Incentive Salience: Dopamine’s Role in Reward

Abstract

Not all individuals who try a potentially addictive drug, or a ‘hard drug’, become addicted. What causes the transition from ‘user’ to ‘addict’? The incentive salience hypothesis is one explanation. The process of reward can be separated into ‘wanting’ and ‘liking’; but are mediated by different neural systems. Dopamine mediates ‘wanting’ but not ‘liking’. Incentive salience, or motivation, must be attributed to stimuli to transform a perceived and ‘liked’ stimulus into one that is also ‘wanted’ and able to elicit voluntary action, such as compulsive drug taking. According to the incentive salience hypothesis, drugs cause many psychological changes in the brain. One main change is ‘sensitization’ or hypersensitivity to the incentive motivational effects of drugs and drug-associated stimuli. Incentive salience hypothesis suggests that there are three psychological processes that compose incentive motivation and reward:Hedonic activation by a unconditioned stimulus (for addicts it is the drug ‘high’) Associative learning of the correlation between conditioned stimuli and unconditioned stimuli. Attribution of incentive salience to the conditioned stimuli. Mesolimbic and mesostriatal dopamine systems are necessary for only the attribution of incentive salience to the conditioned stimuli. Incentive salience can only be attributed to the predictive conditioned stimuli.