Intraglomerular inhibition reduces MC spike responses to ON stimulation. A1, B1, and C1: MC spiking in response to ON stimulation. A2, B2, and C2: normalized population PSTHs. A: control. In aCSF, ON stimulation evoked a short-latency burst of spikes riding on an LLD. B: glomerular injection of 100 μM GBZ dramatically increased spike output. C: washout of GBZ restored normal spike patterns.