BDNF and major depressive disorder: A complex network involving amygdala and neurotrophin regulation emerges from studies in mice where changes in Bdnf methylation pattern were found during contextual fear learning (Suri et al, 2013), and from studies showing dysfunctions in amygdala and neurotrophin levels in neuropsychiatric disorders such as schizophrenia and depression (Nurjono & Chong, 2012; Kuhn et al, 2014).