Fig. 4.

A, B, Outward currents recorded from a cell in endopiriform nucleus. Depolarizing voltage steps to −65, −55,  … , +5 mV were applied for 200 msec (A) or 2 sec (B) from a holding potential of −90 mV. Biexponential fit to the 2 sec response to +5 mV (B,top trace) gave time constants of 376 msec (16.4% of total current) and 1530 msec (54.0% of total current). C, Activation functions estimated from the data in A andB. Early and late peak values were divided by the driving force (assuming E_K = −98 mV) and normalized using the technique described in Materials and Methods. The early peak was distinguishable only for the responses to voltage steps up to −15 mV. Voltages were corrected for series resistance errors. Boltzmann fit parameters: V_0.5 = −29.2 mV,k = 9.35 mV (early peak); V_0.5 = −16.0 mV, k = 8.08 mV (late peak).