show deficits in more

complex motor coordination skills, the generalizability of our negative results

needs to be examined on other more complex tasks.

181. Ma, J.; Barbenel, J. C. A new ambulatory monitoring instrument of posture and

mobility related activities. Biomed-Sci-Instrum. 1997; 33: 88-93; ISSN: 0067-

8856.

UNITED-STATES. Long-term ambulatory monitoring of posture and mobility

related activities provides useful information about the extent of disability and the

outcome of rehabilitation. The aim of this project is developing an instrument

which could distinguish between a set of selected mobility-related physical

activities and produce parameters characterising the subjects' activity pattern; The

selected activities are lying, sitting, standing and walking. A novel activity

transducer and a data logger with 1MB memory are employed in the system

configuration. Analytical algorithms and program are developed. The subject's

whole day activity pattern and the histogram of each activity event are

successfully obtained.

182. Magill, R. A. 1997 C. H. McCloy Research Lecture: Knowledge is more than we can

talk about: implicit learning in motor skill acquisition. Res-Q-Exerc-Sport. 1998

Jun; 69(2): 104-10; ISSN: 0270-1367.

UNITED-STATES. This article discusses the acquisition of knowledge about

environmental regulatory features that guide the selection and execution of

movements involved in performing open motor skills. First, empirical evidence

related to the visual search characteristics of skilled and novice performers is

considered to demonstrate that learning environmental regulatory features is an

important part of performing an open motor skill. Then, the hypothesis is

proposed and discussed that environmental regulatory features can, and probably

should, be learned implicitly, which means the features can be learned and used,

even though the learner is not consciously aware of the specific characteristics of

those features. This article also discusses laboratory-based experiments that

provide evidence supporting this hypothesis and presents implications for

developing instructional strategies and practice conditions.

183. Malchaire, J.; Rodriguez Diaz, L. S.; Piette, A.; Goncalves Amaral, F.; de Schaetzen,

D. Neurological and functional effects of short-term exposure to hand-arm

vibration. Int-Arch-Occup-Environ-Health. 1998 Jun; 71(4): 270-6; ISSN: 0340-

0131.

GERMANY. OBJECTIVE: The aim of the present study was to quantify the

sensory and functional effects resulting from a short-duration (30 min) exposure

to hand-arm vibration. SUBJECTS AND METHODS: Nine subjects went

through nine laboratory experiments. For 32 min they grasped a handle vibrating

at three different amplitudes (5, 20, and 80 ms-2) and at three frequencies (31.5,

125, and 500 Hz). Additionally, a reference experiment was conducted in which

the handle did not vibrate. Three sensory tests [vibration perception threshold

(VPT), pressure perception threshold (PPT), and distal sensory latency time

(DSL)], two functional tests [Purdue peg-board (PPB) and maximal voluntary

force (MVF)], and a questionnaire concerning the perceived paresthesia and

numbness were completed before, during, and after exposure. RESULTS: A 32-

min period of exposure to vibration leads to a temporary threshold shift (TTS) of

the VPT and to the development of paresthesia and numbness. The VPT appears

to vary with the exposure duration according to a first-order model with a time

constant about equal to 3 min. The TTS increases with the vibration acceleration

amplitude and is greater for an exposure frequency of 125 Hz than for that of 31.5

or 500 Hz. It is also greater at the test frequency 125 Hz than at 31.5 Hz. The

other tests do not demonstrate any significant variation. In particular, the PPB

test does not demonstrate any loss of dexterity. CONCLUSION: After some 30

min of exposure to vibration the VPTs are increased and paresthesia and

numbness develop. However, these do not appear to influence significantly the

capacity or performance at work.

184. Malessy, M. J.; Thomeer, R. T.; van Dijk, J. G. Changing central nervous system

control following intercostal nerve transfer. J-Neurosurg. 1998 Oct; 89(4): 568-74;

ISSN: 0022-3085.

UNITED-STATES. OBJECT: The goal of this study was to find which central

nervous system (CNS) pathways are involved in volitional control over

reinnervated biceps or pectoral muscles. METHODS: Intercostal nerves (ICNs)

were coapted to the musculocutaneous nerve (MCN) or the medial pectoral nerve

(MPN) in 23 patients with root avulsions of the brachial plexus to restore biceps

or pectoral muscle function. The facilitatory effects of respiration and voluntary

contraction on cortical motor-evoked potentials of biceps or pectoral muscles

were used to study CNS control over the reinnervated muscles. The time course

of the facilitatory effect of respiration and voluntary contraction differed

significantly. In the end stage of nerve regeneration, the facilitatory effect of

voluntary contraction was significantly larger than that of respiration, indicating

that the CNS control network over the muscle comes to resemble that of the

recipient nerve (MCN or MPN) rather than that of the donor nerve (ICN).

CONCLUSIONS: The strengthening of previously subthreshold synaptic

connections in a CNS network connecting ICN to MCN or MPN neurons may

underlie changing excitability.

185. Manconi, F. M.; Syed, N. A.; Floeter, M. K. Mechanisms underlying spinal motor

neuron excitability during the cutaneous silent period in humans [see comments].

Muscle-Nerve. 1998 Oct; 21(10): 1256-64; ISSN: 0148-639X.

Note: Comment in: Muscle Nerve 1998 Oct;21(10):1243-5.

UNITED-STATES. The transient suppression of muscle contraction during the

cutaneous silent period (CSP) could be produced either through postsynaptic

inhibition of motoneurons or through presynaptic inhibition of the excitatory

inputs to motoneurons that sustain voluntary contraction. We sought to delineate

the mechanisms underlying the CSP in hand muscles by measuring changes in H-

reflexes and motor-evoked potentials (MEPs) produced by transcranial magnetic

stimulation (TMS) during the CSP in 10 healthy volunteers. H-reflexes and MEPs

both measure the excitability of the motoneuron pool and activate similar

subpopulations of motoneurons through different pathways. Inhibition of H-

reflexes and MEPs of similar size was maximal at the midpoint of the CSP and

gradually returned to baseline. The similar time course of recovery suggests that

the H-reflex and MEP are affected by inhibition at a common site, most likely

postsynaptic inhibition of the motoneurons.

186. Maraj, B.; Allard, F.; Elliott, D. The effect of nonregulatory stimuli on the triple jump

approach run. Res-Q-Exerc-Sport. 1998 Jun; 69(2): 129-35; ISSN: 0270-1367.

UNITED-STATES. The purpose of this experiment was to examine the

approach run of the triple jump. Specifically, we examined the effect of

nonregulatory stimuli (Gentile, 1972) on two different ability levels in performing

the triple jump approach run. These nonregulatory constraints (situational factors

such as those seen in actual competition) were employed in three jumping

conditions: Control (to obtain baseline performance measures), Distance (where

participants attempted to obtain as great a jump as possible), and Accuracy

(participants attempted to be as accurate as possible on takeoff without

sacrificing distance). The results showed that the footfall position variability for

all conditions was similar to those previously reported for the long jump

approach run. However, in compliance with the nonregulatory constraints,

participants altered other performance parameters in executing the approach run.

The situational factors created changes that revealed themselves in foot placement

on the takeoff board at the end of the approach run (foot position constant error

and number of fouls increased for the Distance condition) and decreased

horizontal velocity at takeoff in the Accuracy condition. Changes in performance

parameters were related to the context in which the skill was performed and may

further reflect changes made by jumpers in the course, such as a visual-motor task

in competition. We suggest that the characteristics of the approach run may not

be fully revealed by the pattern of footfall variability only, as has been suggested

in previous work (e.g., Lee, Lishman, & Thomson, 1982), but that the situation

under which the jump is performed may have a significant effect on the

performance parameters that emerge in executing this type of motor skill.

187. Marks, R. The effect of restricting arm swing during normal locomotion. Biomed-Sci-

Instrum. 1997; 33: 209-15; ISSN: 0067-8856.

UNITED-STATES. This work examined possible perturbations in contra-lateral

upper and lower limb motion, movement variability, and thoracic rotation, when a

healthy mature adult walked a distance of 12 m at self-paced speed with and

without unilateral passive arm restraint. The 2-dimensional walking data captured

from 11 reflective markers placed on the subject's right side were recorded

sagitally along the plane of progression using an electronic camera and Peak-5

Performance Video-system. The positional data were calculated off-line and

differentiated with respect to one representative stride using Lab View software.

Data were analyzed for 5 successive trials of normal walking; 5 successive walking

trials with unilateral passive restraint; and a further 4 without restraint. Under the

restrained condition the results showed: a) A significant decline in horizontal

displacement of the limbs; b) higher variability of the trajectories generated,

particularly at the ankle; c) a trend towards greater thoracic rotation on the

unrestrained side; and d) altered angular velocity profiles for all upper and lower

limb joints and trunk, which did not always return to baseline values after

restraint removal. Since motivation level, environment, and methodology was

consistent across trials, the findings suggest relatively stereotyped locomotor

patterns in mature humans can be readily modulated in response to task

constraints.

188. Marques Bruna, P.; Grimshaw, P. N. Variability in development of overarm throwing:

a longitudinal case study over the first 6 months of throwing. Percept-Mot-Skills.

1998 Jun; 86(3 Pt 2): 1403-18; ISSN: 0031-5125.

UNITED-STATES. One female subject of 15 months of age, at the onset of over-

arm-throwing behaviour, was tested on a longitudinal study of throwing

development. Data were collected at the onset of throwing and monthly

thereafter, producing 6 sets of data. Kinematic variables were obtained using 3-

dimensional video analysis and digitization. Qualitative observations showed that

both arm-dominated and sequentially linked throws, right- and left-handed

throws, and homolateral and contralateral forward steps were generated in an

array of inconsistent throwing. Sequentially linked throws were generally

'interrupted', whereby the child paused briefly after the Back swing to focus

externally, then the child executed the propulsion. The throwing elbow remained

flexed at ball release. Angles of ball release (referred to the horizontal) fluctuated

from 2.17 degrees to 28.03 degrees for all 6 months of throwing development, and

the speed of ball release varied from 2.08 m/sec. to 4.32 m/sec. Height of ball

release oscillated between 91.5% and 103.3% of the child's height. Horizontal and

vertical components of the velocity of the ball while in the hand differed amongst

both arm-dominated and sequentially linked throws. The time of the Push up

phase in arm-dominated throws varied from 0.14 sec. to 0.50 sec. In sequentially

linked throws the time of the Back swing ranged from 0.18 sec. to 0.22 sec., and

the Propulsion varied from 0.06 sec. to 0.14 sec. This work in identifying such

variability is important, therefore, in the understanding of the motor skill of

throwing.

189. Marques Bruna, P.; Grimshaw, P. N. Variability in development of overarm throwing:

a longitudinal case study over the first 6 months of throwing. Percept-Mot-Skills.

1998 Jun; 86(3 Pt 2): 1403-18; ISSN: 0031-5125.

UNITED-STATES. One female subject of 15 months of age, at the onset of over-

arm-throwing behaviour, was tested on a longitudinal study of throwing

development. Data were collected at the onset of throwing and monthly

thereafter, producing 6 sets of data. Kinematic variables were obtained using 3-

dimensional video analysis and digitization. Qualitative observations showed that

both arm-dominated and sequentially linked throws, right- and left-handed

throws, and homolateral and contralateral forward steps were generated in an

array of inconsistent throwing. Sequentially linked throws were generally

'interrupted', whereby the child paused briefly after the Back swing to focus

externally, then the child executed the propulsion. The throwing elbow remained

flexed at ball release. Angles of ball release (referred to the horizontal) fluctuated

from 2.17 degrees to 28.03 degrees for all 6 months of throwing development, and

the speed of ball release varied from 2.08 m/sec. to 4.32 m/sec. Height of ball

release oscillated between 91.5% and 103.3% of the child's height. Horizontal and

vertical components of the velocity of the ball while in the hand differed amongst

both arm-dominated and sequentially linked throws. The time of the Push up

phase in arm-dominated throws varied from 0.14 sec. to 0.50 sec. In sequentially

linked throws the time of the Back swing ranged from 0.18 sec. to 0.22 sec., and

the Propulsion varied from 0.06 sec. to 0.14 sec. This work in identifying such

variability is important, therefore, in the understanding of the motor skill of

throwing.

