LHB and major depressive disorder: Additionally, MD in rats persistently increases both tonic and bursting LHb activity from early adolescence to adulthood (Authement et al., 2018; Shepard et al., 2018b; Simmons et al., 2020; Langlois et al., 2021) consistent with the literature that LHb hyperactivity in general (and bursting in particular) contributes to the development of depression-like motivational and social deficits, and anhedonic phenotypes (Yang et al., 2018; Klein et al., 2020).