MORPHOLOGICAL TYPES AND TOPOGRAPHICAL DISTRIBUTION OF GANGLION CELLS IN THE CAT RETINA

Abstract

This chapter discusses the three distinctive morphological types of ganglion cells—Alpha cells, Beta cells, and Gamma cells—that have been described from Golgi-stained wholemount preparations of the cat retina. They differ in their dendritic branching patterns, their dendritic field dimensions, and their cell body sizes. Alpha-cells have a large cell body (∼30 μm) from which 4–6 primary dendrites originate; these give off secondary branches that expand into a rather large dendritic tree. The dendritic tree diameter increases from 200 μm in the central area to some 1000 μm in peripheral retina. Beta cells have a medium sized cell body (∼20 μm) and a small bushy dendritic tree. At all retinal locations, the dendritic trees of Beta cells are smaller than the dendritic fields of other ganglion cell classes and they increase from about 25 μm in the central area to 300 μm in peripheral retina. The axons of Beta cells are smaller than the axons of Alpha cells. All Gamma cells have small cell bodies and thin axons.