Asymmetry of the internal connections of the striate cortex of the cat in the projection zone of the center of the field of vision.

Abstract

Studies were carried out on the organization of the internal connections of the striate cortex in cats in the projection zone of the center (0-5 degrees) of the field of vision by microintophoretic application of horseradish peroxidase to electrophysiologically identified orientational columns. The area containing neurons showing retrograde labeling in most cases extended in the mediolateral direction. Labeled cells were located in the upper (II, III) and lower (V, VI) layers of the cortex, and the shapes and orientations of the areas containing labeled neurons in these layers coincided. Spatial asymmetry was detected in the distribution of labeled neurons relative to the orientational column studied. Labeled cells were located predominantly medial to the columns, regardless of the distance from the projection of the area centralis. Considering the visuotopical map of field 17, the asymmetry detected here provides evidence that neurons in orientational columns have more extensive connections with neurons of the peripheral part of the cortex. An asymmetrical distribution of "silent" 2 zones around the receptive fields of neurons in orientational columns is suggested, and that these appear to receive influences from the periphery of the visual field.