Figure 4. Directional facilitation and suppression of light-evoked, motion-sensitive cholinergic input to DSGCs.

A, EPSC components during two-flash apparent motion in the preferred (1 to 2) and the null (1’ to 2’) direction. A conditioning light flash (1, 60-μm × 120-μm spot) on the preferred side immediately outside the cell's RF center evoked no response by itself, but greatly enhanced the subsequent response to a test light flash (2, 60-μm × 90-μm) within the RF center, indicating a motion-mediated facilitation of HEX- and, to a lesser degree, CPP-sensitive EPSC components in the preferred direction. Flashing the same conditioning light spot on the null side (1’) also did not evoke a response by itself, but reduced the response to the subsequent test flash (2’) located within the RF center, indicating a motion-mediated suppression of HEX- and CPP-sensitive EPSC components in the null direction. Traces were averaged from 2-4 trials. Spatial offset between conditioning and test flashes (center-to-center): 90 μm; temporal delay: 300 ms; apparent motion speed: 300 μm/s. B, Statistical analysis of the facilitation and suppression of the EPSC components during apparent motion, showing different degrees of motion sensitivity in different EPSC components. Error bars: s.e.m. See also Figure S2.