In the adult, they primarily connect areas with the same orientation preference. It is not known how these lateral connections develop, why their patterns are related to the response properties of cortical cells, and what role they play in visual processing. New discoveries have also changed the notion that receptive fields in the adult cortex behave as static filters. Therefore, the primary visual cortex appears to be a continously adapting system in a dynamic equilibrium with the input environment. Computational models can play a fundamental role in understanding the development and function of such dynamic systems.
Cortical function depends upon the collective behavior and interactions of large numbers of neurons.
With the advent of massively parallel computers in the last five years, it has become possible to simulate such large neural systems. At the same time, neurobiological techniques to probe into the brain have reached the level of sophistication necessary to constrain and validate such models. To date, the self-organization of lateral connections in the visual cortex and their role in visual processing has not been investigated computationally. Furthermore, none of the developmental models have attempted to explain the dynamic nature of mature receptive fields. To provide a cogent theory, a computational model of cortical development should demonstrate how both afferent and lateral connections can organize cooperatively and simultaneously, and how the resulting structure can be dynamically maintained in a continuously-adapting equilibrium with the visual input.