Duration of paradoxical sleep episodes. A quantitative and pattern analysis of reticular multi-unit activity in the cat

Abstract

This study was aimed at the possible relationship between the level of brain activation in PS and the duration of episodes. Multi-unit activities from 16 recording sites in the mesencephalic and pontine structures were quantitatively evaluated in five cats and the influence of electrode localization and episode duration on the average patterns of integrated discharges was statistically investigated. The analyses emphasized the slow time course of the early increments in reticular activity and its culmination at a plateau level in the later part of PS phases. Differences in mean amplitude of this plateau were related to the anatomical localization of electrodes but no distinction could be made between reticular areas with respect to the temporal features of activation patterns. Synchronization of phasic bursts was consistently observed between simultaneously recorded structures and this, along with the time course of early increments in SW was consistent with the notion that mesencephalic reticular activity is controlled by leading influences from the pons. No basic differences in the temporal development of reticular activation in PS were found in relation to the duration of episodes.