Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles
Rattachement africain : nl, ch, qa, si, de, hu. Niveau de preuve : code pays fourni par la source.
Le résumé fourni par la source
Abstract Nocturnal human sleep consists of 4 – 6 ninety-minute cycles defined as episodes of non-rapid eye movement (non-REM) sleep followed by an episode of REM sleep. While sleep cycles are considered fundamental components of sleep, their functional significance largely remains unclear. One of the reasons for a lack of research progress in this field is the absence of a data-driven definition of sleep cycles. Here, we proposed to base such a definition on fractal (aperiodic) neural activity, a well-established marker of arousal and sleep stages. We explored temporal dynamics of fractal activity during nocturnal sleep using electroencephalography. Based on the observed pattern of fractal fluctuations, we introduced a new concept of fractal activity-based cycles of sleep or “fractal cycles” for short, defined as a time interval during which fractal activity descends from its local maximum to its local minimum and then leads back to the next local maximum. Next, we assessed correlations between fractal and classical (i.e., non-REM – REM) sleep cycle durations. We also studied cycles with skipped REM sleep, i.e., the cycles where the REM phase is expected to appear except that it does not, being replaced by lightening of sleep. Regarding the sample, we examined fractal cycles in healthy adults (age range: 18 – 75 years, n = 205) as well as in children and adolescents (range: 8 – 17 years, n = 21), the group characterized by deeper sleep and a higher frequency of cycles with skipped REM sleep. Further, we studied fractal cycles in major depressive disorder (n = 111), the condition characterized by altered REM sleep (in addition to its clinical symptoms). We found that fractal and classical cycle durations (89 ± 34 min vs 90 ± 25 min) correlated positively (r = 0.5, p < 0.001). Cycle-to-cycle overnight dynamics showed an inverted U-shape of both fractal and classical cycle durations and a gradual decrease in absolute amplitudes of the fractal descents and ascents from early to late cycles. In adults, the fractal cycle duration and participant’s age correlated negatively (r = −0.2, p = 0.006). Children and adolescents had shorter fractal cycles compared to young adults (76 ± 34 vs 94 ± 32 min, p < 0.001). The fractal cycle algorithm detected cycles with skipped REM sleep in 91 – 98% of cases. Medicated patients with depression showed longer fractal cycles compared to their own unmedicated state (107 ± 51 min vs 92 ± 38 min, p < 0.001) and age-matched controls (104 ± 49 vs 88 ± 31 min, p < 0.001). In conclusion, fractal cycles are an objective, quantifiable, continuous and biologically plausible way to display sleep neural activity and its cycles. They are useful in healthy adult and pediatric populations as well as in patients with major depressive disorder. Fractal cycles should be extensively studied to advance theoretical research on sleep structure.
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Le contrôle bibliographique ouvert
DOI retrouvé dans Crossref DOI retrouvé ; titre concordant.
- Titre Crossref
- Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles
- Date Crossref
- 25/11/2024
- Éditeur
- eLife Sciences Publications, Ltd
- Type
- posted-content
Ce recoupement confirme des métadonnées liées au DOI. Il ne confirme ni la méthode ni les conclusions de l’étude, et il ne compte pas comme une seconde source scientifique indépendante.
Où se fait cette recherche
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Radboud University Nijmegen pays non établi dans la noticeUniversité ou école supérieure
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Radboud University Medical Center pays non établi dans la noticeOrganisme public
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University of Zurich pays non établi dans la noticeUniversité ou école supérieure
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University Children's Hospital Zurich Child Development Center and Children’s Research Center pays non établi dans la noticeÉtablissement de santé
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Child Development Center pays non établi dans la noticeInstitution
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University Psychiatric Hospital pays non établi dans la noticeÉtablissement de santé
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Max Planck Institute of Psychiatry pays non établi dans la noticeStructure de recherche
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Klinikum Ingolstadt pays non établi dans la noticeÉtablissement de santé
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Semmelweis University pays non établi dans la noticeUniversité ou école supérieure
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Radboud University Medical Centre pays non établi dans la noticeUniversité ou école supérieure
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Psychiatric University Hospital Zurich Department of Child and Adolescent Psychiatry and Psychotherapy pays non établi dans la noticeUniversité ou école supérieure
Radboud University Nijmegen, Radboud University Medical Center et University of Zurich, avec 8 autres affiliations.
Une affiliation ne permet pas de déduire la nationalité d’un auteur.