Ganglion, amacrine and horizontal cells of the cat's retina

Abstract

Cell types in the cat's retina were stained by methylene blue given intravitally and by a modification of the Gros-Bielschowsky silver impregnation technique. The dendritic arborisations of the cells were studied in whole mounts and in sections. In peripheral retina each ganglion cell had a horizontal dentritic spread confined to one zone of the inner plexiform layer, usually within its outer half. The diameter of this dendritic arborisation ranged from 18–710μ and all intermediate sizes were seen. In general the cells with large dendritic fields had 3–5 main dendrites arising from the cell body and passing obliquely through the inner plexiform layer to branch in the zone of horizontal spread. The cells with small fields had a single main dendrite passing vertically through the inner plexiform layer. Some small fields had a loose dendritic network, and others a dense ramification of fine dendrites. In the central area of retina ganglion cells were found with a dendritic spread of less than 15μ. Amacrine cells were seen in the outer half of the inner plexiform layer. At the outer edge of the bipolar cell layer, a layer of horizontal cells was well seen in the silver stained retinas.