Fig. 4: Auditory afferents evoked robust feed-forward inhibition.
From: Diversity of interneurons in the lateral and basal amygdala
a Schematic illustrates assessment of light-evoked feed-forward inhibition by AT (upper) and AC (lower) afferents to interneurons in the LA. Pie charts show proportion of interneurons that had biphasic synaptic response to stimulation of AT (green) and AC (blue) input. These delayed outward currents (b) were sensitive to the GABAA antagonist picrotoxin (c), indicating disynaptic inhibition. Quantification of the peak monosynaptic EPSC amplitude at −70 mV against the peak disynaptic IPSC amplitude at −40 mV (d) revealed a significantly smaller E/I ratio during light-evoked AC inputs compared to AT (AT LA IN E/I = 10.6 ± 1.9, n = 20; AC LA IN E/I = 5.9 ± 1.1, n = 19; p = 0.0453) (e), a trend similarly observed in LA IN ACC (p = 0.0637) (f). g Schematic of local feed-forward circuitry tested between interneurons (IN) and principal neurons (PN) within the LA or the BA. Inset: representative traces from a unidirectionally connected IN (top) and PN (bottom), where a somatically-evoked action potential in the presynaptic IN drove a time-locked outward current (held at −40 mV) in the postsynaptic PN. h Probability of connection between local IN and PN in the LA and BA.