190. Masur, H.; Althoff, S.; Erim, Y.; Oberwittler, C.; Hornung, W. P. Postexcitatory

inhibition after transcranial magnetic stimulation of the motor cortex in patients

with drug-induced parkinsonism and in healthy individuals. Int-Clin-

Psychopharmacol. 1998 Mar; 13(2): 79-82; ISSN: 0268-1315.

ENGLAND. The duration of the postexcitatory inhibition after transcranial

magnetic stimulation was investigated in 16 patients with drug-induced

parkinsonism and in 20 healthy control individuals. In the patients, the

chlorpromazine-equivalent of the neuroleptic medication was determined, and the

severity of the drug-induced parkinsonism was measured using the Simpson-

Angus Scale score. Group comparison (U-test) revealed a significant shorter

postexcitatory inhibition in patients than in control individuals. Regression

analyses showed a negative correlation between the Simpson-Angus scale score

and the duration of the postexcitatory inhibition. The correlation only reached

significance for a group of patients who received at least one butyrophenone

derivate. No clear-cut relation was found between the chlorpromazine equivalent

and the postexcitatory inhibition. These results indicate that drug-induced

parkinsonism shares features of genuine Parkinson's disease. Furthermore, it

seems possible to assess the extrapyramidal side effect of butyrophenone

derivates, but not for other neuroleptic drugs, by means of the method described..

0.

191. Matheson, A. J.; Darlington, C. L.; Smith, P. F. Age-related changes in human

optokinetic function. Neuroreport. 1998 Jul 13; 9(10): 2175-7; ISSN: 0959-4965.

ENGLAND. The aim of the present study was to investigate the effects of ageing

on optokinetic function in labyrinthine-intact human subjects. Subjects aged 18-39

years, 40-59 years and > or = 60 years were tested for sensitivity to optokinetic

stimulation using latency to the illusion of circularvection in an optokinetic drum.

The latency to circularvection significantly increased with increasing age. These

results suggest a decline in optokinetic sensitivity with increasing age, which may

be related to age-related deterioration in the optokinetic visual pathways.

192. Mathews, S. Accommodation and the third spatial harmonic. Optom-Vis-Sci. 1998

Jun; 75(6): 450-8; ISSN: 1040-5488.

UNITED-STATES. PURPOSE: Mathews and Kruger recently reported that

accommodative tracking of sine wave grating targets is best between 1 and 7 cpd.

Their study suggests that the spatial third harmonic might not enhance the

accommodative response if the fundamental is higher than roughly 2 cpd. This

study tested the effect of adding the third harmonic with targets that included 1, 3,

and 5 cpd fundamental sine wave gratings, compound gratings with the third

harmonic of each of these fundamentals added in either peaks-add or peaks-

subtract phase, as well as each third harmonic presented alone at one-third of the

contrast of the fundamental gratings. METHODS: Accommodation was

monitored continuously with a dynamic infrared optometer while the subject

viewed the gratings in a Badal stimulus system. Dioptric vergence changed

sinusoidally over a 2.00 or 0.50 D range at 0.2 Hz. A Fast Fourier Transform

extracted the amplitude and phase of each response at the temporal frequency of

the stimulus. RESULTS AND CONCLUSIONS: The third harmonic enhanced

the accommodative response only when the fundamental was 1 cpd. This was

true at both amplitudes of target motion. This contradicts models that suggest that

high spatial frequencies are used to refine the accommodative response. Second,

the responses to the peaks-add and peaks-subtract phase conditions were

essentially the same for each fundamental. This suggests that the effect of

harmonics cannot be described by any simple linear relationship between the

increased luminance gradient of the grating target and the accommodative

response. Third, the accommodative response to gratings with a 5 cpd

fundamental were smaller than the responses to gratings with the 3 cpd

fundamental. This contradicts the gradient hypothesis of accommodative control

inasmuch as the luminance gradient is steeper in the gratings with the 5 cpd

fundamental. Alternatively, it seems that harmonics will enhance an

accommodative response regardless of phase if they are effective accommodative

stimuli on their own.

193. Maxwell, A. J.; Schauble, E.; Bernstein, D.; Cooke, J. P. Limb blood flow during

exercise is dependent on nitric oxide. Circulation. 1998 Jul 28; 98(4): 369-74;

ISSN: 0009-7322.

UNITED-STATES. BACKGROUND: We have recently reported that

hypercholesterolemia reduces aerobic exercise capacity in mice and that this is

associated with a reduced endothelium-dependent vasodilator function,

endothelium-derived nitric oxide (EDNO) production, and urinary nitrate

excretion. These findings led us to test the hypothesis that EDNO production

contributes significantly to limb blood flow during exercise and to determine

whether loss of EDNO production is responsible for the decline in exercise

capacity observed in hypercholesterolemia. METHODS AND RESULTS:

Twelve-week-old wild-type (E+; n=9) and apoE-deficient (E-; n=9) C57BL/6J

mice were treadmill-tested to measure indices defining exercise capacity on a

metabolic chamber-enclosed treadmill capable of measuring oxygen uptake and

carbon dioxide excretion. Urine was collected before and after treadmill exercise for

determination of vascular NO production assessed by urinary nitrate excretion.

The wild-type mice were then given nitro-L-arginine (E+LNA) in the drinking

water (6 mg/dL) for 4 days before undergoing a second treadmill testing and

urinary nitrate measurement. An additional set of 12-week-old wild-type mice

was divided into 2 groups: 1 receiving regular water (E+; n=8) and 1 administered

LNA for 4 days (E+LNA; n=8). These mice, along with an additional set of E

mice (n=8), underwent treadmill testing to determine maximal oxygen uptake

(VO2max). The mice were then cannulated such that the tip of the tubing was

positioned in the ascending aorta. Fluorescent microspheres (20000) were infused

into the carotid cannula while the mice were sedentary and again while

approaching VO2max. When the mice were euthanized, the running muscles were

collected and fluorescence intensity was measured to determine the peak-exercise

redistribution of blood flow to the running muscles (expressed as percentage of

total cardiac output, %COrm) during both states. Both E+LNA and E- mice

demonstrated a markedly reduced postexercise urinary nitrate excretion, aerobic

capacity, and %COrm at VO2max compared with E+. CONCLUSIONS: EDNO

contributes significantly to limb blood flow during exercise. Conditions that

reduce EDNO production disturb the hyperemic response to exercise, resulting in

a reduced exercise capacity.. 0; 0; 0; 10102-43-9; 2149-70-4.

194. Mello, C. F.; Kraemer, C. K.; Filippin, A.; Morsch, V. M.; Rodrigues, A. L.; Martins,

A. F.; Rubin, M. A. Effect of lead acetate on neurobehavioral development of rats.

Braz-J-Med-Biol-Res. 1998 Jul; 31(7): 943-50; ISSN: 0100-879X.

BRAZIL. We investigated the effects of lead exposure during the pre- and

postnatal period on the neurobehavioral development of female Wistar rats (70-75

days of age, 120-150 g) using a protocol of lead intoxication that does not affect

weight gain. Wistar rats were submitted to lead acetate intoxication by giving their

dams 1.0 mM lead acetate. Control dams received deionized water. Growth and

neuromotor development were assessed by monitoring daily the following

parameters in 20 litters: body weight, ear unfolding, incisor eruption, eye opening,

righting, palmar grasp, negative geotaxis, cliff avoidance and startle reflex.

Spontaneous alternation was assessed on postnatal day 17 using a T maze. The

animals' ability to equilibrate on a breaker rim was measured on postnatal day 19.

Lead intoxication was confirmed by measuring renal, hepatic and cerebral lead

concentration in dams and litters. Lead treatment hastened the day of appearance

of the following parameters: eye opening (control: 13.5 +/- 0.6, N = 88; lead: 12.9

+/- 0.6, N = 72; P < 0.05), startle reflex (control: 13.0 +/- 0.8, N = 88; lead: 12.0

+/- 0.7, N = 72; P < 0.05) and negative geotaxis. On the other hand, spontaneous

alternation performance was hindered in lead-exposed animals (control: 37.6 +/-

19.7; lead: 57.5 +/- 28.3% of alternating animals; P < 0.05). These results suggest

that lead exposure without concomitant undernutrition alters rat development,

affecting specific subsets of motor skills.. 0; 301-04-2; 7439-92-1.

195. Menozzi, M.; Krueger, H. [Effects of presbyopia on clinical phoria]. Auswirkungen

der Presbyopie auf die klinische Phorielinie. Klin-Monatsbl-Augenheilkd. 1998

May; 212(5): 382-4; ISSN: 0023-2165.

GERMANY. BACKGROUND: Due to accommodation-vergence cross-link we

can expect that presbyopia will affect vergence as well. From investigations of

cross-link as function of age one may assess strain of visual system due to

presbyopia. Furthermore, this observation will give hints on innervation of ciliary

muscle. MATERIAL AND METHOD: Vergence is assessed as function of

stimulus of accommodation in 27 subjects (24-65 years). RESULTS: Presbyops

tend to be exophoric for near vision. Vergence is linked to accommodation by

means of a quadratic polynome rather than by a linear function. CONCLUSIONS:

We may expect, that missing vergence strains visual system of presbyops.

Results support Hess-Gullstrand theory of presbyopia and indicate a loss of

innervation of ciliary muscle with increasing age.

196. Mergner, T.; Schweigart, G.; Botti, F.; Lehmann, A. Eye movements evoked by

proprioceptive stimulation along the body axis in humans. Exp-Brain-Res. 1998

Jun; 120(4): 450-60; ISSN: 0014-4819.

GERMANY. Proprioceptive input arising from torsional body movements elicits

small reflexive eye movements. The functional relevance of these eye movements

is still unknown so far. We evaluated their slow components as a function of

stimulus frequency and velocity. The horizontal eye movements of seven adult

subjects were recorded using an infrared device, while horizontal rotations were

applied at three segmental levels of the body [i.e., between head and shoulders

(neck stimulus), shoulders and pelvis (trunk stimulus), and pelvis and feet (leg

stimulus)]. The following results were obtained: (1) Sinusoidal leg stimulation

evoked an eye response with the slow component in the direction of the

movement of the feet, while the response to trunk and neck stimulation was

oriented in the opposite direction (i.e., in that of the head). (2) In contrast, the

gain behavior of all three responses was similar, with very low gain at mid- to high

frequencies (tested up to 0.4 Hz) but increasing gain at low frequencies (down to

0.0125 Hz). We show that this gain behavior is mainly due to a gain nonlinearity

for low angular velocities. (3) The responses were compatible with linear

summation when an interaction series was tested in which the leg stimulus was

combined with a vestibular stimulus. (4) There was good correspondence of the

median gain curves when eye responses were compared with psychophysical

responses (perceived body rotation in space; additionally recorded in the

interaction series). However, correlation of gain values on a single-trial basis was

poor. (5) During transient neck stimulation (smoothed position ramp), the neck

response noticeably consisted of two components -- an initial head-directed eye

shift (phasic component) followed by a shift in the opposite direction

(compensatory tonic component). Both leg and neck responses can be described

by one simple, dynamic model. In the model the proprioceptive input is fed into

the gaze network via two pathways which differ in their dynamics and directional

sign. The model simulates either leg or neck responses by selecting an appropriate

weight for the gain of one of the pathways (phasic component). The interaction

results can also be simulated when a vestibular path is added. This model has

similarities to one we recently proposed for human self-motion perception and

postural control. A major difference, though, is that the proprioceptive input to

the gaze-stabilizing network is weak (restricted to low velocities), unlike that used

for perception and postural control. We hold that the former undergoes involution

during ontogenesis, as subjects depend on the functionally more appropriate

vestibulo-ocular reflex. Yet, the weak proprioceptive eye responses that remain

may have some functional relevance. Their tonic component tends to stabilize the

eyes by slowly shifting them toward the primary head position relative to the

body support. This applies solely to the earth-horizontal plane in which the

vestibular signal has no static sensitivity.

