Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (480 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Napping; Nighttime Sleep.
Where it fits in the MeSH classification
- Broader topics
- Psychophysiology; Nervous System Physiological Phenomena
- Narrower topics
- Dreams; Sleep Deprivation; Sleep Duration; Sleep Hygiene; Sleep Latency; Sleep Stages
- See also
- Polysomnography
Research landscape
PubMed indexes 115,945 records tagged with the MeSH heading “Sleep” (counts retrieved 2026-10-29). 35,896 of them (31.0%) were published from 2020 onward, and the busiest period so far is 2020 onward with 35,896 records.
Reviews account for 13,356 records (11.5%) and meta-analyses for 1,557. Randomized controlled trials number 6,767 (5.8%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 35,048 |
| 2000-2009 | 15,792 |
| 2010-2019 | 29,209 |
| 2020 onward | 35,896 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 13,356 | 11.5% |
| Meta-analyses | 1,557 | 1.3% |
| Randomized controlled trials | 6,767 | 5.8% |
Method: PubMed query "Sleep"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in neuroscience
Neuroscience draws on tools with different strengths: cellular and animal work can manipulate circuits directly, while human imaging and electrophysiology observe the living brain at lower resolution. Small imaging studies are prone to false positives, and findings in animals do not always carry over to people. Clinical neurology and psychiatry rely on trials and cohort studies whose outcomes are often symptom scales. Check the species, the sample size, how the outcome was measured and whether results were replicated.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Neocortical long-range inhibition promotes cortical synchrony and sleep | 2026 | Research article Design not recorded in structured metadata | 4 | cc by PMID 42717094 · DOI · PMC13645642 |
| A foundation model for sleep-based risk stratification and clinical outcomes | 2026 | Research article Design not recorded in structured metadata | 3 | cc by PMID 42547512 · DOI · PMC13434717 |
| Replay of procedural memory is independent of the hippocampus | 2026 | Research article Design not recorded in structured metadata | 2 | cc by PMID 42493550 · DOI · PMC13533836 |
Neocortical long-range inhibition promotes cortical synchrony and sleep [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Sleep and wakefulness are associated with distinct cortical patterns of rhythmic activity1.
- Closing excerpt
- Together, these findings show that long-range Sst-Chodl inhibitory neurons not only track behavioural state, but can also actively promote synchronized cortical activity and sleep behaviour, highlighting that cortical circuits have a key role in sleep regulation, alongside established subcortical mechanisms.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (186 words)
Sleep and wakefulness are associated with distinct cortical patterns of rhythmic activity1. During low-arousal states such as slow-wave sleep, synchronous low-frequency rhythms dominate activity across widespread cortical regions. Although inhibitory neurons are increasingly recognized as key regulators of cortical state2-4, the circuit mechanisms that coordinate synchronized activity across local and distant neocortical networks in vivo remain poorly understood. Here we show in mice that cells co-expressing somatostatin (Sst) and chondrolectin (Chodl)-which constitute a sparse and genetically distinct class of neocortical GABAergic inhibitory neurons-are selectively active during low-arousal states and mostly silent during periods of high arousal. In contrast to most neocortical inhibitory neurons, Sst-Chodl cells, despite being extremely sparse, exert widespread influence across the neocortex, through long-range axons that target multiple regions simultaneously. Selective activation of Sst-Chodl cells is sufficient to promote the multi-region cortical synchronization that is characteristic of low-arousal states and to induce sleep. Together, these findings show that long-range Sst-Chodl inhibitory neurons not only track behavioural state, but can also actively promote synchronized cortical activity and sleep behaviour, highlighting that cortical circuits have a key role in sleep regulation, alongside established subcortical mechanisms.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42717094 · DOI · PMC13645642
A foundation model for sleep-based risk stratification and clinical outcomes [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Clinical sleep studies capture multiple physiologic signals, yet interpretation is often reduced to single summary measures of limited prognostic value, such as the apnea-hypopnea index.
- Closing excerpt
- We demonstrate that foundation models recover clinically meaningful risk information embedded in routine sleep recordings that conventional metrics systematically miss, providing a scalable path to precision sleep medicine.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (146 words)
Clinical sleep studies capture multiple physiologic signals, yet interpretation is often reduced to single summary measures of limited prognostic value, such as the apnea-hypopnea index. We present a foundation model that learns rich representations of sleep physiology from more than 10,000 clinical sleep recordings linked to electronic medical records. Here we show that sleep physiology contains latent risk structure invisible to conventional metrics, identifying five patient risk groups with markedly different trajectories for mortality, cardiovascular, and neurological disease. The highest-risk group shows more than double the mortality risk of the lowest, whereas apnea-hypopnea index severity categories show limited predictive value. The framework generalizes to the independent Sleep Heart Health Study, distinguishing high- and low-risk patients despite lower-resolution data. We demonstrate that foundation models recover clinically meaningful risk information embedded in routine sleep recordings that conventional metrics systematically miss, providing a scalable path to precision sleep medicine.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42547512 · DOI · PMC13434717
Replay of procedural memory is independent of the hippocampus [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Sleep is crucial for consolidating all forms of memory and a core mechanism underlying this process is offline replay.
