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Neural Plasticity
Volume 2016, Article ID 1726848, 11 pages
http://dx.doi.org/10.1155/2016/1726848
Research Article

Strengthened Corticosubcortical Functional Connectivity during Muscle Fatigue

1Human Performance and Engineering Research, Kessler Foundation, 1199 Pleasant Valley Way, West Orange, NJ, USA
2Department of Quantitative Health Science, The Cleveland Clinic, 9500 Euclid Avenue/JJN3, Cleveland, OH, USA
3Department of Biomedical Engineering, New Jersey Institute of Technology, 323 Martin Luther King, Jr. Boulevard, Newark, NJ, USA
4Department of Physical Medicine & Rehabilitation, Rutgers New Jersey Medical School, 185 S. Orange Ave, Newark, NJ, USA

Received 15 April 2016; Revised 23 August 2016; Accepted 25 September 2016

Academic Editor: Lin Xu

Copyright © 2016 Zhiguo Jiang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The present study examined functional connectivity (FC) between functional MRI (fMRI) signals of the primary motor cortex (M1) and each of the three subcortical neural structures, cerebellum (CB), basal ganglia (BG), and thalamus (TL), during muscle fatigue using the quantile regression technique. Understanding activation relation between the subcortical structures and the M1 during prolonged motor performance should help delineate how central motor control network modulates acute perturbations at peripheral sensorimotor system such as muscle fatigue. Ten healthy subjects participated in the study and completed a 20-minute intermittent handgrip motor task at 50% of their maximal voluntary contraction (MVC) level. Quantile regression analyses were carried out to compare the FC between the contralateral (left) M1 and CB, BG, and TL in the minimal (beginning 100 s) versus significant (ending 100 s) fatigue stages. Widespread, statistically significant increases in FC were found in bilateral BG, CB, and TL with the left M1 during significant versus minimal fatigue stages. Our results imply that these subcortical nuclei are critical components in the motor control network and actively involved in modulating voluntary muscle fatigue, possibly, by working together with the M1 to strengthen the descending central command to prolong the motor performance.