Muscle fatigue increases beta-band coherence between the firing times of simultaneously active motor units in the first dorsal interosseous muscle.
Muscle fatigue increases beta-band coherence between the firing times of simultaneously active motor units in the first dorsal interosseous muscle.
复制标题
肌肉疲劳增加了第一背侧骨间肌中同时活动的运动单元的放电时间之间的β带一致性。
作者：
Lara Mcmanus;Xiaogang Hu;W. Rymer;N. Suresh;M. Lowery
同时活动的运动单元（MU）的激发时间之间的同步通常被假定为在疲劳收缩期间增加。然而，到目前为止，MU同步的估计依赖于间接的措施，来自表面肌电（EMG）干扰信号。本研究使用肌内连贯性，调查MU放电在第一背侧骨间肌在次最大疲劳收缩期间和之后立即，休息后之间的相关性。在δ（1-4 Hz）、α（8-12 Hz）、β（15-30 Hz）和γ（30-60 Hz）频带范围内检查从分解的表面EMG导出的复合MU尖峰序列之间的相干性。在疲劳后的δ、α和β频带中观察到MU相干性的显著增加。此外，小波相干性揭示了δ-，α-和β-波段相干性增加的趋势，在疲劳收缩期间，受试者表现出较低的初始相干性值显示最大的相对增加。这是伴随着增加MU的短期同步和下降的平均放电率的大多数MU在持续收缩期间检测到。运动神经元池和表面肌电图的模型被用来调查的影响因素的一致性估计。模拟结果表明，运动神经元抑制和放电率的变化不能直接解释疲劳后β-波段相干性的增加。因此，观察到的增加更可能是由于肌肉疲劳时对MU的相关输入强度增加而引起的。
Synchronization between the firing times of simultaneously active motor units (MUs) is generally assumed to increase during fatiguing contractions. To date, however, estimates of MU synchronization have relied on indirect measures, derived from surface electromyographic (EMG) interference signals. This study used intramuscular coherence to investigate the correlation between MU discharges in the first dorsal interosseous muscle during and immediately following a submaximal fatiguing contraction, and after rest. Coherence between composite MU spike trains, derived from decomposed surface EMG, were examined in the delta (1-4 Hz), alpha (8-12 Hz), beta (15-30 Hz), and gamma (30-60 Hz) frequency band ranges. A significant increase in MU coherence was observed in the delta, alpha, and beta frequency bands postfatigue. In addition, wavelet coherence revealed a tendency for delta-, alpha-, and beta-band coherence to increase during the fatiguing contraction, with subjects exhibiting low initial coherence values displaying the greatest relative increase. This was accompanied by an increase in MU short-term synchronization and a decline in mean firing rate of the majority of MUs detected during the sustained contraction. A model of the motoneuron pool and surface EMG was used to investigate factors influencing the coherence estimate. Simulation results indicated that changes in motoneuron inhibition and firing rates alone could not directly account for increased beta-band coherence postfatigue. The observed increase is, therefore, more likely to arise from an increase in the strength of correlated inputs to MUs as the muscle fatigues.
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影响因子：
3.3
作者：
Contessa, Paola;Adam, Alexander;De Luca, Carlo J.
通讯作者：
De Luca, Carlo J.
猫运动神经元对持续和间歇性细胞外激活的适应。
DOI：
10.1113/jphysiol.1993.sp019625
发表时间：
1993
期刊：
The Journal of physiology
影响因子：
--
作者：
Spielmann,JM;Laouris,Y;Nordstrom,MA;Robinson,GA;Reinking,RM;Stuart,DG
通讯作者：
Stuart,DG
影响因子：
2.5
作者：
McManus, Lara;Hu, Xiaogang;Suresh, Nina L.
通讯作者：
Suresh, Nina L.
可变阈值运动神经元模型，包含时间和电压依赖性钾和钙电导。
影响因子：
2.5
作者：
Powers,RK
通讯作者：
Powers,RK
影响因子：
3.3
作者：
BIGLANDRITCHIE, B;FURBUSH, F;WOODS, JJ
通讯作者：
WOODS, JJ