Figure 1.

MEA recordings of the novel rat eyecup preparation can detect the light responses of ipRGCs. A, The responses of an ipRGC to 10 s 480 nm light steps of three different intensities (expressed in log quanta cm⁻² s⁻¹), first in normal Ames' medium (Control) and then in the presence of l-(+)-2-amino-4-phosphonobutyric acid, d-(-)-2-amino-5-phosphonopentanoic acid, and 6,7-dinitroquinoxaline-2,3-dione to block rod/cone signaling (Synaptic block). This ganglion cell was identified as an ipRGC based on its ability to generate sluggish, high-threshold photoresponses during synaptic block, indicative of melanopsin phototransduction. B, Spike histograms illustrating the averaged light responses of all the ipRGCs detected in this experiment (n = 18). The bin size of these histograms is 1 s, and the error bars represent SEM. C, The averaged light responses of all the conventional ON and ON–OFF ganglion cells analyzed in this experiment (n = 29).