Journal Article

Region-specific changes in prefrontal function with age: a review of PET and fMRI studies on working and episodic memory

M. Natasha Rajah and Mark D'Esposito

in Brain

Published on behalf of The Guarantors of Brain

Volume 128, issue 9, pages 1964-1983
Published in print September 2005 | ISSN: 0006-8950
Published online July 2005 | e-ISSN: 1460-2156 | DOI: http://dx.doi.org/10.1093/brain/awh608
Region-specific changes in prefrontal function with age: a review of PET and fMRI studies on working and episodic memory

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Several neuroimaging studies of cognitive ageing have found that age-related deficits in working memory (WM) and episodic memory abilities are related to changes in prefrontal cortex (PFC) function. Reviews of these neuroimaging studies have generally concluded that with age there is a reduction in the hemispheric specialization of cognitive function in the frontal lobes that may either be due to dedifferentiation of function, deficits in function and/or functional reorganization and compensation. Moreover, previous reviews have considered the PFC as homogeneous in function and have not taken into account the possibility that region specific changes in PFC function may occur with age. In the current review we performed a qualitative meta-analytic review of all the functional magnetic resonance imaging ageing studies and positron emission tomography ageing studies of WM and episodic memory that report PFC activation, to determine if any region-specific changes occur. The results indicated that in normal ageing distinct PFC regions exhibit different patterns of functional change, suggesting that age-related changes in PFC function are not homogeneous in nature. Specifically, we hypothesize that normal ageing is related to the differentiation of cortical function in a bilateral ventral PFC and deficits in function in right dorsal and anterior PFC. As a result of these changes, functional compensation in left dorsal and anterior PFC may occur. We hope that future studies will be conducted to either confirm or counter these hypotheses.

Keywords: ageing; compensation; dedifferentiation; episodic memory; working memory; BA = Brodmann area; EM = episodic memory; MFG = middle frontal gyrus; PFC = prefrontal cortex; WM = working memory

Journal Article.  16108 words.  Illustrated.

Subjects: Neurology ; Neuroscience

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