Evidence that peaks in EMG averages can sometimes be caused by inhibition of motoneurons.
Evidence that peaks in EMG averages can sometimes be caused by inhibition of motoneurons.
复制标题
有证据表明肌电图平均值的峰值有时可能是由运动神经元的抑制引起的。
DOI：
10.1152/jn.1989.62.1.212
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发表时间：
1989
影响因子：
2.5
通讯作者：
Lund,JP
中科院分区：
文献类型：
--
作者：
Widmer,CG;Lund,JP
1. 据报道，咀嚼肌在强烈抑制之前会发生兴奋反应。我们测试了这样的假设：肌电图中的这种小单极波，我们称之为早期外感受成分（EEC），实际上是对抑制的第一个反应。 2. 使用 3 x 4 表面电极矩阵并参考颈后部来绘制咬肌电活动图。受试者坐着时，下颌闭合肌肉放松或收缩至最大自愿水平的约 75%。轻敲下巴以引起下颌反射，并通过对上颚的电刺激来引发 EEC。 3. 此外，在最小咬合力和 5、10、15 或 20 N 的收缩水平下记录双极肌电图和下颌位置。 4. 数据是 32 种刺激的计算机平均值（经过校正和未经校正）。 5. 发现 EEC [潜伏期 12.1 +/- 1.0 (SD)ms] 与牵张反射的复极波具有相同的极性、形状和持续时间。 6. 电刺激后，在 EEC 期间或之后立即从未观察到咬合力增加。相反，咬合力在 EEC 出现后 5-7 毫秒开始下降。 7. 即使左右腭电极同时受到高强度刺激，EEC 的振幅也从未超过先前背景肌电图的峰值水平。（摘要截断为 250 字）
1. It has been reported that an excitatory response occurs before strong inhibition in masticatory muscles. We tested the hypothesis that this small monopolar wave in the EMG, called by us the early exteroceptive component (EEC), is in fact the first response to inhibition. 2. A mapping of the electrical activity of the masseter muscle was performed using a 3 x 4 matrix of surface electrodes with reference to the back of the neck. Subjects sat with the jaw closing muscles relaxed or contracting at approximately 75% of the maximum voluntary level. The chin was tapped to evoke a jaw jerk reflex and the EEC was elicited by electrical stimulation to the palate. 3. In addition, bipolar EMGs and jaw position were recorded at minimal bite forces and at contraction levels of 5, 10, 15, or 20 N. 4. Data were computer average, with and without rectification, for 32 stimuli. 5. The EEC [latency 12.1 +/- 1.0 (SD)ms] was found to have the same polarity, shape, and duration as the repolarizing wave of the stretch reflex. 6. After electrical stimulation, an increase of bite force was never observed during or immediately after the EEC. Instead, bite force began to decrease 5-7 ms after the onset of the EEC. 7. The amplitude of the EECs never exceeded the level of the peaks in the preceding background EMG, even when the left and right palatal electrodes were stimulated simultaneously at high intensity.(ABSTRACT TRUNCATED AT 250 WORDS)