Enhancement of potassium ion activity in cat hippocampus during REM sleep

Abstract

During slow-wave sleep, extracellular potassium ion activity in the dorsal hippocampus of the cat was comparable to that during quiet wakefulness. During rapid eye movement (REM) sleep, it showed a gradual increase by 0.2-0.3 mM in the CA1 pyramidal layer and its close vicinity. No phasic increase was observed when REM bursts occurred. The enhanced K+ activity during REM sleep is considered to reflect the overall activity of the neurons in the pyramidal layer.