{"id":2049,"date":"2024-07-01T15:24:42","date_gmt":"2024-07-01T13:24:42","guid":{"rendered":"https:\/\/semmelweis.hu\/psychophysiology\/?p=2049"},"modified":"2024-07-01T15:24:42","modified_gmt":"2024-07-01T13:24:42","slug":"rosenblum-horvath-schneider-bodizs-dresler-fractal-cycles-of-sleep-a-new-aperiodic-activity-based-definition-of-sleep-cycles","status":"publish","type":"post","link":"https:\/\/semmelweis.hu\/psychophysiology\/2024\/07\/01\/rosenblum-horvath-schneider-bodizs-dresler-fractal-cycles-of-sleep-a-new-aperiodic-activity-based-definition-of-sleep-cycles\/","title":{"rendered":"Rosenblum-…-Horv\u00e1th-Schneider-B\u00f3dizs-Dresler: Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles"},"content":{"rendered":"

Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles
\neLife 13:RP96784, 2024
\nhttps:\/\/doi.org\/10.7554\/eLife.96784.1<\/a><\/p>\n

Yevgenia Rosenblum1, Mahdad Jafarzadeh Esfahani1, Nico Adelh\u00f6fer1, Paul Zerr1, Melanie Furrer2, Reto Huber2,3, Axel Steiger4, Marcel Zeising5, Csenge G. Horv\u00e1th6, Bence Schneider6, R\u00f3bert B\u00f3dizs6, Martin Dresler1<\/p>\n

    \n
  1. Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behavior, Nijmegen, Netherlands<\/li>\n
  2. Child Development Center and Children\u2019s Research Center, University Children\u2019s Hospital Z\u00fcrich, University of Z\u00fcrich, Z\u00fcrich, Switzerland<\/li>\n
  3. Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric University Hospital Zurich, Zurich, Switzerland<\/li>\n
  4. Max Planck Institute of Psychiatry, Munich, Germany<\/li>\n
  5. Klinikum Ingolstadt, Centre of Mental Health, Ingolstadt, Germany<\/li>\n
  6. Semmelweis University, Institute of Behavioural Sciences, Budapest, Hungary<\/li>\n<\/ol>\n

    ABSTRACT<\/p>\n

    Nocturnal human sleep consists of 4 \u2013 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 \u201cdata-driven\u201d 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.<\/p>\n

    We explored temporal dynamics of fractal activity during nocturnal sleep using electroencephalography in 205 healthy adults aged 18 \u2013 75 years. Based on the observed pattern of fractal fluctuations, we introduced a new concept, the \u201cfractal\u201d cycle of sleep, 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. Then, we assessed correlations between \u201cfractal\u201d and \u201cclassical\u201d (i.e., non-REM \u2013 REM) sleep cycle durations. We also studied cycles with skipped REM sleep, i.e., the cycles where the REM phase is replaced by \u201clightening\u201d of sleep. Finally, we validated the fractal cycle concept in children and adolescents (range: 8 \u2013 17 years, n = 21), the group characterized by deeper sleep and a higher frequency of cycles with skipped REM sleep, as well as in major depressive disorder (n = 111), the condition characterized by altered sleep structure (in addition to its clinical symptoms).<\/p>\n

    We found that \u201cfractal\u201d and \u201cclassical\u201d cycle durations (89 \u00b1 34 min\u00a0vs.<\/em>\u00a090 \u00b1 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.<\/p>\n

    In adults, the \u201cfractal\u201d cycle duration and participant\u2019s age correlated negatively (r = -0.2, p = 0.006). Children and adolescents had shorter \u201cfractal\u201d cycles compared to young adults (76 \u00b1 34\u00a0vs.<\/em>\u00a094 \u00b1 32 min, p < 0.001). The fractal cycle algorithm detected cycles with skipped REM sleep in 53\/55 (96%) cases.<\/p>\n

    Medicated patients with depression showed longer \u201cfractal\u201d cycles compared to their own unmedicated state (107 \u00b1 51 min\u00a0vs.<\/em>\u00a092 \u00b1 38 min, p < 0.001) and age-matched controls (104 \u00b1 49\u00a0vs.<\/em>\u00a088 \u00b1 31 min, p < 0.001).<\/p>\n

    In conclusion, \u201cfractal\u201d cycles are an objective, quantifiable, continuous and biologically plausible way to display sleep neural activity and its cycling nature. They are useful in healthy, pediatric and clinical populations and should be extensively studied to advance theoretical research on sleep structure.<\/p>\n

     <\/p>\n","protected":false},"excerpt":{"rendered":"

    Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles eLife 13:RP96784, 2024 https:\/\/doi.org\/10.7554\/eLife.96784.1<\/a> Yevgenia Rosenblum1, Mahdad Jafarzadeh Esfahani1, Nico Adelh\u00f6fer1, Paul Zerr1, Melanie Furrer2, Reto Huber2,3, Axel Steiger4, Marcel Zeising5, Csenge G. Horv\u00e1th6, Bence Schneider6, R\u00f3bert B\u00f3dizs6, Martin Dresler1 Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behavior, Nijmegen, Netherlands Child …<\/p>\n","protected":false},"author":101277,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[6,141],"tags":[],"class_list":["post-2049","post","type-post","status-publish","format-standard","hentry","category-articles-in-professional-journals","category-most-recent-articles"],"acf":[],"_links":{"self":[{"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/posts\/2049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/users\/101277"}],"replies":[{"embeddable":true,"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/comments?post=2049"}],"version-history":[{"count":1,"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/posts\/2049\/revisions"}],"predecessor-version":[{"id":2050,"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/posts\/2049\/revisions\/2050"}],"wp:attachment":[{"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/media?parent=2049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/categories?post=2049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/semmelweis.hu\/psychophysiology\/wp-json\/wp\/v2\/tags?post=2049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}