Undergraduate Honors Theses

Thesis Defended

Spring 2013

Document Type

Thesis

Department

Psychology & Neuroscience

First Advisor

Jerry W. Rudy

Abstract

Behavior is guided by motivation; such motivation includes effort and reward. The striatum plays a central role in integrating value of reward and effort associated with behavior, through converging inputs from multiple areas of the brain. Two antagonistic pathways within the striatum are involved in this process; the direct pathway which executes behavior that is rewarded and the indirect pathway which inhibits behavior that is not rewarded or is too effortful. Activation of the direct pathway is aided by increases in dopamine and activation of the indirect pathway is aided by decreases in dopamine. It is thought that A2a receptors have modulatory effects on dopamine signaling in the striatum. However, no study to date has shown the specific effects of A2a receptors in effort-guided behaviors. For this purpose, we developed a new behavioral task to assess effort-guided decision making, in which rats had to choose between to actions that were associated with different amounts of effort. We found that A2a receptor antagonism decreased the sensitivity to effort, but increased ability to assess and adapt to effort changes.

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