Svetlana Levitan

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There is long-standing disagreement among experimentalists about whether transcallosal interhemispheric influences are primarily excitatory or inhibitory. Past computational models exploring this issue have encountered a similar dilemma: inhibitory callosal influences best explain hemispheric functional asymmetries, but excitatory callosal influences best(More)
Cerebral lateralization refers to the poorly understood fact that some functions are better controlled by one side of the brain than the other (e.g. handedness, language). Of particular concern here are the asymmetries apparent in cortical topographic maps that can be demonstrated electrophysiologically in mirror-image locations of the cerebral cortex. In(More)
While recent experimental work has defined asymmetries and lateralization in left and right cortical maps, the mechanisms underlying these phenomena are currently not established. In order to explore some possible mechanisms in theory, we studied a neural model consisting of paired cerebral hemispheric regions interacting via a simulated corpus callosum.(More)
During recent years there has been increasing use of neural models to investigate the implications of hypotheses about brain and cognitive disorders. Here we systematically study the effects of sudden simulated lesions on cortical maps in a neural model consisting of left and right hemispheric regions connected by a corpus callosum. The model identifies(More)
Svetlana Levitan, Ioana Stoica, James A. Reggia Depts of Computer Science and Neurology, Inst. Adv. Comp. Studies University of Maryland, College Park, MD 20742 USA Email:, Abstract Cortical sensory maps in mammalian brain exhibit various kinds of asymmetry and lateralization, the causes and mechanisms of which are not(More)
We address the problem of measuring the degree of hemispheric organization and asymmetry of organization in a computational model of a bihemispheric cerebral cortex. A theoretical framework for such measures is developed and used to produce algorithms for measuring the degree of organization, symmetry, and lateralization in topographic map formation. The(More)
Title of Dissertation: MATHEMATICAL MODELING OF LATERALIZATION AND ASYMMETRIES IN CORTICAL MAPS Svetlana Levitan, Doctor of Philosophy, 1999 Dissertation directed by: Professor James A. Reggia Applied Mathematics Program Recent experimental work in neurobiology has de ned asymmetries and lateralization in the topographic maps found in mirror-image regions(More)
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