A General Factor of Brain White Matter Integrity Predicts Information Processing Speed in Healthy Older People
Open Access
- 2 June 2010
- journal article
- research article
- Published by Society for Neuroscience in Journal of Neuroscience
- Vol. 30 (22), 7569-7574
- https://doi.org/10.1523/jneurosci.1553-10.2010
Abstract
Human white matter integrity has been related to information processing speed, but it is unknown whether impaired integrity results from localized processes or is a general property shared across white matter tracts. Based on diffusion MRI scans of 132 healthy individuals with a narrow age range around 72 years, the integrity of eight major white matter tracts was quantified using probabilistic neighborhood tractography. Principal component analyses (PCAs) were conducted on the correlations between the eight tracts, separately for four tract-averaged integrity parameters: fractional anisotropy, mean diffusivity, and radial and axial diffusivity. For all four parameters, the PCAs revealed a single general factor explaining ∼45% of the individual differences across all eight tracts. Individuals' scores on a general factor that captures the common variance in white matter integrity had significant associations with a general factor of information processing speed for fractional anisotropy (r = −0.24, p = 0.007) and radial diffusivity (r = 0.21, p = 0.016), but not with general intelligence or memory factors. Individual tracts showed no associations beyond what the common integrity factor explained. Just as different types of cognitive ability tests share much of their variance, these novel findings show that a substantial amount of variance in white matter integrity is shared between different tracts. Therefore, impaired cortical connection is substantially a global process affecting various major tracts simultaneously. Further studies should investigate whether these findings relate more to the role of tract integrity and information processing speed in nonpathological cognitive aging or in lifelong-stable processes.Keywords
This publication has 37 references indexed in Scilit:
- Microstructural correlations of white matter tracts in the human brainNeuroImage, 2010
- Cerebral White Matter Integrity and Cognitive Aging: Contributions from Diffusion Tensor ImagingNeuropsychology Review, 2009
- White Matter Microstructural Integrity and Cognitive Function in a General Elderly PopulationArchives of General Psychiatry, 2009
- The Adaptive Brain: Aging and Neurocognitive ScaffoldingAnnual Review of Psychology, 2009
- Quantitative tractography metrics of white matter integrity in diffusion-tensor MRINeuroImage, 2008
- Cognitive processing speed and the structure of white matter pathways: Convergent evidence from normal variation and lesion studiesNeuroImage, 2008
- Cerebral White Matter Integrity Mediates Adult Age Differences in Cognitive PerformanceJournal of Cognitive Neuroscience, 2008
- Tract probability maps in stereotaxic spaces: Analyses of white matter anatomy and tract-specific quantificationNeuroImage, 2008
- The Lothian Birth Cohort 1936: a study to examine influences on cognitive ageing from age 11 to age 70 and beyondBMC Geriatrics, 2007
- Positive correlations between corpus callosum thickness and intelligenceNeuroImage, 2007