197. Mezey, L. E.; Harris, C. M.; Shawkat, F. S.; Timms, C.; Kriss, A.; West, P.; Taylor,

D. S. Saccadic strategies in children with hemianopia. Dev-Med-Child-Neurol.

1998 Sep; 40(9): 626-30; ISSN: 0012-1622.

ENGLAND. Multiple hypometric (undershooting) saccades are generally

reported as a compensatory strategy in adults with homonymous hemianopia.

However, hypermetric (overshooting) saccades have been reported to develop

spontaneously as a beneficial strategy in response to predictable targets. We

examined the saccades of 10 children (aged 5 to 16 years) with homonymous

hemianopia to determine the type of compensatory eye-movement strategies

employed 6 months to 16 years after hemianopia onset. Homonymous

hemianopia was identified using perimetry and/or pattern visual evoked potentials

and supported with results of neuroimaging. Eye movements were recorded using

bitemporal electrooculography. Saccades were elicited to a red light source in a

semipredictable paradigm. We found that hypermetria was not a consistent

compensatory strategy in our patients. In spite of the predictability of our

paradigm and the long follow-up period, multiple hypometric saccades into the

blind field appeared to be the preferred strategy.

198. Mezey, L. E.; Harris, C. M.; Shawkat, F. S.; Timms, C.; Kriss, A.; West, P.; Taylor,

D. S. Saccadic strategies in children with hemianopia. Dev-Med-Child-Neurol.

1998 Sep; 40(9): 626-30; ISSN: 0012-1622.

ENGLAND. Multiple hypometric (undershooting) saccades are generally

reported as a compensatory strategy in adults with homonymous hemianopia.

However, hypermetric (overshooting) saccades have been reported to develop

spontaneously as a beneficial strategy in response to predictable targets. We

examined the saccades of 10 children (aged 5 to 16 years) with homonymous

hemianopia to determine the type of compensatory eye-movement strategies

employed 6 months to 16 years after hemianopia onset. Homonymous

hemianopia was identified using perimetry and/or pattern visual evoked potentials

and supported with results of neuroimaging. Eye movements were recorded using

bitemporal electrooculography. Saccades were elicited to a red light source in a

semipredictable paradigm. We found that hypermetria was not a consistent

compensatory strategy in our patients. In spite of the predictability of our

paradigm and the long follow-up period, multiple hypometric saccades into the

blind field appeared to be the preferred strategy.

199. Mihelin, M.; Liscic, R. M. A custom designed system to measure corticospinal tract

jitter. Electroencephalogr-Clin-Neurophysiol. 1998 Apr; 109(2): 194-7; ISSN:

0013-4694.

IRELAND. Typical latency of an individual limb muscle response to magnetic or

electric stimulation of the human cortex is in the range of 10-50 ms. For the

latency variability, i.e., jitter studies, a resolution of at least 20 micros is needed.

Commercially available EMG equipment needs custom-designed upgrading to

allow for such studies. Two solutions were designed: (i) a hardware unit allowing

an adjustable delay of data acquisition after the delivered stimuli; and (ii) diverting

of the amplified biological signal and the EMG equipment trigger to an external

computer equipped with an analogue-to-digital conversion (ADC) module.

Custom-designed software made fast ADC possible during the whole period of

data acquisition. Both concepts were applied to a Vickers Medical Mystro

electromyograph, and have been successfully used in the Ljubljana (Slovenia)

Institute of Clinical Neurophysiology for the last 2 years.

200. Miles, F. A. The neural processing of 3-D visual information: evidence from eye

movements. Eur-J-Neurosci. 1998 Mar; 10(3): 811-22; ISSN: 0953-816X.

FRANCE. Primates have several reflexes that generate eye movements to

compensate for bodily movements that would otherwise disturb their gaze and

undermine their ability to process visual information. Two vestibulo-ocular

reflexes compensate selectively for rotational and translational disturbances of the

head, and each has visual backups that operate as negative feedback tracking

mechanisms to deal with any residual disturbances of gaze. Of particular interest

here are three recently discovered visual tracking mechanisms that specifically

address translational disturbances and operate in machine-like fashion with ultra-

short latencies (< 60 ms in monkeys, < 85 ms in humans). These visual reflexes

deal with motions in all three dimensions and operate as automatic servos, using

preattentive parallel processing to provide signals that initiate eye movements

before the observer is even aware that there has been a disturbance. This

processing is accomplished by visual filters each tuned to a different feature of the

binocular images located in the immediate vicinity of the plane of fixation. Two of

the reflexes use binocular stereo cues and the third is tuned to particular patterns

of optic flow associated with the observer's forward motion. Some

stereoanomalous subjects show tracking deficits that can be attributed to a lack of

just one subtype of cortical cell encoding motion in one particular direction in a

narrow depth plane centred on fixation. Despite their rapid, reflex nature, all three

mechanisms rely on cortical processing and evidence from monkeys supports the

hypothesis that all are mediated by the medial superior temporal (MST) area of

cortex. Remarkably, MST seems to represent the first stage in cortical motion

processing at which the visual error signals driving each of the three reflexes are

fully elaborated at the level of individual cells.

201. Miller, J. A.; Gross, M. M. Locomotor advantages of Neandertal skeletal morphology

at the knee and ankle. J-Biomech. 1998 Apr; 31(4): 355-61; ISSN: 0021-9290.

UNITED-STATES. We quantified Neandertal knee extensor and ankle

plantarflexor moments to determine whether differences between Neandertal and

recent human skeletal morphology represent important functional differences.

Neandertal skeletal differences in the patella, tibial tuberosity, and calcaneus were

used to modify a computer model of recent humans to calculate the moment arms

and moments of Neandertal knee extensor and ankle plantarflexor muscles. We

also conducted sensitivity studies on the effect of musculotendon parameters on

the Neandertal moments. As expected, we found that Neandertal moment arms

were greater than recent humans at the ankle (122-141%); however, the magnitude

of the increase was not well-predicted from measurements of size differences

between Neandertal and recent human skeletons. At the knee, Neandertal moment

arms were greater than those of recent humans in the locomotor range (108%) but

less so at more flexed knee angles (102%). Not all Neandertal skeletal adaptations

at the knee contributed to increased moment arm. Knee extensor moments were

enhanced in the Neandertal models in the locomotor range (111%), regardless of

musculotendon parameters. At the ankle, however, Neandertal plantarflexor

moment was greater than that of recent humans (149-200%) at all joint angles

only if muscle fiber length increased proportionately with moment arm. Our

results demonstrate that Neandertal skeletal morphology, compared to that of

recent humans, generated greater moments at both the knee and ankle in the

locomotor range but not at higher angles of knee flexion or ankle plantarflexion.

202. Misra, U. K.; Kalita, J. Neurophysiological studies in herpes simplex encephalitis.

Electromyogr-Clin-Neurophysiol. 1998 Apr; 38(3): 177-82; ISSN: 0301-150X.

BELGIUM. In herpes simplex encephalitis (HSE), simultaneous electro-

encephalogram (EEG) and evoked potential studies have not been reported,

although EEG changes have been described. In this communication, EEG,

somatosensory and motor evoked potentials have been reported in 9 patients with

HSE. The patients' age ranged between 2 and 70 years and 3 were females. Seven

patients had seizures, CT scan was abnormal in 6 and MRI in remaining 3

patients. Seven patients received acyclovir therapy; one patient died and 6 had

poor outcome. The initial EEG was carried out within 5 days of ictus and was

abnormal in all the patients. The EEG abnormalities included frontotemporal delta

slowing in 5, periodic lateralised epileptiform discharge in 3, runs of spike and

periodic activity in one patient each. At 3 months, EEG was normal in 6 patients

but it did not correlate with clinical recovery. Central motor conduction time

(CMCT) to upper limb and median somatosensory evoked potential (SEP) were

normal in all. CMCT to lower limbs and tibial SEPs were unrecordable in one

patient who had wide spread herpes simplex virus (HSV-1) infection associated

with AIDS, and died on 18th day of illness. From this study, we conclude that

EEG although is frequently abnormal and may provide useful diagnostic

information in a setting of encephalitis but evoked potential changes are

infrequent; and if present an association of HIV infection should be considered.

203. Miyazaki, K. Impact loading on the foot and ankle and its attenuation during level

walking. Kurume-Med-J. 1998; 45(1): 75-80; ISSN: 0023-5679.

JAPAN. We studied impact loading on the foot and ankle at heel strike during

level walking. Cadaveric testing was carried out on a skin-mounted accelerometer

to estimate the bone or joint impact, and gait analysis was performed to evaluate

the impact on the foot and ankle and its attenuation during level walking.

Simulation using a rigid-body model estimated the impulse at landing during level

walking. The skin-mounted accelerometer showed the same tendency as the bone-

mounted accelerometer in cadaveric testing. In the gait analysis, impact at the

calcaneus was attenuated at the medial malleolus and was less attenuated with the

ankle fixation. In the simulation, impact became greater if the foot and ankle

functions were eliminated. These results suggest that the foot and ankle are

directly involved in attenuating the impact at heel strike during level walking.

204. Moriyama, T.; Yamanouchi, N.; Kodama, K.; Murakami, A.; Okada, S. I.; Noda, S.;

Komatsu, N.; Sato, T.; Kusaka, T.; Kato, K. Activation of non-primary motor

areas during a complex finger movement task revealed by functional magnetic

resonance imaging. Psychiatry-Clin-Neurosci. 1998 Jun; 52(3): 339-43; ISSN:

1323-1316.

AUSTRALIA. We examined the brain activation induced by a complex finger

movement task using functional magnetic resonance imaging (fMRI) with echo

planar imaging (EPI). Imaging planes were set up for the observation of non-

primary motor areas. Among five normal males examined, four subjects naive to

the task showed activations in contralateral primary and supplementary motor

areas and the ipsilateral superior anterior part of the cerebellar hemisphere. Also,

the bilateral premotor areas and the contralateral ventrolateral nucleus of thalamus

were occasionally activated. No changes were observed in the putamen and globus

pallidus. The subject accustomed to the task showed activation in the narrow

areas of the contralateral primary motor and supplementary motor and premotor

areas but not in the cerebellum. These results suggest that fMRI has nearly the

same degree of detectability to that of positron emission tomography (PET) in

regard to motor functions.

205. Moriyama, T.; Yamanouchi, N.; Kodama, K.; Murakami, A.; Okada, S. I.; Noda, S.;

Komatsu, N.; Sato, T.; Kusaka, T.; Kato, K. Activation of non-primary motor

areas during a complex finger movement task revealed by functional magnetic

resonance imaging. Psychiatry-Clin-Neurosci. 1998 Jun; 52(3): 339-43; ISSN:

1323-1316.

