2 Neuroscience2.7 Neural circuits
2.7.1.9 Motivation, reward and pleasure
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Written by Resident Doctor Committee · Published
Wanting and liking
Motivation starts and sustains goal-directed behaviour. Wanting and liking are separate reward processes that can come apart.
Process | What it is | Main signalling |
|---|---|---|
Wanting (incentive salience) | Cue-triggered motivational attraction to a reward | Mesolimbic dopamine |
Liking | Pleasure on consuming the reward | Opioid and endocannabinoid hotspots in the accumbens shell and ventral pallidum |
Incentive salience was described by Berridge and Robinson to explain drug craving.
Dopamine depletion reduces approach and effort more than pleasure reactions to sweet taste.
The mesolimbic pathway
The ventral tegmental area is the origin of the mesolimbic dopamine pathway, which projects to the nucleus accumbens (ventral striatum) and underlies reward and repeated drug use.
Prediction error
Many dopamine neurones signal reward prediction errors, which teach value rather than code pleasure.
Event | Dopamine response |
|---|---|
Unexpected reward | Phasic burst |
Cue that predicts reward | Burst moves to the cue, none at delivery |
Expected reward omitted | Dip below baseline |
Incentive salience in addiction and grief
Incentive sensitisation means that in addiction, mesolimbic dopamine wanting becomes sensitised, so cue-triggered craving persists.
Opioid and endocannabinoid liking declines at the same time, so wanting rises as pleasure falls.
Prolonged grief: incentive salience has been extended to its persistent yearning, supported by nucleus accumbens activation to reminders of the deceased.