Figure 3.

Gain, noise, and threshold for a single mouse ganglion cell. A, Gain estimated from consecutive responses to three flash strengths (open symbols) and averaged across flash strengths and repeated measurements (filled circles) for several background intensities. Gain was defined as the mean of the response trial correlations (see Fig. 2C). B, Flash-independent noise for several backgrounds. Flash-independent noise was defined as the SD of correlations between noise trials and the template (see Fig. 2F). C, Flash-dependent noise for several backgrounds. Flash-dependent noise measures the variability attributable to the flash itself (i.e., the variability remaining after subtracting flash-independent noise). Flash-dependent noise was estimated for a flash strength equal to detection threshold (see D and Materials and Methods). D, Threshold for several backgrounds, calculated according to Equation 4. The threshold represents the flash strength (Rh* per rod) at which the signal-to-noise ratio for a flash/no-flash two-interval forced-choice experiment is 1 (see Materials and Methods).