FIGURE 2.

A and B, flash response families of dark-adapted control (A) and Rec^−/− M-cones (B) from transretinal ERG recordings. Cone responses were evoked by a series of 500-nm test flashes (10 ms in duration) with intensities (in photons μm⁻²) 87, 360, 1200, 3300, and 1.1 × 10⁴ for control and 360, 1200, 3300, and 1.1 × 10⁴ for the Rec^−/− retina. The largest response in each case was triggered by unattenuated white flash. C, fractional single photon responses of control (black) and Rec^−/− (red) cones. The cone collecting area was estimated to be 0.12 μm² (see Equation 6 and “Experimental Procedures” for details). Inset, normalized dim flash responses of control (black) and Rec^−/− (red) cones. D, intensity-response data for control (black, n = 16) and Rec^/− (red, n = 7) cones, fit with the Naka-Rushton equation (Equation 1). See Table 2 for parameter values. Norm., normalized; Resp., response.