Is Physical Activity Associated with Brain Metabolites and Functional Network Connectivity in People with Multiple Sclerosis

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system that results in negative changes in global and localized brain volume, metabolites and functional network connectivity. There is further evidence for the decline in physical activity in MS, and this may be associated with changes in global and localized brain volume, metabolites and functional network connectivity. The current study examined the relationship between physical activity levels and global and localizer brain volume, metabolites and functional network connectivity in persons with MS.

We recruited 78 people with MS (51 female) with Expanded Disability Status Scale scores ≤5 and age range between 18 and 50 years. Physical activity was measured by the International Physical Activity Questionnaire. Functional network connectivity was measured via functional magnetic resonance imaging (fMRI) in seven major cortical and subcortical networks including four cortical hubs and three subcortical hubs. Global, segmental brain volume and lesion load were evaluated by MRI. Localized brain metabolites in the thalamus, hippocampus, medial prefrontal cortex (MPC) and anterior cingulate cortex (ACC) were determined by in vivo magnetic resonance spectroscopy (MRS).

Bivariate correlation analysis indicated that physical activity had significant moderate-to-strong relationships with brain metabolites including N-acetyl aspartate (r=0.41 to 0.62) and Myo-inositol (r= -0.42 to -0.56) in the hippocampus, MPC, and ACC. Physical activity was associated with choline level (r=0.32 and 0.34) only in the thalamus and hippocampus. Based on fMRI data, physical activity was correlated with the default-mode network, cerebellar network and thalamic network (r=0.29 to 0.43). Physical activity was associated with volumetric imaging metrics of the global brain (r=0.47) and thalamus (r=0.38) volume (all analysis p0.05).

Our findings indicate that physical activity might be associated with beneficial changes in the brain metabolic status and functional network connectivity in people with MS. This supports modifying physical activity behavior as an approach for neuroplasticity in MS.