脑皮层运动诱发电位实验研究

Experimental study on cortical motor evoked potentials

目的探讨对脑中央区皮层进行皮层电位诱发的最佳刺激参量。方法使用皮层电极在10只新西兰雄兔中央后回感觉皮层对应部位记录N20-P25波,沿中央后回运动区皮层向前移动电极直至记录到一个波型相反、波幅相近、位相倒置的波型(P20-N25波),定为运动中枢刺激点。使用不同刺激参量直接刺激该点,在上肢掌长肌记录运动诱发电位(MEP)。结果10只新西兰雄兔均记录到N20-P25波和P20-N25波,并成功诱发MEP。各组高频串刺激的刺激电流阈值均低于单波刺激,差异有统计学意义(P<0.05)。结论MEP是一种安全、有效的监测方法;高频串刺激在脑中央区皮层MEP监护中优于单波刺激;当串刺激参量限于一定范围(时程0.2～0.3 ms,频率300～500 Hz,方波个数3～5个)时,均能安全、有效地诱导出皮层MEP。

Objective To investigate the optimal parameter of stimuli current in inducing motor evoked potentials（MEPs） in the cortex of the central area of brain. Methods Ten New Zealand male rabbits were recorded the largest N20-P25 response with direct stimulation of the electrodes put at the postcentral gyrus. The electrodes were moved forward towards the precentral gyrus to a point where a reverse somatosensory evoked potential （SEP） （P20-N25） was received. This point was stimulated with different parameters of stimuli current and MEP was recorded through palmaris longus. Results N20-P25 response,reverse SEP（P20-N25） and MEP were recorded in all the New Zealand male rabbits. The threshold of train stimulation current was significantly lower than that of single pulse stimulation current（ P 〈 0.05）. Conclusion MEP is an effective and safe method for cortical monitoring. Train stimulation plays a better role in monitoring cortical MEP in the central area of the brain. When duration is confined to 0.2 to 0.3 ms, frequency 300 to 500 Hz, and wave counts 3 to 5, cortical MEP can be safely and effectively induced through train stimulation.