Ripperger, Hayley
(2022)
Associations Between Cardiorespiratory Fitness and Hippocampal Subfield Morphology in Older Adults.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
The hippocampus experiences a 1-2% annual decrease in total volume starting around age 50.Previous research has demonstrated that cardiorespiratory fitness is associated withhippocampal volume, and that aerobic exercise interventions are capable of increasing hippocampal volume in older adults. However, human studies using magnetic resonance imaging (MRI) technology have used sequences and analytical approaches that only determine total hippocampal size; however, the hippocampus is made up of subfields (CA1, CA2, CA3, dentate gyrus (DG), and subiculum) with distinct cytoarchitectural and functional characteristics. Animal studies demonstrate that exercise influences the volume of some of these subfields more than others, indicating that there are likely regionally-specific effects within the hippocampus.
Here we examined the association between cardiorespiratory fitness and hippocampal subfield morphology in a sample of relatively inactive and cognitively-normal older adults. All participants (N=641) underwent a maximal VO2 exercise test to assess cardiorespiratory fitness as well as an MRI, and we used a software package called Automated Segmentation of Hippocampal Subfields (ASHS) to identify and label the subfields of the hippocampus. We examined whether cardiorespiratory fitness was associated with the volume of each of the hippocampal subfields and/or total hippocampal volume, and examined whether any associations were statistically moderated by age or sex. Our results partially replicated previous findings by demonstrating that in cognitively healthy older adults, cardiorespiratory fitness was associated with total right hippocampal volume. In addition, cardiorespiratory fitness was associated with the volume of certain subfields within the right hippocampus: CA1, CA2, and subiculum. Furthermore, we found that age and sex were important moderators, with age moderating cardiorespiratory fitness for left CA1 and left total hippocampal volume, and with sex moderating cardiorespiratory fitness for both the left and right DG. Our findings demonstrate that “younger” older adults and males appear to benefit most from having higher cardiorespiratory fitness. We conclude that cardiorespiratory fitness may have differential effects on the hippocampal subfields in males versus females, and in younger versus older old adults. This may help account for mixed findings in the literature, as well as inform who might experience the greatest brain benefits by increasing their cardiorespiratory fitness.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Ripperger, Hayley | hsr5@pitt.edu | hsr5 | |
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| ETD Committee: |
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| Date: |
13 August 2022 |
| Date Type: |
Publication |
| Defense Date: |
8 June 2022 |
| Approval Date: |
19 November 2024 |
| Submission Date: |
27 July 2022 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
50 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Psychology |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Hippocampus, aging, exercise |
| Date Deposited: |
19 Nov 2024 16:35 |
| Last Modified: |
20 Nov 2024 16:58 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/43525 |
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