BDNF and major depressive disorder: Some of the studies examining the level of BDNF in post-mortem brain samples showed reduced values compared to controls, regardless of psychiatric diagnosis, in the prefrontal cortex and hippocampus (Dwivedi et al., 2003; Karege et al., 2005b; Ducray et al., 2006; Hochstrasser et al., 2011), as well as in the amygdala (Ray et al., 2014) and the anterior cingulate cortex (Tripp et al., 2012) of subjects suffering from major depressive disorder.