Rapid eye movement density and pattern in the sleep of normal young adults.

Abstract

ABSTRACTThe dispersion and concentration of rapid eye movements (REMs) during nocturnal sleep was measured in 10 healthy adult subjects. A frequency distribution of the time intervals between REMs was multimodal, and provided an estimate for the minimal time separating the REMs into aggregates. A gap of 22 min between two successive REMs almost certainly delineated the groups of REMs on either side of the gap as REM Periods (REMPs). Although the minimal time necessary to define bursts of REMs within the REMP was not as clear, it appeared to be in the vicinity of 8 sec. Bursts in the late REMPs tended to be longer and have more REMs than did bursts in the early REMPs. Yet, there was no marked difference in the number of bursts per min of REMP in comparing the early and late REMPs.A consistent pattern of ocular activity was noted within the first 20 min of REMPs. REM activity peaked 5‐10 min after the onset of the REMP and then declined significantly 10 min later. The data also suggested the existence of a cyclic pattern, i.e. a 40 min REMP had two peaks of REM activity, and a 60 min REMP had three peaks. The relationship of visual imagery in dreaming to REM activity was discussed.