Pattern Formation in the Development of Primary Visual Cortex
by
Peter J. Thomas
Salk Institute

The mammalian visual cortex maps retinal or visual field position ("retinotopy") and preferred orientation of visual stimuli across its surface. Simultaneous measurements of retinotopy and orientation preference in vivo suggest that positive correlation exists between the cortical location of dislocations in these two maps (Das and Gilbert, 1997). These findings contradict classical predictions of dimension reduction models for cortical maps (Durbin and Mitchison, 1990). The symmetries of cortical map formation models exert a significant influence on pattern development. However, classical models for cortical map formation have inappropriate symmetry properties (reviewed in Swindale 1996). By applying equivariant bifurcation theory to coupled map formation we derive symmetry-induced, model-independent coupling of the orientation preference and retinotopic maps and show that this coupling induces correlations between the local rates of change of the two maps that agree with those observed experimentally.

Date received: September 19, 2003