Figure 4. Pretectal neurons evoked after-responses to cessation of prolonged motion.

Upon cessation of prolonged motion (30–60 s), the cell in A–C produced inhibitory after-responses in the preferred direction, whereas the cell in D–F produced excitatory after-responses in the null direction. However, cessation of brief motion (e.g. 3 s) did not evoke after-responses. Arrows point to the termination of after-responses determined by the intersection of histograms with the mean spontaneous rate (continuous lines) minus (A–C) or plus (D–F) s.d. (dotted lines). Five repeats were averaged. Time bin = 100 ms in A and D, 500 ms in others.