Neural Circuits Controlling Voluntary Physical Activity

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Presenter(s)

Nadja Brown

Abstract or Description

Neural circuits controlling voluntary physical activity

Nadja Brown, Margaret K Tanner, Alyssa Hohorst, Esteban C Loetz, Benjamin N Greenwood

Exercise is a major factor contributing to a healthy lifestyle, yet many people do not exercise regularly. Understanding how the brain governs voluntary exercise could lead to novel targets to increase exercise participation. Rats are a good model to study exercise motivation because they will voluntarily run on wheels. After an acquisition phase during which daily running increases, rats reach stable, high levels of running resembling a habit. Interestingly, female rats reach the habitual phase faster than males. The goal of this experiment is to determine the neural circuits underlying the maintenance of exercise habits in both sexes, and the rapid escalation of exercise in females. A brain dopamine (DA) circuit from the substantia nigra (SN) to the dorsolateral striatum (DLS) is involved in motivation and habits, but its role in voluntary exercise is unknown. Females have greater stimulus-evoked DA responses than males, so it is possible that exercise recruits the SN-DLS circuit more readily in females than males, thus accelerating the development of an exercise habit. Here, we will use a chemogenetic approach to silence SN-DLS circuit activity during wheel running to test the hypothesis that SN-DLS circuit activity is responsible for habitual exercise. We predict that SN-DLS circuit silencing will reduce the escalation of wheel running to the habitual phase, and this should occur in females earlier than in males. These data will suggest that the SN-DLS circuit is responsible for the maintenance of voluntary physical activity.