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Title:Aging and Cognitive Control: Hemispheric Differences and White Matter Integrity
Author(s):Leaver, Echo E.
Doctoral Committee Chair(s):Fabiani, Monica
Department / Program:Psychology
Discipline:Psychology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Psychology, Psychobiology
Abstract:The ability to flexibly control cognitive processed declines with aging. Age-related changes in cognitive control have been associated with white matter as well as gray matter decline. Specifically, it has been established that anterior regions of the corpus callosum (aCC) decline with advanced age. This decline in aCC may lead to a reduction in the ability of the pre-frontal cortices to coordinate their activity and successfully engage in top-down control of posterior regions. Thus, the decline in cognitive control observed in aging can be said to result from "cortical disconnection." However, it has also been suggested that the right hemisphere (RH) ages more quickly than the left hemisphere. This would indicate that older adults would have more impairment in RH tasks. The current study explored the relative contributions of these two mechanisms in cognitive changes in aging. Electrophysiological (ERP) data were recorded from 48 subjects who were divided into 4 groups (young with large aCC, young with small aCC, old with large aCC, old with small aCC). ERP data was collected while participants engaged in a task in which they were required to switch between processing global and local aspects of congruent and incongruent stimuli. The presentation of a precue informed them on which aspect (global or local) of the following imperative stimulus to focus on. Behavioral data revealed the predicted main effects for all subjects: decreased accuracy and longer reaction times on local, incongruent, and switch trials. Behavioral and ERP data indicated that decline in aCC and in right hemisphere function play important roles in age-related changes in cognitive control.
Issue Date:2008
Type:Text
Language:English
Description:124 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.
URI:http://hdl.handle.net/2142/82162
Other Identifier(s):(MiAaPQ)AAI3337838
Date Available in IDEALS:2015-09-25
Date Deposited:2008


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