Movement-related cortical potentials during muscle fatigue induced by upper limb submaximal isometric contractions

Abstract

The aim of this study was to examine the central neurophysiological mechanisms during fatigue induced by submaximal isometric contractions. A total of 23 individuals participated in the study and were assigned to fatigue and nonfatigue groups. Handgrip force, root mean square (RMS) of surface electromyography (sEMG) signal and movement-related cortical potentials during self-paced submaximal handgrip isometric contractions were assessed for each participant. The experimental data showed significant decreases in both maximal voluntary contraction [-24.3%; F(3, 42)=19.62, P<0.001, ηp=0.48] and RMS [-30.1%; F(3, 42)=19.01, P<0.001, ηp=0.57] during maximal voluntary contractions and a significant increase [F(3, 42)=14.27, P<0.001, ηp=0.50] in the average RMS of sEMG over four blocks in the fatigue group. There was no significant difference in the readiness potential between the fatigue and the nonfatigue groups at early stages, and at late stages, significant differences were observed only at the Fp1 and FC1 sites. Motor potential amplitudes were significantly higher in the fatigue group than in the nonfatigue group irrespective of block or electrode positions. Positive waveforms were observed in the prefrontal cortex in states without muscle fatigue, whereas a negative waveform pattern was observed with muscle fatigue. Significant within-subject correlations were observed between motor potential at the C1 site and RMS of sEMG (r=-0.439, P=0.02, ηp=0.11). Neurophysiological evidence indicates that cortical activity increases in the prefrontal cortex, primary motor cortex and supplementary motor cortex with muscle fatigue. Muscle fatigue appears to have considerable effects on the components of movement-related cortical potentials during movement execution, whereas the readiness potential before movement is sensitive to cognitive demands during prolonged exercise. Our results provide additional evidence for a link between central motor command during movement execution and motor unit recruitment.

EEG-Based Spectral Analysis Showing Brainwave Changes Related to Modulating Progressive Fatigue During a Prolonged Intermittent Motor Task

“…Submaximal handgrip isometric contractions inducing progressive fatigue resulted in a significant increase in MRCP at the precentral (Cz and FCz) and central contralateral (C3) electrode sites (Johnston et al, 2001 ). In like manner, the central fatigue induced by submaximal (Guo et al, 2014 ) and lower limb (Berchicci et al, 2013 ) isometric contractions increased the amplitude of MRCP in M1, prefrontal cortex, SMA, and premotor cortex. The muscle fatigue was reported to increase the MRCP amplitude during movement execution (De Morree et al, 2012 ).…”

“…There are ample evidences to believe that the fatigue task involving submaximal isometric contractions causes a significant rise in movement-related cortical potentials (MRCP) in brain regions that include primary motor cortex (M1), SMA, and premotor cortex, e.g., studies related to upper limb (Johnston et al, 2001 ; Schillings et al, 2006 ; De Morree et al, 2012 ; Guo et al, 2014 ) and lower limb (Berchicci et al, 2013 ). Similarly, a significant increase in the alpha- or beta-band EEG power in SMA, frontal, parietal lobe, and Brodmann area 11 was attributed to fatigue caused by cycling (Schneider et al, 2009 ; Hilty et al, 2011 ; Enders et al, 2016 ).…”

Characteristics of the Contingent Negative Variation during Lower Limb Functional Movement with an Audio-Visual Cue

“…The CNV can be used to monitor the intention to move before the movement begins, as well as during the actual movement. Factors such as fatigue, level of attention, and movement type can all modulate the CNV [15][16][17]. One of the main benefits of using the CNV in stroke rehabilitation is the ability to detect movement intentions early, which may improve the effectiveness of BCI-based therapies.…”

EEG-Based Spectral Analysis Showing Brainwave Changes Related to Modulating Progressive Fatigue During a Prolonged Intermittent Motor Task

“…There are ample evidences to believe that the fatigue task involving submaximal isometric contractions causes a significant rise in movement-related cortical potentials (MRCP) in brain regions that include primary motor cortex (M1), SMA, and premotor cortex, e.g., studies related to upper limb (Johnston et al, 2001; Guo et al, 2014; De Morree et al, 2012; Schillings et al, 2006) and lower limb (Berchicci et al, 2013). Similarly, a significant increase in the alpha- or beta-band EEG power in SMA, frontal, parietal lobe, and Brodmann area 11 was attributed to fatigue caused by cycling (Schneider et al, 2009; Hilty et al, 2011; Enders et al, 2016).…”