The nervous system uses oscillations to convey information efficiently. Inter-muscular coherence in the 15-35Hz range is thought to represent common cortical drive to muscles, but is also in the frequency band in which electrical stimulation is applied to restore movement following neurological disease or injury. We wished to determine if, when stimulation is applied at the peak frequency of the coherence spectra it was still possible to determine voluntary effort. Using healthy human subjects we stimulated muscles in the arms and legs, separate experiments, while recording EMG activity from pairs of muscles including the stimulated muscles. Offline coherence analysis was performed. When stimulation is greater than motor threshold, and applied at the peak of the coherence spectra a new peak appears in the spectra, presumably representing a new frequency of oscillation within the nervous system. This does not appear at lower stimulation levels, or with lower frequencies. The nervous system is capable of switching oscillatory frequencies to account for noise in the environment.

中文翻译：

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存在电刺激时的肌肉间连贯性

神经系统利用振动来有效地传达信息。15-35Hz范围内的肌肉间连贯性被认为代表了普通的皮层对肌肉的驱动，但是在神经刺激或神经系统疾病后，通过电刺激恢复运动的频带也是如此。我们希望确定，当以相干谱的峰值频率施加刺激时，是否仍然有可能确定自愿性努力。使用健康的人类受试者，我们分别进行了实验，刺激了手臂和腿部的肌肉，同时记录了包括受刺激的肌肉在内的成对肌肉的EMG活性。进行离线一致性分析。当刺激大于运动阈值并施加在相干光谱的峰值处时，光谱中会出现一个新的峰值，大概代表了神经系统内新的振荡频率。这在较低的刺激水平或较低的频率下不会出现。神经系统能够切换振荡频率以解决环境中的噪声。