Furthermore, in tests for depression-like behaviors, such as the learned helplessness or forced swim tests, hippocampal BDNF infusions produce antidepressant-like effects (Shirayama et al., 2002), while targeted hippocampal deletion of BDNF was sufficient to cause depression-like behaviors (Taliaz et al., 2010). This evidence concerns the gene BDNF and depressive disorder.