Fig. 2

Example responses of a single Cnga3 ^−/− ganglion cell across brightness levels. a Full-field contrast step stimulus, consisting of positive and negative contrast steps. b Absolute intensities of the stimulus shown in a at different experimental light levels. c, d Raster plots (left) and firing rates (right) for a single ganglion cell in response to the full-field positive (c) and negative (d) contrast steps. Blocks of five consecutive repetitions (left) are averaged in one trace on the right. This cell showed responses at all light levels (very weakly responding at 10⁰ R* rod⁻¹ s⁻¹), with a short suppression of responses in the beginning of 10⁴ R* rod⁻¹ s⁻¹. Note that in this ganglion cell, the rod-mediated responses are even stronger at high (10⁴–10⁷ R* rod⁻¹ s⁻¹) than at lower (1–10³ R* rod⁻¹ s⁻¹) light levels