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Cereb Cortex. 2012 Jun;22(6):1395-406. doi: 10.1093/cercor/bhr222. Epub 2011 Aug 24.

Changes in regional and temporal patterns of activity associated with aging during the performance of a lexical set-shifting task.

Author information

1
Functional Neuroimaging Unit, Institut Universitaire de Gériatrie de Montréal, Montréal, QC H3W 1W5, Canada.

Abstract

Some older individuals seem to use compensatory mechanisms to maintain high-level performance when submitted to cognitive tasks. However, whether and how these mechanisms affect fronto-striatal activity has never been explored. The purpose of this study was to investigate how aging affects brain patterns during the performance of a lexical analog of the Wisconsin Card Sorting Task, which has been shown to strongly depend on fronto-striatal activity. In the present study, both younger and older individuals revealed significant fronto-striatal loop activity associated with planning and execution of set-shifts, though age-related striatal activity reduction was observed. Most importantly, while the younger group showed the involvement of a "cognitive loop" during the receiving negative feedback period (which indicates that a set-shift will be required to perform the following trial) and the involvement of a "motor loop" during the matching after negative feedback period (when the set-shift must be performed), older participants showed significant activation of both loops during the matching after negative feedback period only. These findings are in agreement with the "load-shift" model postulated by Velanova et al. (Velanova K, Lustig C, Jacoby LL, Buckner RL. 2007. Evidence for frontally mediated controlled processing differences in older adults. Cereb Cortex. 17:1033-1046.) and indicate that the model is not limited to memory retrieval but also applies to executive processes relying on fronto-striatal regions.

PMID:
21868390
DOI:
10.1093/cercor/bhr222
[Indexed for MEDLINE]

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