Monash Alfred Psychiatry Research Centre, Central Clinical School, The Alfred and Monash University, Melbourne, Australia.
Brain Stimul. 2013 Nov;6(6):868-76. doi: 10.1016/j.brs.2013.04.004. Epub 2013 Apr 28.
Concurrent transcranial magnetic stimulation and electroencephalography (TMS-EEG) is an emerging method for studying cortical network properties. However, various artifacts affect measurement of TMS-evoked cortical potentials (TEPs), especially within 30 ms of stimulation.
OBJECTIVE/HYPOTHESIS: The aim of this study was to assess the origin and recovery of short-latency TMS-EEG artifacts (<30 ms) using different stimulators and under different experimental conditions.
EEG was recorded during TMS delivered to a phantom head (melon) and 12 healthy volunteers with different TMS machines, at different scalp positions, at different TMS intensities, and following paired-pulse TMS. Recovery from the TMS artifact and other short-latency artifacts were compared between conditions.
Following phantom stimulation, the artifact resulting from different TMS machines (Magstim 200, Magventure MagPro R30 and X100) and pulse shapes (monophasic and biphasic) resulted in different artifact profiles. After accounting for differences between machines, TMS artifacts recovered within ∼12 ms. This was replicated in human participants, however a large secondary artifact (peaks at 5 and 10 ms) became prominent following stimulation over lateral scalp positions, which only recovered after ∼25-40 ms. Increasing TMS intensity increased secondary artifact amplitude over both motor and prefrontal cortex. There was no consistent modulation of the secondary artifact following inhibitory paired-pulse TMS (interstimulus interval = 100 ms) over motor cortex.
The secondary artifact observed in humans is consistent with activation of scalp muscles following TMS. TEPs can be recorded within a short period of time (10-12 ms) following TMS, however measures must be taken to avoid muscle stimulation.
经颅磁刺激和脑电图（TMS-EEG）同步是一种新兴的研究皮质网络特性的方法。然而，各种伪影会影响 TMS 诱发皮质电位（TEP）的测量，尤其是在刺激后 30ms 内。
目的/假设：本研究旨在评估不同刺激器和不同实验条件下，短潜伏期 TMS-EEG 伪影（<30ms）的起源和恢复。
在使用不同的 TMS 机器、在不同的头皮位置、在不同的 TMS 强度以及在进行成对脉冲 TMS 后，在一个幻影头部（瓜）和 12 名健康志愿者记录 EEG 期间，记录 TMS 诱发的脑电活动。比较不同条件下 TMS 伪影和其他短潜伏期伪影的恢复情况。
在对幻影进行刺激后，来自不同 TMS 机器（Magstim 200、Magventure MagPro R30 和 X100）和脉冲形状（单相和双相）的伪影导致了不同的伪影模式。在考虑到机器之间的差异后，TMS 伪影在大约 12ms 内恢复。这在人类参与者中得到了复制，然而，在刺激外侧头皮位置后，一个大的二级伪影（在 5 和 10ms 处出现峰值）变得明显，只有在大约 25-40ms 后才能恢复。增加 TMS 强度会增加运动皮质和前额皮质上的二级伪影幅度。在运动皮质上，抑制性成对脉冲 TMS（刺激间隔=100ms）后，二级伪影没有一致的调制。
在人类中观察到的二级伪影与 TMS 后头皮肌肉的激活一致。TEP 可以在 TMS 后短时间（10-12ms）内记录，但必须采取措施避免肌肉刺激。
