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.

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.

Supraspinal fatigue during intermittent maximal voluntary contractions of the human elbow flexors

2000 ◽  
Vol 89 (1) ◽  
pp. 305-313 ◽  
Author(s):  
Janet L. Taylor ◽  
Gabrielle M. Allen ◽  
Jane E. Butler ◽  
S. C. Gandevia
Keyword(s):  
Evoked Potential ◽  
Intermittent Exercise ◽  
Human Subjects ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Central Fatigue ◽  
Duty Cycles ◽  
Flexor Muscles ◽  
Elbow Flexor Muscles ◽  
Voluntary Contractions

Responses to transcranial magnetic stimulation in human subjects ( n = 9) were studied during series of intermittent isometric maximal voluntary contractions (MVCs) of the elbow. Stimuli were given during MVCs in four fatigue protocols with different duty cycles. As maximal voluntary torque fell during each protocol, the torque increment evoked by cortical stimulation increased from ∼1.5 to 7% of ongoing torque. Thus “supraspinal” fatigue developed in each protocol. The motor evoked potential (MEP) and silent period in the elbow flexor muscles also changed. The silent period lengthened by 20–75 ms (lowest to highest duty cycle protocol) and recovered significantly with a 5-s rest. The MEP increased in area by >50% in all protocols and recovered significantly with 10 s, but not 5 s, of rest. These changes are similar to those during sustained MVC. The central fatigue demonstrated by the torque increments evoked by the stimuli did not parallel the changes in the electromyogram responses. This suggests that part of the fatigue developed during intermittent exercise is “upstream” of the motor cortex.

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.

Exteroceptive Suppression of Temporalis Muscle Activity: Findings in Headache

Cephalalgia ◽  
1993 ◽  
Vol 13 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Thomas-Martin Wallasch ◽  
Hartmut Göbel
Keyword(s):  
Muscle Activity ◽  
Silent Period ◽  
Tension Type Headache ◽  
Temporalis Muscle ◽  
Pharmacological Agents ◽  
Chronic Tension Type Headache ◽  
Exteroceptive Suppression ◽  
Headache Diagnosis ◽  
Secondary Phenomenon ◽  
Type Headache

Exteroceptive suppression of temporalis muscle activity was proposed by Schoenen and co-workers in 1987 as a tool in headache diagnosis and research. Their finding of a decreased or abolished second silent period (ES2) in chronic tension-type headache sufferers has been confirmed by several independent laboratories during the last five years. Temporalis silent periods have also been studied in various other types of headaches. Their modulation by neuropsychological factors and pharmacological agents has also been investigated as well as their retest reliability. The pathophysiological concept of muscle contraction in tension-type headache has been challenged by studies using temporalis silent periods. The exterocepfive suppression of temporalis muscle activity points unequivocally towards a central pathogenetic mechanism, although it remains unclear whether the abnormalities of temporalis ES2 represent the primary dysfunction or a secondary phenomenon in chronic tension-type headache.

Hydrothermal Synthesis of Bi1.5ZnNb1.5O7 Nanopowders

2007 ◽  
Vol 561-565 ◽  
pp. 495-498 ◽  
Author(s):  
Jin Liang Huang ◽  
Xiao Wang ◽  
Liu Shuan Yang ◽  
Chun Wei Cui ◽  
Xing Hua Yang
Keyword(s):  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Pyrochlore Phase ◽  
Synthesis Temperature ◽  
Minimum Size ◽  
Hydrothermal Reactions ◽  
Prolonged Reaction Time ◽  
Scherrer Equation ◽  
Xrd Patterns

The cubic pyrochlore phase Bi1.5ZnNb1.5O7 nanopowder was successfully synthesized by the hydrothermal method (HTM) from the starting materials: Bi(NO3)3·5H2O, ZnO, Nb2O5 and the mineralizer: KOH. The XRD patterns prove that the cubic pyrochlore phase Bi1.5ZnNb1.5O7 nanopowder can be obtained by HTM, and TEM photographs show that the powders present the regularly granular shape, when the hydrothermal reactions were conducted at synthesis temperatures 140~220°C and reaction time for 6~48h. The crystalline sizes of the powders were calculated by the Scherrer equation to be about 43~49nm. The crystalline sizes decreased both with the increase in synthesis temperature and the prolonged reaction time until they reached to the minimum size about 43nm at 220°C for 24h.However, they tended to increase when the reaction time was above 24h.

