Effects of a 12-Week Aerobic Spin Intervention on Resting State Networks in Previously Sedentary Older Adults.

Kaundinya Gopinath,Joe R Nocera,Kyle Hortman,Javier Omar,Lisa C Krishnamurthy,Bruce Crosson,Keith M Mcgregor,Kevin M Mammino,Venkatagiri Krishnamurthy

doi:10.3389/fpsyg.2018.02376

Kaundinya Gopinath, Joe R Nocera + Show 7 more

Open Access

https://doi.org/10.3389/fpsyg.2018.02376

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Abstract

Objective: We have previously demonstrated that aerobic exercise improves upper extremity motor function concurrent with changes in motor cortical activity using task-based functional magnetic resonance imaging (fMRI). However, it is currently unknown how a 12-week aerobic exercise intervention affects resting-state functional connectivity (rsFC) in motor networks. Previous work has shown that over a 6-month or 1-year exercise intervention, older individuals show increased resting state connectivity of the default mode network and the sensorimotor network (Voss et al., 2010b; Flodin et al., 2017). However, the effects of shorter-term 12-week exercise interventions on functional connectivity have received less attention.Method: Thirty-seven sedentary right-handed older adults were randomized to either a 12-week aerobic, spin cycling exercise group or a 12-week balance-toning exercise group. Resting state functional magnetic resonance images were acquired in sessions PRE/POST interventions. We applied seed-based correlation analysis to left and right primary motor cortices (L-M1 and R-M1) and anterior default mode network (aDMN) to test changes in rsFC between groups after the intervention. In addition, we performed a regression analysis predicting connectivity changes PRE/POST intervention across all participants as a function of time spent in aerobic training zone regardless of group assignment.Results: Seeding from L-M1, we found that participants in the cycling group had a greater PRE/POST change in rsFC in aDMN as compared to the balance group. When accounting for time in aerobic HR zone, we found increased heart rate workload was positively associated with increased change of rsFC between motor networks and aDMN. Interestingly, L-M1 to aDMN connectivity changes were also related to motor behavior changes in both groups. Respective of M1 laterality, comparisons of all participants from PRE to POST showed a reduction in the extent of bilateral M1 connectivity after the interventions with increased connectivity in dominant M1.Conclusion: A 12-week physical activity intervention can change rsFC between primary motor regions and default mode network areas, which may be associated with improved motor performance. The decrease in connectivity between L-M1 and R-M1 post-intervention may represent a functional consolidation to the dominant M1.Topic Areas: Neuroimaging, Aging.

Highlights

Aerobic exercise is an inexpensive, ecological lifestyle intervention that has long been shown to benefit movement and cognition in older adults (Larson and Bruce, 1987; Hatziandreu et al, 1988)
A cross-sectional study of resting state networks in older adults showed that older adults who engaged in higher levels of physical activity over 10 years showed increased default mode network (DMN) connectivity, in posterior cingulate regions (Boraxbekk et al, 2016)
When the authors tested the change in VO2 peak as a predictor of changes in functional network connectivity, they reported that increased VO2 peak correlated with differential connectivity of two resting-state networks: the DMN and the sensorimotor network (M1S1)

Summary

Introduction

Aerobic exercise is an inexpensive, ecological lifestyle intervention that has long been shown to benefit movement and cognition in older adults (Larson and Bruce, 1987; Hatziandreu et al, 1988). While the beneficial impact of aerobic exercise on brain density and cortical activity is becoming increasingly established, much less is known about the effect of exercise intervention on resting state connectivity in older adults. A seminal study by Voss et al (2010b) first showed significant increases in resting state functional Magnetic Resonance Imaging (rsfMRI) connectivity in the default mode network (DMN) and frontal executive networks in older adults after a 1 year aerobic exercise intervention (Voss et al, 2010b). A recent study by (Flodin et al, 2017) investigated changes in resting state connectivity across different known task networks. When the authors tested the change in VO2 peak as a predictor of changes in functional network connectivity, they reported that increased VO2 peak correlated with differential connectivity of two resting-state networks: the DMN and the sensorimotor network (M1S1)

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