Erickson Erickson KI KI Miller Miller DL DL Roecklein Roecklein KA KA The aging hippocampus: interactions between exercise, depression, and BDNF The aging hippocampus: interactions between exercise, depression, and BDNF Neuroscientist Neuroscientist 2012 2012 18 18 1 1 82 82 97 97 21531985 21531985. This evidence concerns the gene BDNF and major depressive disorder.