Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Denmark; Clinical Neuroscience Laboratory, Institute of Psychology, Norwegian University of Science and Technology, Trondheim, Norway.
Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Denmark.
Neuroimage. 2019 Jan 15;185:300-312. doi: 10.1016/j.neuroimage.2018.10.052. Epub 2018 Oct 19.
Transcranial Magnetic Stimulation (TMS) excites populations of neurons in the stimulated cortex, and the resulting activation may spread to connected brain regions. The distributed cortical response can be recorded with electroencephalography (EEG). Since TMS also stimulates peripheral sensory and motor axons and generates a loud "click" sound, the TMS-evoked EEG potentials (TEPs) reflect not only neural activity induced by transcranial neuronal excitation but also neural activity due to somatosensory and auditory processing. In 17 healthy young individuals, we systematically assessed the contribution of multisensory peripheral stimulation to TEPs using a TMS-compatible EEG system. Real TMS was delivered with a figure-of-eight coil over the left para-median posterior parietal cortex or superior frontal gyrus with the coil being oriented perpendicularly or in parallel to the target gyrus. We also recorded the EEG responses evoked by realistic sham stimulation over the posterior parietal and superior frontal cortex, mimicking the auditory and somatosensory sensations evoked by real TMS. We applied state-of-the-art procedures to attenuate somatosensory and auditory confounds during real TMS, including the placement of a foam layer underneath the coil and auditory noise masking. Despite these precautions, the temporal and spatial features of the cortical potentials evoked by real TMS at the prefrontal and parietal site closely resembled the cortical potentials evoked by realistic sham TMS, both for early and late TEP components. Our findings stress the need to include a peripheral multisensory control stimulation in the design of TMS-EEG studies to enable a dissociation between truly transcranial and non-transcranial components of TEPs.
经颅磁刺激（TMS）可兴奋刺激皮层中的神经元群体，而由此产生的激活可能会扩散到连接的脑区。分布的皮层反应可以通过脑电图（EEG）记录。由于 TMS 还会刺激周围的感觉和运动轴突，并产生响亮的“咔嗒”声，因此 TMS 诱发的脑电图电位（TEP）不仅反映了经颅神经元兴奋引起的神经活动，还反映了感觉和听觉处理引起的神经活动。在 17 名健康的年轻人中，我们使用 TMS 兼容的 EEG 系统系统地评估了多感觉外周刺激对 TEPs 的贡献。真实 TMS 通过放置在左旁中线后顶叶或额上回的八字形线圈进行传递，线圈垂直或平行于目标回。我们还记录了在后顶叶和额上回进行真实模拟刺激时诱发的 EEG 反应，模拟了真实 TMS 引起的听觉和感觉感觉。我们应用了最先进的程序来减轻真实 TMS 期间的感觉和听觉混淆，包括在线圈下方放置一层泡沫和听觉噪声掩蔽。尽管采取了这些预防措施，但真实 TMS 在额顶和顶叶部位诱发的皮质电位的时间和空间特征与逼真的模拟 TMS 诱发的皮质电位非常相似，无论是早期还是晚期 TEP 成分。我们的研究结果强调了在 TMS-EEG 研究设计中纳入外周多感觉控制刺激的必要性，以实现 TEPs 中真正经颅和非经颅成分的分离。
