Fast sIPSCs arise close to the soma.A, Composite photomicrograph (left) of a CA1 pyramidal cell showing the four positions at which bicuculline was puffed onto the cell body or apical dendrite (marked byarrowheads). The recording pipette can be seen entering the field of view from the right. Sample traces are illustrated for each puffer pipette position (right column). The time of the puff is indicated by thearrowhead; recording was at 35°C. Calibration: 2 sec, 100 pA. B, Summary data for the cell illustrated inA. Shown are sIPSC amplitudes without the puffer pipette near the cell (Ctrl) and averaged 2 sec after the bicuculline puff at four positions relative to the cell (black bars). Because of leakage from the puffer pipette, the baseline sIPSC amplitude was reduced in a spatially restricted manner (striped bars) also, similar to the effect on sIPSCs immediately after the puff.