Sleep and dreaming in the light of reactive and predictive homeostasis

Simor, Péter; Peigneux, Philippe; Bódizs, Róbert

doi:10.1016/j.neubiorev.2023.105104

Cited by 9 publications

(9 citation statements)

References 191 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S5 in Supplementary Material 2). Given that SWA is a primary marker of sleep homeostasis, this pattern possibly reflects the dissipation of a sleep need during the course of night sleep (Bódizs et al, 2023). In contrast, fractal slopes show a cycling nature over the entire night's sleep (Fig.…”

Section: Fractal and Classical Cycles Comparisonmentioning

confidence: 99%

“…One can, therefore, speculate that ascending parts and peaks of fractal cycles coincide with acetylcholine release. The troughs of fractal cycles, in turn, might reflect a higher homeostatic pressure and even cause feelings of sleepiness and the search for the opportunity of initiating sleep, as these are periods of the steepest fractal activity, which implies a higher ratio of lower over higher frequency power in the EEG (Bódizs et al, 2023).…”

Section: Fractal Cycles: Definition and Motivationmentioning

confidence: 99%

“…The decision to incorporate fractal activity analysis in sleep cycle research was based on the reports that fractal (aperiodic) dynamics may reflect the bistability of the network (the overall tendency of alternating up and down states) (Baranauskas et al, 2012) and/or alterations in the balance between neural excitatory and inhibitory currents (Gao et al, 2017). Circumstantial evidence suggests that fractal activity is a measure of sleep homeostasis or sleep intensity, reflecting sleep-wake history, sleep stage differences, sleep cycles, age-effects, local sleep and sleep disorders (Bódizs et al, 2023). Recently, it has been reported that during human sleep, spectral slopes positively correlate with pupil size, a marker of arousal levels linked to the activity of the locus coeruleus-noradrenergic system (Carro-Domínguez et al, 2023).…”

Section: Hypothetical Functional Significance Of Aperiodic Activity A...mentioning

confidence: 99%

See 2 more Smart Citations

Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles

Rosenblum¹,

Esfahani

Adelhöfer

et al. 2023

Preprint

Self Cite

View full text Add to dashboard Cite

Background: Textbooks define the classical sleep cycle as an episode of non-rapid eye movement (non-REM) sleep followed by an episode of REM sleep; sometimes, a REM episode can be "skipped". While sleep cycles are considered fundamental components of sleep, their functional significance remains to a large extent unclear. One of the reasons for a lack of research progress in the field is the absence of a data-driven definition. Here, we propose to reset the scientific definition of sleep cycles on fractal (aperiodic) neural activity as a well-established marker of arousal and sleep stages, arguing that this will considerably advance the field. Methods: We used electroencephalography to compute fractal slopes and explore their temporal dynamics over the course of nocturnal sleep. We defined the "fractal cycle of sleep" as a time interval during which fractal slopes descend from their local maximum to their local minimum and then lead back to the next local maximum. Next, we assessed the correspondence between the "fractal" and "classical" sleep cycles, including "skipped" cycles. Finally, we explored fractal cycles in childhood and adolescence, a life period with ongoing sleep architecture changes, as well as in major depressive disorder, a clinical condition characterized by disturbed sleep architecture. Results: Timings of "fractal" and "classical" cycles coincided in 763/940 (81%) cases and their durations (89±34 min vs 90±25 min) correlated positively (r=0.5, p<0.001). The fractal cycle algorithm detected "skipped" cycles in 53/55 (96%) cases. In adults (range: 18-75 years, n=205), the "fractal" cycle duration and participant's age correlated negatively (r=-0.2, p=0.006). Children and adolescents (range: 8-17 years, n=21) had shorter "fractal" cycles compared to young adults (range: 23-25 years, n=24) (mean: 76±34 vs 94±32 min, p<0.001). 38 unmedicated patients with depression showed shorter "fractal" cycles compared to their own medicated state (92±38 min vs 107±51 min, p<0.001). 111 medicated patients showed longer "fractal" cycles compared to 109 matched controls (104±49 vs 88±31 min, p<0.001). Conclusions: We show that "fractal cycles" are an objective, quantifiable and biologically plausible way to display sleep neural activity and its cycles, able to provide additional information compared to hypnograms. Likewise, "fractal cycles" can be used to study the effect of antidepressants on sleep.

