A single session of exercise increases connectivity in sensorimotor-related brain networks: a resting-state fMRI study in young healthy adults.

Ahmad S Rajab,David E Crane,Michelle Hampson,Bradley J Macintosh,Andrew D Robertson,Laura E Middleton

doi:10.3389/fnhum.2014.00625

Abstract

Habitual long term physical activity is known to have beneficial cognitive, structural, and neuro-protective brain effects, but to date there is limited knowledge on whether a single session of exercise can alter the brain’s functional connectivity, as assessed by resting-state functional magnetic resonance imaging (rs-fMRI). The primary objective of this study was to characterize potential session effects in resting-state networks (RSNs). We examined the acute effects of exercise on the functional connectivity of young healthy adults (N = 15) by collecting rs-fMRI before and after 20 min of moderate intensity aerobic exercise and compared this with a no-exercise control group (N = 15). Data were analyzed using independent component analysis, denoising and dual regression procedures. Regions of interest-based group session effect statistics were calculated in RSNs of interest using voxel-wise permutation testing and Cohen’s D effect size. Group analysis in the exercising group data set revealed a session effect in sub-regions of three sensorimotor related areas: the pre and/or postcentral gyri, secondary somatosensory area and thalamus, characterized by increased co-activation after exercise (corrected p < 0.05). Cohen’s D analysis also showed a significant effect of session in these three RSNs (p< 0.05), corroborating the voxel-wise findings. Analyses of the no-exercise dataset produced no significant results, thereby providing support for the exercise findings and establishing the inherent test–retest reliability of the analysis pipeline on the RSNs of interest. This study establishes the feasibility of rs-fMRI to localize brain regions that are associated with acute exercise, as well as an analysis consideration to improve sensitivity to a session effect.

Highlights

Exercise research has traditionally focused on the effects of physical activity on the cardiovascular and musculoskeletal system
The average ratings of perceived exertion (RPE) was 3.9 ± 1.4, after 10 min of exercise and 4.5 ± 1.8 after 20 min; both of which fall in the descriptive range of “somewhat strong” to “strong.” Systolic blood pressure remained significantly higher than baseline at 10 min post-exercise
heart rate (HR) was significantly higher at the start of the postexercise resting-state functional magnetic resonance imaging (rs-functional magnetic resonance imaging (fMRI)) scan

Summary

Introduction

Exercise research has traditionally focused on the effects of physical activity on the cardiovascular and musculoskeletal system. Human studies show that regular exercise can produce structural brain changes (Colcombe et al, 2006), may reverse age-related decline (Erickson et al, 2011) and can contribute to positive cognitive changes (Kramer et al, 1999; Hillman et al, 2008). The bulk of this exercise neuroimaging literature involves long term exercise; less is known about the single session effects that accumulate to produce long term benefits. We attempt to establish resting-state functional magnetic resonance imaging (fMRI) as a neuroimaging marker that can be used to study how exercise impacts the brain

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