Multielectrode Array Recordings of RGCs from Retinal Whole Mounts for Assessing the Light Sensitivity of CoChRs
(A) Representative recordings of CoChR-mediated spiking activities in wt-CoChR-, CoChR-LC-, and CoChR-3M-treated retinas. The spiking activities were elicited by 1-s light pulses with incrementally increasing light intensities adjusted with neutral density (ND) filters of 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.0, and 0. The light intensities measured as photons/cm2s are also shown. The threshold light intensities required to elicit spiking activities in wt-CoChR-, CoChR-LC-, and CoChR-3M-treated retinas were observed with ND filters of 2.5, 3.0, and 3.5, respectively (marked with arrows). (B) The distributions of the normalized number of RGCs (averaged through the recorded retinas, mean ± SD) versus threshold light intensities for wt-CoChR (4 retinas, 226 cells), CoChR-LC (6 retinas, 299 cells), and CoChR-3M (6 retinas, 319 cells).