Hashimoto Toshihiro, Inaba Daisuke, Matsumura Michikazu, Naito Eiichi
Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Neurosci Res. 2004 Dec;50(4):427-36. doi: 10.1016/j.neures.2004.08.002.
A single-pulse TMS to the human motor cortex (M1) influences reaction time (RT). We may summarize from previous studies where different groups of subjects participated in various types of RT tasks that TMS above motor threshold (MT) delays RT, whereas TMS below MT shortens RT and that these RT changes depends on TMS timings during RT period. However, these effects have never been systematically investigated in a single study where an identical group of subjects participated. The purpose of this study is to test previous TMS effects in a study of simple RT task. Seven subjects isometrically abducted their right index fingers as quickly as possible when a visual stimulus appeared. A single-pulse TMS was randomly delivered over the left M1 at various timings during RT period in a single trial (at 0, 40, 60, 80 or 100 ms after the visual stimulus). Motor-evoked potential (MEP) and EMG activity for response were recorded from the right finger muscles. Only the TMS above MT delivered at 80 or 100 ms, which increased MEP amplitude, significantly delayed RT and increased the size of response EMG activities that may reflect contents of central motor commands. The TMS below MT at these timings, which occasionally evoked MEP, exclusively shortened RT despite the fact that the response EMG size was unchanged. A single-pulse TMS has different effects on the ongoing neuronal processes in M1 during the pre-movement period: TMS above MT may temporally retard the processes and also affect contents of central motor commands, whereas TMS below MT may simply facilitate its processes without affecting motor commands.
对人类运动皮层（M1）进行单脉冲经颅磁刺激（TMS）会影响反应时间（RT）。我们可以从之前不同组别的受试者参与各种反应时间任务的研究中总结出，高于运动阈值（MT）的TMS会延迟反应时间，而低于MT的TMS会缩短反应时间，并且这些反应时间的变化取决于反应时间期间的TMS时机。然而，在同一组受试者参与的单一研究中，这些效应从未得到系统研究。本研究的目的是在简单反应时间任务的研究中测试先前的TMS效应。当视觉刺激出现时，7名受试者尽可能快地等长外展其右手食指。在单次试验的反应时间期间的不同时机（视觉刺激后0、40、60、80或100毫秒），对左侧M1随机施加单脉冲TMS。从右手手指肌肉记录运动诱发电位（MEP）和反应的肌电图活动。只有在80或100毫秒时施加的高于MT的TMS，其增加了MEP幅度，显著延迟了反应时间并增加了可能反映中枢运动指令内容的反应肌电图活动的大小。在这些时机低于MT的TMS，偶尔会诱发MEP，尽管反应肌电图大小不变，但却专门缩短了反应时间。单脉冲TMS在运动前期间对M1中正在进行的神经元过程有不同影响：高于MT的TMS可能会暂时延迟这些过程并影响中枢运动指令的内容，而低于MT的TMS可能只是促进其过程而不影响运动指令。
