Tuesday, February 14, 2023

Faculty Recruit: Setting the Occasion for Motivated Behavior

12:00 PM to 1:30 PM

East Hall #4448

While there will be no live stream of this event, it will be recorded and available for review.

This event is hosted by the U-M Department of Psychiatry and features Dr. Kurt Fraser, Postdoctoral Fellow, University of California- Berkeley.

Dr. Kurt Fraser

The ability to resolve the uncertainty surrounding reward-associated cues is essential for the proper organization and generation of reward-seeking. I will describe a series of studies where I adapt and exploit a phenomenon called occasion setting to identify behavioral and neurobiological correlates of hierarchical reward-seeking. In this task, rodents are trained to discriminate when a conditioned stimulus will be followed by a sucrose reward by exploiting the prior and non-overlapping presentation of a separate discrete stimulus, an occasion setter. Only when the occasion setter’s presentation precedes the conditioned stimulus does the conditioned stimulus predict sucrose delivery.

I show that these “context-like” occasion setters are motivationally desired and act to shape behavior by transforming the motivational value of conditioned stimuli. I will show that neural activity in the nucleus accumbens, basolateral amygdala, and orbitofrontal cortex is essential for this behavioral process. Further, I have found that single neurons in the nucleus accumbens encode occasion setters and their subsequent ability to alter the value of a conditioned stimulus.

Finally, I will demonstrate that the activity of midbrain dopamine neurons is necessary for occasion setting and that dopamine release in the nucleus accumbens not only encodes occasion setters but dynamically scales when the conditioned stimulus would or would not predict reward predicated on the prior presence or absence of the occasion setting cue. I will also describe ongoing work to assess the contributions of acetylcholine signaling in the nucleus accumbens to occasion setting. Collectively these results detail neural and behavioral mechanisms for the generation of flexible cue-triggered reward-seeking which have implications for our understanding of aberrant motivation in psychiatric illness.