Depolarization pulses in the pattern of cosine waves accelerate AISS induction at hippocampal GABAergic neurons. Cosine waveforms include depolarization and hyperpolarization. AISS is induced under the control and subsequent cosine waveforms after the first round of AISS disappears for 6 minutes, a time interval similar to Figure 1. A) shows AISS induction under the control (top trace) and the cosine (Cos) waveforms (bottom trace). Calibration bars are 20 mV and 10 seconds. B) illustrates the dynamical changes in threshold potentials under the control (blue symbols) and cosine waveforms (red symbols). C) shows the number of spikes needed for AISS onset under the control (blue bar) and cosine waveforms (red bar; asterisk, p < 0.01, n = 8).