Cognitive Neuroscience Unit, School of Psychology, Deakin University, Victoria, Australia.
The Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Victoria, Australia.
J Neurophysiol. 2021 May 1;125(5):1768-1787. doi: 10.1152/jn.00617.2020. Epub 2021 Mar 31.
Combined single-pulse transcranial magnetic stimulation (TMS) and electroencephalography (EEG) has been used to probe the features of local networks in the cerebral cortex. Here, we investigated whether we can use this approach to explore long-range connections between the cerebellum and cerebral cortex. Ten healthy adults received single-pulse suprathreshold TMS to the cerebellum and an occipital/parietal control site with double-cone and figure-of-eight coils while cerebral activity was recorded. A multisensory electrical control condition was used to simulate the sensation of the double-cone coil at the cerebellar site. Two cleaning pipelines were compared, and the spatiotemporal relationships of the EEG output between conditions were examined at sensor and source levels. Cerebellar stimulation with the double-cone coil resulted in large artifact in the EEG trace. The addition of SOUND filtering to the cleaning pipeline improved the signal such that further analyses could be undertaken. The cortical potentials evoked by the active TMS conditions showed strong relationships with the responses to the multisensory control condition after ∼50 ms. A distinct parietal component at ∼42 ms was found following cerebellar double-cone stimulation. Although evoked potentials differed across all conditions at early latencies, it is unclear as to whether these represented TMS-related network activation of the cerebellarthalamocortical tract, or whether components were dominated by sensory contamination and/or coil-driven artifact. This study highlights the need for caution when interpreting outcomes from cerebellar TMS-EEG studies. This is the first study to systematically assess the feasibility of obtaining TMS-evoked potentials from cerebellar stimulation with concurrent EEG. An innovative control condition using electrical stimulation was modified to mimic the sensory aspects of cerebellar stimulation with a double-cone coil, and a state-of-the art cleaning pipeline was trialled. The extent of artifact contamination in signals from stimulation of a cerebellar and an occipital/parietal control site using two TMS coil types was highlighted.
联合单次经颅磁刺激 (TMS) 和脑电图 (EEG) 已被用于探测大脑皮层局部网络的特征。在这里，我们研究了是否可以使用这种方法来探索小脑与大脑皮层之间的远程连接。十名健康成年人接受了单次超阈值 TMS 刺激小脑和枕部/顶叶对照部位，同时记录大脑活动。使用多感官电控制条件来模拟小脑部位双锥线圈的感觉。比较了两种清洗管道，并在传感器和源水平检查了条件之间 EEG 输出的时空关系。双锥线圈刺激小脑会导致 EEG 迹线中的大伪影。在清洗管道中添加 SOUND 滤波可改善信号，以便进行进一步的分析。主动 TMS 条件下诱发的皮质电位在 50 ms 后与多感官控制条件的反应具有很强的关系。在小脑双锥刺激后约 42 ms 时发现了一个明显的顶叶成分。尽管在早期潜伏期时，所有条件下的诱发电位都不同，但尚不清楚这些是否代表小脑丘脑皮质束的 TMS 相关网络激活，或者组件是否主要受到感官污染和/或线圈驱动的伪影的影响。本研究强调了在解释小脑 TMS-EEG 研究结果时需要谨慎。这是第一项系统评估使用 EEG 从小脑 TMS 刺激获得 TMS 诱发电位的可行性的研究。使用电刺激修改了创新的对照条件，以模拟双锥线圈小脑刺激的感官方面，并试用了最先进的清洗管道。突出了两种 TMS 线圈类型刺激小脑和枕部/顶叶对照部位时信号中伪影污染的程度。
