White matter microstructure mediates the relationship between cardiorespiratory fitness and spatial working memory in older adults - PubMed (original) (raw)

doi: 10.1016/j.neuroimage.2015.09.053. Epub 2015 Oct 9.

Timothy D Verstynen 2, Agnieszka Z Burzynska 3, Michelle W Voss 4, Ruchika Shaurya Prakash 5, Laura Chaddock-Heyman 6, Chelsea Wong 6, Jason Fanning 7, Elizabeth Awick 7, Neha Gothe 8, Siobhan M Phillips 9, Emily Mailey 10, Diane Ehlers 7, Erin Olson 11, Thomas Wojcicki 12, Edward McAuley 7, Arthur F Kramer 6, Kirk I Erickson 13

Affiliations

White matter microstructure mediates the relationship between cardiorespiratory fitness and spatial working memory in older adults

Lauren E Oberlin et al. Neuroimage. 2016.

Abstract

White matter structure declines with advancing age and has been associated with a decline in memory and executive processes in older adulthood. Yet, recent research suggests that higher physical activity and fitness levels may be associated with less white matter degeneration in late life, although the tract-specificity of this relationship is not well understood. In addition, these prior studies infrequently associate measures of white matter microstructure to cognitive outcomes, so the behavioral importance of higher levels of white matter microstructural organization with greater fitness levels remains a matter of speculation. Here we tested whether cardiorespiratory fitness (VO2max) levels were associated with white matter microstructure and whether this relationship constituted an indirect pathway between cardiorespiratory fitness and spatial working memory in two large, cognitively and neurologically healthy older adult samples. Diffusion tensor imaging was used to determine white matter microstructure in two separate groups: Experiment 1, N=113 (mean age=66.61) and Experiment 2, N=154 (mean age=65.66). Using a voxel-based regression approach, we found that higher VO2max was associated with higher fractional anisotropy (FA), a measure of white matter microstructure, in a diverse network of white matter tracts, including the anterior corona radiata, anterior internal capsule, fornix, cingulum, and corpus callosum (PFDR-corrected<.05). This effect was consistent across both samples even after controlling for age, gender, and education. Further, a statistical mediation analysis revealed that white matter microstructure within these regions, among others, constituted a significant indirect path between VO2max and spatial working memory performance. These results suggest that greater aerobic fitness levels are associated with higher levels of white matter microstructural organization, which may, in turn, preserve spatial memory performance in older adulthood.

Keywords: Aging; Fitness; Memory; White matter.

Copyright © 2015 Elsevier Inc. All rights reserved.

PubMed Disclaimer

Figures

Figure 1

Figure 1

Shown are significant associations between cardiorespiratory fitness (CRF), fractional anisotropy (FA), and mean spatial working memory performance from Experiment 1. (A) Clusters of voxels where fitness was significantly associated with FA. Warm-colored voxels show positive associations, cool-colored voxels demonstrate negative associations. Side panels indicate slice placements. Age, gender, and years of education were included as covariates. Clusters are thresholded to k≥20 contiguous voxels and a false discovery rate of 0.05. The z-plane coordinates of each slice, in MNI space, are presented at the bottom. For visualization purposes, tbss_fill was used to dilate statistical maps. (B) For illustration purposes, scatterplots and best-fit lines for the relationship between CRF and FA in selected regions. (C) Spatial distribution of indirect path voxel clusters. Cyan-colored voxel clusters show a positive indirect effect, brown voxel clusters indicate a negative indirect effect. Ant, anterior; IC, internal capsule; CC, corpus callosum; Ext, external; FA, fractional anisotropy.

Figure 2

Figure 2

Shown are associations between cardiorespiratory fitness (CRF), fractional anisotropy (FA), and spatial working memory performance from Experiment 2, with the same plotting conventions as Figure 1. Ant, anterior; FA, fractional anisotropy; CC, corpus callosum; IC, internal capsule; CR, corona radiata.

Figure 3A

Figure 3A

Shown are results from the conjunction analysis of the relationship between fitness and FA in Experiment 1 and Experiment 2.

Figure 3B

Figure 3B

Shown are the results from the conjunction analysis of the indirect path voxels in Experiment 1 and Experiment 2.

Similar articles

Cited by

References

    1. Bennett IJ, Madden DJ. Disconnected aging: cerebral white matter integrity and age-related differences in cognition. Neuroscience. 2014;276:187–205. - PMC - PubMed
    1. Burdette JH, Laurienti PJ, Espeland MA, Morgan A, Telesford Q, Vechlekar CD, Hayasaka S, Jennings JM, Katula JA, Kraft RA. Using network science to evaluate exercise-associated brain changes in older adults. Frontiers in aging neuroscience. 2010;2:23. - PMC - PubMed
    1. Burzynska AZ, Chaddock-Heyman L, Voss MW, Wong CN, Gothe NP, Olson EA, Knecht A, Lewis A, Monti JM, Cooke GE. Physical activity and cardiorespiratory fitness are beneficial for white matter in low-fit older adults. PLoS One. 2014;9:e107413. - PMC - PubMed
    1. Burzynska AZ, Preuschhof C, Bäckman L, Nyberg L, Li S-C, Lindenberger U, Heekeren HR. Age-related differences in white matter microstructure: region-specific patterns of diffusivity. NeuroImage. 2010;49:2104–2112. - PubMed
    1. Charlton R, Barrick T, McIntyre D, Shen Y, O'Sullivan M, Howe F.e., Clark C, Morris R, Markus H. White matter damage on diffusion tensor imaging correlates with age-related cognitive decline. Neurology. 2006;66:217–222. emsp14, al. - PubMed

Publication types

MeSH terms

Grants and funding

LinkOut - more resources