Watanabe Takamitsu, Hanajima Ritsuko, Shirota Yuichiro, Ohminami Shinya, Tsutsumi Ryosuke, Terao Yasuo, Ugawa Yoshikazu, Hirose Satoshi, Miyashita Yasushi, Konishi Seiki, Kunimatsu Akira, Ohtomo Kuni
Department of Physiology, the University of Tokyo School of Medicine, Tokyo, Japan.
Hum Brain Mapp. 2014 May;35(5):1896-905. doi: 10.1002/hbm.22300. Epub 2013 Jul 29.
Several recent studies using functional magnetic resonance imaging (fMRI) have shown that repetitive transcranial magnetic stimulation (rTMS) affects not only brain activity in stimulated regions but also resting-state functional connectivity (RSFC) between the stimulated region and other remote regions. However, these studies have only demonstrated an effect of either excitatory or inhibitory rTMS on RSFC, and have not clearly shown the bidirectional effects of both types of rTMS. Here, we addressed this issue by performing excitatory and inhibitory quadripulse TMS (QPS), which is considered to exert relatively large and long-lasting effects on cortical excitability. We found that excitatory rTMS (QPS with interstimulus intervals of 5 ms) decreased interhemispheric RSFC between bilateral primary motor cortices, whereas inhibitory rTMS (QPS with interstimulus intervals of 50 ms) increased interhemispheric RSFC. The magnitude of these effects on RSFC was significantly correlated with that of rTMS-induced effects on motor evoked potential from the corresponding muscle. The bidirectional effects of QPS were also observed in the stimulation over prefrontal and parietal association areas. These findings provide evidence for the robust bidirectional effects of excitatory and inhibitory rTMSs on RSFC, and raise a possibility that QPS can be a powerful tool to modulate RSFC.
最近几项使用功能磁共振成像（fMRI）的研究表明，重复经颅磁刺激（rTMS）不仅会影响受刺激区域的大脑活动，还会影响受刺激区域与其他远处区域之间的静息态功能连接（RSFC）。然而，这些研究仅证明了兴奋性或抑制性rTMS对RSFC的影响，并未清楚显示两种类型rTMS的双向效应。在此，我们通过进行兴奋性和抑制性四脉冲TMS（QPS）来解决这一问题，QPS被认为对皮质兴奋性有相对较大且持久的影响。我们发现，兴奋性rTMS（刺激间隔为5毫秒的QPS）降低了双侧初级运动皮层之间的半球间RSFC，而抑制性rTMS（刺激间隔为50毫秒的QPS）增加了半球间RSFC。这些对RSFC的影响程度与rTMS对相应肌肉运动诱发电位的影响程度显著相关。在对前额叶和顶叶联合区的刺激中也观察到了QPS的双向效应。这些发现为兴奋性和抑制性rTMS对RSFC的强大双向效应提供了证据，并提出QPS可能是调节RSFC的有力工具。
