Between-subject variance in the magnitude of corticomuscular coherence during tonic isometric contraction of the tibialis anterior muscle in healthy young adults

2011 ◽  
Vol 106 (3) ◽  
pp. 1379-1388 ◽  
Author(s):  
Junichi Ushiyama ◽  
Tatsuya Suzuki ◽  
Yoshihisa Masakado ◽  
Kimitaka Hase ◽  
Akio Kimura ◽  
...  
Keyword(s):  
Isometric Contraction ◽  
Sensorimotor Cortex ◽  
Muscle Activity ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Tibialis Anterior Muscle ◽  
Continuous Distribution ◽  
Oscillatory Activity ◽  
Moderate Intensity ◽  
Corticomuscular Coherence

Oscillatory activity of the sensorimotor cortex has been reported to show coherence with muscle activity in the 15- to 35-Hz frequency band (β-band) during weak to moderate intensity of isometric contraction. The present study examined the variance of the magnitude of the corticomuscular coherence across a large number of subjects. We quantified the coherence between EEG over the sensorimotor cortex and rectified electromyogram (EMG) from the tibialis anterior muscle during tonic isometric contraction at 30% of maximal effort in 100 healthy young individuals. We estimated the maximal peak of EEG-EMG coherence (Cohmax) and the ratio of the sum of the autopower spectral density function within the β-band to that of all frequency ranges for both EEG (EEGβ-PSD) and EMG (EMGβ-PSD) signals. The frequency histogram of Cohmax across all subjects showed a broad bell-shaped continuous distribution (range, 0.048–0.816). When the coherence was thresholded at the estimated significance level of P < 0.05 (0.114), 46 out of 100 subjects showed significant EEG-EMG coherence. Cohmax occurred within the β-band in the majority of subjects who showed significant EEG-EMG coherence ( n = 43). Furthermore, Cohmax showed significant positive correlations with both EEGβ-PSD ( r = 0.575, P < 0.001) and EMGβ-PSD ( r = 0.606, P < 0.001). These data suggest that even during simple tonic isometric contraction, the strength of oscillatory coupling between the sensorimotor cortex and spinal motoneurons varies among individuals and is a contributory factor determining muscle activation patterns such as the degree of grouped discharge in muscle activity within the β-band for each subject.

Muscle fatigue-induced enhancement of corticomuscular coherence following sustained submaximal isometric contraction of the tibialis anterior muscle

2011 ◽  
Vol 110 (5) ◽  
pp. 1233-1240 ◽  
Author(s):  
Junichi Ushiyama ◽  
Masanori Katsu ◽  
Yoshihisa Masakado ◽  
Akio Kimura ◽  
Meigen Liu ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Isometric Contraction ◽  
Sensorimotor Cortex ◽  
Tibialis Anterior ◽  
Tibialis Anterior Muscle ◽  
Muscular Activity ◽  
Spectral Density Function ◽  
Voluntary Contraction ◽  
Oscillatory Activity ◽  
Acute Changes

Oscillatory activity of the sensorimotor cortex shows coherence with muscle activity within the 15- to 35-Hz frequency band (β-band) during weak to moderate sustained isometric contraction. We aimed to examine the acute changes in this corticomuscular coupling due to muscle fatigue and its effect on the steadiness of the exerted force. We quantified the coherence between the electroencephalogram (EEG) recorded over the sensorimotor cortex and the rectified surface electromyogram (EMG) of the tibialis anterior muscle as well as the coefficient of variance of the dorsiflexion force (ForceCV) and sum of the auto-power spectral density function of the force within the β-band (Forceβ-PSD) during 30% of maximal voluntary contraction (MVC) for 60 s before (prefatiguing task) and after (postfatiguing task) muscle fatigue induced by sustained isometric contraction at 50% of MVC until exhaustion in seven healthy male subjects. The magnitude of the EEG-EMG coherence increased in the postfatiguing task in six of seven subjects. The maximal peak of EEG-EMG coherence stayed within the β-band in both pre- and postfatiguing tasks. Interestingly, two subjects, who had no significant EEG-EMG coherence in the prefatiguing task, showed significant coherence in the postfatiguing task. Additionally, ForceCV and Forceβ-PSD significantly increased after muscle fatigue. These data suggest that when muscle fatigue develops, the central nervous system enhances oscillatory muscular activity in the β-band stronger coupled with the sensorimotor cortex activity accomplishing the sustained isometric contraction at lower performance levels.

