FIGURE 4.

Four major brain dopaminergic pathways as well as depression-related brain regions and a schematic of brain circuitry implicated in depression. Dopaminergic (DAergic; orange) and glutamatergic (Gluergic; green) direct inputs converge on γ-aminobutyric acid (GABA)ergic (blue) neurons in the NAc to regulate behaviors of depression. The dopaminergic pathway from the VTA to the NAc plays a key role in reward-related behavior. Direct dopaminergic outputs of the VTA arise from the NAc, PFC, VP, BLA, and Hp, while the VTA, VP, BLA, and LHb receive NAc GABAergic inputs as well VTA, PFC, BLA, and Hp glutamatergic inputs. Besides, VTA receives PFC and LHb glutamatergic inputs. ACC, anterior cingulate cortex; HP, hippocampus; LHb, lateral habenula; PFC, prefrontal cortex; NAc, nucleus accumbens; VTA, ventral tegmental area; VP, ventral pallidum.