Our new preprint on the effect of stress on responses to extinguished alcohol cues is available here. This manuscript was prepared for a special journal issue honoring Dr. Nadia Chaudhri, whose work on context-induced reinstatement of Pavlovian alcohol seeking inspired these experiments. We examined the impact of three stressors that have been shown to reinstate operant responding for alcohol reward: yohimbine (a pharmacological stressor), intermittent footshock, and an odor cue previously paired with social defeat. We found that yohimbine reinstated both alcohol and sucrose seeking in a Pavlovian setting, but footshock and a social defeat cue failed to enhance alcohol seeking behavior.

In April, Collin presented a poster on his honors thesis project, “The Contributions of GABAergic Neurons in the Ventral Pallidum to Food Reward Consumption” at the University of Minnesota’s Spring Undergraduate Research Symposium. Collin worked with Alexandra Scott, a graduate student in the lab, to investigate the impact of inhibition of activation of GABAergic neurons in the ventral pallidum on consumption of sucrose or rat chow. He used designer receptors exclusively activated by designer drugs (aka DREADDs) to target this cell type specifically. Interestingly he found that activation of these neurons potentiated by sucrose and rat chow consumption, but that this effect only occurred in male rats. Great work, Collin!

The lab was recently awarded a new NIH Research Project Grant Program (R01) from NIDA to study the neural mechanisms of incentive motivated and goal-directed reward-seeking behaviors. The incentive motivational value of drug-associated cues drives several facets of addiction, including escalation of drug use and the propensity to relapse even after long periods of abstinence. Cues with high incentive value elicit complex motivational and emotional states, invigorating reward-seeking behaviors that are incommensurate with the value of expected rewards. In contrast, goal-directed reward-seeking behavior relies on accurate mental representations of the expected value of predicted outcomes. Effective long-term treatments for addiction must precisely target brain mechanisms of behaviors driven by the incentive value of cues, while sparing or facilitating healthy decision-making, including goal-directed control of behavior. Yet, we know little about how the brain mechanisms underlying incentive motivation are related to those required for mental representations of future rewards. This project utilizes single unit and circuit/cell-type specific approaches to understand the relationship between the neural circuit mechanisms underlying these distinct drivers of reward-seeking behavior. Specifically, we are exploring the hypothesis that incentive and expected value representations are encoded by distinct ventral pallidal projections to the ventral tegmental area versus the mediodorsal thalamus.

We are looking for new team members at all levels to help us with this and other projects! More information can be found in the Join the Lab section of the website, which will be updated with specific postings as they are available. In the meantime please feel free to reach out to Dr. Richard (richardj@umn.edu) if you’re looking to join us.

Graduate student Dakota Palmer was recently award an individual Ruth L. Kirschstein National Research Service Award (NRSA) from NIDA/NIH! This “F31” fellowship will fund the remainder of his graduate studies.

Dakota’s project is entitled “Dissociating Invigoration and Reinforcement by GABAergic Ventral Pallidum Projections to the Ventral Tegmental Area During Cue-Elicited Reward-Seeking.” Dakota uses a combination of fiber photometry with calcium sensors, and optogenetic manipulations, to dissect neural circuit specific contributions to reward-seeking behavior.

Congratulations Dakota!!!