Innovation, Implementation and Clinical Translation (IIMPACT) in Health, University of South Australia, City East Campus, GPO Box 2471, Adelaide, South, 5001, Australia.
Lifespan Human Neurophysiology Group, Adelaide Medical School, The University of Adelaide, Adelaide, 5005, Australia.
Brain Struct Funct. 2021 Jul;226(6):1893-1907. doi: 10.1007/s00429-021-02299-4. Epub 2021 May 27.
A patterned repetitive transcranial magnetic stimulation protocol, known as continuous theta burst stimulation (cTBS), can suppress corticospinal excitability via mechanisms that appear similar to long-term depression synaptic plasticity. Despite much potential, this technique is currently limited by substantial response variability. The purpose of this study was to investigate whether baseline resting state functional connectivity is a determinant of response to cTBS. Eighteen healthy young adults participated in up to three experimental sessions. Single-pulse transcranial magnetic stimulation was used to quantify change in corticospinal excitability following cTBS. Three minutes of resting electroencephalographic activity was recorded, and functional connectivity was estimated using the debiased weighted phase lag index across different frequency bands. Partial least squares regression identified models of connectivity between a seed region (C3) and the whole scalp that maximally accounted for variance in cTBS responses. There was no group-level effect of a single cTBS train or spaced cTBS trains on corticospinal excitability (p = 0.092). A low beta frequency band model of connectivity accounted for the largest proportion of variance in spaced cTBS response (R = 0.50). Based on the low beta frequency model, a-priori regions of interest were identified and predicted 39% of variance in response to spaced cTBS at a subsequent session. Importantly, weaker connectivity between the seed electrode (C3) and a cluster approximating a frontocentral region was associated with greater spaced cTBS response (p = 0.02). It appears M1-frontocentral networks may have an important role in determining the effects of cTBS on corticospinal excitability.
一种模式化的重复性经颅磁刺激方案，即连续 theta 爆发刺激（cTBS），可以通过类似于长时程抑郁突触可塑性的机制来抑制皮质脊髓兴奋性。尽管有很大的潜力，但这种技术目前受到很大的反应可变性的限制。本研究的目的是探讨静息状态功能连接是否是对 cTBS 反应的决定因素。18 名健康年轻成年人参与了多达三个实验疗程。单脉冲经颅磁刺激用于量化 cTBS 后皮质脊髓兴奋性的变化。记录了 3 分钟的静息脑电图活动，并使用无偏加权相位滞后指数在不同频带之间估计功能连接。偏最小二乘回归确定了种子区域（C3）和整个头皮之间的连接模型，这些模型最大限度地解释了 cTBS 反应的变异性。单次 cTBS 训练或间隔 cTBS 训练对皮质脊髓兴奋性没有组水平的影响（p=0.092）。连接的低β频带模型解释了间隔 cTBS 反应变异性的最大比例（R=0.50）。基于低β频带模型，确定了先验的感兴趣区域，并预测了在随后的会议上间隔 cTBS 反应的 39%的变异性。重要的是，种子电极（C3）和一个近似额顶区域的集群之间的连接较弱与较大的间隔 cTBS 反应相关（p=0.02）。似乎 M1-额顶网络在确定 cTBS 对皮质脊髓兴奋性的影响方面可能起着重要作用。
