Fig. 4: Asymmetric responses of foveal and peripheral cones to light increments and decrements.

A, B Exemplar foveal and peripheral cone voltage responses to a series of light increments and decrements at a background light level of 50,000 R^*/s. C Normalized contrast response curves of foveal and peripheral cones at a lower (5000 R^*/s) and higher (50,000 R^*/s) background light level. The contrast responses are equally asymmetric between foveal (n_f = 4 for 5000 and 50,000 R^*/s background luminance) and peripheral cones (n_p = 16 and 15 for 5000 and 50,000 R^*/s background luminances, respectively). D The ratio of mean responses to equal and opposite contrast steps (OFF/ON ratio) as a function of contrast magnitude calculated for the cones in (C). E Exemplar foveal and peripheral cone voltage responses to a brief (10 ms) light increment and decrement flashes at a background light level of 50,000 R^*/cone/s. F Times to the peak of foveal (n_f = 5) and peripheral cone (n_p = 5) voltage responses to positive (+) and negative (−) 100% contrast flash at a background light level of 50,000 R^*/cone/s were similar. Lighter open circles represent peak response gains from each cell. Points with error bars represent mean ± sem. Source data are provided as a Source Data file. We used the paired t-test for the statistical analysis in (F). The significance threshold was placed at α = 0.05 (n.s., p > 0.05).