Figure 7.

Comparison of RGC discrimination performance with rod limit. A, Schematic of model used to estimate sensitivity of rod pool. Samples drawn from the distribution of discrimination signals for early and late flashes were weighted by the receptive field (RF) profile and summed. Discrimination was based on the sign of the difference of these summed signals. B, RGC receptive field measured with white noise stimulation. Ellipse shows the 2 SD contour of an elliptical Gaussian fit to the receptive field (see Materials and Methods). C-E, Discrimination contours for individual RGCs from three retinas (thick lines) and corresponding rod limits (thin lines). The estimated number of rods within the 2 SD boundary for each RGC was 630, 780, and 450. Estimated detection thresholds (vertical asymptote of discrimination curve) were 0.30, 0.06, and 0.27 Rh^*/rod.