Cortical brain states and corticospinal synchronization influence TMS-evoked motor potentials
Cortical brain states and corticospinal synchronization influence TMS-evoked motor potentials
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DOI：
10.1152/jn.00387.2013
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发表时间：
2014-02-01
影响因子：
2.5
通讯作者：
Schoenwiesner, Marc
中科院分区：
文献类型：
--
作者：
Keil, Julian;Timm, Jana;Schoenwiesner, Marc
经颅磁刺激（TMS）影响皮质过程。然而，最近的研究结果表明，TMS的疗效反过来取决于正在进行的皮层振荡的状态。虽然已知从手部肌肉记录的肌电图（EMG）活动的功率和相位以及皮层和手部肌肉之间的神经同步会影响经颅磁刺激的效果，但迄今为止，还没有研究表明清醒时皮层振荡的相位会产生影响。我们在运动皮层上应用单脉冲TMS，记录运动诱发电位以及脑电图和肌电图。我们将正在进行的脑电图和肌电信号的相位和功率与运动诱发电位（MEP）振幅相关联。我们还研究了皮层和手部肌肉活动之间的功能连接（皮质-肌肉相干性）与MEP振幅。18 Hz左右频带的EEG和EMG功率和相位与MEP幅值相关。高β -频带（类似于34 Hz）皮质肌肉相干性与MEP振幅呈线性正相关，表明在应用经颅磁刺激时，皮层和手部肌肉之间的强同步性导致了较大的MEP。在先前研究的基础上，我们证明了经颅磁刺激诱导的运动效应明显依赖于正在进行的脑电图相状态和功率波动。我们得出结论，不仅输入信息的采样，而且皮层通信流的敏感性也周期性地依赖于神经相。
Transcranial magnetic stimulation (TMS) influences cortical processes. Recent findings indicate, however, that, in turn, the efficacy of TMS depends on the state of ongoing cortical oscillations. Whereas power and phase of electro-myographic (EMG) activity recorded from the hand muscles as well as neural synchrony between cortex and hand muscles are known to influence the effect of TMS, to date, no study has shown an influence of the phase of cortical oscillations during wakefulness. We applied single-pulse TMS over the motor cortex and recorded motor-evoked potentials along with the electroencephalogram (EEG) and EMG. We correlated phase and power of ongoing EEG and EMG signals with the motor-evoked potential (MEP) amplitude. We also investigated the functional connectivity between cortical and hand muscle activity (corticomuscular coherence) with the MEP amplitude. EEG and EMG power and phase in a frequency band around 18 Hz correlated with the MEP amplitude. High beta-band (similar to 34 Hz) corticomuscular coherence exhibited a positive linear relationship with the MEP amplitude, indicating that strong synchrony between cortex and hand muscles at the moment when TMS is applied entails large MEPs. Improving upon previous studies, we demonstrate a clear dependence of TMS-induced motor effects on the state of ongoing EEG phase and power fluctuations. We conclude that not only the sampling of incoming information but also the susceptibility of cortical communication flow depends cyclically on neural phase.