Department of Neuropsychiatry, Graduate School of Medicine, Keio University School of Medicine, Tokyo, Japan.
Department of Neuropsychiatry, Graduate School of Medicine, Keio University School of Medicine, Tokyo, Japan; Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
Neurosci Biobehav Rev. 2021 Dec;131:293-312. doi: 10.1016/j.neubiorev.2021.09.029. Epub 2021 Sep 20.
Unconscious state has been investigated in numerous studies so far, but pathophysiology of this state is not fully understood. Recently, combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) has been developed to allow for non-invasive assessment of neurophysiology in the cerebral cortex. We conducted a systematic literature search for TMS-EEG studies on human unconscious state using PubMed with cross-reference and manual searches. The initial search yielded 137 articles, and 19 of them were identified as relevant, including one article found by manual search. This review included 10 studies for unresponsive wakefulness syndrome (UWS), 9 for minimally conscious states (MCS), 5 for medication-induced unconscious states, and 6 for natural non-rapid eye movement states. These studies analyzed TMS-evoked potential to calculate perturbational complexity index (PCI) and OFF-periods. In particular, PCI was found to be a potentially useful marker to differentiate between UWS and MCS. This review demonstrated that TMS-EEG could represent a promising neuroscientific tool to investigate various unconscious states. Further TMS-EEG research may help elucidate the neural basis of unconscious state.
迄今为止，已有大量研究对无意识状态进行了探讨，但该状态的病理生理学仍未被完全理解。最近，结合经颅磁刺激（TMS）和脑电图（EEG）已被开发出来，以允许对大脑皮层的神经生理学进行非侵入性评估。我们使用 PubMed 进行了系统的文献检索，并进行了交叉引用和手动搜索，以寻找关于人类无意识状态的 TMS-EEG 研究。初步搜索产生了 137 篇文章，其中 19 篇被确定为相关，其中包括一篇通过手动搜索找到的文章。本综述包括 10 项关于无反应性觉醒综合征（UWS）的研究、9 项关于最小意识状态（MCS）的研究、5 项关于药物诱导的无意识状态的研究和 6 项关于自然非快速眼动状态的研究。这些研究分析了 TMS 诱发的电位，以计算扰动量复杂指数（PCI）和 OFF 期。特别是，发现 PCI 是区分 UWS 和 MCS 的一个潜在有用的标志物。本综述表明，TMS-EEG 可能代表一种有前途的神经科学工具，可用于研究各种无意识状态。进一步的 TMS-EEG 研究可能有助于阐明无意识状态的神经基础。
