Pascual-Leone A, Valls-Solé J, Wassermann E M, Brasil-Neto J, Cohen L G, Hallett M
Human Cortical Physiology Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892.
Brain. 1992 Aug;115 ( Pt 4):1045-59. doi: 10.1093/brain/115.4.1045.
In a simple reaction time (RT) paradigm, magnetic stimulation of different intensities was delivered over different scalp positions and at variable delays before (negative) or after (positive) the go-signal. Magnetic stimulation shortened RT to different go-signals (auditory, visual and somatosensory stimuli) by approximately 30 ms when delivered over the motor cortex contralateral to the responding arm at intensities below motor threshold. This effect was maximal at a delay of approximately +10 ms. A similar effect was found with suprathreshold stimulation to the ipsilateral motor cortex. Magnetic stimulation over other scalp areas did not affect RT regardless of the delay. No differences were found between the effects on elbow flexion and thumb abduction. The shortening of RT was not associated with changes in the timing development of premovement excitability increase in the motor cortex. We conclude that magnetic stimulation shortens RT by inducing an earlier initiation of this excitability increase.
在一个简单反应时（RT）范式中，在不同头皮位置以及在“开始”信号之前（负向）或之后（正向）的不同延迟时间施加不同强度的磁刺激。当以低于运动阈值的强度在与反应手臂对侧的运动皮层上施加磁刺激时，磁刺激可使对不同“开始”信号（听觉、视觉和体感刺激）的反应时缩短约30毫秒。这种效应在大约 +10毫秒的延迟时最大。对同侧运动皮层进行阈上刺激时也发现了类似的效应。无论延迟情况如何，在其他头皮区域进行磁刺激均不影响反应时。在对肘关节屈曲和拇指外展的影响方面未发现差异。反应时的缩短与运动皮层中运动前兴奋性增加的时间发展变化无关。我们得出结论，磁刺激通过诱导这种兴奋性增加的更早起始来缩短反应时。
