BDNF and major depressive disorder: We finally selected BDNF in the study, as: (1) BDNF controls both hippocampal neurogeneis and the pathogenesis of depression (Lee and Son, 2009; Castren and Rantamaki, 2010); (2) the biosynthesis of BDNF is regulated by CREB, which has already been demonstrated to be affected by TMP (Conti et al., 2002; Wu et al., 2013); (3) a previous study showed that TMP treatment promotes the expression of BDNF after severe brain injury in rats (Ma et al., 2008); and (4) TMP also increases the phosphorylation of pERK1/2, a key downstream kinase of BDNF (Tian et al., 2010).