Shapkov Iu T, Kozarov D
Acta Physiol Pharmacol Bulg. 1982;8(4):3-7.
Twenty subjects were investigated for voluntary control of separate motor units (MU) in the biceps brachii muscle under visual and auditory feedback. After 20-fold repetition of the task for sustaining stable firing frequency it turned out that in every trial the frequency was different and the variability of the interimpulse intervals changed in an unexpected way. It increased with the lengthening of the interimpulse intervals, but in an uneven manner. There appeared a decrease of the variability at steps of about 20 ms. A supraspinal excitatory input, rhythmically acting, is supposed to be the cause of this unevenness.
对20名受试者在视觉和听觉反馈下肱二头肌中单个运动单位（MU）的自主控制进行了研究。在对维持稳定放电频率的任务进行20次重复后发现，每次试验中的频率都不同，且脉冲间期的变异性以一种意想不到的方式变化。它随着脉冲间期的延长而增加，但方式并不均匀。在约20毫秒的步长上出现了变异性的降低。一种有节奏地起作用的脊髓上兴奋性输入被认为是这种不均匀性的原因。
