5HT: DOPAMINE, LEARNING AND MOTIVATION
Nature Reviews Neuroscience - Reviews: "The hypothesis that dopamine is important for reward has been proposed in a number of forms, each of which has been challenged. Normally, rewarding stimuli such as food, water, lateral hypothalamic brain stimulation and several drugs of abuse become ineffective as rewards in animals given performance-sparing doses of dopamine antagonists. Dopamine release in the nucleus accumbens has been linked to the efficacy of these unconditioned rewards, but dopamine release in a broader range of structures is implicated in the 'stamping-in' of memory that attaches motivational importance to otherwise neutral environmental stimuli.
Brain dopamine has been linked to both motor and motivational functions. Several motivational hypotheses have been challenged and found inadequate, but it remains clear that dopamine is vital for the 'stamping-in' of stimulus–reward and response–reward associations.
Stimulus–reward associations are, in turn, crucial for the subsequent motivation in a previous-reward situation. Response habits are triggered by environmental stimuli that have been previously associated with reward, and the initiation of such response habits is not dependent on immediate dopamine function. If repeated with dopamine function blocked, however, the old stimulus–reward associations are extinguished and response motivation progressively weakens.
While the motivational effectiveness of reward-associated stimuli does not require immediate dopamine function, phasic dopamine elevations can nonetheless amplify stimulus effectiveness. This amplification is thought to be a dopamine function in the nucleus accumbens.
The role of dopamine in the stamping-in of reward associations might be much less localized. Dopamine seems to have important roles in the consolidation of memory in various structures — structures that are linked to different kinds of learning or to the learning of different things.
A full appreciation of the role of dopamine in motivation must be on the basis of an understanding of not only the role of dopamine in immediate behavioural arousal, but also its role in the learning and memory of learned motivational stimuli."
Roy A. Wise
DOPAMINE, LEARNING AND MOTIVATION
Nature Reviews Neuroscience 5, 483-494 (2004); doi:10.1038/nrn1406
Brain dopamine has been linked to both motor and motivational functions. Several motivational hypotheses have been challenged and found inadequate, but it remains clear that dopamine is vital for the 'stamping-in' of stimulus–reward and response–reward associations.
Stimulus–reward associations are, in turn, crucial for the subsequent motivation in a previous-reward situation. Response habits are triggered by environmental stimuli that have been previously associated with reward, and the initiation of such response habits is not dependent on immediate dopamine function. If repeated with dopamine function blocked, however, the old stimulus–reward associations are extinguished and response motivation progressively weakens.
While the motivational effectiveness of reward-associated stimuli does not require immediate dopamine function, phasic dopamine elevations can nonetheless amplify stimulus effectiveness. This amplification is thought to be a dopamine function in the nucleus accumbens.
The role of dopamine in the stamping-in of reward associations might be much less localized. Dopamine seems to have important roles in the consolidation of memory in various structures — structures that are linked to different kinds of learning or to the learning of different things.
A full appreciation of the role of dopamine in motivation must be on the basis of an understanding of not only the role of dopamine in immediate behavioural arousal, but also its role in the learning and memory of learned motivational stimuli."
Roy A. Wise
DOPAMINE, LEARNING AND MOTIVATION
Nature Reviews Neuroscience 5, 483-494 (2004); doi:10.1038/nrn1406
