Behavioral characteristics and neurobiological substrates shared by Pavlovian sign-tracking and drug abuse

Abstract

Drug abuse researchers have noted striking similarities between behaviors elicited by Pavlovian signtracking procedures and prominent symptoms of drug abuse. In Pavlovian sign-tracking procedures, repeated paired presentations of a small object (conditioned stimulus, CS) with a reward (unconditioned stimulus, US) elicits a conditioned response (CR) that typically consists of approaching the CS, contacting the CS, and expressing consummatory responses at the CS. Signtracking CR performance is poorly controlled and exhibits spontaneous recovery and long-term retention, effects that resemble relapse. Sign-tracking resembles psychomotor activation, a syndrome of behavioral responses evoked by addictive drugs, and the effects of sign-tracking on corticosterone levels and activation of dopamine pathways resemble the neurobiological effects of abused drugs. Finally, the neurobiological profile of individuals susceptible to sign-tracking resembles the pathophysiological profile of vulnerability to drug abuse, and vulnerability to sign-tracking predicts vulnerability to impulsive responding and alcohol self-administration. Implications of sign-tracking for models of drug addiction are considered.

Isolating the incentive salience of reward-associated stimuli: value, choice, and persistence

“…As stated above, much of the previous work on the differential neurobehavioral mechanisms involved in sign-and goaltracking behavior has utilized different cohorts that demonstrate sign-or goal-tracking behavior, and this work has been carried out primarily in relation to individual differences in substance abuse vulnerability, where, in general, individuals that are more likely to sign-track are also those that are more susceptible to the rewarding effects of drugs of abuse (Tomie et al 2008; Robinson et al 2014). As with the cohort approach, all animals tested herein were exposed to PCA training with a lever, leading to the question of why there was so little goal-tracking observed to the lever in the present experiments.…”

“…Interestingly, not all reward-paired stimuli function equivalently; some stimuli are more likely to be attributed with value, and there are individual differences in the likelihood that a stimulus will attain value during stimulus-reward learning (Tomie et al 2008;Robinson et al 2014). Furthermore, the propensity to attribute a reward-predictive stimulus with incentive value has been demonstrated to predict drug reward in a variety of preclinical models of substance abuse Robinson 2010, 2011;Anderson and Spear 2011;Beckmann et al 2011;Peters and De Vries 2014).…”

Adolescent Alcohol Exposure Amplifies the Incentive Value of Reward-Predictive Cues Through Potentiation of Phasic Dopamine Signaling

“…Indeed, individuals who abuse drugs are more likely to exhibit this stimulus-driven affective behavior (Bickel and Marsch, 2001). The sign-tracking phenotype in rats, characterized by the assignment of incentive value to reward-predictive cues, has been previously associated with reduced impulse control and vulnerability to addictive behavior (Flagel et al, 2010;Lovic et al, 2011;Tomie et al, 2008). Importantly, there is a wide variation in the degree to which individuals engage in sign-tracking behavior, thus allowing for a comparison between drug-associated behaviors and the degree to which individuals assign incentive value to predictive cues.…”

Incentive Learning Underlying Cocaine-Seeking Requires mGluR5 Receptors Located on Dopamine D1 Receptor-Expressing Neurons

“…4F). Thus, in addition to the aforementioned deficit in conditioned reinforcement, mGluR5 knockdown on D1-expressing neurons resulted in a deficit in the attribution of incentive properties to the CSϩ necessary for the CS to become highly salient and attractive (Robinson and Berridge, 1993;Tomie et al, 2008).…”