A comparison of human thenar motor-unit properties studied by intraneural motor-axon stimulation and spike-triggered averaging.
A comparison of human thenar motor-unit properties studied by intraneural motor-axon stimulation and spike-triggered averaging.
复制标题
通过神经内运动轴突刺激和尖峰触发平均研究的人类大鱼际运动单位特性的比较。
DOI：
10.1152/jn.1990.64.4.1347
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发表时间：
1990
影响因子：
2.5
通讯作者：
Johansson,RS
中科院分区：
文献类型：
--
作者：
Thomas,CK;Bigland-Ritchie,B;Westling,G;Johansson,RS
1.通过尖峰触发平均记录的人类运动单元的抽搐收缩特性的测量可能会被抽搐之间的部分融合所扭曲，因为运动单元很少以低于8-10 Hz的速率发射。这种融合的效果进行了检查，比较27人鱼际运动单位的反应时，他们的运动轴突刺激在1，8，和10赫兹。2.根据外展和屈曲力分量以及先前报告的各种收缩和松弛速率指数计算合力。将单次抽搐的值与在8和10 Hz刺激期间记录的相同单元的未融合力波动（“明显抽搐”）进行的测量值进行比较。3.对于所有单位，在8和10 Hz的刺激引起部分抽搐融合。在10 Hz下，“表观抽搐”力、收缩时间（CT）和一半松弛时间（1/2 RT）的平均值分别降低至1 Hz刺激诱发的单独抽搐测量的相应值的44%、76%和52%。在8 Hz下观察到类似但较小的降低。4.与快速单元（小于50 ms）相比，当以8和10 Hz刺激时，初始抽搐CT大于60 ms的慢速单元显示出所有“表观抽搐”参数的显著更多的失真。5.将增强的外展力分量数据与先前通过相同肌肉群的尖峰触发平均获得的外展力进行比较。通过尖峰触发平均获得的平均力（“STA抽搐”力：21 mN）显著大于响应于1或10 Hz运动轴突刺激的外展中测量的平均力（分别为14 mN、6 mN）。（250字处删节）
1. Measurements of twitch contractile properties of human motor units recorded by spike-triggered averaging may be distorted by partial fusion between twitches, because motor units seldom fire at rates below 8-10 Hz. The effects of this fusion were examined by comparing the responses of 27 human thenar motor units when their motor axons were stimulated at 1, 8, and 10 Hz. 2. Resultant forces were calculated from the abduction and flexion force components, together with various contraction and relaxation rate indexes as reported previously. Values for single twitches were compared to measurements made from the unfused force fluctuations ("apparent twitches") of the same units recorded during 8 and 10 Hz stimulation. 3. For all units, stimulation at 8 and 10 Hz caused partial twitch fusion. At 10 Hz, mean values for "apparent twitch" forces, contraction times (CT), and one-half relaxation times (1/2RT) were reduced to 44, 76, and 52% of the corresponding values measured from separate twitches evoked by 1 Hz stimulation. Similar but smaller reductions were seen at 8 Hz. 4. Slow units, with initial twitch CT greater than 60 ms, showed significantly more distortion of all "apparent twitch" parameters when stimulated at both 8 and 10 Hz, compared to fast units (less than 50 ms). 5. The potentiated abduction force component data were compared with abduction forces obtained previously by spike-triggered averaging from the same muscle group. Mean force obtained by spike-triggered averaging ("STA twitch" force: 21 mN) was significantly larger than that measured in abduction in response to either 1 or 10 Hz motor-axon stimulation (14 mN, 6 mN, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)