Muscle dependency of corticomuscular coherence in upper and lower limb muscles and training-related alterations in ballet dancers and weightlifters

2010 ◽  
Vol 109 (4) ◽  
pp. 1086-1095 ◽  
Author(s):  
Junichi Ushiyama ◽  
Yuji Takahashi ◽  
Junichi Ushiba
Keyword(s):  
Sensorimotor Cortex ◽  
Lower Limb ◽  
Tibialis Anterior ◽  
Biceps Brachii ◽  
Oscillatory Activity ◽  
Spinal Motoneurons ◽  
Ballet Dancers ◽  
Corticomuscular Coherence ◽  
Lower Limb Muscles ◽  
Limb Muscles

It has been well documented that the 15- to 35-Hz oscillatory activity of the sensorimotor cortex shows coherence with the muscle activity during weak to moderate steady contraction. To investigate the muscle dependency of the corticomuscular coherence and its training-related alterations, we quantified the coherence between electroencephalogram (EEG) from the sensorimotor cortex and rectified electromyogram (EMG) from five upper limb (first dorsal interosseous, flexor carpi radialis, extensor carpi radialis, biceps brachii, triceps brachii) and four lower limb muscles (soleus, tibialis anterior, biceps femoris, rectus femoris), while maintaining a constant force level at 30% of maximal voluntary contraction of each muscle, in 24 untrained, 12 skill-trained (ballet dancers), and 10 strength-trained (weightlifters) individuals. Data from untrained subjects demonstrated the muscle dependency of corticomuscular coherence. The magnitude of the EEG-EMG coherence was significantly greater in the distally located lower limb muscles, such as the soleus and tibialis anterior, than in the upper or other lower limb muscles in untrained subjects ( P < 0.05). These results imply that oscillatory coupling between the sensorimotor cortex and spinal motoneurons during steady contraction differs among muscles, according to the functional role of each muscle. In addition, the ballet dancers and weightlifters showed smaller EEG-EMG coherences than the untrained subjects, especially in the lower limb muscles ( P < 0.05). These results indicate that oscillatory interaction between the sensorimotor cortex and spinal motoneurons can be changed by long-term specialized use of the muscles and that this neural adaptation may lead to finer control of muscle force during steady contraction.

Alterations of tibialis anterior muscle activation pattern in subjects with type 2 diabetes and diabetic peripheral neuropathy

2021 ◽  
Author(s):  
Mateus Favretto ◽  
Sandra Cossul ◽  
Felipe Rettore Andreis ◽  
Luiz R. Nakamura ◽  
Marcelo Ronsoni ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Peripheral Neuropathy ◽  
Isometric Contraction ◽  
Diabetic Peripheral Neuropathy ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Tibialis Anterior Muscle ◽  
Activation Pattern ◽  
Semg Signals

Abstract Diabetic peripheral neuropathy (DPN) is associated with loss of motor units (MUs), which can cause changes in the activation pattern of muscle fibres. This study investigated the pattern of muscle activation using high-density surface electromyography (HD-sEMG) signals from subjects with type 2 diabetes mellitus (T2DM) and DPN. Thirty-five adults participated in the study: 12 healthy subjects (HV), 12 patients with T2DM without DPN (No-DPN) and 11 patients with T2DM with DPN (DPN). HD-sEMG signals were recorded in the tibialis anterior muscle during an isometric contraction of ankle dorsiflexion at 50% of the maximum voluntary isometric contraction (MVIC) during 30-s. The calculated HD-sEMG signals parameters were the normalised root mean square (RMS), normalised median frequency (MDF), coefficient of variation (CoV) and modified entropy (ME). The RMS increased significantly (p = 0.001) with time only for the DPN group, while the MDF decreased significantly (p < 0.01) with time for the three groups. Moreover, the ME was significantly lower (p = 0.005), and CoV was significantly higher (p = 0.003) for the DPN group than the HV group. Using HD-sEMG, we have demonstrated a reduction in the number of MU recruited by individuals with DPN. This study provides proof of concept for the clinical utility of this technique for identifying neuromuscular impairment caused by DPN.

Prolonged reaction time during episodes of elevated β-band corticomuscular coupling and associated oscillatory muscle activity

2013 ◽  
Vol 114 (7) ◽  
pp. 896-904 ◽  
Author(s):  
Ryosuke Matsuya ◽  
Junichi Ushiyama ◽  
Junichi Ushiba
Keyword(s):  
Reaction Time ◽  
Sensorimotor Cortex ◽  
Muscle Activity ◽  
Human Subjects ◽  
Tibialis Anterior Muscle ◽  
Silent Period ◽  
Oscillatory Activity ◽  
Response Onset ◽  
Prolonged Reaction Time ◽  
Voluntary Contractions

Oscillatory activity in the sensorimotor cortex is coherent with 15–35 Hz band (β-band) muscle activity during tonic isometric voluntary contractions. In human subjects with higher corticomuscular coherence, prominent grouped discharge associated with a significant silent period was observed in electromyographic (EMG) signals. We examined the potential effects of β-band corticomuscular coupling on new ballistic movement as assessed by reaction time (RT). First, we quantified the coherence between electroencephalographic (EEG) signals over the sensorimotor cortex and rectified EMG signals from the tibialis anterior muscle during tonic isometric voluntary dorsiflexion at 30% of maximal effort in 15 healthy subjects. Subjects were divided into 2 groups [i.e., those with significant EEG-EMG coherence (COH+, n = 8) and those with no significant coherence (COH−, n = 7)]. Next, subjects performed ballistic contractions from a preliminary state of sustained contractions in reaction to auditory signals. RT was defined as the interval between the signal and the response onset measured by force. There were no intersubject differences in RT between COH+ and COH−. However, when the trials performed by COH+ subjects were divided into 2 groups depending on whether clear grouped discharge in the β-band was observed in the EMG (GD+ or GD−) just prior to the reaction, RT was significantly longer in the GD+ than in the GD− trials. We found that the magnitude of EEG-EMG coherence just before the reaction was significantly greater in the GD+ than in the GD− trials. These results suggest that generation of a new movement is delayed when corticomuscular coupling is elevated.

