A General Factor of Brain White Matter Integrity Predicts Information Processing Speed in Healthy Older People

• DOI: 10.1523/jneurosci.1553-10.2010
• Publication Date: 2010-06-02T17:28:08Z
• Authors: Lars Penke; Susana Muñoz Maniega; Catherine Murray; Alan J. Gow; Maria C. Valdés H...; Jonathan D. Clayden; John M. Starr; Joanna M. Wardlaw; Mark E. Bastin; Ian J. Deary
• Keywords: Male; Brain Mapping; Principal Component Analysis; Intelligence; Statistics as Topic; 05 social sciences; Brain; Neuropsychological Tests; Nerve Fibers, Myelinated; Diffusion Magnetic Resonance Imaging; Mental Processes; Predictive Value of Tests; Humans; Female; 0501 psychology and cognitive sciences; Geriatric Assessment; Aged

Human white matter integrity has been related to information processing speed, but it is unknown whether impaired results from localized processes or a general property shared across tracts. Based on diffusion MRI scans of 132 healthy individuals with narrow age range around 72 years, the eight major tracts was quantified using probabilistic neighborhood tractography. Principal component analyses (PCAs) were conducted correlations between tracts, separately for four tract-averaged parameters: fractional anisotropy, mean diffusivity, and radial axial diffusivity. For all parameters, PCAs revealed single factor explaining ∼45% individual differences Individuals' scores that captures common variance in had significant associations speed anisotropy ( r = −0.24, p 0.007) diffusivity 0.21, 0.016), not intelligence memory factors. Individual showed no beyond what explained. Just as different types cognitive ability tests share much their variance, these novel findings show substantial amount Therefore, cortical connection substantially global process affecting various simultaneously. Further studies should investigate relate more role tract nonpathological aging lifelong-stable processes.