White matter microstructural integrity has been related to cognition. Yet, the potential role of specific white matter tracts on top of a global white matter effect remains unclear, especially when considering specific cognitive domains. Therefore, we determined the tract-specific effect of white matter microstructure on global cognition and specific cognitive domains. In 4400 nondemented and stroke-free participants (mean age 63.7 years, 55.5% women), we obtained diffusion magnetic resonance imaging parameters (fractional anisotropy and mean diffusivity) in 14 white matter tracts using probabilistic tractography and assessed cognitive performance with a cognitive test battery. Tract-specific white matter microstructure in all supratentorial tracts was associated with poorer global cognition. Lower fractional anisotropy in association tracts, primarily the inferior fronto-occipital fasciculus, and higher mean diffusivity in projection tracts, in particular the posterior thalamic radiation, most strongly related to poorer cognition. Altered white matter microstructure related to poorer information processing speed, executive functioning, and motor speed, but not to memory. Tract-specific microstructural changes may aid in better understanding the mechanism of cognitive impairment and neurodegenerative diseases.

Cognition, Diffusion MRI, Epidemiology, Neurodegeneration, Population based, Tractography, White matter
dx.doi.org/10.1016/j.neurobiolaging.2015.11.021, hdl.handle.net/1765/88752
Neurobiology of Aging: age-related phenomena, neurodegeneration and neuropathology
This work was funded by the European Commission 7th Framework Programme; grant id fp7/601055 - VPH Dementia Research Enabled by IT (VPH-DARE@IT)
Department of Radiology

Cremers, L.G.M, de Groot, M, Hofman, A, Krestin, G.P, van der Lugt, A, Niessen, W.J, … Ikram, M.A. (2016). Altered tract-specific white matter microstructure is related to poorer cognitive performance. Neurobiology of Aging: age-related phenomena, neurodegeneration and neuropathology, 39, 108–117. doi:10.1016/j.neurobiolaging.2015.11.021