AUSTRALIA. We examined the brain activation induced by a complex finger

movement task using functional magnetic resonance imaging (fMRI) with echo

planar imaging (EPI). Imaging planes were set up for the observation of non-

primary motor areas. Among five normal males examined, four subjects naive to

the task showed activations in contralateral primary and supplementary motor

areas and the ipsilateral superior anterior part of the cerebellar hemisphere. Also,

the bilateral premotor areas and the contralateral ventrolateral nucleus of thalamus

were occasionally activated. No changes were observed in the putamen and globus

pallidus. The subject accustomed to the task showed activation in the narrow

areas of the contralateral primary motor and supplementary motor and premotor

areas but not in the cerebellum. These results suggest that fMRI has nearly the

same degree of detectability to that of positron emission tomography (PET) in

regard to motor functions.

206. Mueller, D. H. Timeliness of codifying nutrition ABCDE's for BPD [editorial;

comment]. J-Pediatr. 1998 Sep; 133(3): 315-6; ISSN: 0022-3476.

Note: Comment on: J Pediatr 1998 Sep;133(3):340-5.

UNITED-STATES.

207. Muri, R. M.; Heid, O.; Nirkko, A. C.; Ozdoba, C.; Felblinger, J.; Schroth, G.; Hess,

C. W. Functional organisation of saccades and antisaccades in the frontal lobe in

humans: a study with echo planar functional magnetic resonance imaging. J-

Neurol-Neurosurg-Psychiatry. 1998 Sep; 65(3): 374-7; ISSN: 0022-3050.

ENGLAND. The cortical activation pattern of saccades and antisaccades (versus

rest) in the frontal lobe was analysed using an echo planar imaging (EPI) technique

in 10 healthy subjects. Statistical analysis of activity in the dorsolateral prefrontal

cortex disclosed a significantly greater activation during antisaccades in this region

than during saccades. On the other hand, activity in the frontal eye fields was not

statistically different in both tasks. These results confirm the important role of

the dorsolateral prefrontal cortex for the correct performance of antisaccades

obtained by studies in humans with isolated lesions of the dorsolateral prefrontal

cortex.

208. Muri, R. M.; Heid, O.; Nirkko, A. C.; Ozdoba, C.; Felblinger, J.; Schroth, G.; Hess,

C. W. Functional organisation of saccades and antisaccades in the frontal lobe in

humans: a study with echo planar functional magnetic resonance imaging. J-

Neurol-Neurosurg-Psychiatry. 1998 Sep; 65(3): 374-7; ISSN: 0022-3050.

ENGLAND. The cortical activation pattern of saccades and antisaccades (versus

rest) in the frontal lobe was analysed using an echo planar imaging (EPI) technique

in 10 healthy subjects. Statistical analysis of activity in the dorsolateral prefrontal

cortex disclosed a significantly greater activation during antisaccades in this region

than during saccades. On the other hand, activity in the frontal eye fields was not

statistically different in both tasks. These results confirm the important role of

the dorsolateral prefrontal cortex for the correct performance of antisaccades

obtained by studies in humans with isolated lesions of the dorsolateral prefrontal

cortex.

209. Murueta Goyena, Mendizabal F.; Rodriguez Adrados, F. [Simplified

videonystagmoscopy]. Videonistagmoscopia simplificada. Acta-Otorrinolaringol-

Esp. 1998 Apr; 49(3): 253-5; ISSN: 0001-6519.

SPAIN. Videonystagmoscopy visualizes nystagmus on a television monitor and

records it on video tape for later study, records, and reproduction. Early attempts

date from long ago, but the technique only recently has spread, since the

development of complex computerized equipment which, however, confines it to

certain vestibular exploration laboratories. In order for this technique to become

more widely used, simple equipment is needed, such as that described in this

article. Our system consists of a single infrared light minivideo camera that is

attached to the left eye using an eyeglass-mounting system that also occludes the

right eye. The examination method is routine. Our results show the following

advantages over electronystagmography: visualization of the rotary component,

non-interference of visual stimuli, mechanical and electronic stability, speed, and

low cost. If necessary, it can be complemented by electronystagmography and

computer analysis.

210. Nakatoh, S.; Kitagawa, H.; Kawaguchi, Y.; Nakamura, H.; Takano, H.; Tsuji, H.

Effects of coil orientation and magnetic field shield on transcranial magnetic

stimulation in cats. Muscle-Nerve. 1998 Sep; 21(9): 1172-80; ISSN: 0148-639X.

UNITED-STATES. To obtain suitable stimulus conditions for transcranial

magnetic stimulation, the evoked compound muscle action potential (ECMAP),

evoked spinal cord potential (ESCP), and magnetic and electric fields were

analyzed in cats with and without the use of a magnetic field shield. Cats were

stimulated using a figure 8 magnetic coil placed on the cranium above the motor

cortex. The maximum ECMAP amplitude was recorded when the electric current

in the coil was in the mediolateral direction, regardless of whether a magnetic

shield with a 5 x 5 cm window was used. ECMAP and ESCP thresholds were

reduced when magnetic shielding was in place. Due to the edge effect, the

strengths of the magnetic and electric fields were highest in the brainstem area,

which is an inhomogeneous volume conductor of the cat's cranium. A large

induced electric field directed caudally elicited ECMAP and ESCP responses

effectively when a magnetic shield with a 5 x 5 cm window was in place.

211. Nazir, T. A.; Jacobs, A. M.; O'Regan, J. K. Letter legibility and visual word

recognition. Mem-Cognit. 1998 Jul; 26(4): 810-21; ISSN: 0090-502X.

UNITED-STATES. Word recognition performance varies systematically as a

function of where the eyes fixate in the word. Performance is maximal with the

eye slightly left of the center of the word and decreases drastically to both sides

of this optimal viewing position. While manipulations of lexical factors have only

marginal effects on this phenomenon, previous studies have pointed to a relation

between the viewing position effect (VPE) and letter legibility: When letter

legibility drops, the VPE becomes more exaggerated. To further investigate this

phenomenon, we improved letter legibility by magnifying letter size in a way that

was proportional to the distance from fixation (e.g., TABLE). Contrary to what

would be expected if the VPE were due to limits of acuity, improving the legibility

of letters has only a restricted influence on performance. In particular, for long

words, a strong VPE remains even when letter legibility is equalized across

eccentricities. The failure to neutralize the VPE is interpreted in terms of

perceptual learning: Since normally, because of acuity limitations, the only

information available in parafoveal vision concerns low-resolution features of

letters; even when magnification provides better information, readers are unable to

make use of it.

212. Netscher, D.; Dinh, T.; Cohen, V.; Thornby, J. Division of the transverse carpal

ligament and flexor tendon excursion: open and endoscopic carpal tunnel release.

Plast-Reconstr-Surg. 1998 Sep; 102(3): 773-8; ISSN: 0032-1052.

UNITED-STATES. Ten fresh cadaver upper extremities from 10 different

subjects were used in this study of the effect of both open and endoscopic carpal

tunnel release on flexor tendon excursion. The amount of excursion necessary to

bring each finger from the fully extended to the fully flexed position with the

fingertip just touching the palm was measured with the extremity mounted in a

device that moved the wrist from extension through flexion. Endoscopic carpal

tunnel release, open release, and transverse carpal ligament reconstruction were

performed with tendon excursion measurements made in each of four wrist

positions after each procedure. Fingertip to palm distance was also measured. The

measurements of flexor tendon excursion in neutral wrist position with intact

transverse carpal ligament served as the norm for each finger and as the

denominator in the ratio of postoperative to preoperative excursion distances. The

study confirmed the importance of the transverse carpal ligament as a flexor

pulley; transection of the ligament increased the amount of flexor tendon excursion

necessary to achieve finger flexion and fingertip-to-palm contact. Tendon

excursion/digital flexion improved after transposition flap repair. Neither open nor

endoscopic carpal tunnel release conferred any particular benefit to flexor tendon

excursion postoperatively. The proximal palmar aponeurosis does not seem to

have the same pulley effect as the transverse fibers of the distal palm.

213. Ni, W.; Fodor, J. D.; Crain, S.; Shankweiler, D. Anomaly detection: eye movement

patterns. J-Psycholinguist-Res. 1998 Sep; 27(5): 515-39; ISSN: 0090-6905.

UNITED-STATES. The symptom of a garden path in sentence processing is an

important anomaly in the input string. This anomaly signals to the parser that an

error has occurred, and provides cues for how to repair it. Anomaly detection is

thus an important aspect of sentence processing. In the present study, we

investigated how the parser responds to unambiguous sentences that contain

syntactic anomalies and pragmatic anomalies, examining records of eye movement

during reading. While sensitivity to the two kinds of anomaly was very rapid and

essentially simultaneous, qualitative differences existed in the patterns of first-

pass reading times and eye regressions. The results are compatible with the

proposal that syntactic information and pragmatic information are used

differently in garden-path recovery.

214. Ni, W.; Fodor, J. D.; Crain, S.; Shankweiler, D. Anomaly detection: eye movement

patterns. J-Psycholinguist-Res. 1998 Sep; 27(5): 515-39; ISSN: 0090-6905.

UNITED-STATES. The symptom of a garden path in sentence processing is an

important anomaly in the input string. This anomaly signals to the parser that an

error has occurred, and provides cues for how to repair it. Anomaly detection is

thus an important aspect of sentence processing. In the present study, we

investigated how the parser responds to unambiguous sentences that contain

syntactic anomalies and pragmatic anomalies, examining records of eye movement

during reading. While sensitivity to the two kinds of anomaly was very rapid and

essentially simultaneous, qualitative differences existed in the patterns of first-

pass reading times and eye regressions. The results are compatible with the

proposal that syntactic information and pragmatic information are used

differently in garden-path recovery.

215. Nicol, D. J.; Granat, M. H.; Tuson, S. J.; Baxendale, R. H. Variability of the

dishabituation of flexion reflexes for FES assisted gait in spinal injured man. Med-

Eng-Phys. 1998 Apr; 20(3): 182-7; ISSN: 1350-4533.

ENGLAND. Flexion reflexes, elicited by surface stimulation, can be used to

produce a simple form of stepping in spinal cord injured (SCI) humans. A

drawback of this approach is a decreasing magnitude of flexion reflex to repeated

presentations of the stimuli (habituation). Pilot data indicated that high intensity

stimulation could produce dishabituation of the reflex. The aim of this study was

to examine and quantify the inter- and intra-subject variability of the short and

long term conditioning effect of high intensity stimulation on the magnitude of

flexion reflexes in a larger number of SCI subjects. Dishabituation was observed in

all subjects, however the amount of dishabituation observed was small and highly

variable. However the use of high intensity conditioning stimulation may offer a

means of coping with habituation in a small number of subjects.

216. Niehaus, L.; Meyer, B. U.; Roricht, S. Magnetic stimulation over different brain

regions: no differential effects on the elicited sympathetic skin responses.

Electroencephalogr-Clin-Neurophysiol. 1998 Apr; 109(2): 94-9; ISSN: 0013-

4694.

