Year of Publication

2015

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Medicine

Department

Behavioral Science

First Advisor

Dr. Yang Jiang

Abstract

This dissertation introduces a framework for understanding differences in how emotional enhancement effects might influence memory in aging adults and then summarizes the findings of three studies of how repetition effects and emotional enhancement effects influence working memory in older adults without cognitive impairment (NC), older adults with amnestic mild cognitive impairment (MCI), and older adults with mild Alzheimer’s disease (AD). In these experiments, individuals with AD showed cognitive impairment in terms of accuracy and reaction time, but individuals with MCI showed milder behavioral impairment that was confined to manipulations of working memory. Individuals with AD showed relative sparing of repetition effects in behavioral performance, and this sparing was linked to an altered cortical repetition effect using event-related potentials (ERPs). Repetition effects in MCI appear absent in emotional tasks that lack a working memory component, but are present in a neural repetition mechanism that is evoked in the presence of working memory. Finally, persons with MCI showed working memory processing similar to persons without impairment when working with stimuli of low arousal and positive hedonic valence, but when working with stimuli of high arousal and negative hedonic valence, their working memory processing more resembled the AD phenotype.

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