Slow-wave sleep

About: Slow-wave sleep is a research topic. Over the lifetime, 6543 publications have been published within this topic receiving 320663 citations. The topic is also known as: deep sleep.

The case against memory consolidation in REM sleep.

Abstract: We present evidence disputing the hypothesis that memories are processed or consolidated in REM sleep. A review of REM deprivation (REMD) studies in animals shows these reports to be about equally divided in showing that REMD does, or does not, disrupt learning/memory. The studies supporting a relationship between REM sleep and memory have been strongly criticized for the confounding effects of very stressful REM deprivation techniques. The three major classes of antidepressant drugs, monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), and selective serotonin reuptake inhibitors (SSRIs), profoundly suppress REM sleep. The MAOIs virtually abolish REM sleep, and the TCAs and SSRIs have been shown to produce immediate (40-85%) and sustained (30-50%) reductions in REM sleep. Despite marked suppression of REM sleep, these classes of antidepressants on the whole do not disrupt learning/memory. There have been a few reports of patients who have survived bilateral lesions of the pons with few lingering complications. Although these lesions essentially abolished REM sleep, the patients reportedly led normal lives. Recent functional imaging studies in humans have revealed patterns of brain activity in REM sleep that are consistent with dream processes but not with memory consolidation. We propose that the primary function of REM sleep is to provide periodic endogenous stimulation to the brain which serves to maintain requisite levels of central nervous system (CNS) activity throughout sleep. REM is the mechanism used by the brain to promote recovery from sleep. We believe that the cumulative evidence indicates that REM sleep serves no role in the processing or consolidation of memory.

The Sleep of Patients With Obsessive-Compulsive Disorder

Abstract: • Fourteen patients with obsessive-compulsive disorder (OCD) were studied with all-night sleep EEG recordings. Nine of these patients reported abnormal sleep patterns before the polygraphic study. Analysis of the sleep records disclosed significantly decreased total sleep time with more awakenings, less stage 4 sleep, decreased rapid-eye-movement (REM) efficiency, and shortened REM latency compared with those of a group of age-and sex-matched normal subjects. These abnormalities generally resembled those of an age-matched group of depressed patients, although significant differences remained. These findings suggest that such sleep abnormalities as shortened REM latency may not be entirely specific for primary affective illness. They also point to a possible biological link between OCD and affective illness.

Properties of Slow Oscillation during Slow-Wave Sleep and Anesthesia in Cats

Abstract: Deep anesthesia is commonly used as a model of slow-wave sleep (SWS). Ketamine-xylazine anesthesia reproduces the main features of sleep slow oscillation: slow, large-amplitude waves in field potential, which are generated by the alternation of hyperpolarized and depolarized states of cortical neurons. However, direct quantitative comparison of field potential and membrane potential fluctuations during natural sleep and anesthesia is lacking, so it remains unclear how well the properties of sleep slow oscillation are reproduced by the ketamine-xylazine anesthesia model. Here, we used field potential and intracellular recordings in different cortical areas in the cat to directly compare properties of slow oscillation during natural sleep and ketamine-xylazine anesthesia. During SWS cortical activity showed higher power in the slow/delta (0.1-4 Hz) and spindle (8-14 Hz) frequency range, whereas under anesthesia the power in the gamma band (30-100 Hz) was higher. During anesthesia, slow waves were more rhythmic and more synchronous across the cortex. Intracellular recordings revealed that silent states were longer and the amplitude of membrane potential around transition between active and silent states was bigger under anesthesia. Slow waves were mostly uniform across cortical areas under anesthesia, but in SWS, they were most pronounced in associative and visual areas but smaller and less regular in somatosensory and motor cortices. We conclude that, although the main features of the slow oscillation in sleep and anesthesia appear similar, multiple cellular and network features are differently expressed during natural SWS compared with ketamine-xylazine anesthesia.

Spectral analysis of the sleep electroencephalogram during adolescence.

Abstract: OBJECTIVES To describe developmental changes of the human sleep electroencephalogram (EEG) during adolescence using EEG spectral analysis and specifically to compare the nocturnal dynamics of slow-wave activity (EEG spectral power 06-46 Hz, a marker for sleep homeostatic pressure) in prepubertal and mature adolescents DESIGN After 10 nights on a fixed 10-hour sleep schedule without daytime naps, participants were studied during a 10-hour baseline night SETTING Data were collected in a 4-bed sleep research laboratory PARTICIPANTS Eight prepubertal children (pubertal stage Tanner 1; mean age 113 years, SD +/- 12, 4 boys) and 8 mature adolescents (Tanner 5; mean age 141 years, +/- 13, 3 boys) INTERVENTIONS Not applicable MEASUREMENTS All-night polysomnography was performed Sleep stages were scored according to conventional criteria EEG power spectra (of derivation C3/A2) were calculated using a fast Fourier transform routine RESULTS A reduction of non-rapid eye movement (NREM) sleep stage 4 (by 401%) and greater amounts of stage 2 sleep (197%) were found in mature compared to prepubertal adolescents NREM sleep EEG power was lower in the frequency ranges < 7 Hz, 118 to 126 Hz, and 162 to 168 Hz in mature adolescents A reduction of rapid eye movement sleep spectral power was present in the frequency ranges < 86 Hz and 96 to 15 Hz for mature compared to prepubertal adolescents Slow-wave activity showed identical dynamics within individual NREM sleep episodes and across the night in both developmental groups CONCLUSIONS The homeostatic recuperative drive during sleep remains unchanged across puberty The decline of slow-wave sleep during adolescence may reflect developmental changes of the brain rather than changes of sleep regulatory processes