IRELAND. Peak latencies and amplitudes of sympathetic skin responses (SSRs)

of the hand following magnetic stimulation at different sites with two or five

consecutive 10-Hz stimuli were investigated with regard to safety aspects of

repetitive transcranial magnetic cortex stimulation (rTMS). The amount of

sympathetic activation as assessed by the amplitudes of the SSRs depended on

the stimulation site and decreased in the following order: brachial plexus

stimulation > nerve root stimulation > stimulation over the brain > activation by

acoustic coil artefact. When stimulating over six different regions of the cortex

(frontal, central, parieto-occipital, and both hemispheres), the elicited SSRs had

similar amplitudes and peak latencies. The SSRs elicited by rTMS over the motor

cortex were not related to the sum of the amplitudes of excitatory muscle

compound responses. Currents with opposite directions over the motor cortex

markedly influenced the size of the motor responses but not of the SSRs. The

number of consecutive 10-Hz stimuli did not influence the latencies or amplitudes

of the SSRs. It can be concluded that SSRs after magnetic stimulation over

peripheral nerves or the brain are a correlate of an unspecific arousal reaction. A

therapeutic application of short series of rTMS should not be limited by the

amount of sympathetic activation.

217. Nikkhah, G.; Rosenthal, C.; Falkenstein, G.; Samii, M. Dopaminergic graft-induced

long-term recovery of complex sensorimotor behaviors in a rat model of

Parkinson's disease. Zentralbl-Neurochir. 1998; 59(2): 97-103; ISSN: 0044-4251.

GERMANY. Transplantation of embryonic dopamine neurons has evolved as an

alternative neurosurgical treatment strategy for patients with Parkinson's disease

and it is therefore of great interest to further optimise this procedure in

experimental studies. We have applied a modified microtransplantation approach

in unilaterally 6-hydroxydopamine lesioned rats and observed a substantial and

long-lasting functional recovery in complex spontaneous behaviors, such as skilled

forelimb use and stepping behavior. The results demonstrate that the rat model of

Parkinson's disease is a highly useful tool to study mechanisms of neural

plasticity and regeneration. The ability of dopaminergic grafts to restore complex

sensorimotor behaviors in animals also indicate their great potential for the

development of a successful clinical application.. 1199-18-4; 51-61-6.

218. Nixon, P. D.; Passingham, R. E. The striatum and self-paced movements. Behav-

Neurosci. 1998 Jun; 112(3): 719-24; ISSN: 0735-7044.

UNITED-STATES. Monkeys (Macacca fascicularis) were tested for their ability

to perform learned, self-initiated arm movements for reward, both before and after

receiving bilateral putamen lesions. The rate at which they made the movements

was significantly reduced postoperatively, but their performance on a visually

cued control task was normal. It is argued that the impairment was not a

consequence of poor motor control or motivation, but that it reflected a reduced

capacity to recall learned movements in the absence of external cues. The results

complement similar findings for monkeys with supplementary motor cortex

(SMA) lesions; the putamen is interconnected with the SMA in a cortico-striatal-

thalamocortical loop.

219. Nixon, P. D.; Passingham, R. E. The striatum and self-paced movements. Behav-

Neurosci. 1998 Jun; 112(3): 719-24; ISSN: 0735-7044.

UNITED-STATES. Monkeys (Macacca fascicularis) were tested for their ability

to perform learned, self-initiated arm movements for reward, both before and after

receiving bilateral putamen lesions. The rate at which they made the movements

was significantly reduced postoperatively, but their performance on a visually

cued control task was normal. It is argued that the impairment was not a

consequence of poor motor control or motivation, but that it reflected a reduced

capacity to recall learned movements in the absence of external cues. The results

complement similar findings for monkeys with supplementary motor cortex

(SMA) lesions; the putamen is interconnected with the SMA in a cortico-striatal-

thalamocortical loop.

220. O'Driscoll, G. A.; Lenzenweger, M. F.; Holzman, P. S. Antisaccades and smooth

pursuit eye tracking and schizotypy. Arch-Gen-Psychiatry. 1998 Sep; 55(9):

837-43; ISSN: 0003-990X.

UNITED-STATES. BACKGROUND: Eye tracking deficits are one of a few

widely validated behavioral markers of risk for schizophrenia. Recently, it has

been proposed that antisaccade performance may also constitute a marker of

schizophrenia risk. This study investigated whether eye tracking and antisaccade

deficits could be found in another population with putative liability to

schizophrenia-nonclinical subjects with elevated scores on a psychometric index

of perceptual aberrations. METHODS: Subjects were 55 university students who

received either high or normal scores on the Perceptual Aberration Scale, a

measure of schizotypy indexing body image and perceptual distortions. Subjects

completed a smooth pursuit eye tracking task and an antisaccade task. Eye

movements were monitored using an infrared limbus tracker. RESULTS: Subjects

with high Perceptual Aberration Scale scores (putative "schizotypes") had lower

pursuit quality and a lower percentage correct on the antisaccade task than the

controls. The 2 groups did not differ in antisaccade or error latencies. The increase

in antisaccade errors in the schizotypes was accounted for almost entirely by an

increase in perseverative errors, but virtually no difference between groups on

random errors. Antisaccade performance was significantly related to pursuit

quality. CONCLUSIONS: Subjects with elevated Perceptual Aberration Scale

scores have performance deficits on oculomotor tasks that have been linked to

latent liability to schizophrenia, namely, smooth pursuit and antisaccade

performance. The antisaccade errors in the schizotype group were primarily

perseverations, a behavioral pattern often associated with frontal lobe dysfunction

and observed in the performance of schizophrenic patients.. 0.

221. O'Driscoll, G. A.; Lenzenweger, M. F.; Holzman, P. S. Antisaccades and smooth

pursuit eye tracking and schizotypy. Arch-Gen-Psychiatry. 1998 Sep; 55(9):

837-43; ISSN: 0003-990X.

UNITED-STATES. BACKGROUND: Eye tracking deficits are one of a few

widely validated behavioral markers of risk for schizophrenia. Recently, it has

been proposed that antisaccade performance may also constitute a marker of

schizophrenia risk. This study investigated whether eye tracking and antisaccade

deficits could be found in another population with putative liability to

schizophrenia-nonclinical subjects with elevated scores on a psychometric index

of perceptual aberrations. METHODS: Subjects were 55 university students who

received either high or normal scores on the Perceptual Aberration Scale, a

measure of schizotypy indexing body image and perceptual distortions. Subjects

completed a smooth pursuit eye tracking task and an antisaccade task. Eye

movements were monitored using an infrared limbus tracker. RESULTS: Subjects

with high Perceptual Aberration Scale scores (putative "schizotypes") had lower

pursuit quality and a lower percentage correct on the antisaccade task than the

controls. The 2 groups did not differ in antisaccade or error latencies. The increase

in antisaccade errors in the schizotypes was accounted for almost entirely by an

increase in perseverative errors, but virtually no difference between groups on

random errors. Antisaccade performance was significantly related to pursuit

quality. CONCLUSIONS: Subjects with elevated Perceptual Aberration Scale

scores have performance deficits on oculomotor tasks that have been linked to

latent liability to schizophrenia, namely, smooth pursuit and antisaccade

performance. The antisaccade errors in the schizotype group were primarily

perseverations, a behavioral pattern often associated with frontal lobe dysfunction

and observed in the performance of schizophrenic patients.. 0.

222. Ohhira, S.; Miyahara, H.; Fujita, N.; Ueda, T.; Yamanaka, T.; Murai, T.; Yamamoto,

T.; Matsunaga, T. Influence of hyperlipidemia and smoking on age-related changes

in caloric response and pure-tone hearing. Acta-Otolaryngol-Suppl-Stockh. 1998;

533: 40-5; ISSN: 0365-5237.

NORWAY. To examine the influence of hyperlipidemia and smoking on age-

related changes in caloric response and pure-tone hearing, a caloric test and pure-

tone audiometry were performed in 14 healthy volunteers and in 78 tinnitus

patients without subjective hearing loss. The patients were from 24 to 84 years of

age, and were divided into 4 groups: the no-risk group (N group), the smoking

alone group (S group), the hyperlipidemia alone group (L group), and the smoking

plus hyperlipidemia group (S-L group). Slow phase eye velocity of the caloric

nystagmus (SPEV) and average hearing level at high frequencies were compared

between the N groups and the other groups. There was a significant difference in

SPEV only between the N and S-L groups, but not in the hearing level. This

suggests that age-related changes in the caloric response be promoted by

atherosclerosis, unlike presbycusis.

223. Ohue, S.; Kumon, Y.; Kohno, K.; Nagato, S.; Nakagawa, K.; Ohta, S.; Sakaki, S.;

Kusunoki, K. [Surgical management for preserving motor function in patients with

gliomas near the primary motor cortex: usefulness of preoperative identification of

motor cortex and intraoperative monitoring of motor evoked potentials]. No-

Shinkei-Geka. 1998 Jul; 26(7): 599-606; ISSN: 0301-2603.

JAPAN. Preoperative identification of precentral gyrus and intraoperative

monitoring of motor evoked potentials (MEPs) were performed to preserve

postoperative motor function in seven patients with gliomas near the primary

motor cortex. Tumors were astrocytomas in 3 patients, glioblastomas in 2

patients, anaplastic astrocytoma and mixed glioma in one patient each.

Preoperative identification of the primary motor cortex was performed by three-

dimensional (3D) display of magnetic resonance (MR) images and by functional

images using MR imaging and single-photon emission tomography. The primary

motor cortex identified by 3D display of MR images coincided well with that

identified by functional images. 3D display of MR images was also useful for

detecting the relationship between the tumor and the primary motor cortex.

Intraoperatively, the central sulcus was confirmed by the finding of phase reversal

of cortical somatosensory evoked potential, and this corresponded with the

preoperative identifications by 3D display and by functional mapping. The

primary motor cortex was stimulated electrically, and MEP (corticospinal evoked

potential) was continuously monitored during surgery using electrodes inserted in

the cervical epidural space. The amplitude of direct waves of MEPs during

surgery was maintained above half of that recorded at the beginning of tumor

removal, and all patients showed preservation of preoperative motor function.

These results suggest that preoperative identification of precentral gyrus and

intraoperative MEP monitoring provide useful information for preserving motor

function in patients with gliomas near the primary motor cortex.

224. Oliva, M.; Martin Garcia, M. A.; Bartual, J.; Ariza, A.; Garcia Teno, M. [The head-

thrust test (HTT): physiopathological considerations and its clinical use in daily

practice]. El test de movimientos cefalicos bruscos [head-thrust test (HTT)]:

consideraciones fisiopatologicas y utilidad en la clinica diaria. Acta-

Otorrinolaringol-Esp. 1998 May; 49(4): 275-9; ISSN: 0001-6519.

SPAIN. The basis of the head-thrust test is that when a head thrust is made in

the horizontal plane, the ipsilateral semicircular channel (SCC) shows gaze

stabilization because the homolateral SCC is completely inhibited. This test was

studied by electronystagmography and the main parameters, the amplitude and

latency of the compensatory ocular movements, were analyzed. The sensitivity,

specificity, and positive and negative predictive value of this test were estimated

in a series of 22 patients. The values were, respectively, 54, 100, 100 and 68%.

225. Onodera, S.; Hicks, T. P. Projections from substantia nigra and zona incerta to the

cat's nucleus of Darkschewitsch. J-Comp-Neurol. 1998 Jul 13; 396(4): 461-82;

ISSN: 0021-9967.

