Figure 4
From: Hunger Promotes Fear Extinction by Activation of an Amygdala Microcircuit
Fasting in Y4KO mice results in activation of the medial intercalated cell (mITC) and enhanced basolateral amygdala (BLA) to centromedial amygdala (CEm) feed-forward inhibition. (a–c) Expression of immediate-early gene cFos in the ITC of a fasted Y4KO compared with (d–f), a non-fasted Y4KO control reveals (g) increased activation of ITC neurons, (h) experimental setup for ex vivo electrophysiology indicating home-cage controls, wild-type (WT) and Y4KO undergoing fear acquisition on day 1, extinction on day 2, and electrophysiology on day 3 under fed conditions and experimental group with a 16 h fasting period before and during extinction training, (i) enhanced feed-forward inhibition from BLA to CEm via mITC in WT mice after successful fear extinction, (j) lack of increased feed-forward inhibition in fed Y4KO after extinction training corresponding to impaired fear extinction and (k) rescue of impaired fear extinction in Y4KO mice by fasting facilitates enhanced feed-forward inhibition between BLA and CEm. (l) Example traces from WT and Y4KO mice of the individual groups with increasing stimulation intensities (n=WT home cage 4 mice, 12 cells; WT food+Ext 4 mice, 15 cells; Y4KO home cage 5 mice, 13 cells; Y4KO food+Ext 4 mice, 14 cells; Y4KO fasting+Ext 4 mice, 12 cells; *P<0.05, two-way analysis of variance (ANOVA) for repeated measurements for electrophysiology, and Y4KO food: n=8, Y4KO fasting: n=8; Student’s t test for c-Fos immunohistochemistry). KO, knock out.
