Comparisons of directionally selective with other ganglion cells of the turtle retina: Intracellular recording and staining

Publisher Website
Google Scholar
Abstract
Directionally selective (DS) and other ganglion cells of the turtle retina were studied in in vitro eyecup preparations by using intracellular recording and staining techniques. DS ganglion cells responded to moving gratings with periodic, depolarizing synaptic potentials in both preferred and null directions. Although depolarizations were usually larger in the preferred than in the null directions, in a few cells spike discharges were directional but depolarizations were not. Directionality could disappear if inappropriate field sizes or grating spatial frequencies were used. Unlike non‐DS cells, one‐half of the DS cells penetrated showed two sizes of action potentials upon photostimulation. It is proposed that the smaller spikes originated at axonal initial segments and failed to invade the somas actively. DS cells also exhibited postspike depolarizations (PSDs). Three types of DS ganglion cells (ON‐OFF, OFF center, and ON center) were identified morphologically with Lucifer yellow injection. Other ganglion cells, which were also recorded from and stained intracellularly, are compared to the DS cells.