The effect of somatosensory evoked potentials on the onset of voluntary movement

本研究的目的是探讨自主运动时体感诱发电位（SEPs）的序列变化，并与自主运动和cnv模式进行比较。通过右拇指运动前和运动时记录sep、运动相关皮质电位和CNVs。在刺激右腕正中神经的条件下，根据计算机设定的7 epoch （500 msec）的运动起始时间关系，研究脑N20和N18的运动起始时间。记录了16名（实验(1)）和18名（实验(2)）受试者的脑电图，并在肌电开始前2.0秒至肌电偏移后0.5秒连续7次平均脑电图。N20的衰减，即门控，在运动前后都能明显观察到，在运动过程中衰减最大，而N18的衰减不明显（实验(1)）。刺激中枢神经引起的N20变化与N18不同。然而，在刺激皮肤的条件下，这两种成分之间的差异并没有显示出来（实验(2)）。根据这些发现，门控被认为反映了传入信息处理的变化，而不是在中央水平，而是在外围部位。

The purpose of the study was to investigate the sequential changes of somatosensory evoked potentials (SEPs) accompanying voluntary movement, in comparison of self-voluntary movement and CNV-paradigm. The SEPs, Movement related cortical potentials and CNVs were recorded through the epoch preceding and accompanying movement of right thumb. Cerebral N20 and N18 were investigated according to the temporal relationship between the onset of movement and 7 epoch (500 msec) set by computer under the condition of stimulating the median nerve of right wrist. SEPs were recorded in 16 (experimental (1)) and 18 (experimental (2)) subjects and averaged in 7 successive epochs extending from 2.0 sec before onset of EMG to 0.5 sec after offset of EMG. The attenuation of both N20, i.e, gating, were clearly observed in epoch pre- and post-movement and was greatest in the epoch during movement, but that of N18 was not clear (experimental (1)). The change of N20 elicited by stimulating central nerve was different from that of N18. However, the difference between both components was not shown under the condition of stimulairig cutanuous (experimental (2)). From these findings, the gating is considered to be reflected the changes of afferent information processing at not central level but peripheral sites.