Main pathways
Dopamine neurons are concentrated in small areas of the midbrain and project widely. A pathway to the striatum is crucial for movement, which is why its degeneration produces the symptoms of Parkinson's disease. Other pathways reach limbic and frontal areas involved in motivation and cognition.
Prediction errors
Influential recordings in monkeys showed that many dopamine neurons fire when a reward is better than expected, and fall silent when an expected reward does not arrive. This resembles a reward prediction error, a teaching signal used in computational models of learning.
Wanting versus liking
Kent Berridge and Terry Robinson argue that dopamine relates more to wanting a reward, or incentive salience, than to enjoying it. Researchers continue to debate the balance between learning and motivational accounts. Claims about a dopamine detox or dopamine levels explaining daily habits go well beyond what the evidence supports.
Further reading
- Schultz, W., Dayan, P., & Montague, P. R. (1997). A neural substrate of prediction and reward. Science, 275, 1593-1599.
- Berridge, K. C., & Robinson, T. E. (1998). What is the role of dopamine in reward: Hedonic impact, reward learning, or incentive salience? Brain Research Reviews, 28, 309-369.
- Wise, R. A. (2004). Dopamine, learning and motivation. Nature Reviews Neuroscience, 5, 483-494.