無麻酔・無拘束ネコの漸加反応

Recruiting Responses in Unanesthetized, Unrestrained Cats

I．はじめに

　1942年のMorison and Dempseyの報告以来，漸加反応（recruiting response）を駆動する視床核の種類および漸加反応の特徴などについては，多数の報告が発表されている。しかし，それらの研究の大部分は麻酔した動物か，またはクラーレで非動化された動物についてなされたものであり，無麻酔・無拘束の動物について，その動物の行動と漸加反応の形態との相関を検討した研究ははなはだ少ない^14）16）。

　われわれは，ここ数年来，慢性に電極を植えこんだ，無麻酔・無拘束のネコを使つて，漸加反応の形態と意識状態との相関を検索してきたが，今回は，主として，オシロスコープ連続撮影装置およびデジタル型電子計算機を用いて分析した結果について報告する。

We have analyzed the recruiting responses evoked by electrical stimulation of CL and CM in the thalamus by using a continuous recording camera and a medical data processing computer and have examined the differences between the recruiting responses observed during various stages of wakefulness and sleep in unanesthetized, unrestrained cats having electrodes implanted for recording the EEG, EMG and EOG.

The results obtained are as follows.

1. The recordings obtained by the continuous recording camera showed that the waxing and waning of recruiting responses were inconspicuous when the animal was attentive (to food or to loud noise) or moving, but appeared very clearly during the slow-wave sleep. However, during the paradoxical sleep stage with rapid eye movements, the recruiting res-ponses did not exhibit clear-cut waxing and waning.

2. The recordings obtained by the medical data processing computer revealed that negative-phase res-ponses with long latencies could be evoked continuously during the period from attentive wakefulness through paradoxical sleep. The numerical values of latency, duration and amplitude of these negative-phase res-ponses were largest during slow-wave sleep.

On the other hand, the short-latency responses of biphasic positive and negative deflections or of mono-phasic negative deflection preceding the above-ment-ioned long-latency, negative-phase responses, were observed during attentive wakefulness and during paradoxical sleep, but disappeared during slow-wave sleep. The mechanism of these short-latency responses still remains to be determined. (This work was col-laborated by Y. Shimazono, S. Chikazawa, M. Okabe, J. Ando, T. Takeshima and 0. Takeuchi and was supported in part by FFRP Grant 63-281).