Responses of the starburst amacrine cells to moving stimuli

1. Rabbit retinas were isolated from the eye and incubated in the presence of 3H-choline. Samples of retina taken from a defined midperipheral eccentricity were spread over the domed end of a fiberoptic bundle that formed the floor of a superfusion chamber. The rate of release of labeled acetylcholine by the starburst amacrine cells was studied. 2. When the retina was stimulated by moving gratings, the cells vigorously increased their secretion of acetylcholine. Responses were observed when the bars were as small as 60 microns in width. Systematically varying the spatial and temporal frequency of stimulation revealed that temporal frequency was the dominant variable: the cells responded best to stimuli of 1-4 Hz, whether those stimuli were flashing lights, fine gratings moving slowly, or coarse gratings moving rapidly. 3. With temporal frequency constant, the cells' responses decreased as the spatial frequency of the grating increased. The decreased response to fine gratings is most likely due, at least in part, to lateral interactions that become stronger as the light and dark bars become more closely spaced. These could occur in either the outer or inner retina. 4. The velocity tuning curve for the starburst cells' release of acetylcholine matched fairly well the velocity tuning of ON-OFF directionally selective cells in the rabbit. It did not correspond at all well with the tuning curve for the ON directionally selective cells. If the ON cells receive input from the starburst cells, that input appears to be quite indirect.(ABSTRACT TRUNCATED AT 400 WORDS)