For whole cell recordings, patch electrodes (2–3 Ωm) were filled with internal solution containing (in mm): CsMeSO3 119, TEA-Cl 10, NaCl 5, EGTA 2, HEPES 10, Na-ATP 4, Na-GTP 0.3, QX-314 5, with osmolarity adjusted to 275–285 mOsm (pH 7.25–7.35). Visually identified pyramidal neurons within the BLA were used for electrophysiological studies as described previously.34 Whole cell recordings were made using an Axopatch 700B amplifier (Molecular Devices, Sunnyvale, CA, USA). Voltage-clamp recordings were made at a holding potential of + 10 mV. Monosynaptically evoked inhibitory postsynaptic currents (eIPSCs) were elicited by constant current stimulation via a concentric bipolar stimulating electrode placed in the BLA just medial to the external capsule. eIPSC amplitudes were typically adjusted to 300–1200pA with stimulation intensities ranging from 10 to 40 μA. Test pulse simulations were elicited at 0.1 Hz. LTDi (long-term depression of inhibitory, GABAergic, transmission) was induced by eliciting 100 pulses at a frequency of 1 Hz (LFS1; low-frequency stimulation) at twice the stimulation intensity as the test pulse. Access resistance (Ra) was monitored online and cells showing changes in Ra of >20% or
