Effect of activating or inhibiting cells in the superior colliculus on avoidance responses driven by the ACS. A, Schematic of the superior colliculus cells inhibited in the experiments shown in B and C. B, Effect of green light applied in the superior colliculus on ACS+LCS trials for animals that express Arch in GABAergic (Vgat-SC-Arch) or putative glutamatergic (CaMKII-SC-Arch) cells in the superior colliculus. C, Trial speed, trial velocity, and intertrial speed for the data in B. D, Schematic of the superior colliculus cells activated in the experiments shown in E and F. E, Effect of blue light applied in the superior colliculus on ACS+LCS trials for animals that express ChR2 in GABAergic (Vgat-SC-ChR2) or putative glutamatergic (CaMKII-SC-ChR2) cells in the superior colliculus. F, Trial speed, trial velocit,y and intertrial speed for the data in B.