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FUNCTIONAL BRAIN NETWORKS AND STRUCTURAL PATHOLOGY: INSIGHTS INTO THE NEURAL MECHANISMS OF RESILIENCE

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abstract
The world’s population is aging at a rapid rate and healthcare costs on society are expected to increase significantly. A primary concern of older adults is loss of independence, which is often driven by mobility decline. However, despite previous work, there is still unexplained variance in physical function of older adults. Interestingly, about 30% of older adults show no cognitive or physical deficits despite increased pathologic burden within the brain. Physical resilience with age is now considered a key feature of healthy aging, but our understanding of the development of and mechanisms of resilience are limited. Neuroimaging studies, functional brain networks studies in particular, offer unique opportunities to study mobility decline and physical resilience within the brain even prior to the irreversible accumulation of structural pathology. This dissertation uses data from the Brain Networks and Mobility (B-NET) to investigate three important gaps in the current literature. The study in Chapter 2 aimed to characterize the effect of motor imagery (MI) on graph theory brain network architecture in an effort to expand the number of techniques available to study the neural correlates of mobility. Our overall hypothesis was that resilient individuals would display shifts in functional connectivity when compared with their non-resilient counterparts. Analyses in Chapter 3 assessed differences in functional connectivity between resilient and non-resilient individuals grouped by scores of the short physical performance battery (SPPB) and white matter hyperintensity (WMH) volume. Finally, Chapter 4 expanded upon Chapter 3 by examining differences in functional connectivity between resilient amyloid positive (Aβ+) individuals and those who are amyloid negative (Aβ-). We first identified pathology-specific effects on the consistency of sensorimotor community structure (SMN-CS) such that Aβ accumulation resulted in decreases in consistency, despite no decrease in mobility scores, while no significant effect of WMH volume was observed. We then characterized a potentially resilient-specific mechanism across Chapters 3 & 4 where resilient participants displayed a unique pattern of second-order connections from the SMN to the anterior cingulate cortex (ACC). To our knowledge, these are the first studies to characterize the neural mechanisms of physical resilience and provide a theoretical framework to study resilience using physical function, brain structure, and functional connectivity.
subject
Aging
Alzheimer's Disease
Functional Brain Networks
Mobility
Reserve
Resilience
contributor
Neyland, Blake Robert (author)
Hugenschmidt, Christina E. (committee chair)
Laurienti, Paul J. (committee member)
Kritchevsky, Stephen B. (committee member)
Lockhart, Samuel N. (committee member)
Haq, Ihtsham Ul (committee member)
date
2021-09-01T08:35:28Z (accessioned)
2021 (issued)
degree
Neuroscience (discipline)
2022-08-31 (liftdate)
embargo
2022-08-31 (terms)
identifier
http://hdl.handle.net/10339/99066 (uri)
language
en (iso)
publisher
Wake Forest University
title
FUNCTIONAL BRAIN NETWORKS AND STRUCTURAL PATHOLOGY: INSIGHTS INTO THE NEURAL MECHANISMS OF RESILIENCE
type
Dissertation

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