This suggests that BDNF acts within the VTA-NAc pathway, inducing a depression-like phenotype (Eisch et al., 2003; Berton et al., 2006; Nestler and Carlezon, 2006; Krishnan et al., 2007), whereas it produces antidepressant-like effects in the hippocampus and PFC (Nestler et al., 2002; Shirayama et al., 2002; Duman and Monteggia, 2006). Here, BDNF is linked to major depressive disorder.