Fig. 13.

Excitatory input to rabbit DSGCs increases gradually with contrast at high and low velocities. A: light-evoked excitatory currents in a representative DSGC in response to a narrow moving bar, 200 μm wide. The excitation is shown in response to motion in null and preferred directions at high (1,000 μm/s, left) and low (200 μm/s, right) velocities and contrasts 10%, 30%, and 90%. B: contrast dependence of the integrated On and Off excitatory currents in response to a narrow bar moving in the null direction at 1,000 μm/s (left) and 200 μm/s (right); n = 24. The integrated currents were normalized and fit with the Hill equation (see materials and methods). The curves for the contrast dependence of the inhibition are taken from Fig. 12D.