A, YFP/GFP expression in the ganglion cell layer of Hb9 × Chat‐Cre:ChR2 mouse retina. Chat‐positive neurons (starbursts) were YFP labelled and Hb9 neurons (DSGCs) expressed GFP (arrowhead). Scale bar = 50 μm. B, the light‐evoked photoreceptor‐mediated spike responses of an Hb9 cell in Chat‐Cre:ChR2 mouse retina, in control (left) and in the presence of dl‐AP4 + CNQX (right). A 200 μm diameter, white spot of intensity 20 R*/rod/s was used to elicit photoreceptor‐mediated responses. C, the response of the same cell when ChR2 was stimulated using a blue LED (108 R*/rod/s; left; n = 8). The ChR2‐stimulated spiking could be blocked by HEX (right; n = 4). D, the currents generated in a voltage clamped Hb9 neuron held at −60 mV (EPSC; ACh) and 0 mV (IPSC; GABA) in response to ChR2 stimulation in dl‐AP4 + CNQX. E, in the same cell addition of DCG blocked both the ACh and the GABA currents. F, summary of the mean peak GABA currents (left) and ACh currents (right) in the presence and absence of DCG (n = 6; P < 0.005*).