title: Myelination of the right parahippocampal cingulum is associated with physical activity in young healthy adults.
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.
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK. bracht@puk.unibe.ch.|Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University, Cardiff, UK. bracht@puk.unibe.ch.|Translational Research Centre, University Hospital of Psychiatry, University of Bern, Bolligenstrasse 111, 3000, Bern, Switzerland. bracht@puk.unibe.ch.
authors.forename: Tobias
authors.initials: T
authors.lastname: Bracht
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK.|Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University, Cardiff, UK.
authors.forename: Derek K
authors.initials: DK
authors.lastname: Jones
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK.|Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University, Cardiff, UK.
authors.forename: Sonya
authors.initials: S
authors.lastname: Bells
authors.affiliation: Translational Research Centre, University Hospital of Psychiatry, University of Bern, Bolligenstrasse 111, 3000, Bern, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Walther
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK.|Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University, Cardiff, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Drakesmith
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK.|Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University, Cardiff, UK.|MRC Centre for Neuropsychiatry Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK.
authors.forename: David
authors.initials: D
authors.lastname: Linden
mesh_terms: D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D015444:Exercise; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009186:Myelin Sheath; D020534:Parahippocampal Gyrus / Q000033:anatomy & histology* / Q000502:physiology; D066127:White Matter / Q000033:anatomy & histology* / Q000502:physiology; D055815:Young Adult
keywords: Actigraphy; Activity; Diffusion tensor imaging; Hippocampus; Neuroplasticity; White matter