Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus SUVA, Sion, Switzerland.
MySpace Lab, Department of Clinical Neuroscience, Centre Hospitalier Universitaire Vaudois (CHUV), Switzerland.
Brain Stimul. 2019 May-Jun;12(3):693-701. doi: 10.1016/j.brs.2018.12.972. Epub 2018 Dec 23.
When single pulse transcranial magnetic stimulation (TMS) is applied over the primary motor cortex (M1) with sufficient intensity, it evokes muscular contractions (motor-evoked potentials, MEPs) and muscle twitches (TMS-evoked movements). Participants may also report various hand sensations related to TMS, but the perception elicited by TMS and its relationship to MEPs and evoked movements has not been systematically studied.
The main aim of this work is to evaluate participants' kinesthetic and somatosensory hand perceptions elicited by single-pulse TMS over M1-hand area at different intensities of stimulation and their relation with MEPs and TMS-evoked movements.
We compared the number of MEPs (measured by electromyography), TMS-evoked movements (measured by an accelerometer) and participants' hand perception (measured by verbal report) elicited by TMS at different intensity of stimulation. This way, we estimated the amplitude of MEPs and the acceleration of TMS-evoked movements sufficient to trigger TMS evoked hand perceptions.
We found that TMS-evoked hand perceptions are induced at 105% of the individual resting motor threshold, a value significantly different from the threshold inducing MEPs (about 100%) and TMS-evoked movements (about 110%). Our data indicate that only MEPs with an amplitude higher than 0.62 mV and TMS-evoked movements with acceleration higher than 0.42 m/s2 were associated with hand perceptions at threshold.
Our data reveal the main features of TMS-evoked hand perception and show that in addition to MEPs and TMS-evoked movements, this is a separate discernible response associated to single-pulse TMS over M1.
当单脉冲经颅磁刺激（TMS）以足够的强度施加于初级运动皮层（M1）时，它会引起肌肉收缩（运动诱发电位，MEPs）和肌肉抽搐（TMS 诱发运动）。参与者还可能报告与 TMS 相关的各种手部感觉，但 TMS 诱发的感知及其与 MEPs 和诱发运动的关系尚未得到系统研究。
这项工作的主要目的是评估参与者在不同刺激强度下经 M1 手部区域单脉冲 TMS 诱发的本体感觉和体感手部感知，并研究其与 MEPs 和 TMS 诱发运动的关系。
我们比较了不同刺激强度下 TMS 诱发的肌电图（EMG）测量的 MEPs 数量、加速度计测量的 TMS 诱发运动和参与者的手部感知（通过口头报告）。通过这种方式，我们估计了足以引发 TMS 诱发手部感知的 MEPs 振幅和 TMS 诱发运动的加速度。
我们发现 TMS 诱发的手部感知是在个体静息运动阈值的 105%时产生的，这个值与诱发 MEPs（约 100%）和 TMS 诱发运动（约 110%）的阈值有显著差异。我们的数据表明，只有振幅高于 0.62 mV 的 MEPs 和加速度高于 0.42 m/s2 的 TMS 诱发运动与阈值时的手部感知相关。
我们的数据揭示了 TMS 诱发手部感知的主要特征，并表明除了 MEPs 和 TMS 诱发运动之外，这是一种与 M1 上的单脉冲 TMS 相关的单独可识别的反应。
