Stefan Katja, Gentner Reinhard, Zeller Daniel, Dang Suyin, Classen Joseph
Human Cortical Physiology and Motor Control Laboratory, Department of Neurology, University of Wuerzburg, Josef-Schneider Strasse 11, Wuerzburg, Germany.
Neuroimage. 2008 Mar 1;40(1):265-74. doi: 10.1016/j.neuroimage.2007.11.037. Epub 2007 Dec 4.
Theta-burst stimulation (TBS), a novel repetitive transcranial magnetic stimulation (TMS) protocol, is capable of suppressing the amplitude of contralateral motor-evoked potentials (MEP) for several minutes after the end of a conditioning train over the motor cortex. It remains unknown whether TBS leads to effects on motor cortical excitability when applied to contralateral brain sites distant but connected to motor cortex and whether TBS triggers measurable changes in force control. Subjects received bursts (50 Hz) of three subthreshold magnetic stimuli repeated at 5 Hz for 20 s (TBS-300) or 40 s (TBS-600) over the hand area of the left motor cortex (M1(LEFT)). With TBS-300, conditioning of right motor cortex (M1(RIGHT)), right dorsal premotor cortex (PMd(RIGHT)), and a mid-occipital (MO) region also were tested. Corticospinal excitability was probed by evoking MEPs in abductor pollicis brevis (APB) muscle by single suprathreshold stimuli over M1(LEFT) or M1(RIGHT) before and after TBS. Force level control was assessed in an isometric right thumb abduction task. With TBS-600, the time course of physiological and behavioral changes was monitored. TBS over either of the motor cortices reduced the amplitude of MEP in the contralateral APB and increased it in the ipsilateral APB. In contrast, conditioning TBS over PMd(RIGHT) or MO did not modify MEP size. Post-TBS right thumb force level control was impaired, with contralateral M1(LEFT) stimulation only, for a duration of at least 5 min. TBS may induce remote physiological effects and reveals local functional properties of the underlying brain region.
theta 爆发刺激（TBS）是一种新型的重复经颅磁刺激（TMS）方案，在运动皮层进行条件刺激序列结束后的数分钟内，它能够抑制对侧运动诱发电位（MEP）的波幅。当将 TBS 应用于与运动皮层距离较远但有连接的对侧脑区时，它是否会对运动皮层兴奋性产生影响，以及 TBS 是否会引发力量控制方面可测量的变化，目前尚不清楚。受试者在左侧运动皮层（M1（左））的手部区域接受以 5Hz 重复的 50Hz 三个阈下磁刺激脉冲串，持续 20 秒（TBS - 300）或 40 秒（TBS - 600）。对于 TBS - 300，还测试了右侧运动皮层（M1（右））、右侧背侧运动前区（PMd（右））和枕中（MO）区域的条件刺激。在 TBS 前后，通过在 M1（左）或 M1（右）上施加单个阈上刺激来诱发拇短展肌（APB）中的 MEP，从而探测皮质脊髓兴奋性。在等长右拇指外展任务中评估力量水平控制。对于 TBS - 600，监测生理和行为变化的时间进程。对任一运动皮层进行 TBS 均可降低对侧 APB 中 MEP 的波幅，并增加同侧 APB 中 MEP 的波幅。相比之下，对 PMd（右）或 MO 进行条件刺激 TBS 并未改变 MEP 的大小。仅在对侧 M1（左）刺激后，TBS 后右拇指力量水平控制受损，持续时间至少为 5 分钟。TBS 可能会诱发远程生理效应，并揭示潜在脑区的局部功能特性。
