Coupling of antagonistic ankle muscles during co-contraction in humans
Coupling of antagonistic ankle muscles during co-contraction in humans
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DOI：
10.1007/s00221-002-1152-3
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发表时间：
2002-10-01
影响因子：
2
通讯作者：
Nielsen, JB
中科院分区：
文献类型：
--
作者：
Hansen, S;Hansen, NL;Nielsen, JB
对35名健康受试者的胫前肌(TA)和比目鱼肌(SOL)自主共收缩时所记录的肌电耦合进行了时间域和频域分析。不同受试者或同一受试者在不同场合观察到两种模式。一种模式由两个信号的累积量密度函数中的中心峰值组成，通常伴随着1535赫兹频段的相干性。另一种模式是在累积量密度函数中有一个中心低谷，它主要伴随着10赫兹附近的相干。在这种情况下，通常在累积量密度函数中观察到时间滞后为100ms的振荡。这两种模式可以在同一受试者身上观察到，但通常不是同时观察到的。在累积量密度函数中，10赫兹附近的相干性与中央波谷相关，在弱收缩时比在强收缩时更少见。相反，在15-35赫兹频段相干性的中心峰在弱收缩时最常见。当收缩持续一段时间后，与中央波谷的10赫兹相干有发生的趋势。当大直径传入的感觉反馈被缺血阻断时，这两种模式都可以观察到。当配对的TA和SOL肌电记录(19例受试者中的10例)在1535赫兹频段观察到一个中心峰时，两个肌肉的肌电活动与运动皮质腿部区域的脑电活动在同一频段也观察到耦合。当观察到中央波谷和10赫兹附近的相干性时(19个受试者中有8个)，8个受试者中有7个在脑电和肌电之间没有明显的一致性。在最后一个受试者中，观察到了10赫兹左右的相干。这些结果表明，拮抗性踝关节运动神经元存在两种不同的中枢输入系统：一种是激活一块肌肉而抑制拮抗者，另一种是共同激活拮抗性运动神经元。数据表明，至少后一种输入取决于运动皮质活动。
In 35 healthy human subjects coupling of EMGs recorded from the tibialis anterior (TA) and soleus (Sol) muscles during voluntary co-contraction was analysed in the time and frequency domains. Two patterns were observed in different subjects or in the same subject on different occasions. One pattern consisted of central peaks in the cumulant density function of the two signals, which was often accompanied by coherence in the 1535 Hz frequency band. The other pattern consisted of a central trough in the cumulant density function, which was mostly accompanied by coherence around 10 Hz. When this was the case oscillations were usually observed in the cumulant density function with time lags of 100 ms. Both patterns could be observed in the same subject, but usually not at the same time. Coherence around 10 Hz associated with a central trough in the cumulant density function was less common during weak than during strong co-contraction. The central peak with coherence in the 15-35 Hz frequency band in contrast tended to be most common during weak contraction. There was a tendency for the 10-Hz coherence with central trough to occur when the contractions had been maintained for some time. Both patterns could be observed when sensory feedback in large diameter afferents was blocked by ischaemia. When a central peak with coherence in the 1535 Hz frequency band was observed for paired TA and Sol EMG recordings (10 out of 19 subjects), a coupling in the same frequency band was also observed between the EMG activities from the two muscles and the EEG activity recorded from the leg area of the motor cortex. When the central trough and the coherence around 10 Hz was observed for the EMG recordings (8 out of 19 subjects), no significant coherence was observed between EEG and EMG in 7 of the 8 subjects. In the last subject coherence around 10 Hz was observed. It is suggested that these findings signify the existence of two different central input systems to antagonistic ankle motoneurones: one input activates one muscle while depressing the antagonist and the other coactivates antagonistic motoneurones. The data suggest that at least the latter input depends on motor cortical activity.