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MECHANISMS OF STRESS EFFECTS ON LEARNING AND DECISION MAKING
IN YOUNGER AND OLDER ADULTS
by
Nichole Renee Lighthall
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(GERONTOLOGY)
August 2012
Copyright 2012 Nichole Renee Lighthall
Object Description
| Title | Mechanisms of stress effects on learning and decision making in younger and older adults |
| Author | Lighthall, Nichole Renee |
| Author email | nichole.lighthall@usc.edu;nichole.lighthall@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Gerontology |
| School | Leonard Davis School of Gerontology |
| Date defended/completed | 2012-06-19 |
| Date submitted | 2012-08-03 |
| Date approved | 2012-08-03 |
| Restricted until | 2012-08-03 |
| Date published | 2012-08-03 |
| Advisor (committee chair) | Mather, Mara |
| Advisor (committee member) |
Bechara, Antoine Zelinski, Elizabeth M. Tjan, Bosco S. |
| Abstract | Stress is common in daily life and often present when making important decisions that involve risk or that require learning from the positive and negative outcomes of past choices (reinforcement-based learning). An emerging literature indicates that stress can strongly influence these types of learning and decision making, but the mechanisms of these stress effects are not yet clear. Stress affects numerous brain regions and networks involved in motivated learning and decision making including those subserving reward processing, attentional control, perception, and integration hubs for cognitive, affective, and sensory information. ❧ The first aim of this dissertation was to determine whether and how these neural networks may mediate stress effects on learning and decision making (Study 1 and Study 3). Findings from Study 1 indicated that stress affects the involvement of the dorsal striatum and anterior insula in young adults during risky decision making involving monetary reward, but stress effects are opposite for men and women. Results from Study 3 revealed that stress affects the involvement of attentional control and visual perception regions during social reinforcement learning. ❧ A second aim of this dissertation was to examine age differences the impact of stress on reinforcement learning (Study 2 and Study 3). Aging is associated with declines in reinforcement learning abilities and changes to the neural networks involved in reinforcement learning and stress response. Thus, stress may affect reinforcement learning differently in younger and older people. Given older adults' already compromised functioning in this domain, it is important to determine whether stress enhances or impairs reinforcement learning in older age. Study 2 indicated that reinforcement-based learning for positive cue-outcome associations is similarly enhanced by acute stress in younger and older adults, but Study 3 found that only younger adults had this stress-related enhancement. These mixed findings highlighted the potential importance of task difficulty, level of stress arousal, and type of reinforcement in determining when age differences in stress effects will be observed for reinforcement learning. Finally, for brain activation, Study 3 found no significant stress-by-age effects, but did find age differences during social reinforcement learning, indicative of an age-related bias for positive social feedback. In sum, this dissertation provides insight into how motivated learning and decision making are affected by short-term stress and how these stress effects may depend on age. Findings presented here provide information about young and older adults' ability to manage risk- and reward-related decisions and may inform interventions targeted at addressing age-specific cognitive vulnerabilities during stress. |
| Keyword | aging; decision making; learning; reward; stress |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m |
| Contributing entity | University of Southern California |
| Rights | Lighthall, Nichole Renee |
| Physical access | The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the author, as the original true and official version of the work, but does not grant the reader permission to use the work if the desired use is covered by copyright. It is the author, as rights holder, who must provide use permission if such use is covered by copyright. The original signature page accompanying the original submission of the work to the USC Libraries is retained by the USC Libraries and a copy of it may be obtained by authorized requesters contacting the repository e-mail address given. |
| Repository name | University of Southern California Digital Library |
| Repository address | USC Digital Library, University of Southern California, University Park Campus MC 7002, 106 University Village, Los Angeles, California 90089-7002, USA |
| Repository email | cisadmin@dots.usc.edu |
| Archival file | uscthesesreloadpub_Volume4/etd-LighthallN-1132.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@dots.usc.edu |
| Full text | MECHANISMS OF STRESS EFFECTS ON LEARNING AND DECISION MAKING IN YOUNGER AND OLDER ADULTS by Nichole Renee Lighthall A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (GERONTOLOGY) August 2012 Copyright 2012 Nichole Renee Lighthall |
