Fig. 5.

Electrical stimulation activates a pattern of RGCs as revealed through large changes in GCaMP3 fluorescence intensity (see Supplemental Video S1). A: before stimulation, cells are at baseline fluorescence. B: delivering a burst of 120 suprathreshold pulses from a 20-μm-diameter electrode (arrows) causes electrically activated cells to become visibly brighter. C: image subtraction of A from B highlights the pattern of responding cells. Stimulation with 400-μs pulses activates an axon bundle, causing a streaklike antidromic response that extends away from the optic disc. Average normalized change in fluorescence (ΔF/F) for responding RGCs was 75.9 ± 21.5% (n = 34). Scale bar is 100 μm.