Glossary · Y học
Dopamine
A neurotransmitter involved in mood and the control of complex movements. It is popularly reduced to a "pleasure chemical", but its best-studied role is encoding a reward prediction error — a signal that an outcome was better or worse than expected — rather than simply producing pleasure.
According to NINDS, dopamine can be excitatory or inhibitory and is involved in mood and the control of complex movements; the loss of dopamine activity in some parts of the brain leads to the muscular rigidity of Parkinson's disease. That is why dopamine cannot be reduced to a "pleasure chemical": it sits at the centre of the motor system.
In the neuroscience of learning and reward, the well-supported view is that dopamine encodes a reward prediction error: the dopamine signal rises when an outcome is BETTER than expected and dips when it is WORSE than expected, so the brain learns which actions are worth repeating. This is the picture set out in the reviews by Glimcher (2011) and by Watabe-Uchida and colleagues (2021).
Recent work adds nuance: dopamine is also involved in movement, motivation and goal-directed planning, so its role is broader — not narrower — than the everyday notion of "pleasure".