UNITED-STATES. The goal of the present experiments was to examine the

relationships of the nucleus of Darkschewitsch (ND) with the substantia nigra

pars reticulata (SNr), the zona incerta (ZI), and the oculomotor nuclei by using

wheat germ agglutinin-horseradish peroxidase (WGA-HRP) as a retrograde and

anterograde neuronal tracer injected into various sites of the cat's brain. To

eliminate the possibility that fibres of passage from the motor cortex passing

through the SNr and ZI were responsible for the ND label, WGA-HRP also was

injected into the SNr or the ZI after a large area of the frontal cortex, including the

motor area, was destroyed. Retrograde axonal transport demonstrated that many

cells of the rostromedial part of the ZI project to the ND, with the ipsilateral

projections being dominant. Some cells of the caudomedial part of the SNr project

to the ND, again, with the ipsilateral projection being dominant. A few small cells

in the ND project bilaterally to the oculomotor nucleus. Anterograde tracer

demonstrated that the SNr-ND terminal fields are less dense than the ZI-ND

terminal fields. A few fine terminal fibres were observed bilaterally in the

oculomotor, trochlear, and abducens nuclei. Electron microscopic examination

demonstrated that these fine, labelled terminals contain pleomorphic vesicles and

have symmetrical synaptic contacts with dendrites. These results indicate that the

ND, a structure that is known to be important for the control of axial muscles

(i.e., eye, head, and body muscles), is the target of projections from restricted

areas of the SNr and ZI: areas that, during saccadic eye movement, may lead to

disinhibition of the ND-oculomotor projection. Accordingly, the ND may

function to inhibit the activity of extraocular muscles during saccades.. EC

1.11.1.-; 0; 0; 9012-63-9.

226. Onodera, S.; Hicks, T. P. Projections from substantia nigra and zona incerta to the

cat's nucleus of Darkschewitsch. J-Comp-Neurol. 1998 Jul 13; 396(4): 461-82;

ISSN: 0021-9967.

UNITED-STATES. The goal of the present experiments was to examine the

relationships of the nucleus of Darkschewitsch (ND) with the substantia nigra

pars reticulata (SNr), the zona incerta (ZI), and the oculomotor nuclei by using

wheat germ agglutinin-horseradish peroxidase (WGA-HRP) as a retrograde and

anterograde neuronal tracer injected into various sites of the cat's brain. To

eliminate the possibility that fibres of passage from the motor cortex passing

through the SNr and ZI were responsible for the ND label, WGA-HRP also was

injected into the SNr or the ZI after a large area of the frontal cortex, including the

motor area, was destroyed. Retrograde axonal transport demonstrated that many

cells of the rostromedial part of the ZI project to the ND, with the ipsilateral

projections being dominant. Some cells of the caudomedial part of the SNr project

to the ND, again, with the ipsilateral projection being dominant. A few small cells

in the ND project bilaterally to the oculomotor nucleus. Anterograde tracer

demonstrated that the SNr-ND terminal fields are less dense than the ZI-ND

terminal fields. A few fine terminal fibres were observed bilaterally in the

oculomotor, trochlear, and abducens nuclei. Electron microscopic examination

demonstrated that these fine, labelled terminals contain pleomorphic vesicles and

have symmetrical synaptic contacts with dendrites. These results indicate that the

ND, a structure that is known to be important for the control of axial muscles

(i.e., eye, head, and body muscles), is the target of projections from restricted

areas of the SNr and ZI: areas that, during saccadic eye movement, may lead to

disinhibition of the ND-oculomotor projection. Accordingly, the ND may

function to inhibit the activity of extraocular muscles during saccades.. EC

1.11.1.-; 0; 0; 9012-63-9.

227. Onodera, S.; Hicks, T. P. Projections from substantia nigra and zona incerta to the

cat's nucleus of Darkschewitsch. J-Comp-Neurol. 1998 Jul 13; 396(4): 461-82;

ISSN: 0021-9967.

UNITED-STATES. The goal of the present experiments was to examine the

relationships of the nucleus of Darkschewitsch (ND) with the substantia nigra

pars reticulata (SNr), the zona incerta (ZI), and the oculomotor nuclei by using

wheat germ agglutinin-horseradish peroxidase (WGA-HRP) as a retrograde and

anterograde neuronal tracer injected into various sites of the cat's brain. To

eliminate the possibility that fibres of passage from the motor cortex passing

through the SNr and ZI were responsible for the ND label, WGA-HRP also was

injected into the SNr or the ZI after a large area of the frontal cortex, including the

motor area, was destroyed. Retrograde axonal transport demonstrated that many

cells of the rostromedial part of the ZI project to the ND, with the ipsilateral

projections being dominant. Some cells of the caudomedial part of the SNr project

to the ND, again, with the ipsilateral projection being dominant. A few small cells

in the ND project bilaterally to the oculomotor nucleus. Anterograde tracer

demonstrated that the SNr-ND terminal fields are less dense than the ZI-ND

terminal fields. A few fine terminal fibres were observed bilaterally in the

oculomotor, trochlear, and abducens nuclei. Electron microscopic examination

demonstrated that these fine, labelled terminals contain pleomorphic vesicles and

have symmetrical synaptic contacts with dendrites. These results indicate that the

ND, a structure that is known to be important for the control of axial muscles

(i.e., eye, head, and body muscles), is the target of projections from restricted

areas of the SNr and ZI: areas that, during saccadic eye movement, may lead to

disinhibition of the ND-oculomotor projection. Accordingly, the ND may

function to inhibit the activity of extraocular muscles during saccades.. EC

1.11.1.-; 0; 0; 9012-63-9.

228. Panger, M. A. Object-use in free-ranging white-faced capuchins (Cebus capucinus) in

Costa Rica. Am-J-Phys-Anthropol. 1998 Jul; 106(3): 311-21; ISSN: 0002-9483.

UNITED-STATES. Chimpanzees and capuchins demonstrate greater varieties

and higher rates of tool-use when compared to other non-human primates.

Although capuchins have been studied extensively in captivity, data on their tool-

using behavior under free-ranging conditions are limited. This is the first long-term

field research to systematically study complex object manipulation in capuchins.

The aims of this research are 1) to examine the types, rates, and contexts of tool-

and object-use in free-ranging capuchins and 2) to determine if free-ranging

capuchins' object manipulation behavior is comparable to the behavior exhibited

by captive individuals. Data on 3 troops of white-faced capuchins (Cebus

capucinus) were collected from February 1995 to January 1996 at Palo Verde,

Costa Rica. Data were collected using focal animal and ad libitum sampling

techniques. Any observed incident of tool-use and object-use was recorded. No

tool-use was observed during the 11-month study. Object-use (pound, rub, and

fulcrum-use) occurred at a rate of 0.19/hr and made up less than 1% of the

monkeys' time (there were no differences among the age/sex classes). The results

indicate that free-ranging capuchins do not exhibit the range of tool-using behavior

demonstrated by their captive counterparts. This may be the result of differential

motivational responses to objects, arboreal lifestyle, absence of adequate tool

material, and/or absence of food resources that require extraction involving tool-

use.

229. Patterson, C. M. The role of the primary care physician in maximizing cognitive and

behavioral recovery from moderate to severe pediatric traumatic brain injury. J-

Ark-Med-Soc. 1998 Aug; 95(3): 109-13; ISSN: 0004-1858.

UNITED-STATES. Traumatic brain injury (TBI) is a major cause of death and

the most common cause of acquired disability in children. Moderate to severe TBI

typically results in cognitive deficits, and behavioral and psychosocial adjustment

problems, sometimes compromising long term development. Although variable,

considerable recovery can occur, especially over the first one to two years post-

injury. Appropriate educational and psychological intervention is critical to

positive outcome. The primary care physician (PCP) has a major role in

monitoring progress and intervention, and therefore in maximizing outcome. The

short term neurocognitive and neurobehavioral sequelae and recovery pattern for

traumatic brain injury, and the role of the primary care physician in maximizing

recovery based on risk factors are described. Some intervention resources are

included.

230. Pavlova, I. V. [The functional asymmetry of the rabbit medial hypothalamus during

the avoidance reaction]. Funktsional'naia asimmetriia medial'nogo gipotalamusa

krolika pri reaktsii izbeganiia. Zh-Vyssh-Nerv-Deiat-Im-I-P-Pavlova. 1998 May;

48(3): 396-404; ISSN: 0044-4677.

RUSSIA. Thresholds of avoidance reactions and changes in correlated neuronal

activity in the visual and sensorimotor cortical areas were studied in rabbits under

conditions of stimulation of right (RH) and left (LH) medial hypothalamus.

Avoidance threshold were lower during stimulation of the LH (112 +/- 12 mcA)

than during stimulation of the RH (166 +/- 22 mcA). The stimulation of LH was

more effective in inducing reorganization in correlated activity of neurons: only

after the left stimulation (inducing active avoidance) the number of neuronal pairs

with correlated activity in the left hemisphere increased (49%) and delays up to

120 ms appeared between the discharges of visual and sensorimotor cortical

neurons (the first one led). The obtained evidence suggests the more important

role of the LH than RH in motivation.

231. Pellegrini, A. D.; Smith, P. K. Physical activity play: the nature and function of a

neglected aspect of playing [see comments]. Child-Dev. 1998 Jun; 69(3): 577-98;

ISSN: 0009-3920.

Note: Comment in: Child Dev 1998 Jun;69(3):604-6. Comment in: Child Dev

1998 Jun;69(3):607-8.

UNITED-STATES. In this review, we consider the nature and possible

developmental functions of physical activity play, defined as a playful context

combined with a dimension of physical vigor. We distinguish 3 kinds of physical

activity play, with consecutive age peaks: rhythmic stereotypies peaking in

infancy, exercise play peaking during the preschool years, and rough-and-tumble

play peaking in middle childhood. Gender differences (greater prevalence in males)

characterize the latter 2 forms. Function is considered in terms of beneficial

immediate and deferred consequences in physical, cognitive, and social domains.

Whereas most theories assume that children's play has deferred benefits, we

suggest that forms of physical activity play serve primarily immediate

developmental functions. Rhythmic stereotypies in infancy are hypothesized to

improve control of specific motor patterns. Exercise play is hypothesized to

function primarily for strength and endurance training; less clear evidence exists

for possible benefits for fat reduction and thermoregulation. In addition, there may

be cognitive benefits of exercise play that we hypothesize to be largely incidental

to its playful or physical nature. Rough-and-tumble play has a distinctive social

component; we hypothesize that it serves primarily dominance functions;

evidence for benefits to fighting skills or to emotional coding are more equivocal.

Further research is indicated, given the potentially important implications for

children's education, health, and development.

232. Penta, M.; Thonnard, J. L.; Tesio, L. ABILHAND: a Rasch-built measure of manual

ability. Arch-Phys-Med-Rehabil. 1998 Sep; 79(9): 1038-42; ISSN: 0003-9993.

UNITED-STATES. OBJECTIVE: To apply the Rasch measurement model to

the development of a clinical tool for measuring manual (dis)ability

(ABILHAND). DESIGN: Manual ability was evaluated in terms of the difficulty

perceived by a hand-impaired patient on 57 representative unimanual or bimanual

activities. SETTING: A clinical laboratory. PATIENTS: Eighteen rheumatoid

arthritis patients (14 women, 4 men) were interviewed after wrist arthrodesis (10

right, 4 left, and 4 both wrists). Their ages ranged from 38 to 77 years, time since

diagnosis ranged from 7 to 41 years, and time since surgery ranged from 0.5 to 17

years. MAIN OUTCOME MEASURE: ABILHAND, administered at a mean

duration of 7 years after arthrodesis. RESULTS: Forty-six of the 57 items define a

common, single manual ability continuum with widespread measurement range

and regular item distribution. Items relating to feeding, grooming, and dressing

upper body worked consistently with their counterparts in other disability scales.

More difficult items extend the measurement range beyond that of most existing

manual ability scales. CONCLUSION: Even in a small sample of patients, using

the Rasch methodology enabled the investigators to produce a useful scale of

manual (dis)ability and to define manual ability as a unique construct, at least in

patients with rheumatoid arthritis.

