Incentive salience is a cognitive process that confers a "desire" or "want" attribute, which includes a motivational component, to a rewarding stimulus. Reward is the attractive and motivational property of a stimulus that induces appetitive behavior – also known as approach behavior – and consummatory behavior. The "wanting" of incentive salience differs from "liking" in the sense that liking is the pleasure that is immediately gained from the acquisition or consumption of a rewarding stimulus; the "wanting" of incentive salience serves a "motivational magnet" quality of a rewarding stimulus that makes it a desirable and attractive goal, transforming it from a mere sensory experience into something that commands attention, induces approach, and causes it to be sought out. Incentive salience is regulated by a number of brain structures, but it is assigned to stimuli by a region of the ventral striatum known as the nucleus accumbens shell. Incentive salience is primarily regulated by dopamine neurotransmission in the mesocorticolimbic projection, but activity in other dopaminergic pathways and hedonic hotspots also modulate incentive salience.
The assignment of incentive salience to stimuli is dysregulated in addiction. Addictive drugs are intrinsically rewarding and therefore function as primary positive reinforcers of continued drug use that are assigned incentive salience. During the development of an addiction, the repeated association of otherwise neutral and even non-rewarding stimuli with drug consumption triggers an associative learning process that causes these previously neutral stimuli to act as conditioned positive reinforcers of addictive drug use. As conditioned positive reinforcers of drug use, these previously neutral stimuli are assigned incentive salience – sometimes at pathologically high levels due to reward sensitization – which can transfer to the primary reinforcer with which it was originally paired. Thus, if an individual remains abstinent from drug use for some time and encounters one of these drug cues, a craving for the associated drug may reappear. For example, anti-drug agencies previously used posters with images of drug paraphernalia as an attempt to show the dangers of drug use. However, such posters are no longer used because of the effects of incentive salience in causing relapse upon sight of the stimuli illustrated in the posters. In addiction, the "liking" of a drug or other stimulus becomes dissociated from "wanting" due to the sensitization of incentive salience. In fact, if the incentive salience associated with drug-taking becomes pathologically amplified, the user may want the drug more and more while liking it less and less as tolerance develops to the drug's pleasurable effects.
Neuropsychopharmacology
Dopaminergic psychostimulants
improves [|task saliency] and increases arousal, in turn promoting goal-directed behavior. The reinforcing and motivational salience-promoting effects of amphetamine are mostly due to enhanced dopaminergic activity in the mesolimbic pathway.
