Effect of voluntary attention on auditory processing during REM sleep

Abstract

Study Objectives: The study investigates whether there is an effect of voluntary attention to external auditory stimuli during rapid eye movement (REM) sleep in humans by measuring event-related potentials (ERPs). Design: Using a 2-tone auditory-discrimination task, a standard 1000-Hz tone and a deviant 2000-Hz tone were presented to participants when awake and during sleep. In the ATTENTIVE condition, participants were requested to detect the deviant stimuli during their sleep whenever possible. In the PASSIVE sleep condition, participants were only exposed to the tones. ERPs were measured during REM sleep and compared between the 2 conditions. Setting: All experiments were conducted at the sleep laboratory of Hiroshima University. Participants: Twenty healthy university student volunteers. Interventions: N/A. Measurements and Results: In the tonic period of REM sleep (the period without REM), P200 and P400 were elicited by deviant stimuli, with scalp distributions maximal at central and occipital sites, respectively. The P400 in REM sleep showed larger amplitudes in the ATTENTIVE condition, whereas the P200 amplitude did not differ between the 2 conditions. No effects on ERPs due to attention were observed during stage 2 sleep. Conclusions: The instruction to pay attention to external stimuli during REM sleep influenced the late positive potentials. Thus electrophysiologic evidence of voluntary attention during REM sleep has been demonstrated.