Hunger State Modulation of Dopamine Dynamics Across Subregions of Striatum
Sciences and Mathematics, College of
Psychological Science, Department of
SURS Faculty Advisor
Dr. Carole Scherling
Our perception of the world and how we modify our behavior in response to changes in our environment is not just a matter of sensory experience, but depends on the interplay between external signals and our internal states. For example, food is appetitive when hungry but can trigger nausea when sated. Understanding how homeostatic states change neural circuits to modulate the representation of external stimuli is essential to understanding behavioral control. Prior studies have asked how hunger states influence motivation and its neural correlates in the form of dopamine in the nucleus accumbens (NAc), a subregion of the striatum known to mediate motivation. However, distinct striatal subregions, including dorsomedial (DMS) and dorsolateral striatum (DLS), contribute to different aspects of behavioral control, for example by controlling the balance between goal-directed and habitual behavior. Therefore, all of striatum must act coordinately to properly adapt behavior to changes in the external environment. Currently, it is unclear how hunger states modulate responses in subregions of striatum and whether non-food associated stimuli are modulated differently than food associated cues. To this end, we hypothesized that homeostatic states such as hunger and satiety influence dopamine signaling differentially across subregions of the striatum. Using mice as a model organism, we first performed stereotaxic surgery to inject a virally-delivered, genetically-encoded dopamine sensor (dLight) and implanted fiberoptics in precise brain regions – DLS, DMS. We then presented the mice with visual, auditory, or rewarding stimuli at random time points while measuring real-time dopamine release in mice that were food-restricted versus fed mice. We found that prior to forming an association between light stimuli and sucrose reward, few differences in DLS and DMS dopamine response to external stimuli exist between sated and food restricted states. However, once an association is formed between houselight presentation and sucrose delivery, these differences in dopamine response between sated and food-restricted states become widespread across stimuli and sub-region of striatum.
Crow, John N., "Hunger State Modulation of Dopamine Dynamics Across Subregions of Striatum" (2022). Science University Research Symposium (SURS). 62.