Coupled Changes in Brain White Matter Microstructure and Fluid Intelligence in Later Life
- Stuart J. Ritchie1,2,*,
- Mark E. Bastin2,4,5,6,*,
- Elliot M. Tucker-Drob7,*,
- Susana Muñoz Maniega2,4,5,6,
- Laura E. Engelhardt7,
- Simon R. Cox1,2,
- Natalie A. Royle2,4,5,6,
- Alan J. Gow2,8,
- Janie Corley1,
- Alison Pattie1,
- Adele M. Taylor1,
- Maria del C. Valdés Hernández2,4,5,6,
- John M Starr2,3,
- Joanna M. Wardlaw2,4,5,6, and
- Ian J. Deary1,2
- 1Department of Psychology,
- 2Centre for Cognitive Ageing and Cognitive Epidemiology, and
- 3Alzheimer Scotland Dementia Research Centre, The University of Edinburgh, Edinburgh EH8 9JZ, UK,
- 4Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh EH16 4SA, UK,
- 5Brain Research Imaging Centre, The University of Edinburgh, Edinburgh EH4 2XU, UK,
- 6Scottish Imaging Network, a Platform for Scientific Excellence (SINAPSE), Edinburgh, UK,
- 7Department of Psychology, University of Texas, Austin, Texas 78712-0187, and
- 8Department of Psychology, Heriot-Watt University, Edinburgh EH14 4AS, UK
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Author contributions: S.J.R., M.E.B., E.M.T.-D., J.M.S., J.M.W., and I.J.D. designed research; S.J.R., M.E.B., S.M.M., S.R.C., N.A.R., A.J.G., J.C., A.P., A.M.T., M.d.C.V.H., and J.M.W. performed research; M.E.B., S.M.M., S.R.C., N.A.R., M.d.C.V.H., and J.M.W. contributed unpublished reagents/analytic tools; S.J.R., E.M.T.-D., and L.E.E. analyzed data; S.J.R., M.E.B., E.M.T.-D., and I.J.D. wrote the paper.
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↵*S.J.R., M.E.B., and E.M.T.-D. contributed equally to this work.
Abstract
Understanding aging-related cognitive decline is of growing importance in aging societies, but relatively little is known about its neural substrates. Measures of white matter microstructure are known to correlate cross-sectionally with cognitive ability measures, but only a few small studies have tested for longitudinal relations among these variables. We tested whether there were coupled changes in brain white matter microstructure indexed by fractional anisotropy (FA) and three broad cognitive domains (fluid intelligence, processing speed, and memory) in a large cohort of human participants with longitudinal diffusion tensor MRI and detailed cognitive data taken at ages 73 years (n = 731) and 76 years (n = 488). Longitudinal changes in white matter microstructure were coupled with changes in fluid intelligence, but not with processing speed or memory. Individuals with higher baseline white matter FA showed less subsequent decline in processing speed. Our results provide evidence for a longitudinal link between changes in white matter microstructure and aging-related cognitive decline during the eighth decade of life. They are consistent with theoretical perspectives positing that a corticocortical “disconnection” partly explains cognitive aging.
- cognitive aging
- diffusion tensor imaging
- fluid intelligence
- fractional anisotropy
- processing speed
- white matter microstructure
- Received March 5, 2015.
- Revision received April 12, 2015.
- Accepted April 25, 2015.
- Copyright © 2015 Ritchie et al.
This article is freely available online through the J Neurosci Author Open Choice option.
