Changes in white matter fiber density and morphology across the adult lifespan: A cross‐sectional fixel‐based analysis
Open Access
- 18 April 2020
- journal article
- research article
- Published by Wiley in Human Brain Mapping
- Vol. 41 (12), 3198-3211
- https://doi.org/10.1002/hbm.25008
Abstract
White matter (WM) fiber bundles change dynamically with age. These changes could be driven by alterations in axonal diameter, axonal density, and myelin content. In this study, we applied a novel fixel‐based analysis (FBA) framework to examine these changes throughout the adult lifespan. Using diffusion‐weighted images from a cohort of 293 healthy volunteers (89 males/204 females) from ages 21 to 86 years old, we performed FBA to analyze age‐related changes in microscopic fiber density (FD) and macroscopic fiber morphology (fiber cross section [FC]). Our results showed significant and widespread age‐related alterations in FD and FC across the whole brain. Interestingly, some fiber bundles such as the anterior thalamic radiation, corpus callosum, and superior longitudinal fasciculus only showed significant negative relationship with age in FD values, but not in FC. On the other hand, some segments of the cerebello‐thalamo‐cortical pathway only showed significant negative relationship with age in FC, but not in FD. Analysis at the tract‐level also showed that major fiber tract groups predominantly distributed in the frontal lobe (cingulum, forceps minor) exhibited greater vulnerability to the aging process than the others. Differences in FC and the combined measure of FD and cross section values observed between sexes were mostly driven by differences in brain sizes although male participants tended to exhibit steeper negative linear relationship with age in FD as compared to female participants. Overall, these findings provide further insights into the structural changes the brain's WM undergoes due to the aging process.Keywords
Funding Information
- Ministry of Education, Culture, Sports, Science and Technology (26117002, 80569781)
- Ministry of Health, Labour and Welfare
This publication has 62 references indexed in Scilit:
- A Validation Study of the Japanese Version of the Addenbrooke’s Cognitive Examination-RevisedDementia and Geriatric Cognitive Disorders Extra, 2012
- Correlations among Brain Gray Matter Volumes, Age, Gender, and Hemisphere in Healthy IndividualsPLOS ONE, 2011
- Diffusion tensor imaging and beyondMagnetic Resonance in Medicine, 2011
- Exercise training increases size of hippocampus and improves memoryProceedings of the National Academy of Sciences of the United States of America, 2011
- Age changes in myelinated nerve fibers of the cingulate bundle and corpus callosum in the rhesus monkeyJournal of Comparative Neurology, 2010
- Microstructural white matter changes in normal aging: A diffusion tensor imaging study with higher-order polynomial regression modelsNeuroImage, 2010
- Development, validation, and comparison of ICA-based gradient artifact reduction algorithms for simultaneous EEG-spiral in/out and echo-planar fMRI recordingsNeuroImage, 2009
- Aging, gender, and the elderly adult brain: An examination of analytical strategiesNeurobiology of Aging, 2008
- Tract probability maps in stereotaxic spaces: Analyses of white matter anatomy and tract-specific quantificationNeuroImage, 2008
- The Addenbrooke's Cognitive Examination Revised (ACE‐R): a brief cognitive test battery for dementia screeningInternational Journal of Geriatric Psychiatry, 2006