Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, People's Republic of China.
J Neurophysiol. 2024 Nov 1;132(5):1530-1540. doi: 10.1152/jn.00320.2024. Epub 2024 Oct 23.
Continuous theta burst stimulation (cTBS) is a noninvasive brain stimulation technique. cTBS modulation is an effective treatment for motor dysfunction rehabilitation in post-stroke patients. However, there's currently a lack of research on the effects of cTBS stimulation on the contralesional hemisphere. To better understand the role of cTBS in motor rehabilitation, we investigated the neuroregulatory mechanisms of cTBS in the contralateral cortex using transcranial magnetic stimulation-evoked electroencephalography (TMS-EEG). In this randomized, sham-controlled, single-blind study, 18 healthy subjects received two separate stimulation conditions: cTBS or sham stimulation applied to the left primary motor cortex (M1). TMS-EEG measurements were taken before and immediately after stimulation. We investigated the TMS-evoked potentials (TEPs), evoked oscillatory responses (EOR), and phase synchronization index (PSI) of TMS-EEG. The effects of cTBS were analyzed using two-way repeated-measures analysis of variance (RMANOVA). There was a significant "cTBS condition × time" interaction effect on the theta and gamma bands of EOR, and on interhemisphere PSI (inter-PSI) and global PSI in both cTBS stimulation conditions. (theta: = 4.526, = 0.041; gamma: = 5.574, = 0.024; inter-PSI: = 5.028, = 0.032; global PSI: = 5.129, = 0.030). After real cTBS modulation, the energy in the theta and gamma frequency bands was significantly higher than before (theta: = 5.747, = 0.022; gamma: = 5.545, = 0.024). The inter-PSI and global PSI significantly increased after real cTBS modulation (inter-PSI: = 6.209, = 0.018; global PSI: = 6.530, = 0.015). cTBS modulation significantly increased EOR and PSI in contralateral brain regions, thereby enhancing cortical excitability and cortical functional connectivity throughout the brain. This provides a theoretical basis for cTBS neuromodulation in patients with stroke. In right-handed individuals, the left hemisphere exhibits higher excitability. According to hemispheric competition theory, applying continuous theta burst stimulation (cTBS) to inhibit excitability in the left hemisphere can reduce its inhibitory effect on the right, thereby promoting neural excitability. This study applied cTBS to the left M1 of healthy individuals and, for the first time, recorded transcranial magnetic stimulation-evoked electroencephalography (TMS-EEG) from the right M1 to analyze the effects of cTBS on cortical oscillations and network connectivity in the contralateral cortex.
连续 theta 爆发刺激（cTBS）是一种非侵入性的脑刺激技术。cTBS 调制是一种治疗中风后患者运动功能障碍的有效方法。然而，目前关于 cTBS 刺激对病变对侧半球的影响的研究还很少。为了更好地了解 cTBS 在运动康复中的作用，我们使用经颅磁刺激诱发脑电图（TMS-EEG）研究了 cTBS 在对侧皮质中的神经调节机制。在这项随机、假刺激对照、单盲研究中，18 名健康受试者接受了两种不同的刺激条件：cTBS 或假刺激应用于左侧初级运动皮层（M1）。在刺激前后进行 TMS-EEG 测量。我们研究了 TMS 诱发的电位（TEPs）、诱发的振荡反应（EOR）和 TMS-EEG 的相位同步指数（PSI）。使用双因素重复测量方差分析（RMANOVA）分析 cTBS 的效果。在 EOR 的 theta 和 gamma 波段以及 cTBS 刺激条件下的半球间 PSI（inter-PSI）和全局 PSI 上存在显著的“cTBS 条件×时间”交互效应。（theta：= 4.526，= 0.041；gamma：= 5.574，= 0.024；inter-PSI：= 5.028，= 0.032；全局 PSI：= 5.129，= 0.030）。在真正的 cTBS 调制后，theta 和 gamma 频带中的能量明显高于调制前（theta：= 5.747，= 0.022；gamma：= 5.545，= 0.024）。在真正的 cTBS 调制后，inter-PSI 和全局 PSI 显著增加（inter-PSI：= 6.209，= 0.018；全局 PSI：= 6.530，= 0.015）。cTBS 调制显著增加了对侧脑区的 EOR 和 PSI，从而增强了整个大脑的皮质兴奋性和皮质功能连接。这为中风患者的 cTBS 神经调节提供了理论依据。在右利手个体中，左侧半球表现出更高的兴奋性。根据半球竞争理论，应用连续 theta 爆发刺激（cTBS）抑制左侧半球的兴奋性可以降低其对右侧的抑制作用，从而促进神经兴奋性。本研究将 cTBS 应用于健康个体的左侧 M1，并首次从右侧 M1 记录经颅磁刺激诱发脑电图（TMS-EEG），以分析 cTBS 对皮质振荡和对侧皮质网络连接的影响。
