NEGR1 and major depressive disorder: In this study, we investigated whether NEGR1 affects dendritic arborization of neurons in the NAc and DG, which are critically connected with depression phenotypes.32,33 We first conducted experiments to verify whether Negr1 KO mice exhibit anxiety- and depression-like behaviors, as reported in previous studies.20,24,31 In the three-chamber sociability test, Negr1 KO mice spent more time in the empty cage zone than in the stranger mouse cage zone, while WT littermate mice spent more time in the stranger cage zone (p < 0.05) (Figure 1(a)).