Fig. 2.
Serial connections limit wide-field but not narrow-field BC L-IPSCs. Wide-field (825 μm, A) and narrow-field (25 μm, B) light stimuli (A1 and B1 and thick dark gray bar in traces) were applied to rod, on cone, and off cone BCs. Bicuculline (50 μM) was added to block GABAARs. In all BC types, blocking GABAARs increased the charge transfer (Q) of wide-field L-IPSCs (A and C), suggesting that serial inhibitory connections between ACs limit wide-field light activated L-IPSCs (rod, P < 0.05; on, P < 0.05; off, P < 0.05). In contrast, blocking GABAARs decreased the Q of narrow-field L-IPSCs (B and D), suggesting narrow-field light activated only direct connections (rod, n = 10, P < 0.001; on, n = 6, P < 0.01; off, n = 5, P < 0.05). Inset in B1 is the trace in B1 at an increased scale. The scale bars are 200 ms and 10 pA in A, 1 and 3, B, 1 and 3; 5 pA in A2 and B2. The dotted line represents control in C and D.