ELECTRIC AND MAGNETIC STIMULATION OF HUMAN MOTOR CORTEX - SURFACE EMG AND SINGLE MOTOR UNIT RESPONSES
ELECTRIC AND MAGNETIC STIMULATION OF HUMAN MOTOR CORTEX - SURFACE EMG AND SINGLE MOTOR UNIT RESPONSES
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DOI：
10.1113/jphysiol.1989.sp017626
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发表时间：
1989-05-01
影响因子：
5.5
通讯作者：
THOMPSON, PD
中科院分区：
文献类型：
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作者：
DAY, BL;DRESSLER, D;THOMPSON, PD
1.采用刺激后时间直方图（PSTH）技术和复合表面肌电（EMG）记录方法，研究了不同形式的脑刺激对第一骨间背侧肌（FDI）单个运动单位放电模式的影响。采用电、磁刺激方法，通过7名正常受试者的完整头皮刺激大脑。施加电刺激，其中阳极在外侧中央头皮上并且阴极在顶点处（阳极刺激）或阳极在顶点处并且阴极在外侧（阴极刺激）。磁刺激使用了一个9厘米直径的线圈在顶点为中心;电流在线圈顺时针或逆时针流动时，从上面看。2.超运动阈值刺激产生了一个或多个狭窄的（< 2 ms）峰的增加，在PSTH的所有32个单位的研究。阳极刺激总是产生一个早期峰值。由其他形式的刺激或由高强度的阳极刺激产生的峰的延迟被分成相对于该早期峰的四个时间段，在-0.5到0.5、1-2、2.5-3.5和4- 5.5ms之后的间隔。出现在这些间隔内的峰分别被称为P0（最早的阳极）、P1、P2和P3。3.在阈值，阳极刺激诱发的PO峰，在更高的强度，P2或更常见的P3也复发。P0峰的大小似乎在高强度下饱和。4.在5的6名受试者中，阴极刺激表现得像阳极刺激，除了有一个较低的阈值招聘的P2或P3峰相对于P0峰。在另一例受试者中，P3峰在P0峰之前招募。5.在阈下，连续磁刺激常产生多个峰。这些总是包括P1峰，通常是P3峰。P0峰在PSTH从来没有产生顺时针刺激的强度，我们可以探索与技术。6.抗磁刺激从未募集P1峰;在大多数受试者中，首先募集P3峰，并且在较高强度下伴随有P0或P2峰。7.在大多数情况下，当在PSTH中观察到一个以上的峰值时，装置在每次电击后仅在一个首选间隔中击发。然而，当使用高强度刺激时，在5个单位中观察到双放电。两次放电之间的间隔与PSTH中峰之间的间隔相同。8. FDI肌肉中的表面EMG反应表现为从已研究的单个运动单元的行为可预测的方式。9.这些结果进行了讨论的D和I波假说提出的锥体束神经元的反应，暴露的运动皮层在灵长类动物的表面阳极刺激。
1. The effects of different forms of brain stimulation on the discharge pattern of single motor units were examined using the post-stimulus time histogram (PSTH) technique and by recordiing the compound surface electromyographic (EMG) responses in the first dorsal interosseous (FDI) muscle. Electrical and magnetic methods were used to stimulate the brain through the intact scalp of seven normal subjects. Electrical stimuli were applied either with the anode over the lateral central scalp and the cathode at the vertex (anodal stimulation) or with the anode at the vertex and the cathode lateral (cathodal stimulation). Magnetic stimulation used a 9 cm diameter coil centered at the vertex; current in the coil flowed either clockwise or anticlockwise when viewed from above. 2. Supramotor threshold stimuli produced one or more narrow (< 2 ms) peaks of increased firing in the PSTH of all thirty-two units studied. Anodal stimulation always produced an early peak. The latencies of the peaks produced by other forms of stimulation, or by high intensities of anodal stimulation, were grouped into four time bands relative to this early peak, at intervals of -0.5 to 0.5, 1-2, 2.5-3.5 and 4-5.5 ms later. Peaks occurring within these intervals are referred to as P0 (the earliest anodal), P1, P2 and P3 respectively. 3. At threshold, anodal stimulation evoked only the PO peak; at higher intensities, the P2 or more commonly the P3 also was recurited. The size of the P0 peak appeared to saturate at high intensities. 4. In five of six subjects, cathodal stimulation behaved like anodal stimulation, except that there was a lower threshold for recruitment of the P2 or P3 peak relative to that of the P0 peak. In the other subject, the P3 peak was recruited before the P0 peak. 5. Clockwise magnetic stimulation, at threshold, often produced several peaks. These always included a P1 peak, and usually a P3 peak. A P0 peak in the PSTH was never produced by a clockwise stimulation at intensities which we could explore with the technique. 6 Anticlockwise magnetic stimulation never recruited a P1 peak; in most subjects a P3 peak was recruited first and at higher intensities was accompanied by P0 or P2 peaks. 7. On most occasions when more than one peak was observed in a PSTH, the unit fired in only one of the preferred intervals after each shock. However, double firing was seen in five units when high intensities of stimulation were used. The intervals between the two discharges was the same as the intervals between peaks in the PSTH. 8. Surface EMG responses in the FDI muscle behaved in a way predictable from the behaviour of the single motor units which had been studied. 9. These results are discussed in terms of the D and I wave hypothesis proposed for responses of pyramidal tract neurones to surface anodal stimulation of the exposed motor cortex in primates.