Fig. 6.

Gabazine attenuates GABA_A inhibition and decreases short-pass duration selectivity without decreasing excitation. Whole-cell recordings and reconstructions of inhibitory and excitatory conductances before and after focal iontophoresis (+70 nA) of gabazine (3 mM), a selective antagonist of GABA_A receptors, to attenuate inhibition. Recordings were made at several times after starting iontophoresis and then ∼10 min after stopping iontophoresis (recovery). Single (black traces) and averaged (gray traces) responses recorded at 0.0 nA are shown; responses recorded at −0.061 nA of current clamp are also shown for the 2–2.5 min gabazine condition. The number of spikes elicited over the stimulus repetitions is shown at the tail of each averaged trace. Resting potential = −66 mV; stimulus amplitude = 44 dB SPL; carrier frequency = 650 Hz.