Figure 6.

Rod photoreceptor gain and flash-independent noise. A, Outer segment current responses of a mouse rod photoreceptor to flashes producing an average of 2.4 Rh*/rod with no background. Flash was delivered at time 0 and was 10 ms in duration. Template (thick trace) is the average of 40 responses. Noise records were taken from the 400 ms period before the flash, and response trials were taken from the 400 ms period after. Filtered at 30 Hz. B, Responses to flashes producing an average of 2.4 Rh*/rod with a background of 0.71 Rh*/rod/s. Template (thick trace) is the average of 40 responses. C, Background dependence of gain for 17 mouse rod photoreceptors. Smooth fit from Equation 5 with m = −0.75 ± 0.04 (mean ± SEM), a = 0.64, b fixed at 1.3, c = 0.31, and d fixed at 1. Superimposed in gray is the gain plot from mouse ganglion cells from Figure 5A. Error bars are SEM. D, Background dependence of flash-independent noise. Smooth fit from Equation 5 with a = 1.20, b fixed at 4, c = 0.07, d = 0.56, and m = −0.39.