233. Perakyla, T.; Tikkanen, H.; von Knorring, J.; Lepantalo, M. Poor reproducibility of

exercise test in assessment of claudication. Clin-Physiol. 1998 May; 18(3): 187-

93; ISSN: 0144-5979.

ENGLAND. To assess reproducibility of the exercise test in intermittent

claudication, a prospective, comparative, randomized study was undertaken. Ten

patients with stable intermittent claudication of ischaemic origin were exercised on

a flat surface (0-Ex), with 12% steady inclination (12-Ex) and with progressively

increasing inclination (p-Ex) in a random order during three different sessions. The

ankle-brachial index (ABI) at rest and after exercise (rABI, exABI), initial and

maximum walking distance (IWD, MWD) and metabolic equivalent (MET) were

obtained as the main outcome measures. The results were analysed using

intraindividual coefficients of variation (CVs) and standard deviations (SDs). The

ABI values of the worst extremity were used in evaluation of results.

Reproducibility of the exercise ABI appeared to be good, especially during

progressively increasing exercise, the mean CV being 9 +/- 5%. The best mean CV

was observed during p-Ex (16% +/- 14%) for maximum walking distance. The

mean CV for initial walking distances ranged from 30% to 54%. Treadmill exercise

testing to measure walking distances is highly inaccurate and the value of exercise

on the flat treadmill should be questioned. Graded exercise appeared to be the

most reproducible in this respect. The ABI after exercise, however, was a reliable

single parameter when assessing arterial insufficiency causing decreased walking

capacity.

234. Ploner, C. J.; Gaymard, B.; Rivaud, S.; Agid, Y.; Pierrot Deseilligny, C. Temporal

limits of spatial working memory in humans. Eur-J-Neurosci. 1998 Feb; 10(2):

794-7; ISSN: 0953-816X.

FRANCE. An essential feature attributed to working memory is the labile and

transient nature of its representations. Using an oculomotor task, we examined the

stability of spatial working memory in 16 normal human subjects. Eye

movements towards remembered spatial cues (memory-guided saccades) were

electro-oculographically recorded after memorization delays that varied

unpredictably between 0.5 and 30s. A peaked time-course of saccadic targeting

errors, with maximal errors around 20s delay, was found, showing that delay-

dependent decay of spatial information in working memory occurs, but is time-

limited and reverts significantly beyond delays of about 20s. These data (i)

indicate temporal limits of spatial working memory and (ii) provide the first

behavioural evidence for the existence of two parallely generated mental

representations of space that successively control memory-guided behaviour in

humans.

235. Ploner, C. J.; Gaymard, B.; Rivaud, S.; Agid, Y.; Pierrot Deseilligny, C. Temporal

limits of spatial working memory in humans. Eur-J-Neurosci. 1998 Feb; 10(2):

794-7; ISSN: 0953-816X.

FRANCE. An essential feature attributed to working memory is the labile and

transient nature of its representations. Using an oculomotor task, we examined the

stability of spatial working memory in 16 normal human subjects. Eye

movements towards remembered spatial cues (memory-guided saccades) were

electro-oculographically recorded after memorization delays that varied

unpredictably between 0.5 and 30s. A peaked time-course of saccadic targeting

errors, with maximal errors around 20s delay, was found, showing that delay-

dependent decay of spatial information in working memory occurs, but is time-

limited and reverts significantly beyond delays of about 20s. These data (i)

indicate temporal limits of spatial working memory and (ii) provide the first

behavioural evidence for the existence of two parallely generated mental

representations of space that successively control memory-guided behaviour in

humans.

236. Porr, B.; Cozzi, A.; Worgotter, F. How to "hear" visual disparities: real-time

stereoscopic spatial depth analysis using temporal resonance. Biol-Cybern. 1998

May; 78(5): 329-36; ISSN: 0340-1200.

GERMANY. In a stereoscopic system, both eyes or cameras have a slightly

different view. As a consequence, small variations between the projected images

exist ('disparities') which are spatially evaluated in order to retrieve depth

information (Sanger 1988; Fleet et al. 1991). A strong similarity exists between

the analysis of visual disparities and the determination of the azimuth of a sound

source (Wagner and Frost 1993). The direction of the sound is thereby determined

from the temporal delay between the left and right ear signals (Konishi and

Sullivan 1986). Similarly, here we transpose the spatially defined problem of

disparity analysis into the temporal domain and utilize two resonators

implemented in the form of causal (electronic) filters to determine the disparity as

local temporal phase differences between the left and right filter responses. This

approach permits real-time analysis and can be solved analytically for a step

function contrast change, which is an important case in all real-world applications.

The proposed theoretical framework for spatial depth retrieval directly utilizes a

temporal algorithm borrowed from auditory signal analysis. Thus, the suggested

similarity between the visual and the auditory system in the brain (Wagner and

Frost 1993) finds its analogy here at the algorithmical level. We will compare the

results from the temporal resonance algorithm with those obtained from several

other techniques like cross-correlation or spatial phase-based disparity estimation

showing that the novel algorithm achieves performances similar to the 'classical'

approaches using much lower computational resources.

237. Powell, K. E.; Heath, G. W.; Kresnow, M. J.; Sacks, J. J.; Branche, C. M. Injury rates

from walking, gardening, weightlifting, outdoor bicycling, and aerobics. Med-Sci-

Sports-Exerc. 1998 Aug; 30(8): 1246-9; ISSN: 0195-9131.

UNITED-STATES. PURPOSE:The objective of this survey was to estimate the

frequency of injuries associated with five commonly performed moderately

intense activities: walking for exercise, gardening and yard work, weightlifting,

aerobic dance, and outdoor bicycling. METHODS: National estimates were

derived from weighted responses of over 5,000 individuals contacted between

April 28 and September 18, 1994, via random-digit dialing of U.S. residential

telephone numbers. Self-reported participation in these five activities in the late

spring and summer of 1994 was common, ranging from an estimated 14.5 +/- 1.2%

of the population for aerobics (nearly 30 million people) to 73.0 +/- 1.5% for

walking (about 138 million people). RESULTS: Among participants, the activity-

specific 30-d prevalence of injury ranged from 0.9 +- 0.5% for outdoor bicycle

riding to 2.4 +- 1.3% for weightlifting. The estimated number in the 30 d of

people injured in the 30 d before their interview ranged from 330,000 for outdoor

bicycle riding to 2.1 million for gardening or yard work. Incidence rates for injury

causing reduced participation in activity were 1.1 +/- 0.5x100 participantsx30 d

for walking, 1.1 +/- 0.4 for gardening, and 3.3 +/- 1.9 for weightlifting. During

walking and gardening, men and women were equally likely to be injured, but

younger people (18-44 yr) were more likely to be injured than older people (45 +

yr). Injury rates were low, yet large numbers of people were injured because

participation rates were high. Most injuries were minor, but injuries may reduce

participation in these otherwise beneficial activities. CONCLUSIONS: Additional

studies to confirm the magnitude of the problem, to identify modifiable risk

factors, and to recommend methods to reduce the frequency of such injuries are

needed.

238. Pridmore, S.; Fernandes Filho, J. A.; Nahas, Z.; Liberatos, C.; George, M. S. Motor

threshold in transcranial magnetic stimulation: a comparison of a

neurophysiological method and a visualization of movement method. J-ECT. 1998

Mar; 14(1): 25-7; ISSN: 1095-0680.

UNITED-STATES. Motor threshold is a means of quantifying stimulus in

transcranial magnetic stimulation. Two methods are used. One involves

neurophysiology techniques and the other is visualization of movement. The aim

was to compare the percentage of total machine output (PTMO) necessary to

achieve motor threshold using these different methods. Neurophysiological and

visualization of movement thresholds were determined in six subjects. In all

subjects, the two thresholds were achieved with a < 10% difference in PTMO.

Determination of motor threshold with a neurophysiological and a visualization of

movement method produced similar results.

239. Pridmore, S.; Fernandes Filho, J. A.; Nahas, Z.; Liberatos, C.; George, M. S. Motor

threshold in transcranial magnetic stimulation: a comparison of a

neurophysiological method and a visualization of movement method. J-ECT. 1998

Mar; 14(1): 25-7; ISSN: 1095-0680.

UNITED-STATES. Motor threshold is a means of quantifying stimulus in

transcranial magnetic stimulation. Two methods are used. One involves

neurophysiology techniques and the other is visualization of movement. The aim

was to compare the percentage of total machine output (PTMO) necessary to

achieve motor threshold using these different methods. Neurophysiological and

visualization of movement thresholds were determined in six subjects. In all

subjects, the two thresholds were achieved with a < 10% difference in PTMO.

Determination of motor threshold with a neurophysiological and a visualization of

movement method produced similar results.

240. Prilutsky, B. I.; Gregor, R. J.; Ryan, M. M. Coordination of two-joint rectus femoris

and hamstrings during the swing phase of human walking and running. Exp-Brain-

Res. 1998 Jun; 120(4): 479-86; ISSN: 0014-4819.

GERMANY. It has been hypothesized previously that because a strong

correlation was found between the difference in electromyographic activity

(EMG) of rectus femoris (RF) and hamstrings (HA; EMG(RF)-EMG(HA)) and

the difference in the resultant moments at the knee and hip (Mk-Mh) during

exertion of external forces on the ground by the leg, input from skin receptors of

the foot may play an important role in the control of the distribution of the

resultant moments between the knee and hip by modulating activation of the two-

joint RF and HA. In the present study, we examined the coordination of RF and

HA during the swing phase of walking and running at different speeds, where

activity of foot mechanoreceptors is not modulated by an external force. Four

subjects walked at speeds of 1.8 m/s and 2.7 m/s and ran at speeds of 2.7 m/s and

3.6 m/s on a motor-driven treadmill. Surface EMG of RF, semimembranosus

(SM), and long head of biceps femoris (BF) and coordinates of the four leg joints

were recorded. An inverse dynamics analysis was used to calculate the resultant

moments at the ankle, knee, and hip during the swing phase. EMG signals were

rectified and low-pass filtered to obtain linear envelopes and then shifted in time

to account for electromechanical delay between EMG and joint moments. During

walking and running at all studied speeds, mean EMG envelope values of RF were

statistically (P<0.05) higher in the first half of the swing (or at hip flexion/knee

extension combinations of joint moments) than in the second half (or at hip

extension/knee flexion combinations of joint moments). Mean EMG values of BF

and SM were higher (P<0.05) in the second half of the swing than in the first half.

EMG and joint moment peaks were substantially higher (P<0.05) in the swing

phase of walking at 2.7 m/s than during the swing phase of running at the same

speed. Correlation coefficients calculated between the differences (EMG(RF)-

EMG(HA)) and (Mk-Mh), taken every 1% of the swing phase, were higher than

0.90 for all speeds of walking and running. Since the close relationship between

EMG and joint moments was obtained in the absence of an external force applied

to the foot, it was suggested that the observed coordination of RF and HA can be

regulated without a stance-specific modulation of cutaneous afferent input from

the foot. The functional role of the observed coordination of RF and HA was

suggested to reduce muscle fatigue.

241. Priori, A.; Berardelli, A.; Rona, S.; Accornero, N.; Manfredi, M. Polarization of the

human motor cortex through the scalp. Neuroreport. 1998 Jul 13; 9(10): 2257-60;

ISSN: 0959-4965.

ENGLAND. Direct currents (DC) applied directly to central nervous system

structures produce substantial and long-lasting effects in animal experiments. We

tested the functional effects of very weak scalp DC (< 0.5 mA, 7 s) on the human

motor cortex by assessing the changes in motor potentials evoked by transcranial

magnetic brain stimulation. We performed four different experiments in 15 healthy

volunteers. Our findings led to the conclusion that such weak (< 0.5 mA) anodal

scalp DC, alternated with a cathodal DC, significantly depresses the excitability

of the human motor cortex, providing evidence that a small electric field crosses

the skull and influences the brain. A possible mechanism of action of scalp DC is

the hyperpolarization of the superficial excitatory interneurones in the human

motor cortex.

