Cntnap2  ^−/− neurons are generally more excitable. (A) Sample voltage-clamp recordings from wildtype (top left) and Cntnap2^−/− (bottom left) neurons and representative magnified fast inward currents from wildtype (grey) and Cntnap2^−/− (black) voltage-clamp recordings. (B) No differences in resting membrane potential, but (C) Cntnap2^−/− neurons have a lower cell capacitance. (D) Voltage-clamp recordings normalized to cell capacitance reveal Cntnap2^−/− neurons have a higher current density of transient voltage-activated inward currents and activation at lower voltages. (E) Representative current-clamp recording of action potentials from wildtype (grey) and Cntnap2^−/− (black) neurons with firing threshold and rheobase indicated. (F) The action potential firing threshold and (G) rheobase current at which the neurons fire the first action potential reveal Cntnap2^−/−neurons are more excitable. All data are represented as mean ± SE (B: wildtype n = 16 cells, C, D: wildtype n = 17 cells, F: wildtype n = 15 cells, G: wildtype n = 16 cells; B–G: Cntnap2^−/−  n = 10 cells). ^*P <0.05.