Some of the common down genes in maternal C57 mice and depression were for the MAP kinase pathway and some of the common down genes included: FOS, EGR1, DUSP1, BDNF, NR4A1, NR3C1, the neuropeptide somatostatin (SST), and one of the its receptors, SSTR2. Here, SSTR2 is linked to major depressive disorder.