Kossev A, Gerasimenko Y, Gantchev N, Christova P
Central Laboratory of Biophysics Bulgarian Academy of Sciences, Sofia.
Electromyogr Clin Neurophysiol. 1991 Jan-Feb;31(1):27-33.
The influence of the rate of firing of separate human motor units (MUs) from m. biceps brachii on the propagation velocity of the extraterritorial MU potentials was investigated. The experiments were carried out under normal physiological conditions--different level of isometric voluntary activity and different rate of firing--respectively. The subjects succeeded to keep 3-5 different levels of relatively constant rate of firing with mean value of the interimpulse intervals ranging from 67.8 to 183.2 ms. Wire subcutaneous branched electrodes and conventional bipolar wire electrodes were used to separate potentials from single motor units and as a trigger to average surface electromyographic (EMG) signals. MUs with superficially and deep lying muscle fibers were investigated. The propagation velocity of the potentials of superficially lying MUs was calculated from the time shift between the EMG signals picked up by means of two monopolar surface electrodes placed along the direction of the muscle fibers. For deep lying MUs the changes in the propagation velocity were estimated indirectly by the changes in the duration of the extraterritorial MU potentials. No systematic relationship between the rate of firing and the velocity of propagation was found.
研究了肱二头肌单个运动单位（MU）的放电频率对肌外运动单位电位传播速度的影响。实验分别在正常生理条件下进行，即不同水平的等长随意活动和不同的放电频率。受试者成功保持了3至5个不同水平的相对恒定放电频率，脉冲间期平均值在67.8至183.2毫秒之间。采用皮下线状分支电极和传统双极线状电极来分离单个运动单位的电位，并作为触发信号来平均表面肌电图（EMG）信号。对具有浅表和深层肌纤维的运动单位进行了研究。浅表运动单位电位的传播速度是根据沿肌纤维方向放置的两个单极表面电极采集的EMG信号之间的时间差来计算的。对于深层运动单位，通过肌外运动单位电位持续时间的变化间接估计传播速度的变化。未发现放电频率与传播速度之间存在系统性关系。
