Comparison of topographic and spatial-frequency characteristics of the lateral suprasylvian and striate cortex in cats

Abstract

Differences in spatial frequency and topographic characteristics of receptive fields of neurons in two visual projection areas (striate cortex and lateral suprasylvian region) were analyzed on the basis of results of the writer's previous and present investigations. Receptive fields of neurons in the suprasylvian cortex are large; their size increases with eccentricity and the transmission band occupies a region of low and intermediate spatial frequencies. Receptive fields of striate cortical neurons, on the other hand, are small; they increase in size with eccentricity and the transmission band lies in the region of intermediate and high spatial frequencies. The latent period of evoked potentials is longer in the striate than in the suprasylvian cortex. Analysis of spatial low-frequency information is processed in the suprasylvian cortex a little earlier than high-frequency information is processed in the striate cortex. Retinotopically organized interaction of projection zones enables the two descriptions of a perceived scene to be correlated.