FIG. 3.

Pentobarbital reduces the frequency and amplitude of BLA gamma oscillations by modulation of BLA principal neuron IPSPs. (A) Example traces of extracellular recording (ec) of field gamma oscillation in the BLA in control gamma oscillation and in the presence of the barbituate, pentobarbital. The corresponding power spectra, control (black) and pentobarbital (grey), demonstrate the sensitivity of the BLA gamma oscillation to prolongation of the GABA_A receptor kinetics. KA, kainic acid. (B) Intracellular recording of cell with membrane potential held at −20 mV to reveal the IPSPs the cell is receiving in control and pentobarbital. Example traces illustrate the reduction in amplitude and increase in decay time of gamma frequency BLA principal neuron IPSPs produced by pentobarbital. Cross-correlogram [field (black) vs. principal cell IPSPs (grey)] to show the correlation between oscillatory activity and the inhibitory potentials the cell is receiving in control and pentobarbital. Scale bars: 100 μV, 100 ms (A); 5 mV, 100 ms (B); 10 mV, 20 ms (B).