ELECTROMYOGRAM SUPPRESSION DURING SLEEP, DREAM RECALL, AND ORIENTATION TIME

Abstract

ABSTRACT Five subjects had their nocturnal sleep monitored (EEG, EOG, submental EMG) for a total of 42 nights. A total of 196 awakenings to retrieve sleep mentation was distributed among three awakening categories: Non‐Rapid Eye Movement (NREM) sleep before the EMG suppression heralding REM‐sleep onset; NREM sleep immediately following the EMG suppression heralding REM‐sleep onset; and early moments of REM sleep accompanied by EMG suppression. Suppressed‐EMG NREM awakenings tended to be associated with lower dream recall frequency and lower Dreamlike Fantasy Scale ratings than did high‐EMG NREM awakenings. Orientation times upon experimental awakenings were longer on suppressed‐EMG pre‐REM awakenings than on high‐EMG pre‐REM awakenings. A momentary “deepening” of sleep (in terms of less memorable and vivid mental content and of decreased reactivity to the awakening stimulus) thus appears to accompany the pre‐REM suppression of neck and chin EMG potentials.