Age-related white matter microstructural differences partly mediate age-related decline in processing speed but not cognition
2012 (English)In: Biochimica et Biophysica Acta - Molecular Basis of Disease, ISSN 0925-4439, Vol. 1822, no 3, 408-415 p.Article in journal (Refereed) Published
Aging is associated with declining cognitive performance as well as structural changes in brain gray and white matter (WM). The WM deterioration contributes to a disconnection among distributed brain networks and may thus mediate age-related cognitive decline. The present diffusion tensor imaging (DTI) study investigated age-related differences in WM microstructure and their relation to cognition (episodic memory, visuospatial processing, fluency, and speed) in a large group of healthy subjects (n = 287) covering 6 decades of the human life span. Age related decreases in fractional anisotropy (FA) and increases in mean diffusivity (MD) were observed across the entire WM skeleton as well as in specific WM tracts, supporting the WM degeneration hypothesis. The anterior section of the corpus callosum was more susceptible to aging compared to the posterior section, lending support to the anterior-posterior gradient of WM integrity in the corpus callosum. Finally, and of critical interest. WM integrity differences were found to mediate age-related reductions in processing speed but no significant mediation was found for episodic memory, visuospatial ability, or fluency. These findings suggest that compromised WM integrity is not a major contributing factor to declining cognitive performance in normal aging. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.
Place, publisher, year, edition, pages
Elsevier, 2012. Vol. 1822, no 3, 408-415 p.
White matter, Cognition, Aging, Mediation, DTI
Research subject Psychology
IdentifiersURN: urn:nbn:se:su:diva-76267DOI: 10.1016/j.bbadis.2011.09.001ISI: 000300807000012OAI: oai:DiVA.org:su-76267DiVA: diva2:527434
We thank the staff of the BETULA Project, R. Adolfsson, and the staff at the Umeå Center for Functional Brain Imaging, as well as the staff (especially Åke Sandgren) at the faculty of science and technology to provide super computer access. This study was supported by the Göran Gustafsson Award in Medicine (to L.N.), a grant from the Swedish Science Council (to L.N.), and a Wallenberg Scholar Grant from the Knut and Alice Wallenberg Foundation (to L.N.). The BETULA Project is supported by a grant from the Swedish Science Council (to L.-G.N. and L.N.).2012-05-212012-05-102012-10-03Bibliographically approved