Rolling balance board of adjustable geometry as a tool to assess balancing skill and to estimate reaction time delay

2021 ◽  
Vol 18 (176) ◽  
Author(s):  
Csenge A. Molnar ◽  
Ambrus Zelei ◽  
Tamas Insperger
Keyword(s):  
Reaction Time ◽  
Time Delay ◽  
Feedback Control ◽  
Mechanical Model ◽  
Human Subjects ◽  
Reaction Times ◽  
Physical Parameters ◽  
Stabilizing Feedback Control ◽  
Model Subject ◽  
Balance Board

The relation between balancing performance and reaction time is investigated for human subjects balancing on rolling balance board of adjustable physical parameters: adjustable rolling radius R and adjustable board elevation h . A well-defined measure of balancing performance is whether a subject can or cannot balance on balance board with a given geometry ( R , h ). The balancing ability is linked to the stabilizability of the underlying two-degree-of-freedom mechanical model subject to a delayed proportional–derivative feedback control. Although different sensory perceptions involve different reaction times at different hierarchical feedback loops, their effect is modelled as a single lumped reaction time delay. Stabilizability is investigated in terms of the time delay in the mechanical model: if the delay is larger than a critical value (critical delay), then no stabilizing feedback control exists. Series of balancing trials by 15 human subjects show that it is more difficult to balance on balance board configuration associated with smaller critical delay, than on balance boards associated with larger critical delay. Experiments verify the feature of the mechanical model that a change in the rolling radius R results in larger change in the difficulty of the task than the same change in the board elevation h does. The rolling balance board characterized by the two well-defined parameters R and h can therefore be a useful device to assess human balancing skill and to estimate the corresponding lumped reaction time delay.

scholarly journals Effects during isometric voluntary contractions of elbow flexion muscles on EMG-reaction time (EMG-RT).

1987 ◽  
Vol 6 (1) ◽  
pp. 3-10
Author(s):  
Masae YONAI ◽  
Masuo MURO ◽  
Akira NAGATA ◽  
Koichi SHIMOSHIKIRYO
Keyword(s):  
Reaction Time ◽  
Elbow Flexion ◽  
Voluntary Contractions

scholarly journals Effects of tonic muscle pain on fusimotor control of human muscle spindles during isometric ankle dorsiflexion

2019 ◽  
Vol 121 (4) ◽  
pp. 1143-1149
Author(s):  
Lyndon J. Smith ◽  
Vaughan G. Macefield ◽  
Ingvars Birznieks ◽  
Alexander R. Burton
Keyword(s):  
Muscle Spindle ◽  
Muscle Pain ◽  
Tibialis Anterior Muscle ◽  
Muscle Spindles ◽  
Muscle Spindle Afferents ◽  
Firing Rates ◽  
Leg Muscles ◽  
Tonic Muscle ◽  
Voluntary Contractions ◽  
Ankle Dorsiflexors

Studies on anesthetized animals have revealed that nociceptors can excite fusimotor neurons and thereby change the sensitivity of muscle spindles to stretch; such nociceptive reflexes have been suggested to underlie the mechanisms that lead to chronic musculoskeletal pain syndromes. However, the validity of the “vicious cycle” hypothesis in humans has yielded results contrasting with those found in animals. Given that spindle firing rates are much lower in humans than in animals, it is possible that some of the discrepancies between human experimental data and those obtained in animals could be explained by differences in background fusimotor drive when the leg muscles are relaxed. We examined the effects of tonic muscle pain during voluntary contractions of the ankle dorsiflexors. Unitary recordings were obtained from 10 fusimotor-driven muscle spindle afferents (6 primary, 4 secondary) supplying the ankle dorsiflexors via a microelectrode inserted percutaneously into the common peroneal nerve. A series of 1-min weak contractions was performed at rest and during 1 h of muscle pain induced by intramuscular infusion of 5% hypertonic saline into the tibialis anterior muscle. We did not observe any statistically significant increases in muscle spindle firing rates of six afferents followed during tonic muscle pain, although discharge variability increased slightly. Furthermore, a participant’s capacity to maintain a constant level of force, while relying on proprioceptive feedback in the absence of visual feedback, was not compromised during pain. We conclude that nociceptive inputs from contracting muscle do not excite fusimotor neurons during voluntary isometric contractions in humans. NEW & NOTEWORTHY Data obtained in the cat have shown that muscle pain causes a marked increase in the firing of muscle spindles, attributed to a nociceptor-driven fusimotor reflex. However, our studies of muscle spindles in relaxed leg muscles failed to find any effect on spindle discharge. Here we showed that experimental muscle pain failed to increase the firing of muscle spindle afferents during weak voluntary contractions, when fusimotor drive sufficient to increase their firing is present.

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