Contraction level-related modulation of corticomuscular coherence differs between the tibialis anterior and soleus muscles in humans

2012 ◽  
Vol 112 (8) ◽  
pp. 1258-1267 ◽  
Author(s):  
Junichi Ushiyama ◽  
Yoshihisa Masakado ◽  
Toshiyuki Fujiwara ◽  
Tetsuya Tsuji ◽  
Kimitaka Hase ◽  
...  
Keyword(s):  
Frequency Band ◽  
Sensorimotor Cortex ◽  
Maximal Voluntary Contraction ◽  
Tibialis Anterior ◽  
Voluntary Contraction ◽  
Moderate Intensity ◽  
Emg Activity ◽  
Scalp Eeg ◽  
Maximal Peak ◽  
Frequency Changes

The sensorimotor cortex activity measured by scalp EEG shows coherence with electromyogram (EMG) activity within the 15- to 35-Hz frequency band (β-band) during weak to moderate intensity of isometric voluntary contraction. This coupling is known to change its frequency band to the 35- to 60-Hz band (γ-band) during strong contraction. This study aimed to examine whether such contraction level-related modulation of corticomuscular coupling differs between muscles with different muscle compositions and functions. In 11 healthy young adults, we quantified the coherence between EEG over the sensorimotor cortex and rectified EMG during tonic isometric voluntary contraction at 10–70% of maximal voluntary contraction of the tibialis anterior (TA) and soleus (SOL) muscles, respectively. In the TA, the EEG-EMG coherence shifted from the β-band to the γ-band with increasing contraction level. Indeed, the magnitude of β-band EEG-EMG coherence was significantly decreased, whereas that of γ-band coherence was significantly increased, when the contraction level was above 60% of maximal voluntary contraction. In contrast to the TA, the SOL showed no such frequency changes of EEG-EMG coherence with alterations in the contraction levels. In other words, the maximal peak of EEG-EMG coherence in the SOL existed within the β-band, irrespective of the contraction levels. These findings suggest that the central nervous system regulates the frequency of corticomuscular coupling to exert the desired levels of muscle force and, notably, that the applicable rhythmicity of the coupling for performing strong contractions differs between muscles, depending on the physiological muscle compositions and functions of the contracting muscle.

scholarly journals Aerobic Exercise Attenuates Pain Sensitivity: An Event-Related Potential Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Kangyong Zheng ◽  
Changcheng Chen ◽  
Suyong Yang ◽  
Xueqiang Wang
Keyword(s):  
Aerobic Exercise ◽  
Tibialis Anterior ◽  
Pain Threshold ◽  
Tibialis Anterior Muscle ◽  
Event Related Potential ◽  
Moderate Intensity ◽  
Contact Heat ◽  
Low Intensity ◽  
Inhibitory Function ◽  
Heat Stimulus

In this study, electroencephalography (EEG) was utilized to explore the neurophysiological mechanisms of aerobic exercise-induced hypoalgesia (EIH) and provide a theoretical basis for the application of aerobic exercise in pain assessment and treatment. Forty-five healthy subjects were randomly divided into moderate-intensity aerobic exercise [70% heart rate reserve (HRR)], low-intensity aerobic exercise (50% HRR), or control groups (sitting). Aerobic exercise was performed with cycling. Pressure pain threshold (PPT), heat pain threshold (HPT), event-related potential (ERP) induced by contact heat stimulus and pain scoring were measured before and after the intervention. We found that moderate-intensity aerobic exercise can increase the PPT (rectus femoris: t = −2.71, p = 0.017; tibialis anterior muscle: t = −2.36, p = 0.033) and HPT (tibialis anterior muscle: t = −2.219, p = 0.044) of proximal intervention sites rather than distal sites, and decreased pain scorings of contact heat stimulus. After moderate-intensity aerobic exercise, alpha oscillation power reflecting the central descending inhibitory function was enhanced (t = −2.31, p &lt; 0.05). Low-intensity aerobic exercise mainly reduced the pain unpleasantness rating (Block 1: t = 2.415, p = 0.030; Block 2: t = 3.287, p = 0.005; Block 4: t = 2.646, p = 0.019; Block 5: t = 2.567, p = 0.022). Aerobic exercise had an overall EIH effect. Its hypoalgesic effect was related to exercise intensity and affected by the site and type of pain stimulus. Moderate-intensity aerobic exercise effectively reduced the sensitivity to various painful stimuli, and low-intensity aerobic exercise selectively inhibited the negative emotional pain response. The hypoalgesic mechanism of aerobic exercise involves the enhancement of the central descending inhibitory function.

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