Fig. 5: PAG-projecting ACC neurons encode vicarious freezing and affective pain experience.
From: Cortical representations of affective pain shape empathic fear in male mice
a Schematic of FosTRAP and experimental timeline. b Representative TdTomato-positive cells in the ACC, PAG, and BLA of the control and OFC-experienced mice. In the control group, OB mice were exposed to non-shocked DM. c Quantification of Ai14-positive TRAPed cells across seven brain regions (ACC, anterior cingulate cortex; PAG, periaqueductal gray; BLA, basolateral amygdala; NAC, nucleus accumbens; MD, mediodorsal thalamus; CL, centrolateral nucleus of the thalamus; PF, parafascicular nucleus of the thalamus; n = 5 (control) and n = 7 (OFC-experienced); two-sided unpaired t-test with Welch’s correction, Holm-Ĺ Ădák post hoc test: ACC, t = 2.235, p = 0.049; PAG, t = 2.865, p = 0.025; BLA, t = 3.926, p = 0.002). d, f Left: Schematic of virus injections into the ACC, PAG d, and BLA f. AAV-DIO-GCaMP8f was infused into the right ACC, and retrograde AAV-Cre was infused into the right PAG d or the right BLA (f). Right: Example images of injection site showing GCaMP8f expression and raw images of the field of view with individual cell bodies. Green, GCaMP8f; blue, DAPI. e, g Venn diagrams showing behavior-encoding cells in PAG- projecting e and BLA-projecting g ACC neurons during OFC and Direct-shock. Scale bars: white, 200 ÎĽm; yellow, 50 ÎĽm. h - k Histograms showing the likelihood of any LDA decoder performance level compared with 0.5 (chance level; dotted line) in the ACC neurons projecting to the PAG h, i and the BLA j, k. The OB-freezing classifier based on OFC1 showed higher performance in predicting OB-freezing in OFC2 h, two-sided shuffle test, p = 0.004) and Shock-freezing during Direct-shock i, two-sided shuffle test, p = 0.04) in PAG-projecting cells, but not in BLA-projecting cells j, k. Source data are provided as a Source Data file. * p < 0.05, ** p < 0.01, All data are presented as means ± S.E.M.
