Gray matter alterations in early aging: A diffusion magnetic resonance imaging study
Article first published online: 31 DEC 2013
Copyright © 2013 Wiley Periodicals, Inc.
Human Brain Mapping
Volume 35, Issue 8, pages 3841–3856, August 2014
How to Cite
Rathi, Y., Pasternak, O., Savadjiev, P., Michailovich, O., Bouix, S., Kubicki, M., Westin, C.-F., Makris, N. and Shenton, M.E. (2014), Gray matter alterations in early aging: A diffusion magnetic resonance imaging study. Hum. Brain Mapp., 35: 3841–3856. doi: 10.1002/hbm.22441
- Issue published online: 8 JUL 2014
- Article first published online: 31 DEC 2013
- Manuscript Accepted: 24 NOV 2013
- Manuscript Revised: 1 NOV 2013
- Manuscript Received: 4 JUN 2013
- National Institute of Health (NIH) . Grant Number: R01MH097979 (Rathi), R01 NS 078337 (Shenton), R01 MH082918 (Shenton), R01MH074794 (Westin), P41RR013218, P41EB015902 (PI: Dr. Kikinis, Core PI: Dr. Westin), R01 AG042512 (Kubicki, Makris), and R21NS079905, R21NS077059 (Dickerson).
- diffusion MRI;
- gray matter;
Many studies have observed altered neurofunctional and structural organization in the aging brain. These observations from functional neuroimaging studies show a shift in brain activity from the posterior to the anterior regions with aging (PASA model), as well as a decrease in cortical thickness, which is more pronounced in the frontal lobe followed by the parietal, occipital, and temporal lobes (retrogenesis model). However, very little work has been done using diffusion MRI (dMRI) with respect to examining the structural tissue alterations underlying these neurofunctional changes in the gray matter. Thus, for the first time, we propose to examine gray matter changes using diffusion MRI in the context of aging. In this work, we propose a novel dMRI based measure of gray matter “heterogeneity” that elucidates these functional and structural models (PASA and retrogenesis) of aging from the viewpoint of diffusion MRI. In a cohort of 85 subjects (all males, ages 15–55 years), we show very high correlation between age and “heterogeneity” (a measure of structural layout of tissue in a region-of-interest) in specific brain regions. We examine gray matter alterations by grouping brain regions into anatomical lobes as well as functional zones. Our findings from dMRI data connects the functional and structural domains and confirms the “retrogenesis” hypothesis of gray matter alterations while lending support to the neurofunctional PASA model of aging in addition to showing the preservation of paralimbic areas during healthy aging. Hum Brain Mapp 35:3841–3856, 2014. © 2013 Wiley Periodicals, Inc.