The architecture of cross-hemispheric communication in the aging brain: linking behavior to functional and structural connectivity.
Journal Article (Journal Article)
Contralateral recruitment remains a controversial phenomenon in both the clinical and normative populations. To investigate the neural correlates of this phenomenon, we explored the tendency for older adults to recruit prefrontal cortex (PFC) regions contralateral to those most active in younger adults. Participants were scanned with diffusion tensor imaging and functional magnetic rresonance imaging during a lateralized word matching task (unilateral vs. bilateral). Cross-hemispheric communication was measured behaviorally as greater accuracy for bilateral than unilateral trials (bilateral processing advantage [BPA]) and at the neural level by functional and structural connectivity between contralateral PFC. Compared with the young, older adults exhibited 1) greater BPAs in the behavioral task, 2) greater compensatory activity in contralateral PFC during the bilateral condition, 3) greater functional connectivity between contralateral PFC during bilateral trials, and 4) a positive correlation between fractional anisotropy in the corpus callosum and both the BPA and the functional connectivity between contralateral PFC, indicating that older adults' ability to distribute processing across hemispheres is constrained by white matter integrity. These results clarify how older adults' ability to recruit extra regions in response to the demands of aging is mediated by existing structural architecture, and how this architecture engenders corresponding functional changes that allow subjects to meet those task demands.
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Duke Authors
Cited Authors
- Davis, SW; Kragel, JE; Madden, DJ; Cabeza, R
Published Date
- January 2012
Published In
Volume / Issue
- 22 / 1
Start / End Page
- 232 - 242
PubMed ID
- 21653286
Pubmed Central ID
- PMC3236798
Electronic International Standard Serial Number (EISSN)
- 1460-2199
Digital Object Identifier (DOI)
- 10.1093/cercor/bhr123
Language
- eng
Conference Location
- United States