Incentive salience

Incentive salience is a desire or want attribute, which includes a motivational component, that is assigned by the brain – specifically, by the nucleus accumbens shell – 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 primarily regulated by dopamine neurotransmission in the mesocorticolimbic projection, but activity in other dopaminergic pathways and hedonic hotspots (e.g., the ventral pallidum) also modulate incentive salience.

Incentive salience is the form of motivational salience that is associated with positive reinforcement and rewarding stimuli (an attractive phenomenon). Incentive salience contrasts with aversive salience, which is the form of motivational salience that is associated with positive punishment and undesirable stimuli (an avoidance phenomenon).

The assignment of incentive salience to stimuli is dysregulated in addiction. 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 become secondary reinforcers of addictive drug use. As secondary reinforcers of drug use, these previously neutral stimuli are assigned incentive salience (which manifests as a craving), sometimes at pathologically high levels, which transfers to the primary reinforcer (i.e., the use of an addictive drug) with which it was originally paired. Thus, if a person's addiction subsides and the individual subsequently encounters one of these secondary reinforcers, a craving for that 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.

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