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.

Developmental aspects of sleep slow waves: Linking sleep, brain maturation and behavior

Abstract: Sleep slow waves are the major electrophysiological features of non-rapid eye movement (NREM) sleep. Although there is growing understanding of where slow waves originate and how they are generated during sleep, the function of slow waves is still largely unclear. A recently proposed hypothesis relates slow waves to the homeostatic regulation of synaptic plasticity. While several studies confirm a correlation between experimentally triggered synaptic changes and slow-wave activity (SWA), little is known about its association to synaptic changes occurring during cortical maturation. Interestingly, slow waves undergo remarkable changes during development that parallel the time course of cortical maturation. In a recent cross-sectional study including children and adolescents, the topographical distribution of SWA was analyzed with high-density electroencephalography. The results showed age-dependent differences in SWA topography: SWA was highest over posterior regions during early childhood and then shifted over central derivations to the frontal cortex in late adolescence. This trajectory of SWA topography matches the course of cortical gray maturation. In this chapter, the major changes in slow waves during development are highlighted and linked to cortical maturation and behavior. Interestingly, synaptic density and slow-wave amplitude increase during childhood are highest shortly before puberty, decline thereafter during adolescence, reaching overall stable levels during adulthood. The question arises whether SWA is merely reflecting cortical changes or if it plays an active role in brain maturation. We thereby propose a model, by which sleep slow waves may contribute to cortical maturation. We hypothesize that while there is a balance between synaptic strengthening and synaptic downscaling in adults, the balance of strengthening/formation and weakening/elimination is tilted during development.

NREM sleep instability is reduced in children with attention-deficit/hyperactivity disorder.

Abstract: Study objectives To evaluate non-rapid eye movement sleep instability (NREM), as measured by the cyclic alternating pattern (CAP), in a cohort of children with attention-deficit/hyperactivity disorder (ADHD) and normal controls. Design Prospective study. Settings Sleep laboratory. Participants Twenty consecutive outpatients with ADHD (18 boys and 2 girls; age range 6-13 years, mean age 9.3 years) and 20 normal children matched for age and socioeconomic status underwent polysomnographic recordings for 2 consecutive nights in a standard laboratory setting. Sleep was visually scored for sleep macrostructure and CAP, according to standard criteria. Measurements and results Children with ADHD showed significantly reduced sleep duration and increased rate of stage shifts. All children with ADHD had an apnea-hypopnea index less than 1. Those with ADHD presented lower total CAP rates and lower CAP rates during sleep stage 2 than did normal controls. Moreover, in children with ADHD, we found a lower number of CAP sequences and a reduced total A1 index, mainly in light sleep (sleep stages 1 and 2). We did not find differences in A subtype percentages, but there was a longer duration of A1 subtypes in children with ADHD. Conclusions Children with ADHD showed a lower CAP rate and a lower number of CAP sequences; this supports the hypothesis of the existence of a hypoarousal state in these patients.

Persistent effects of (+/- )3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") on human sleep.

Abstract: (+/- )3,4-methylenedioxymethamphetamine (MDMA) is a recreational drug of abuse which damages serotonin neurons in animals. It is not known whether MDMA is also neurotoxic in humans, and if so, whether there are functional consequences. Given the putative role of serotonin in sleep, it was hypothesized that one manifestation of serotonin neurotoxicity in humans might be disturbances of sleep. To determine whether MDMA use has effects on sleep, all-night polysomnograms of 23 MDMA users were compared to those of 22 age- and sex-matched controls. On average, MDMA users had 19 minutes less total sleep and 23.2 minutes less non-REM (NREM) sleep than controls. These statistically significant differences in NREM sleep were due primarily to an average of 37 minutes less stage 2 sleep, with no significant differences noted in stages 1, 3 or 4. Although it is not known whether the alterations in sleep observed in MDMA users are due to serotonin neurotoxicity, the present findings suggest that MDMA use can lead to persistent changes in CNS structures involved in human sleep generation.