Age-related white matter microstructural differences partly mediate age-related decline in processing speed but not cognition

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1822

Article

Salami, Alireza^1,2  Eriksson, Johan²  Nilsson, Lars-Goran^4,5  Nyberg, Lars^2,3 

[1] Umea Univ, Dept Integrat Med Biol, Ctr Funct Brain Imaging, Physiol Sect, S-90187 Umea, Sweden

[2] Umea Ctr Funct Brain Imaging, S-90187 Umea, Sweden

[3] Umea Univ, Dept Radiat Sci, S-90187 Umea, Sweden

[4] Stockholm Univ, Stockholm Brain Inst, S-10691 Stockholm, Sweden

[5] Stockholm Univ, Dept Psychol, S-10691 Stockholm, Sweden

关键词: White matter;    Cognition;    Aging;    Mediation;    DTI;   

DOI  :  10.1016/j.bbadis.2011.09.001

来源: Elsevier

【 摘 要 】

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. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

Free