睡眠及び麻酔脳波の音刺激に対する反応—覚醒過程の臨床脳波的研究

EFFECTS OF SOUND STIMULI ON HUMAN EEG DURING SLEEP AND ANESTHESIA

第I章　緒言

　自然睡眠に関する脳波的研究に於てLoomis等^{73）85）86）}によつてはじめて注目され，その後Davis等^19）20）によつてとりあげられたk-com-plexは，睡眠中に与えられた聴覚刺激に対する数100μVにも及ぶ脳波上の大きな反応であるが，此の現象は睡眠の，ある深度に於てのみ認められる汎性、非特異性の反応であつて，その生物学的重要性はDavisの示唆にもかかわらず余り追究されたとはいえない。即ちその後Dawsonの脳波重畳法^{22）23）56）}，Rosenblithの脳波平均装置^41）による観察によつて，覚醒時自発脳波の下にかくされているk-complex様の反応が認められはしたが，各種の生理的条件或は刺激の条件下に於ける此の種の反応の発生機構の研究は，本川教授の指摘^85）せられる如く尚残された問題である。

　元来，生物が外界の刺激を受け，それに対して適当な反応をするためには，能率のよい刺激受容器が必要である。そのために発達した感覚系の中で，他の体制知覚系に比し視覚・聴覚系はとりわけ高度の発達をとげたものであり，その知覚はspatial及びtemporal patternに至るまで分化し，受容分析系，積分系の発達と相俟つて，高等動物の神経系の高次活動に於て果す役割は大きい^84）111）。

The electroencephalographic responses to a given sound which had the intensities of ra-nges from 70 to 80 phone were observed duri-ng natural sleep and various anesthesia in normal adults and children. The courses and stages of them (5-6 mg/kg of pentobarbital and 4-5mg/kg of Eunal were administered intravensusly, 2cc/kg of 4% chloral hydrate-solution were perrectally and ether were by open drop method) were traced and classified according to the energy-rate of each frequ-ency-bands counted by automatically analy-zed data.

In the most deeply slept and anesthetized, there were no any responses. At the deep stages, k-complex were found when singly and repetitively. stimulated. During the mo-derate depth, there were found of responses having a short electrical silence between a provoked potential and after-discharge in the distinct sense. At the more lightend stage, tne responses loss their after-discharges to the single stimuli and show the diffuse syn-chronized responses which were formed as like as spike and wave complex to 2-4 per second and recruitment to repetitive stimuli of 5-8 per second.