(A) Schematic illustrating focal application of glutamate in the I PL. (B - D) Representative traces (top panels) and summary data (bottom panels) of currents elicited by glutamate in different BC types: Group I ON CBCs (B, n = 7), group II ON CBCs (C, n = 4) and RBCs (D, n = 5). (E, G) Dual current- (I = 0 pA, VRest ~ −65 mV) and voltage-clamp (EPSCs, VM ~ −60 mV) recordings from ON CBCs and ON RGCs, respectively. Traces are shown in control solution, during application of 90 µM AP5 and 20 µM NBQX (E) or 200 µM MFA (G), and after washout of these drugs. (F, H) Average (± SEM) rate of waves in these conditions (AP5, NBQX n = 5; MFA n = 6). See also Figures S7.