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THE NEURAL CORRELATES OF VISUAL CONTRAST SENSITIVITY DYSFUNCTION IN OLDER ADULTS

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title
THE NEURAL CORRELATES OF VISUAL CONTRAST SENSITIVITY DYSFUNCTION IN OLDER ADULTS
author
Tanase, Alexis Diana
abstract
Older adults with visual impairment (VI), such as poor contrast sensitivity (CS), are prone to experience many limitations, but the underlying neuro-ophthalmic mechanism remains unclear. CS is an individual’s capacity to detect light and dark shading differences. Poor CS is associated with worse performance on routine tasks, cognition, mobility, and increased risk of falls and car accidents, and injuries which can contribute to lower quality of life. To investigate a neuro-ophthalmic relationship between CS and the brain, functional magnetic resonance imaging (fMRI) data from 192 cognitively-unimpaired older adults ≥70 years old at baseline from the Brain Networks and Mobility (B-NET) study were analyzed. Functional brain networks were divided into interconnected communities, and lower baseline CS was linked to degraded community structures particularly in the sensorimotor network (SMN) during rest, and in the visual network (VN) and default mode network (DMN) during a motor imagery (MI) task. In a longitudinal analysis, worse baseline CS predicted lower community structure integrity at 30-months, notably in the VN, dorsal attention network (DAN), and DMN during the MI task, as well as degraded DMN during rest. Overall, poor CS is associated with decreased functional connectivity and is predictive of future brain network disintegration. Thus, poor CS identifies a subset of older adults at risk of future decrements in brain circuits important for vision and associated activities such as driving or mobility. Further research should explore if decreased CS can be improved and positively influence functional brain health in older adults. In terms of clinical relevance, brain networks associated with CS may also underlie the low physical function observed in people with poor CS.
subject
Aging
Brain networks
Community structure
Contrast sensitivity
fMRI
Vision neuroscience
contributor
Laurienti, Paul J. (advisor)
Laurienti, Paul J. (committee member)
Thompson, Atalie C. (committee member)
Sappington, Rebecca M. (committee member)
date
2024-05-23T08:36:26Z (accessioned)
2024 (issued)
degree
Neuroscience – MS (discipline)
embargo
2025-05-22 (terms)
2025-05-22 (liftdate)
identifier
http://hdl.handle.net/10339/109454 (uri)
language
en (iso)
publisher
Wake Forest University
type
Thesis

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