BDNF and Anxiety: Ceruloplasmin-knockout mice develop an anxiety phenotype at 3 months of age that is associated with reduced iron levels in the hippocampus, anxiety-like behavior in open field and elevated plus tests, elevated plasma corticosterone, and a reduction of serotonin (5HT), norepinephrine (NE), and brain-derived neurotrophic factor (BDNF) in the hippocampus.