基于运动皮层重复经颅磁刺激的脑电信息解析及响应机制研究

Stroke is a leading cause of serious long-term adult disability around the world. How to help patients restore motor function has attracted a wide spread attention of the whole society. In recent years, repetitive transcranial magnetic stimulation (rTMS) has been an important noninvasive brain stimulation used in rehabilitation therapy after stroke, which has gained a great deal of achievements in clinical rehabilitation. Real-time Electroencephalography (EEG) information offers the capacity to characterize excitability and connectivity, which can be used to deeply understand the rehabilitation mechanism of rTMS. However, the existing research mainly focuses on the change in brain activity between before and after rTMS, and fewer of literature is about real-time brain response during rTMS. This project adopts concurrent rTMS-EEG technology, which records real-time EEG during rTMS delivery. Propose a novel stimulus artifact removal algorithm to remove the rTMS artifact. Extract time-domain, frequency-domain, and space EEG features. It will provide key technical support for parameter optimization and rehabilitation evaluation of rTMS; Moreover, through building a model of brain network under rTMS, explore activation patterns of the stimulated brain area and the non-stimulated brain area and integration and interaction functions between different areas. It expands understandings of response mechanism induced by rTMS. This project will provide scientific basis for promoting the clinical rehabilitation of rTMS.

脑卒中是全世界导致成人残疾的首要原因，如何帮助患者恢复运动功能已受到全社会广泛关注。近年来，重复经颅磁刺激（repetitive Transcranial Mgnetic Simulation, rTMS）已成为重要的非侵入式脑卒中康复手段，在临床中取得了显著成效。虽然rTMS刺激过程中实时脑电信息能够直接反映rTMS引起的大脑兴奋性和连通性，是深入了解rTMS康复机制的重要手段，但是现有研究主要对比磁刺激前后大脑活性变化，鲜有文献报道刺激过程中的实时大脑响应。本课题拟采用经颅磁刺激同步脑电技术，同步采集磁刺激下脑电信息，设计伪迹去除算法以移除伪迹干扰，提取时、频、空等脑电特征，为rTMS参数优化和康复评价提供关键技术支持；并且通过构建脑网络，探索rTMS过程中脑区激活状况以及不同脑区间的整合和交互作用，拓展了rTMS诱发的大脑响应机制。本研究将为推进rTMS的临床应用提供新的科学依据。

脑卒中具有发病率高、死亡率高和致残率高的特点，常伴有运动功能障碍，严重影响患者生活质量。重复经颅磁刺激（Repetitive Transcranial Magnetic Stimulation, rTMS）康复技术被认为是一种有效的卒中运动功能康复治疗方法。但是，其神经康复机制仍不明确。因此，本研究从脑电振荡模式、大脑功能网络以及脑电微状态等方面对rTMS诱发的大脑响应进行局部/全局多维度解析，从而深入探索rTMS的神经康复机理，为其临床应用提供新的科学依据与指导。首先，在神经振荡模式方面，提取了运动区低频rTMS刺激后的神经振荡特征，发现了rTMS引起的神经振荡活动呈现频率特异性和区域特异性，具体表现为：同侧顶区产生一个延迟alpha振荡增强，对侧顶区产生一个瞬时的theta振荡增强；其次，在大脑功能网络方面，分别构建了刺激前后多个时间点的静息脑网络，计算并比较脑功能网络特征参数，发现了低频rTMS作用于运动区后，同侧节点集聚系数显著降低，对侧运动区节点度显著增加，这表征着同侧信息传输速率减低，对侧运动区的重要性增加，证明了运动区低频rTMS对大脑存在同侧抑制、对侧增强的作用，脑功能网络特征有望被用于rTMS的康复疗效评价中；再次，在脑电微状态方面，发现持续爆破式磁刺激（Continuous Theta Burst Stimulation, cTBS）作用于左侧运动皮层后，没有改变微状态空间拓扑结构，微状态A的持续时间和发生率显著提升，而微状态B的持续时间和发生率显著下降，结合行为学指标进行相关分析，确定了与运动皮层cTBS的特异性神经响应状态是微状态B，cTBS刺激对微状态B具有长持续的抑制作用。这些研究结果不仅拓展了rTMS诱发的大脑响应机制，并且为推进rTMS的临床应用和康复评估提供了新的理论依据。