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Alexei Koulakov and Dmitri Chklovskii

Sloan Center for Theoretical Neurobiology, The Salk Institute

Ocular dominance patterns in mammalian visual cortex: A wire length optimization approach

We consider the problem of the ocular mapping from retinas of two eyes to the primary visual cortex from the point of view of minimization of intra-cortex axon length. We apply this principle to the mixture of the neurons belonging to two classes: responsible for the left and right eye. We obtain segregation of the uniform binary mixture into alternating regions of right and left-eye dominance (ocular dominance patterns). Two types of patterns are considered: Stripes, which comprises the series of stripes of right and left-eye dominance, and Patches, in which patches of neurons belonging to one class are surrounded by the other. The latter structure exists when one class is diluted with respect to the other. The former is formed when two ocular dominance classes have average densities that are close. Based on the parameters of our model we build the phase diagram reflecting the coexistence of these patterns. This phase diagram is in agreement with the existing experiment on Cebus and macaque monkeys. Our results can be easily generalized to other binary cortical systems.

Tony Zador
Sat Mar 27 10:58:21 PST 1999