Non-rapid eye movement sleep

About: Non-rapid eye movement sleep is a research topic. Over the lifetime, 8661 publications have been published within this topic receiving 389465 citations. The topic is also known as: NREM.

Morning work: effects of early rising on sleep and alertness.

Abstract: The aim of the present study is to investigate how early morning work affects sleep and alertness. Twenty-two females, employed as airline cabin crew members, participated in the study. The design included two sleep conditions (work day and free day) for an early group and for a control group. The results show that early morning work reduced sleep to 5 hours and 12 minutes and that the reduction of sleep consisted of less stage 2 and rapid eye movement (REM) sleep. However, when the analysis was restricted to the first 5 hours, no differences in sleep stages, arousals, or sleep continuity were obtained between groups or conditions. Analysis of electroencephalogram (EEG) power density for the 0.5-16.5 Hz bands across nonREM periods showed no differences. With respect to the subjective ratings, early morning work was associated with more apprehension of difficulties in awakening and insufficient sleep. Daytime alertness and ease of awakening did not differ between groups, but the early group had significantly more sleepiness and complained more of unrefreshing sleep in connection with the work day compared to the free day. Ratings of insufficient sleep and high daytime sleepiness were mainly predicted (multiple regression analyses) by short total sleep time (TST), whereas apprehension of an unpleasant awakening was predicted by an early wake-up time. It was concluded that early morning work causes a reduction of sleep time and an increase in apprehension stress.

V. Reports of Mental Activity during Sleep

Abstract: The variety of mental activity during sleep was investigated by obtaining reports of this activity upon awakening from two different kinds of sleep: (1) REM (rapid eye-movement) periods, which are characterized by a low voltage, random EEG and the presence of rapid eye-movements, and (2) NREM periods, which are characterized by 12–14 cps sleep spindles and/or slow, high amplitude delta EEG activity and the absence of rapid eye-movements. A total of 186 awakening reports were obtained from 17 subjects who spent from one to three nights each sleeping in the laboratory. As had been described in earlier investigations, reports of mental activity during sleep were obtained more frequently on awakenings from REM periods than on awakenings from NREM periods. However, a considerable amount of mental activity was obtained on NREM awakenings. As compared with REM period mentation, this NREM mental activity was described as more like thinking and less like dreaming, less vivid, less visual, more conceptual, under gr...

Daytime Sleep Enhances Consolidation of the Spatial but Not Motoric Representation of Motor Sequence Memory

Abstract: Motor sequence learning is known to rely on more than a single process. As the skill develops with practice, two different representations of the sequence are formed: a goal representation built under spatial allocentric coordinates and a movement representation mediated through egocentric motor coordinates. This study aimed to explore the influence of daytime sleep (nap) on consolidation of these two representations. Through the manipulation of an explicit finger sequence learning task and a transfer protocol, we show that both allocentric (spatial) and egocentric (motor) representations of the sequence can be isolated after initial training. Our results also demonstrate that nap favors the emergence of offline gains in performance for the allocentric, but not the egocentric representation, even after accounting for fatigue effects. Furthermore, sleep-dependent gains in performance observed for the allocentric representation are correlated with spindle density during non-rapid eye movement (NREM) sleep of the post-training nap. In contrast, performance on the egocentric representation is only maintained, but not improved, regardless of the sleep/wake condition. These results suggest that motor sequence memory acquisition and consolidation involve distinct mechanisms that rely on sleep (and specifically, spindle) or simple passage of time, depending respectively on whether the sequence is performed under allocentric or egocentric coordinates.