Effects of recent chronic and episodic life stress on ventral striatal activation during reward anticipation

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Bradley M. Avery (Creator)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Advisor
Suzanne Vrshek-Schallhorn

Abstract: Dysregulated reward processes are a transdiagnostic feature of several psychiatric disorders, and reward-related deficits predict a relatively poor prognosis in individuals with depression. Research utilizing animal models and limited human research suggests that the experience of stress is associated with disrupted reward processes, an effect that is likely mediated by the deleterious effects of stress on dopaminergic signaling. However, neurobiological mechanisms contributing to reward deficits are poorly understood, and no studies to date have examined the association of naturalistic life stress and functional neural correlates of reward processes in humans. As such, it is unclear whether either the main effects of stress or stress acting together with certain individual differences might predict disrupted neural reward functioning. Thus, the present study sought to examine this association, initially hypothesizing that greater interpersonal, but not non-interpersonal life stress assessed using the UCLA Life Stress Interview would be associated with blunted blood oxygen level-dependent (BOLD) reactivity in the ventral striatum in response to reward anticipation during the Monetary Incentive Delay task. Contrary to hypotheses, there was no main effect of naturalistic life stress in any domain (chronic, episodic, interpersonal, non-interpersonal) on ventral striatal reactivity to reward anticipation. Secondary exploratory analyses instead revealed a moderating effect of the personality trait Grit, defined as perseverance towards long-term goals, such that higher levels of Grit predicted significantly less negative effects of chronic interpersonal stress on bilateral ventral striatal reactivity during reward anticipation. Results implicate robust reward-related ventral striatal reactivity in the context of life stress as a critical underpinning of goal-pursuit in the context of life stress, and support a wider literature indicating a role of reward and positive emotion in general coping.

Additional Information

Publication
Dissertation
Language: English
Date: 2020
Keywords
Depression, fMRI, Grit, Reward, Stress, Ventral Striatum
Subjects
Depression, Mental
Reward (Psychology)
Stress (Psychology)
Resilience (Personality trait)
Perseverance (Ethics)

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