Myelination of the right parahippocampal cingulum is associated with physical activity in young healthy adults.

Tobias Bracht,Mark Drakesmith,Sonya Bells,Derek K Jones,Sebastian Walther,David Linden

doi:10.1007/s00429-016-1183-3

Tobias Bracht, Mark Drakesmith + Show 4 more

Open Access

https://doi.org/10.1007/s00429-016-1183-3

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Abstract

Recent evidence suggests that individual differences in physical activity (PA) may be associated with individual differences in white matter microstructure and with grey matter volume of the hippocampus. Therefore, this study investigated the association between PA and white matter microstructure of pathways connecting to the hippocampus. A total of 33 young, healthy adults underwent magnetic resonance imaging (MRI). High angular resolution diffusion-weighted imaging and multi-component relaxometry MRI scans (multi-component driven equilibrium pulse observation of T1 and T2) were acquired for each participant. Activity levels (AL) of participants were calculated from 72-h actigraphy recordings. Tractography using the damped Richardson Lucy algorithm was used to reconstruct the fornix and bilateral parahippocampal cinguli (PHC). The mean fractional anisotropy (FA) and the myelin water fraction (MWF), a putative marker of myelination, were determined for each pathway. A positive correlation between both AL and FA and between AL and MWF were hypothesized for the three pathways. There was a selective positive correlation between AL and MWF in the right PHC (r = 0.482, p = 0.007). Thus, our results provide initial in vivo evidence for an association between myelination of the right PHC and PA in young healthy adults. Our results suggest that MWF may not only be more specific, but also more sensitive than FA to detect white matter microstructural alterations. If PA was to induce structural plasticity of the right PHC this may contribute to reverse structural alterations of the right PHC in neuropsychiatric disorder with hippocampal pathologies.

Highlights

Physical activity and white matter microstructureThe benefits of physical activity (PA) for physical and mental health are well established (Hillman et al 2008; Soundy et al 2015)
Myelination of hippocampal pathways and physical activity. This is the first tractography study linking white matter microstructure of hippocampal pathways to PA. This is the first study investigating the association between PA and myelin water fraction (MWF), a more specific measure of myelination than fractional anisotropy (FA)
Our findings suggest that higher PA is associated with higher myelination of the right parahippocampal cinguli (PHC)

Summary

Introduction

The benefits of physical activity (PA) for physical and mental health are well established (Hillman et al 2008; Soundy et al 2015). Meta-analyses in children suggest that higher PA is associated with improved cognitive performance (Sibley and Etnier 2003; Fedewa and Ahn 2011). A cross-sectional study found that higher PA is associated with better performance in executive functioning in children (van der Niet et al 2014). Cognitive performance and pleasure are linked to brain structure (Fields 2008; Johansen-Berg 2010; Bracht et al 2015a). There has been an increasing interest in the effect of PA on the structure of the brain

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