Large-Scale Cortical Functional Organization and Speech Perception across the Lifespan

Sheppard, J. P., Wang, J. P., Wong, P. C. M. (January 2011) Large-Scale Cortical Functional Organization and Speech Perception across the Lifespan. PLoS ONE, 6 (1). ISSN 1932-6203

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URL: http://www.ncbi.nlm.nih.gov/pubmed/21304991
DOI: 10.1371/journal.pone.0016510

Abstract

Aging is accompanied by substantial changes in brain function, including functional reorganization of large-scale brain networks. Such differences in network architecture have been reported both at rest and during cognitive task performance, but an open question is whether these age-related differences show task-dependent effects or represent only task-independent changes attributable to a common factor (i.e., underlying physiological decline). To address this question, we used graph theoretic analysis to construct weighted cortical functional networks from hemodynamic (functional MRI) responses in 12 younger and 12 older adults during a speech perception task performed in both quiet and noisy listening conditions. Functional networks were constructed for each subject and listening condition based on inter-regional correlations of the fMRI signal among 66 cortical regions, and network measures of global and local efficiency were computed. Across listening conditions, older adult networks showed significantly decreased global (but not local) efficiency relative to younger adults after normalizing measures to surrogate random networks. Although listening condition produced no main effects on whole-cortex network organization, a significant age group x listening condition interaction was observed. Additionally, an exploratory analysis of regional effects uncovered age-related declines in both global and local efficiency concentrated exclusively in auditory areas (bilateral superior and middle temporal cortex), further suggestive of specificity to the speech perception tasks. Global efficiency also correlated positively with mean cortical thickness across all subjects, establishing gross cortical atrophy as a task-independent contributor to age-related differences in functional organization. Together, our findings provide evidence of age-related disruptions in cortical functional network organization during speech perception tasks, and suggest that although task-independent effects such as cortical atrophy clearly underlie age-related changes in cortical functional organization, age-related differences also demonstrate sensitivity to task domains.

Item Type: Paper
Uncontrolled Keywords: age-related differences human cerebral-cortex complex brain networks surface-based analysis small-world prefrontal cortex older-adults individual-differences anatomical network cognitive decline
Subjects: organism description > animal behavior
organs, tissues, organelles, cell types and functions > organs types and functions > brain
organs, tissues, organelles, cell types and functions > organs types and functions
organism description > animal behavior > speech
CSHL Authors:
Communities: CSHL labs > Churchland lab
Watson School > Publications
Depositing User: Matt Covey
Date: January 2011
Date Deposited: 06 Feb 2013 15:44
Last Modified: 29 Sep 2014 18:49
PMCID: PMC3031590
Related URLs:
URI: http://repository.cshl.edu/id/eprint/27197

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