Fig. 1.

A, An ON–OFF DS cell injected with Lucifer yellow immediately after recording. The ON layer is in focus, with the OFF layer out of focus in the image. The characteristic morphology confirms the identity of the recorded unit as a classic ON–OFF DS cell. Scale bar, 100 μm. B, Two-spot apparent motion under control condition and in the presence of 50 μm curare. The index of facilitation was calculated as (R_t −R₀)/R₀, where R_t is response of the second spot when preceded by the first spot, and R₀ is the response of the second spot alone. The experimental paradigm is diagrammed in Figure 2. A negative facilitation index indicates inhibition. Data points show mean ± SEM for three cells.