Fig. 3.

A model of striatal DA level and subsequent influence of appetitive and inhibitory areas on executive control. Right panel, dotted line normal tonic and phasic DA release from the ventral tegmental area (VTA) to the nucleus accumbens (Nacc). Left panel, bottom the influences of inhibitory and appetitive areas are well balanced and adequately regulated. Right panel, solid line 1 vulnerable individuals have an increased tonic DA level, leading to reduced influence of inhibitory control areas via increased D₂ receptor activation (left panel, middle) [58, 81–84, 91•]; 2 increased D₂ receptor activation interferes with the dip following punishments [55]; 3 adequate reinforcing stimuli now lead to suprathreshold D₁ receptor stimulation, which drives the formation of pathological habits [40••]