- Closing excerpt
- These findings demonstrate that procedural replay occurs independently of the hippocampus, indicating that replay-driven memory consolidation can operate through parallel, independent mechanisms.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (148 words)
Sleep is crucial for consolidating all forms of memory and a core mechanism underlying this process is offline replay. Current models propose that replay originates in the hippocampus and triggers reactivation across cortical and subcortical networks. However, conflicting evidence about the role of the hippocampus in offline consolidation of nondeclarative memories raises the question of whether hippocampal replay drives their consolidation. Here we show that replay occurs in the dorsal striatum during offline consolidation of a procedural memory in mice, independently of the hippocampus, and that its content predicts subsequent performance improvements. Neural sequences linked to salient behavioral events were prioritized for replay, with positive and negative behavioral outcomes having opposing effects on individual replay events. All features of replay persisted despite complete bilateral hippocampal lesions. These findings demonstrate that procedural replay occurs independently of the hippocampus, indicating that replay-driven memory consolidation can operate through parallel, independent mechanisms.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42493550 · DOI · PMC13533836
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Sleep characteristics across the lifespan in 1.1 million people from the Netherlands, United Kingdom and United States: a systematic review and meta-analysis [4]
- Research article Prevalence of meeting 24-Hour Movement Guidelines from pre-school to adolescence: A systematic review and meta-analysis including 387,437 participants and 23 countries [5]
- Research article The effect of sleep deprivation and restriction on mood, emotion, and emotion regulation: three meta-analyses in one [6]
- Research article Sleep loss and emotion: A systematic review and meta-analysis of over 50 years of experimental research [7]
- Research article The effect of caffeine on subsequent sleep: A systematic review and meta-analysis [8]
- Research article Interrater reliability of sleep stage scoring: a meta-analysis [9]
References
- Ratliff JM, Terral G, Vazquez A, Lutzu S, Manning A, Perez-Catalan N, et al.. Neocortical long-range inhibition promotes cortical synchrony and sleep. . 2026. PMID 42717094 · DOI · PMC13645642
- Bilal E, Araujo MLD, Beck KL, Heinzinger CM, Ghosn S, Saab CY, et al.. A foundation model for sleep-based risk stratification and clinical outcomes. . 2026. PMID 42547512 · DOI · PMC13434717
- Thompson EJ, Rollik LB, Waked B, Mills G, Pati S, Kaur J, et al.. Replay of procedural memory is independent of the hippocampus. . 2026. PMID 42493550 · DOI · PMC13533836
- Kocevska D, Lysen TS, Dotinga A, Koopman-Verhoeff ME, Luijk MPCM, Antypa N, et al.. Sleep characteristics across the lifespan in 1.1 million people from the Netherlands, United Kingdom and United States: a systematic review and meta-analysis. Nat Hum Behav. 2021. PMID 33199855 · DOI
- Tapia-Serrano MA, Sevil-Serrano J, Sánchez-Miguel PA, López-Gil JF, Tremblay MS, García-Hermoso A. Prevalence of meeting 24-Hour Movement Guidelines from pre-school to adolescence: A systematic review and meta-analysis including 387,437 participants and 23 countries. J Sport Health Sci. 2022. PMID 35066216 · DOI · PMC9338333
- Tomaso CC, Johnson AB, Nelson TD. The effect of sleep deprivation and restriction on mood, emotion, and emotion regulation: three meta-analyses in one. Sleep. 2021. PMID 33367799 · DOI · PMC8193556
- Palmer CA, Bower JL, Cho KW, Clementi MA, Lau S, Oosterhoff B, et al.. Sleep loss and emotion: A systematic review and meta-analysis of over 50 years of experimental research. Psychol Bull. 2024. PMID 38127505 · DOI
- Gardiner C, Weakley J, Burke LM, Roach GD, Sargent C, Maniar N, et al.. The effect of caffeine on subsequent sleep: A systematic review and meta-analysis. Sleep Med Rev. 2023. PMID 36870101 · DOI
- Lee YJ, Lee JY, Cho JH, Choi JH. Interrater reliability of sleep stage scoring: a meta-analysis. J Clin Sleep Med. 2022. PMID 34310277 · DOI · PMC8807917
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.