Autaptic currents of hippocampal microisland neurons and their modulation by somatostatin. A andB show EACs and IACs, respectively, recorded from two different neurons by the stimulation protocol shown inC. Currents in the bottom panels were recorded before (control), during, and after (wash) the application of 1 μm TTX (A, B), 10 μm CNQX (A), and 30 μm BMI (B), respectively. The time scale in C applies to the currents shown in A, B, D, and E. D, EACs measured at a holding potential of −70 mV before (control), during, and after (wash) the application of 1 μmsomatostatin. E shows the same sequence of recordings obtained in a neuron displaying IACs measured at a holding potential of −40 mV. F summarizes the effects of 1 μmsomatostatin on EACs and IACs. The boxes encompass the median 25th through 75th percentiles and contain a linemarking the median 50th percentile point. The caps of the error bars indicate the median 10th and 90th percentiles.