GRIN2B and major depressive disorder: Postmortem investigations of N-methyl-d-aspartate receptors (NMDARs) subunit expression in the brains of MDD subjects compared with those of non-depressed controls show (a) an increase or no change of NR1 subunit expression in the hippocampus [107-109], (b) an increase of NR2A and NR2B subunit expression in the hippocampus [107,108], (c) a decrease or no change in NR1 subunit expression in the prefrontal cortex [110,111], (d) a decrease of NR2A and NR2B subunit expression in the prefrontal cortex [110], and (e) an increase of NR2A subunit expression in the lateral amygdalae [255].