242. Priori, A.; Berardelli, A.; Rona, S.; Accornero, N.; Manfredi, M. Polarization of the

human motor cortex through the scalp. Neuroreport. 1998 Jul 13; 9(10): 2257-60;

ISSN: 0959-4965.

ENGLAND. Direct currents (DC) applied directly to central nervous system

structures produce substantial and long-lasting effects in animal experiments. We

tested the functional effects of very weak scalp DC (< 0.5 mA, 7 s) on the human

motor cortex by assessing the changes in motor potentials evoked by transcranial

magnetic brain stimulation. We performed four different experiments in 15 healthy

volunteers. Our findings led to the conclusion that such weak (< 0.5 mA) anodal

scalp DC, alternated with a cathodal DC, significantly depresses the excitability

of the human motor cortex, providing evidence that a small electric field crosses

the skull and influences the brain. A possible mechanism of action of scalp DC is

the hyperpolarization of the superficial excitatory interneurones in the human

motor cortex.

243. Quarck, G.; Etard, O.; Darlot, C.; Denise, P. Motion sickness susceptibility correlates

with otolith- and canal-ocular reflexes. Neuroreport. 1998 Jul 13; 9(10): 2253-6;

ISSN: 0959-4965.

ENGLAND. Since motion sickness (MS) never occurs in individuals who lack

functional vestibular apparatus, it has been suggested that MS susceptible

individuals have more sensitive vestibular systems than non-susceptible people.

However, previous investigations involving only stimulation of the semi-circular

canals have been inconclusive. We measured gain and time constant (TC) of

horizontal canal-ocular reflex (COR) and magnitude of otolith-ocular reflex

(OOR). We found that MS susceptibility was not correlated to COR gain but was

negatively correlated to OOR magnitude. Thus, MS susceptible individuals do not

have more sensitive vestibular systems. We also found a positive correlation

between MS susceptibility and TC. We hypothesize that central vestibular

integration (velocity storage mechanism), by increasing low frequency vestibular

inputs, would favour MS.

244. Quinn, K. J.; Didier, A. J.; Baker, J. F.; Peterson, B. W. Modeling learning in brain

stem and cerebellar sites responsible for VOR plasticity. Brain-Res-Bull. 1998 Jul

1; 46(4): 333-46; ISSN: 0361-9230.

UNITED-STATES. A simple model of vestibuloocular reflex (VOR) function

was used to analyze several hypotheses currently held concerning the

characteristics of VOR plasticity. The network included a direct vestibular

pathway and an indirect path via the cerebellum. An optimization analysis of this

model suggests that regulation of brain stem sites is critical for the proper

modification of VOR gain. A more physiologically plausible learning rule was also

applied to this network. Analysis of these simulation results suggests that the

preferred error correction signal controlling gain modification of the VOR is the

direct output of the accessory optic system (AOS) to the vestibular nuclei vs. a

signal relayed through the cerebellum via floccular Purkinje cells. The potential

anatomical and physiological basis for this conclusion is discussed, in relation to

our current understanding of the latency of the adapted VOR response.

245. Rambold, H.; Helmchen, C.; Straube, A.; Buttner, U. Seesaw nystagmus associated

with involuntary torsional head oscillations. Neurology. 1998 Sep; 51(3): 831-7;

ISSN: 0028-3878.

UNITED-STATES. OBJECTIVE: To assess the diagnostic value of eye-head

coupling in seesaw nystagmus (SSN). BACKGROUND: SSN is a rare binocular

disorder characterized by alternating skew deviation and conjugate ocular torsion.

METHODS: We examined a patient with a congenital nystagmus that switched to

a pendular SSN on near viewing and was associated with involuntary torsional

head oscillations. RESULTS: The binocular torsional eye movements were in

phase with the clinically visible head oscillations (i.e., head movements were not

compensatory for the torsional eye movements). CONCLUSION: This finding

suggests that torsional eye-head coupling in pendular SSN has a common

pathologic origin. We suggest that alternating vertical disparity of both eyes in

pendular SSN is compatible with an oscillating signal acting on an intact vestibular

system. The absence of brainstem lesions on high-resolution MRI supports this

assumption.

246. Rantanen, T.; Guralnik, J. M.; Izmirlian, G.; Williamson, J. D.; Simonsick, E. M.;

Ferrucci, L.; Fried, L. P. Association of muscle strength with maximum walking

speed in disabled older women. Am-J-Phys-Med-Rehabil. 1998 Jul; 77(4): 299-

305; ISSN: 0894-9115.

UNITED-STATES. Our aim was to study the association of lower limb strength

with maximum walking speed in disabled older women and to try to detect the

reserve capacity threshold for maximum walking speed and the minimum strength

required for walking at a speed of 1.22 m x s(-1), which is required in crossing

signaled intersections. The data are from the baseline of Women's Health and

Aging Study, a population-based study on causes and course of disability.

Altogether, 1,002 disabled women participated in the tests, which took place at

their homes. Maximum isometric hip flexion and knee extension forces were

measured on both sides using a handheld dynamometer. For analytic purposes,

knee extension torque/body mass ratio (KET/BM) was calculated. Maximum

walking speed was measured with a stopwatch during a 4-m walk. KET/BM had a

significant effect on walking speed after controlling for number of chronic

conditions, balance, use of walking aid, joint pain, age, and body height and mass.

A total of 42.3% of the variation in maximum walking speed was explained by

these variables. The cumulative percentage distribution of KET/BM of those able

to attain a maximum walking speed of 1.22 m x s(-1) (n = 148) was flat to the

level of 1.1 N x m x kg(-1), after which it turned upward, indicating that the

probability of attaining 1.22 m x s(-1) started to increase after that level. By using

segmented linear regression analysis, 2.3 N x m x kg(-1) was found to be the cutoff

point beyond which an increase in KET/BM did not correspond to an increase in

maximum walking speed. Muscle strength was positively but not linearly

associated with maximum walking speed. Strength testing may help to identify

people close to functional thresholds and, thus, at risk of impaired walking, who

would benefit most from strengthening exercises.

247. Richter Levin, G. Acute and long-term behavioral correlates of underwater trauma--

potential relevance to stress and post-stress syndromes. Psychiatry-Res. 1998

Jun 2; 79(1): 73-83; ISSN: 0165-1781.

IRELAND. As a consequence of a brief but significantly extreme stressor, an

individual will experience a stress response, which may sometimes develop into

Acute Stress Disorder (ASD) or Post-Traumatic Stress Disorder (PTSD). Though

a rat model for ASD and PTSD is not expected to encompass the richness and

complexity of the disorders in humans, it will enable the study of the common

underlying mechanisms that generate the disorders, the study of pre-trauma

etiological aspects of the disorders and the screening of drugs with potential

relevance to the treatment of the disorders. One well-documented aspect of PTSD

is the enhancing influence of contextual elements on the appearance of symptoms

of the post-stress trauma. To exploit this effect, we have chosen to assess the

effects of an underwater trauma in the Morris water maze since the effects of such

trauma on memory and attention can be later evaluated in the context of the

trauma. At both 1 h and 3 weeks after the trauma, significant behavioral deficits

were observed in the water maze. The effects of the underwater trauma on the

performance of rats in the water maze were context specific. Underwater trauma

in a different (out-of-context) water container had no effects on the ability of rats

to perform a spatial memory task in the water maze. An elevated level of anxiety

was found in the plus maze test, independently of whether the trauma was

performed in the water maze or in a different (out-of-context) water container.

The results indicate that a within-context underwater trauma has both acute and

lasting behavioral consequences which can be assessed using a spatial memory test

in the context of the trauma. The results are discussed in relation to their relevance

to stress and PTSD.

248. Ringendahl, H. [Standardization of a motor performance series for measuring fine

motor disorders in Parkinson disease]. Normierung der Motorischen

Leistungsserie (MLS) fur die Messung feinmotorischer Storungen beim Morbus

Parkinson. Nervenarzt. 1998 Jun; 69(6): 507-15; ISSN: 0028-2804.

GERMANY. Some 114 patients with idiopathic Parkinson's disease (not

demented, no tremor dominance; mean age: 67.0 years; mean duration of illness:

6.1 years) were subjected to the manual dexterity test "MLS" ("Motorische

Leistungs Serie"). A retest was carried out 24 h later with no change in medication.

Thus, adequate conditions were present for testing the stability of dimensions of

manual dexterity. In addition, data from the initial measurement were normalized

(T norms). The correlations of the values from both measurements (retest

reliability) underscore the constancy of manual dexterity functions. Subtest show

adequate stability of measurement so that they can be used for diagnosing

dexterity disturbances in individual patients. Charts listing normal values and

critical differences allow intra- and interindividual comparisons. It is thus possible

to make statistically sound predictions for individual patients concerning the

effectiveness of therapy or progression of illness with respect to manual

dexterity. In addition, differences on the left and right sides can be tested for

statistic significance.

249. Rogers, B.; Andrus, J.; Msall, M. E.; Arvedson, J.; Sim, J.; Rossi, T.; Martin, D.;

Hudak, M. Growth of preterm infants with cystic periventricular leukomalacia.

Dev-Med-Child-Neurol. 1998 Sep; 40(9): 580-6; ISSN: 0012-1622.

ENGLAND. Etiology of the high rates of growth failure in children with cerebral

palsy (CP) remains unclear. The purpose of this study was to evaluate the

relation between growth failure in preterm infants with cystic periventricular

leukomalacia (CPVL) and neonatal health complications. The population

consisted of all preterm infants (51) with a gestational age of <33 weeks who were

admitted to the Children's Hospital of Buffalo from 1988 to 1993 and who had

CPVL. Out of the 41 survivors with CPVL who were followed, 39 developed CP

and 18 developed growth failure during infancy. At the time of greatest growth

failure, the majority (72%) of infants had signs of undernutrition as defined by the

Waterlow (1972) classification. Oral feeding impairment was the sole risk factor

for the occurrence of growth failure. Undernutrition appears to be important in

the occurrence of growth failure in preterm infants with CPVL and CP.

250. Romeo, S.; Berardelli, A.; Pedace, F.; Inghilleri, M.; Giovannelli, M.; Manfredi, M.

Cortical excitability in patients with essential tremor. Muscle-Nerve. 1998 Oct;

21(10): 1304-8; ISSN: 0148-639X.

UNITED-STATES. We used transcranial magnetic stimulation in 10 patients

with essential tremor and 8 matched healthy subjects. A round stimulating coil

was placed over the vertex and electromyographic activity was recorded from the

first dorsal interosseous muscle. Paired transcranial stimuli were delivered at

interstimulus intervals of 3, 5, 20, 100, 150, and 200 ms. The intensity of the

conditioning stimulus was 80% of motor threshold at short and 150% at long

interstimulus intervals (ISIs). We also measured the silent period obtained after a

single magnetic pulse delivered at 150% of motor threshold during a submaximal

muscle contraction. Patients and controls had similar motor threshold and similar

latencies. Paired magnetic stimuli given at short and long ISIs at rest, and during a

voluntary muscle contraction, elicited similar responses in both groups. The silent

period evoked by transcranial magnetic stimulation had a similar duration in

patients with ET and controls. In conclusion, these findings suggest that patients

with essential tremor have normal cortical motor area excitability.

251. Ropret, R.; Kukolj, M.; Ugarkovic, D.; Mat