Together these findings suggest rigid appetitive associative encoding in BLA–NAc of sign-tracking rats hinders the expression of flexible behavior when outcome value changes.Ī body of evidence suggests that sign- and goal-tracking differences predict vulnerability to Substance Use Disorder (SUD Tomie et al., 2008 Flagel et al., 2009 Saunders and Robinson, 2010 Saunders et al., 2013 Yager et al., 2015 Kawa et al., 2016 Villaruel and Chaudhri, 2016).

Consistent with a prior BLA–NAc disconnection lesion study, we find contralateral chemogenetic inactivation of BLA and NAc core reduces lever, but not the foodcup approach in PLA. Contralateral BLA–NAc chemogenetic inactivation promoted a flexible lever approach in sign-tracking rats but disrupted the flexible foodcup approach in goal-tracking rats. We sated rats on training pellets (devalued condition) or chow (valued condition) before systemic clozapine injections (0.1 mg/kg) to inactivate BLA and contralateral NAc during two outcome devaluation probe tests, in which we measured lever and foodcup approach. To determine sign- and goal-tracking groups, we trained rats in five PLA sessions in which brief lever insertion predicts food pellet delivery. Using a contralateral chemogenetic inactivation design, we injected contralateral BLA and NAc core with inhibitory DREADD (hm4Di-mCherry) or control (mCherry) constructs. Here, we sought to determine whether BLA–NAc communication, which is necessary for sign, but not goal-tracking, drives a rigid appetitive approach of sign-tracking rats that are insensitive to manipulations of outcome value. While sign-tracking rats inflexibly respond to cues even after the associated reward is devalued, goal-tracking rats flexibly reduce responding to cues during outcome devaluation. During PLA, sign-tracking rats preferentially approach an insertable lever cue, while goal-tracking rats approach a foodcup where rewards are delivered.

Rats rely on communication between the basolateral amygdala (BLA) and nucleus accumbens (NAc) to express lever directed approach in a Pavlovian lever autoshaping (PLA) task that distinguishes sign- and goal-tracking rats.

2Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, United States.

1Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States.

Rats by robert sullivan summary