Wiring of Receptive Fields and Functional Maps in Primary Visual Cortex

Abstract

This chapter deals with the question of how receptive fields and cortical maps are wired before the onset of the classical critical period. In particular, we ask how simple-cell receptive fields may arise without an intermediate phase of overlap between ON and OFF subregions and without the need for correlated spontaneous activity in the developing thalamus. We discuss one possible solution, the statistical connectivity hypothesis, which postulates that initial wiring of the cortex is highly constrained by the spatial arrangement of the retinal ganglion cell mosaic and their coverage ratios. We examine a recently confirmed prediction of the theory: that orientation bandwidth must depend on the location of neurons within the orientation map. Finally, the theory is shown to predict the existence of orientation scotomas: At any given retinal location, not all orientations can be represented equally well by neurons in primary visual cortex.