Fig. 2: Piriform cortex (PC) excitability neurons are activated by social defeat.

A After SIT-90 min, mice were sacrificed followed by c-Fos staining to detect the neuronal activity. The c-Fos-positive cells in the PC of the control (left) and susceptible (right) mice were shown through immunofluorescence. Scale bar, 200 μm. B The mean density of c-Fos-positive cells in the PC (t₄ = 3.009, p = 0.0396; Unpaired student’s t-test), BLA (t₄ = 3.273, p = 0.0307; Unpaired student’s t-test), AOM (t₄ = 0.08456, p = 0.9367; Unpaired student’s t-test), PV (t₄ = 1.764, p = 0.1524; Unpaired student’s t-test), DG (t₄ = 0.9232, p = 0.4081; Unpaired student’s t-test), dCA1 (t₄ = 0.057, p = 0.9573; Unpaired student’s t-test), Prl (t₄ = 0.5723, p = 0.5978; Unpaired student’s t-test) and IL (t₄ = 1.019, p = 0.3657; Unpaired student’s t-test). Con, n = 3; Sus, n = 3. C Merged confocal image of c-Fos (Green) co-stained with CaMKIIα (Purple) in PC slices. The white arrowheads indicate the colocalized cells that expressed both c-Fos and CaMKIIα neurons. Scale bar, 25 μm. D The density of c-Fos and CaMKIIα co-labeled cells were measured (t₄ = 20.36, p < 0.001; Unpaired student’s t-test). Con, n = 3; Sus, n = 3. E Experimental timeline for recording dynamic Ca²⁺ signals in GCaMP6m-expressing PC neurons. F Representative images of the injection site in the PC. Scale bar, 500 μm. G Heatmap showing Ca²⁺ signals aligned to the onset of social interaction in the social interaction. Each row represents a trial. H Representative line of the averaged Ca²⁺ signals. I Summary plots of the ΔF/F signal (t₁₄ = 2.846, p = 0.0130; Unpaired student’s t-test). Con, n = 8, mice = 3; Sus, n = 8, mice = 3. Data are presented as the mean ± SEM. *p < 0.05, ***p < 0.001.