Mita K, Akataki K, Miyagawa T
Institute for Developmental Research, Aichi Prefectural Colony, Kasugai, Japan.
Front Med Biol Eng. 1990;2(3):223-31.
The electromyogram (EMG) in a ballistic voluntary action of muscle after a slight sustained contraction shows a short period of decrease or disappearance of the activity prior to the onset of phasic discharge. The EMG of elbow extensor (triceps brachii) prior to phasic discharge was analyzed as a non-stationary stochastic process. The distribution of the EMG amplitude began to change from 100 ms before the phasic discharge. The statistical test showed that the EMG activity became non-Gaussian from 30 to 50 ms before the phasic discharge. The standard deviation of the EMG showed a decreasing tendency from 80 to 100 ms prior to the phasic discharge. The statistical evidence for the EMG depression was also confirmed in fourth and sixth order coefficients of the orthogonal expansion of the probability density function. These results suggested that the EMG process profoundly changed its statistical characteristics just before the phasic discharge.
在轻微持续收缩后肌肉的弹道式随意动作中，肌电图（EMG）显示在相位性放电开始之前，活动有一段短暂的减少或消失。将相位性放电前肘伸肌（肱三头肌）的肌电图作为一个非平稳随机过程进行分析。肌电图幅度的分布在相位性放电前100毫秒开始变化。统计检验表明，在相位性放电前30至50毫秒，肌电图活动变为非高斯分布。肌电图的标准差在相位性放电前80至100毫秒呈下降趋势。概率密度函数正交展开的四阶和六阶系数也证实了肌电图抑制的统计证据。这些结果表明，肌电图过程在相位性放电之前就深刻地改变了其统计特征。
