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Neural Networks for Positive and Negative Emotion Processing in Multiple Sclerosis
Restricted (Penn State Only)
Doctor of Philosophy
Date of Defense:
December 07, 2015
Peter Andrew Arnett, Dissertation Advisor
Peter Andrew Arnett, Committee Chair
Frank Gerard Hillary, Committee Member
Koraly Elisa Perez-Edgar, Committee Member
Jennifer Elise Graham-Engeland, Outside Member
Multiple sclerosis (MS) is a neurological disease with varied symptoms, including physical, cognitive, and emotional impairment. Degeneration of axon fibers could have focal and widespread effects on neural functioning and behavior, including emotional experience. Depression, particularly common in MS, has been characterized as a disorder of both positive and negative emotion, dimensions that may function with some independence. In healthy people, positive and negative emotion have demonstrated different effects on cognitive performance. The objective of this set of studies was to describe the experience of positive and negative emotion in people with MS and to determine structural and functional neural networks that may underlie this experience. In Study 1, the Chicago Multiscale Depression Inventory (CMDI) Positive scale was validated as a measure of positive emotion. In Study 2, diffusion tensor imaging (DTI) was used to examine microstructural integrity of neural tracts and to determine differences in regions related to positive and negative emotion. Additionally, functional magnetic resonance imaging (fMRI) was used to identify regions of neural activation during a working memory task that correlate with emotion. Findings did not demonstrate a direct relationship between microstructural tract integrity and emotion, but instead psychosocial variables moderated a relationship with negative emotion. Working memory was correlated with negative emotion but not positive emotion. However, fMRI analysis did not differentiate activation of regions specifically related to positive versus negative emotion during the task. Negative emotion may be a particularly strong influence on overall depression and behavior in people with MS, although more information is needed to understand the structure and function of positive and negative emotion systems.
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