肱二头肌的 M 波在第一相中具有固定（肩部样）成分：对 M 波分析的影响和建议。
The M waves of the biceps brachii have a stationary (shoulder-like) component in the first phase: implications and recommendations for M-wave analysis.
机构信息
Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain.
Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunication, Politecnico di Torino, Torino, Italy.
出版信息
Physiol Meas. 2021 Feb 9;42(1):015007. doi: 10.1088/1361-6579/abb791.
OBJECTIVE
We recently documented that compound muscle action potentials (M waves) recorded over the 'pennate' vastus lateralis showed a sharp deflection (named as a shoulder) in the first phase. Here, we investigated whether such a shoulder was also present in M waves evoked in a muscle with different architecture, such as the biceps brachii, with the purpose of elucidating the electrical origin of such afeature.
APPROACH
M waves evoked by maximal single shocks to the brachial plexus were recorded in monopolar and bipolar configurations from 72 individuals using large (10 mm diameter) electrodes and from eight individuals using small (1 mm diameter) electrodes arranged in a linear array. The changes in M-wave features at different locations along the muscle fiber direction were examined.
MAIN RESULTS
The shoulder was recognizable in most (87%) monopolar M waves, whereas it was rarely observed (6%) in bipolar derivations. Recordings made along the fiber direction showed that the shoulder was a stationary (non-propagating) feature, with short duration (spiky), which had positive polarity at all locations along the fibers. The latency of the shoulder (9.5 ± 0.5 ms) was significantly shorter than the estimated time taken for the action potentials to reach the biceps tendon (12.8 ms).
SIGNIFICANCE
The shoulder must be generated by a dipole source, i.e. a source created at a fixed anatomical position, although the exact origin of this dipole is uncertain. Our results suggest that the shoulder may not be due to the end-of-fiber signals formed at the biceps brachii tendon. The shoulder is not related to any specific arrangement of muscle fibers, as it has been observed in both pennate and fusiform muscles. Being a stationary (non-propagating) component, the shoulder is not reliable for studying changes in sarcolemmal excitability, and thus should be excluded from the M-wave analysis.
目的
我们最近记录到，在“羽状”股外侧肌上记录到的复合肌肉动作电位（M 波）在第一相出现了明显的偏转（称为肩部）。在这里，我们研究了这种肩部是否也存在于具有不同结构的肌肉（如肱二头肌）中诱发的 M 波中，目的是阐明这种特征的电生理起源。
方法
使用大（10 毫米直径）电极和小（1 毫米直径）电极排列成线性阵列，从 72 个人的臂丛中最大单刺激诱发 M 波，在单极和双极配置中记录 M 波。检查了沿肌纤维方向不同位置的 M 波特征的变化。
主要结果
肩部在大多数（87%）单极 M 波中可识别，而在双极衍生中很少观察到（6%）。沿纤维方向进行的记录显示，肩部是一个固定（非传播）特征，持续时间短（尖峰），在纤维上的所有位置均具有正极性。肩部的潜伏期（9.5±0.5ms）明显短于动作电位到达二头肌肌腱的估计时间（12.8ms）。
意义
肩部必须由偶极子源产生，即产生于固定解剖位置的源，尽管该偶极子的确切起源尚不确定。我们的结果表明，肩部可能不是由于二头肌肱肌腱处形成的纤维末端信号引起的。肩部与肌肉纤维的任何特定排列都没有关系，因为它在羽状和梭形肌肉中都有观察到。作为一个固定（非传播）的成分，肩部对于研究肌细胞膜兴奋性的变化不可靠，因此不应包含在 M 波分析中。
Zotero 插件