Current understanding of the origins of cerebral specialization and of hemispheric interactions is fairly limited. For example, it is unclear which recognized cortical asymmetries lead to lateralization, whether the net influence of one hemisphere on the other is excitatory or inhibitory, and to the extent to which the intact contralateral hemisphere contributes to recovery following a cortical lesion such as a stroke. The long-term goal of this work is to gain a better understanding of these issues by developing and studying neural models of emergent hemispheric lateralization and of hemispheric interactions as those models recover from simulated cortical lesions. The models consist of networks of paired left and right cortical regions connected by a simulated corpus callosum.
The specific aims are: 1. to test the hypothesis that models have excitatory callosal connections and indirect interhemispheric competition can better explain data from biological/behavioral experiments than previous models; 2. to determine how learning one behavioral task can influence the direction/extent of another task's lateralization; 3. to determine how multiple underlying hemispheric asymmetries in a single model interact, altering the direction/extent of lateralization produced by each alone; and 4. to examine lateralization and post-lesion hemispheric interactions in a neurobiologically-grounded model of associative word learning that is directly comparable to behavioral, clinical and functional imaging data. This is the first systematic attempt to better understand cerebral specialization and transcallosal diaschisis using computational models. The results will directly relate to ongoing experimental work, have important implications for current theories of the mechanisms underlying hemispheric functional asymmetries and post-stroke recovery, and may suggest new therapeutic concepts for stroke patients.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS035460-07
Application #
6603229
Study Section
Special Emphasis Panel (ZRG1-IFCN-8 (01))
Program Officer
Marler, John R
Project Start
1996-09-20
Project End
2005-07-31
Budget Start
2003-08-01
Budget End
2004-07-31
Support Year
7
Fiscal Year
2003
Total Cost
$255,161
Indirect Cost
Name
University of Maryland College Park
Department
Biostatistics & Other Math Sci
Type
Other Domestic Higher Education
DUNS #
790934285
City
College Park
State
MD
Country
United States
Zip Code
20742
Sylvester, Jared; Reggia, James (2009) Plasticity-induced symmetry relationships between adjacent self-organizing topographic maps. Neural Comput 21:3429-43
Howard, Mary F; Reggia, James A (2007) A theory of the visual system biology underlying development of spatial frequency lateralization. Brain Cogn 64:111-23
Winder, Ransom; Cortes, Carlos R; Reggia, James A et al. (2007) Functional connectivity in fMRI: A modeling approach for estimation and for relating to local circuits. Neuroimage 34:1093-107
Reggia, James A (2004) Neurocomputational models of the remote effects of focal brain damage. Med Eng Phys 26:711-22
Howard, Mary F; Reggia, James A (2004) The effects of multi-task learning and time-varying hemispheric asymmetry on lateralisation in a neural network model. Laterality 9:113-31
Schulz, Reiner; Reggia, James A (2004) Temporally asymmetric learning supports sequence processing in multi-winner self-organizing maps. Neural Comput 16:535-61
Shevtsova, Natalia; Reggia, James A (2002) Effects of callosal lesions in a model of letter perception. Cogn Affect Behav Neurosci 2:37-51
Schulz, Reiner A; Reggia, James A (2002) Predicting nearest agent distances in artificial worlds. Artif Life 8:247-64
Reggia, J A; Goodall, S; Levitan, S (2001) Cortical map asymmetries in the context of transcallosal excitatory influences. Neuroreport 12:1609-14
Reggia, J A; Goodall, S M; Shkuro, Y et al. (2001) The callosal dilemma: explaining diaschisis in the context of hemispheric rivalry via a neural network model. Neurol Res 23:465-71

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