Spontaneous, compound IPSPs coordinated spike timing and promoted rhythmic firing in the primate BLA.

<p>(A) Spontaneous, compound IPSPs exhibited by a representative pair of primate BLA projection neurons, depolarized to action potential threshold (−45 to −40 mV) using a DC current injection. A raster plot highlights the relative synchrony of spikes following the IPSPs, highlighted in gray boxes. Action potentials are cropped at −30 mV (n = 6). (B) A spike correlation metric (see Methods) is plotted for 6 pairs of primate BLA principal neurons exhibiting compound IPSPs and depolarized to threshold, as in <i>A</i>. Correlation is plotted for each pair as an individual, smoothed trace (thin black lines) representing the mean correlation surrounding every spontaneous, compound IPSP, with the peak of each IPSP aligned to time 0. The mean of all 6 pairs is superimposed as a dotted black line. (C–D) A representative single (C, n = 4) and pair of (D, n = 2) primate BLA principal neurons exhibiting rhythmic firing upon rebound from spontaneous, compound IPSPs. Neurons were depolarized to threshold, as in <i>A</i>. IPSPs and rebound firing are highlighted with gray boxes in <i>C</i>. Action potentials were cropped at −30 mV. (E) A primate BLA principal neuron, depolarized as in <i>A</i>, exhibiting a damped membrane potential oscillation in response to a spontaneous, compound IPSP.