Fig. 1.

Developmental changes in depolarization-induced suppression of inhibition (DSI) in hippocampus. A: in CA1 pyramidal neurons, a 4-s depolarizing step resulted in modest suppression of the evoked inhibitory postsynaptic current (eIPSC) at postnatal days 7–8 and 9 but produced a robust suppression at P15 and P19-21. Each inset superimposes the average of 5 consecutive eIPSCs pre-DSI and 3 trials post-DSI. Square step indicates a 4-s depolarization from −60 to 0 mV. B: DSI magnitude was measured as the mean percentage reduction of 3 consecutive eIPSCs after the depolarizing step. Numbers above each bar indicate the number of cells. * P < 0.05 compared with P7-8 rats.