モニタリングの理解に必要な電気生理学

Electrophysiological Theory for Understanding Electrical Evoked Potential Monitoring

Point

・電極に流した電気は直接生体内には流れない．電極にたまる電気に対応した充電電流が生体内に流れる．

・Naチャネルを超えたNa^＋イオンは神経線維の中を次のチャネルまで移動しない．

・皮膚に置いた電極から記録される電気は，細胞外に出た電気反応の総計である．

　Intraoperative neurophysiological monitoring（IOM）is a fundamental resource for complex neurosurgical procedures to prevent unpredictable neurological deficits and identify the exact location of a neurological function. IOMs have been classified based on evoked potential measurement by electrical stimulation. To understand the mechanism of an evoked potential, we must learn how the electric current is spread in humans. In this chapter, （1）electrical stimulation via stimulation electrode, （2）nerve depolarization by electric current stimulation, and（3）electric voltage gathered by a recording electrode have been described. Some of the contents in this chapter are presented in a perspective which might differ from that of a standard electrophysiological textbook. I hope the readers find their own interpretations on how electric current is spread in humans.