BDNF and major depressive disorder: There is also considerable research on how depression-like behaviors can be produced by the BDNF signaling pathway, and some studies have shown that chronic stress exposure can induce the development of depression-like behavior though damaging the signaling between cyclic adenosine monophosphate-response element binding protein (CREB) and BDNF in the hippocampus, although the underlying mechanism remains largely unknown.