Depression-like behavior indicated by social interaction ratio (top), and VTA mRNA levels of Otx2 and OTX2-predicting genes (bottom), after each manipulation. HSV-Gfp (solid green) or HSV-Otx2 (solid purple) were overexpressed at (A) juvenile PND15 to 17 or (B) adult PND60 to 70 time points. HSV-miR-LacZ (open green) or HSV-miR-Otx2 (open purple) were injected for knockdown at (C) juvenile or (D and E) adult time points. Social defeat and behavioral testing was begun in adulthood 6 weeks after (A and C) juvenile or (E) adult manipulation or (B and D) <1 week after adult manipulation. Hashing indicates postdefeat quantification. Bars are means ± SEM, t < 0.1, *P < 0.05, **P < 0.01, ***P < 0.001; horizontal bars indicate main effect of condition [two-way analysis of variance (ANOVA)] (see table S3).