Di Lazzaro V, Oliviero A, Profice P, Saturno E, Pilato F, Insola A, Mazzone P, Tonali P, Rothwell J C
Istituto di Neurologia, Università Cattolica, Rome, Italy.
Electroencephalogr Clin Neurophysiol. 1998 Oct;109(5):397-401. doi: 10.1016/s0924-980x(98)00038-1.
The present experiments were designed to compare the understanding of the transcranial electric and magnetic stimulation of the human motorcortex.
The spinal volleys evoked by single transcranial magnetic or electric stimulation over the cerebral motor cortex were recorded from a bipolar electrode inserted into the cervical epidural space of two conscious human subjects. These volleys were termed D- and I waves, according to their latency. Magnetic stimulation was performed with a figure-of-eight coil held over the right motor cortex at the optimum scalp position, in order to elicit motor responses in the contralateral FDI using two different orientations over the motor strip. The induced current flowed either in a postero-anterior or in a latero-medial direction.
At active motor threshold intensity, the electric anodal stimulation evoked pure D activity. At this intensity, magnetic stimulation with the induced current flowing in a posterior-anterior direction evoked pure I1 activity. When a latero-medial induced current was used, magnetic stimulation evoked both D and I1 activity. Using electric anodal stimulation, at a stimulus intensity of 9% of the stimulator output above the active motor threshold (corresponding approximately to 1.5 active motor threshold), a small I1 wave appeared only in subject 1. Using magnetic stimulation with a posterior-anterior induced current, at a stimulus intensity of 21% of maximum stimulator output above the active motor threshold (corresponding approximately to 1.8 times threshold in subject 1 and to two times threshold in subject 2), a small D wave appeared in subject 1 but not in subject 2.
Present results demonstrate that, in conscious humans at threshold intensities, electric stimulation evokes D waves and magnetic stimulation (with a posterior-anterior induced current) evokes I waves, while magnetic stimulation (with a latero-medial induced current) evokes both activities.
本实验旨在比较对人类运动皮层经颅电刺激和磁刺激的理解。
在两名清醒的人类受试者的颈段硬膜外间隙插入双极电极，记录在大脑运动皮层单次经颅磁刺激或电刺激诱发的脊髓冲动。根据其潜伏期，这些冲动被称为D波和I波。使用一个八字形线圈在右侧运动皮层上方的最佳头皮位置进行磁刺激，以便在运动区使用两种不同方向诱发对侧第一背侧骨间肌（FDI）的运动反应。感应电流要么沿后-前方向流动，要么沿外侧-内侧方向流动。
在主动运动阈值强度下，阳极性电刺激诱发纯D活动。在此强度下，感应电流沿后-前方向流动的磁刺激诱发纯I1活动。当使用外侧-内侧感应电流时，磁刺激诱发D和I1活动。使用阳极性电刺激，在刺激强度高于主动运动阈值9%的刺激器输出时（约相当于1.5倍主动运动阈值），仅在受试者1中出现一个小的I1波。使用感应电流沿后-前方向流动的磁刺激，在刺激强度高于主动运动阈值21%的最大刺激器输出时（在受试者1中约相当于阈值的1.8倍，在受试者2中约相当于阈值的2倍），在受试者1中出现一个小的D波，但在受试者2中未出现。
目前的结果表明，在阈值强度下的清醒人类中，电刺激诱发D波，磁刺激（感应电流沿后-前方向流动）诱发I波，而磁刺激（感应电流沿外侧-内侧方向流动）则诱发两种活动。
