Department of Rehabilitation, Wuxi Central Rehabilitation Hospital, The Affiliated Mental Health Center of Jiangnan University, 214151 Wuxi, Jiangsu, China.
4 + 4 Medical Doctor Program, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730 Beijing, China.
J Integr Neurosci. 2024 Aug 22;23(8):160. doi: 10.31083/j.jin2308160.
Previous studies have found that inhibitory priming with continuous theta burst stimulation (cTBS) can enhance the effect of subsequent excitatory conditioning stimuli with intermittent theta burst stimulation (iTBS) in the upper limbs. However, whether this combined stimulation approach elicits a comparable compensatory response in the lower extremities remains unclear. This study aimed to investigate how cTBS preconditioning modulated the effect of iTBS on motor cortex excitability related to the lower limb in healthy individuals.
Using a randomised cross-over design, a total of 25 healthy participants (19 females, mean age = 24.80 yr) were recruited to undergo three different TBS protocols (cTBS + iTBS, sham cTBS + iTBS, sham cTBS + sham iTBS) in a random order. Each TBS intervention was administered with one-week intervals. cTBS and iTBS were administered at an intensity of 80% active motor threshold (AMT) delivering a total of 600 pulses. Before intervention (T0), immediately following intervention (T1), and 20 min after intervention (T2), the corticomotor excitability was measured for the tibialis anterior muscle of participants' non-dominant leg using a Magneuro100 stimulator and matched double-cone coil. The average amplitude of the motor-evoked potential (MEP) induced by applying 20 consecutive monopulse stimuli at an intensity of 130% resting motor threshold (RMT) was collected and analysed.
Compare with T0 time, the MEP amplitude (raw and normalised) at T1 and T2 showed a statistically significant increase following the cTBS + iTBS protocol ( < 0.01), but no significant differences were observed in amplitude changes following other protocols (sham cTBS + iTBS and sham cTBS + sham iTBS) ( > 0.05). Furthermore, no statistically significant difference was found among the three protocols at any given time point ( > 0.05).
Preconditioning the lower extremity motor cortex with cTBS prior to iTBS intervention can promptly enhance its excitability in healthy participants. This effect persists for a minimum duration of 20 min.
No: ChiCTR2300069315. Registered 13 March, 2023, https://www.chictr.org.cn.
先前的研究发现，连续 theta 爆发刺激（cTBS）的抑制性启动可以增强间歇性 theta 爆发刺激（iTBS）在上肢中的后续兴奋性调节刺激的效果。然而，这种联合刺激方法在下肢是否会引起类似的代偿反应尚不清楚。本研究旨在探讨 cTBS 预处理如何调节 iTBS 对健康个体下肢运动皮层兴奋性的影响。
采用随机交叉设计，共招募 25 名健康参与者（19 名女性，平均年龄=24.80 岁），按照随机顺序接受三种不同的 TBS 方案（cTBS+iTBS、假 cTBS+iTBS、假 cTBS+假 iTBS）。每种 TBS 干预间隔一周。cTBS 和 iTBS 以 80%主动运动阈值（AMT）的强度施加，共施加 600 个脉冲。在干预前（T0）、干预后即刻（T1）和干预后 20 分钟（T2），使用 Magneuro100 刺激器和匹配的双圆锥线圈测量参与者非优势腿胫骨前肌的皮质运动兴奋性。采集并分析以 130%静息运动阈值（RMT）强度施加 20 次连续单脉冲刺激时诱发的运动诱发电位（MEP）的平均振幅。
与 T0 时间相比，cTBS+iTBS 方案后 T1 和 T2 时 MEP 振幅（原始和归一化）呈统计学显著增加（<0.01），但其他方案（假 cTBS+iTBS 和假 cTBS+假 iTBS）的振幅变化无统计学显著差异（>0.05）。此外，在任何给定时间点，三个方案之间均无统计学显著差异（>0.05）。
在 iTBS 干预前对下肢运动皮层进行 cTBS 预处理可以迅速增强健康参与者的兴奋性。这种效应至少持续 20 分钟。
无：ChiCTR2300069315。注册于 2023 年 3 月 13 日，网址：www.chictr.org.cn。
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