Figure 3.

CCK-8-induced stress susceptibility depends on specific cortical projections. A, At 24 h after submaximal social defeat and 30 min after CCK-8 infusion, mPFC projection regions were laser-stimulated during a test for social interaction. CCK-8 infusion into the PrL induced social avoidance (B, C), reduced exploratory behaviors (D, E), and decreased sucrose preference (F, G) (n = 6–8). *p < 0.05 (two-way ANOVA). ^#p < 0.05, compared with vehicle (t test). H, CCK-8 infusion decreased c-Fos mRNA levels in mPFC, suggesting decreased neuronal activity (n = 7 or 8). *p < 0.05, compared with vehicle (t test). I, Representative photomicrograph of ChR2-GFP expression in two mPFC projections areas, NAc (left) and BLA (right), 6 weeks after injection into PrL. Optogenetic stimulation of cortical projections to BLA (B–F) or NAc (C–G) had opposite effect on measures of social avoidance, sucrose preference, and anxiety-like behavior (n = 6–8). *p < 0.05 (two-way ANOVA).