Fig. 2.

Two-spot apparent motion experiment for an ON–OFF DS cell of the rabbit retina. The first spot was placed just outside of the excitatory center of receptive field for both preferred and null directions (the first spot alone caused no response). The second spot was placed 30 μm inward from the first spot. Responses to the second spot are shown, either alone or preceded by the first spot, with various delays (0–500 msec). Ten trials were averaged for each stimulus sequence. Data shown are mean ± SEM, and the ON and OFF components of the response are combined. Note that different ordinates are used under the various conditions (this was done to make the facilitation more easily compared). Pooled results for a population of cells are shown in Figure 3.