Relationship Between Firing Rate and Recruitment Threshold of Motoneurons in Voluntary Isometric Contractions
Relationship Between Firing Rate and Recruitment Threshold of Motoneurons in Voluntary Isometric Contractions
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DOI：
10.1152/jn.01018.2009
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发表时间：
2010-08-01
影响因子：
2.5
通讯作者：
Hostage, Emily C.
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文献类型：
--
作者：
De Luca, Carlo J.;Hostage, Emily C.
德卢卡 CJ，人质 EC。随意等长收缩中运动神经元的放电率和募集阈值之间的关系。 《神经生理学杂志》104：1034-1046，2010 年。首次发表于 2010 年 6 月 16 日； doi：10.1152/jn.01018.2009。我们使用表面肌电信号分解技术来研究多个同时活动的运动单元的控制特性。招募六名年龄（21 +/- 0.63 岁）和身体素质相当的健康受试者，以 20%、50%、80% 和 100% 最大自主收缩力水平进行股外侧肌 (VL)、第一背侧骨间肌 (FDI) 和胫骨前肌 (TA) 等长收缩。使用提供四个数据通道的五针表面阵列传感器收集肌电图信号。使用新的分解算法将它们分解为成分动作电位。总共获得了 1,273 个运动单位动作电位序列的放电，每次收缩 20-30 个。计算运动单位的募集阈值和平均放电率，并推导出数学方程。结果描述了募集阈值和发射率之间的分层反比关系，包括一阶和二阶导数，即发射率的速度和加速度。这种关系描述了运动神经元池的“工作点”，该点在所有力水平下保持一致，并受到激励的调节。这种关系在受试者之间仅略有不同，而在肌肉之间则更为明显。这些结果支持“洋葱皮”特性，该特性表明运动神经元物理特性中编码的基本控制方案对运动神经元池的“共同驱动”做出一致的反应。
De Luca CJ, Hostage EC. Relationship between firing rate and recruitment threshold of motoneurons in voluntary isometric contractions. J Neurophysiol 104: 1034-1046, 2010. First published June 16, 2010; doi: 10.1152/jn.01018.2009. We used surface EMG signal decomposition technology to study the control properties of numerous simultaneously active motor units. Six healthy human subjects of comparable age (21 +/- 0.63 yr) and physical fitness were recruited to perform isometric contractions of the vastus lateralis (VL), first dorsal interosseous (FDI), and tibialis anterior (TA) muscles at the 20, 50, 80, and 100% maximum voluntary contraction force levels. EMG signals were collected with a five-pin surface array sensor that provided four channels of data. They were decomposed into the constituent action potentials with a new decomposition algorithm. The firings of a total of 1,273 motor unit action potential trains, 20-30 per contraction, were obtained. The recruitment thresholds and mean firing rates of the motor units were calculated, and mathematical equations were derived. The results describe a hierarchical inverse relationship between the recruitment thresholds and the firing rates, including the first and second derivatives, i.e., the velocity and the acceleration of the firing rates. This relationship describes an "operating point" for the motoneuron pool that remains consistent at all force levels and is modulated by the excitation. This relationship differs only slightly between subjects and more distinctly across muscles. These results support the "onion skin" property that suggests a basic control scheme encoded in the physical properties of motoneurons that responds consistently to a "common drive" to the motoneuron pool.