Reward system:

the mesolimbic dopamine pathway connecting the ventral tegmental area (blue dot) and nucleus accumbens (red dot).

a collection of structures, including the nucleus accumbens and ventral tegmental area, that are involved in reinforcing behavior. The reward system is activated when we experience something pleasurable and is a major target of investigation for understanding the effects of addictive drugs.

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2-Minute Neuroscience: Reward System

Know your brain: Reward system