Based on these connections (Jhou et al., 2009; Xie et al., 2016), the LHb modulates neurotransmitter systems including DA and 5-HT, and participates in various physiological and pathophysiological processes such as anxiety, depression, reward-aversion and addiction (Nair et al., 2013; Lecca et al., 2014). Here, LHB is linked to major depressive disorder.