Platform for Scientific Excellence (SINAPSE) Collaboration

Objective: The present study investigates associations between brain white matter tract integrity and cognitive abilities in community-dwelling older people (N 655). We explored two potential confounds of white matter tractcognition associations in later life: (a) whether the associations between tracts and specific cognitive abilities are accounted for by general cognitive ability (g); and (b) how the presence of atrophy and white matter lesions affect these associations. Method: Tract integrity was determined using quantitative diffusion magnetic resonance imaging tractography (tract-averaged fractional anisotropy [FA]). Using confirmatory factor analysis, we compared first-order and bifactor models to investigate whether specific tract-ability associations were accounted for by g. Results: Significant associations were found between g and FA in bilateral anterior thalamic radiations (r range:.16.18, p .01), uncinate (r range:.19.26, p .001), arcuate fasciculi (r range:.11.12, p .05), and the splenium of corpus callosum (r .14, p .01). After controlling for g within the bifactor model, some significant specific cognitive domain associations remained. Results also suggest that the primary effects of controlling for whole brain integrity were on g associations, not specific abilities. Conclusion: Results suggest that g accounts for most of, but not all, the tractcognitio