show abstract

Section: Fractal and Classical Cycles Comparisonmentioning

confidence: 99%

Section: Fractal Cycles: Definition and Motivationmentioning

confidence: 99%

Section: Hypothetical Functional Significance Of Aperiodic Activity A...mentioning

confidence: 99%

See 1 more Smart Citation

Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles

Rosenblum¹,

Esfahani

Adelhöfer

et al. 2023

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…The sleep EEG and self-report data of 67 participants (47 females, mean age: 24.7, Std. Dev: 3.3, range: [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] were considered in the final analyses, yielding in total of 464 nights of EEG recordings (missing data: 7%), 485 entries for morning (missing data: 3%), 468 entries for daytime self-reports (missing data: 6%), and 259 entries for dream features (i.e. a relatively larger rate of missing data was expected for dream-related variables since dream recall does not occur every morning).…”

Section: Participants and Final Datasetmentioning

confidence: 99%

“…These findings suggest that disrupted sleep during the night, especially reduced and fragmented deep sleep (slow wave sleep [SWS]) and consequently, the accumulation of sleep pressure may interfere with the subsequent wake state, and enhance mind-wandering during the day. Likewise, the reduction of more activated sleep states such as REM sleep, which feature the most vivid forms of dreaming during the night [32,33] may also induce a homeostatic (REM) pressure at wake, and increase the propensity of daytime mind-wandering (i.e. an intrusion of dream-like cognition into wakefulness).…”

Section: Introductionmentioning

confidence: 99%

Reduced REM and N2 sleep, and lower dream intensity predict increased mind-wandering

Simor,

Polner,

Báthori

et al. 2023

Sleep

Self Cite

View full text Add to dashboard Cite

Mind-wandering is a mental state in which attention shifts from the present environment or current task to internally driven, self-referent mental content. Homeostatic sleep pressure seems to facilitate mind-wandering as indicated by studies observing links between increased mind-wandering and impaired sleep. Nevertheless, previous studies mostly relied on cross-sectional measurements and self-reports. We aimed to combine the accuracy of objective sleep measures with the use of self-reports in a naturalistic setting in order to examine if objective sleep parameters predict the tendency for increased mind-wandering on the following day. We used mobile sleep EEG headbands and self-report scales over 7 consecutive nights in a group of 67 healthy participants yielding ~ 400 analyzable nights. Nights with more wakefulness and shorter REM and SWS were associated with poorer subjective sleep quality at the intra-individual level. Reduced REM and N2 sleep, as well as less intense dream experiences, predicted more mind-wandering the following day. Our micro-longitudinal study indicates that intra-individual fluctuations in the duration of specific sleep stages predict the perception of sleep quality as assessed in the morning, as well as the intensity of daytime mind-wandering the following hours. The combined application of sleep EEG assessments and self-reports over repeated assessments provides new insights into the subtle intra-individual, night-to-day associations between nighttime sleep and the next day’s subjective experiences.

show abstract

Fundamentals of sleep regulation: Model and benchmark values for fractal and oscillatory neurodynamics

Bódizs,

Schneider,

Ujma

et al. 2024

Progress in Neurobiology

View full text Add to dashboard Cite

Sleep and dreaming in the light of reactive and predictive homeostasis

Cited by 9 publications

References 191 publications

Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles

Fractal cycles of sleep: a new aperiodic activity-based definition of sleep cycles

Reduced REM and N2 sleep, and lower dream intensity predict increased mind-wandering

Fundamentals of sleep regulation: Model and benchmark values for fractal and oscillatory neurodynamics

Contact Info

Product

Resources

About