Figure 4.

A–C, Axon terminal light responses from C57BL/6 wild-type (A, B) and rhodopsin-deficient retinas (C). Light stimuli are the same as in Figure 2. A, B, C57BL/6 wild-type horizontal cell axon terminals showed a range of response properties. The axon terminal in A showed prominent rod components, including slow responses at low intensities and the rod after-effect at intermediate intensities. The axon terminal in B showed primarily cone-dominated response properties. C, Axon terminals from rhodopsin-deficient mice showed exclusively cone-dominated response properties. A–C, Calibration: 2 mV, 250 ms. D, Normalized intensity–response profiles for C57BL/6 wild-type (n = 7) and rhodopsin-deficient horizontal cell axon terminals (n = 3). Error bars indicate mean ± SE. The intensity that elicited half-maximal responses in axon terminals was higher for rhodopsin-deficient retinas than for the wild type (p < 0.05).