Aging disrupts the temporal organization of slow oscillations beyond density reduction.

Overview

1. Laboratorio de Sueño y Memoria, Departamento de Ciencias de la Vida, Instituto Tecnológico de Buenos Aires (ITBA), Iguazú 341, Ciudad Autónoma de Buenos Aires C1437, Argentina
2. Department of Health Psychology, Institute for Psychology, University of Klagenfurt, Klagenfurt 9020, Austria
3. Centro de Neuropsiquiatría y Neurología de la Conducta-CENECON, Facultad de Ciencias Médicas, Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires C1121A6B, Argentina
4. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires C1425, Argentina
5. Departamento de Ingeniería Informática, Instituto Tecnológico de Buenos Aires (ITBA), Ciudad Autónoma de Buenos Aires C1437, Argentina

Abstract

Macroscopic and rhythmic brain oscillations have recently been shown to play a crucial role in glymphatic function by promoting cerebrospinal fluid flow and facilitating the clearance of metabolic waste. While age-related reductions in the number and amplitude of slow oscillations (SOs; 0.5–1 Hz) are well documented and associated with impaired clearance, little is known about how aging affects the temporal structure of these oscillations. Here, we propose that the rhythmic dynamics with which SOs occur represent a critical, yet overlooked, feature supporting glymphatic function. We introduce a novel classification of SOs based on their temporal organization, distinguishing isolated SOs from trains of consecutive oscillations according to inter-SO intervals. Using overnight electroencephalographic recordings from 57 young and 51 elderly adults across three independent datasets, we compared the proportions of isolated and consecutive SOs as well as the distribution of train lengths. Elderly adults displayed a significantly higher proportion of isolated SOs and shorter oscillatory trains than young adults, even after controlling for SO density and stage composition. Temporal shuffling procedures and analyses of density-matched epochs further supported that these differences cannot be attributed solely to density but instead reflect a genuine age-related loss of rhythmicity. These findings reveal that natural aging not only reduces the amount and amplitude of SOs but also disrupts their temporal regularity. This alteration may weaken the sustained ionic currents that drive cerebrospinal fluid flow, compromise the efficiency of metabolic clearance during sleep, and thereby contribute to increased vulnerability to age-related neurodegenerative processes.

Reproduced under the paper's license (CC BY), from the paper cited above.

Code

The paper links to its data, not to its authors' code: see the Data section.

Tracing map

A tracing map links a paper to the code its authors published: this paper has none, so it has no map.

Data

Datasets cited

• doi:10.13026/c2x676, at the source; found in the references
• doi:10.18112/openneuro.ds005555.v1.1.0, at OpenNeuro; found in the references
• osf:b6afs, at OSF; found in “Data availability”

Data availability

All data used in this study are publicly available in their respective publications, except for the EEG data from the elderly adult group in dataset 1. These data were collected by the Laboratorio de Sueño y Memoria at the Instituto Tecnológico de Buenos Aires (ITBA) and are publicly available via the Open Science Framework (OSF) repository (https://osf.io/b6afs) (62).

Reproduced under the paper's license (CC BY), from the paper cited above.

Versions

The history of this record: each version stored by the harvester or made by a correction of its authors or of the maintainers of its code, and what changed in its facts. The texts of the paper (its abstract, its availability statements) are not part of it; versions that changed only those are not listed.

Version 1, 29 September 2026: the first record

Recorded: type, language, journal, volume, issue, pages, dates, 7 authors, 4 keywords, 53 references.

Cite

This paper

Capurro, L., Radloff, M., González, M. C., Gorosito, M. L., Brusco, L. I., Ramele, R., & Forcato, C. (2026). Aging disrupts the temporal organization of slow oscillations beyond density reduction. PNAS nexus, 5(4), pgag108. https://doi.org/10.1093/pnasnexus/pgag108

Similar papers

The papers with a page that share the most with this one: the tools found in their code, their categories, datasets, cited references and authors, the rarest counting most.

[1] doi:10.1093/braincomms/fcag204 [code]

Altered rhythmic and arrhythmic electroencephalographic activity during non-rapid eye movement sleep in amnestic mild cognitive impairment.

Journal: Brain communications

In common: 7 references

[2] doi:10.1093/braincomms/fcag303 [code]

Sleep spindles are linked to white matter connectivity differentially in older adults with and without cognitive impairment.

Journal: Brain communications

In common: systems, 6 references

[3] doi:10.1038/s42003-026-09988-y

Thalamic involvement defines distinct slow-wave subtypes in NREM sleep.

Journal: Communications biology

In common: 5 references

[4] doi:10.1186/s12888-026-08304-6

Transcranial direct current stimulation improves reduced global BOLD-CSF coupling in patients with insomnia disorder and comorbid anxiety: a resting-state functional MRI study.

Journal: BMC psychiatry

In common: 5 references

[5] doi:10.1038/s41598-026-57532-z

Predictability of sleep slow oscillation emergence and spatial extent from pre-onset neural dynamics.

Journal: Scientific reports

In common: systems, 4 references

[6] doi:10.3389/fnagi.2026.1714063

Nightly variations in sleep quality and next-day cognitive performance: an in-home study in healthy older adults.

Journal: Frontiers in aging neuroscience

In common: 4 references

[7] doi:10.2196/80286 [code]

At-Home Sleep Electroencephalography Assessment in Young and Older Adults Using a Novel Wireless Soft Electronics Sleep Monitoring System: Experimental Study.

Journal: JMIR formative research

In common: 4 references

[8] doi:10.1016/j.isci.2026.116601 [code]

Random auditory stimulation during sleep disturbs traveling slow waves and declarative memory.

Journal: iScience

In common: 4 references

[9] doi:10.7554/elife.103956 [code]

Human brain-wide activation of sleep rhythms.

Journal: eLife

In common: systems, 4 references

[10] doi:10.1073/pnas.2526239123 [code]

Quantitative assessment of flow between cerebrospinal and interstitial fluid compartments in humans.

Journal: Proceedings of the National Academy of Sciences of the United States of America

In common: 4 references

Contribute

The authors of this paper can claim it, correct its record and validate its tracing map, and the maintainers of its code (its owner, or a public member of its organization) correct what it says of their repository; anyone signed in can ask for its removal. Every request goes to OSCR's own machine, which answers it; your account page follows them.

Request its removal

To ask OSCR to remove this record, the copies of its authors' scripts or its tracing map, use the removal request page: signed in, you say who you are, what to remove and why, then review and confirm the request. Published rules decide every request (how).

Discussion: questions and error reports about this paper and its code, from signed-in readers and its authors. It opens with sign-in.

Reproductions: reports from readers who ran the authors' code: what they reproduced, with which environment, commit and data. It opens with sign-in.

Activity: what happens around this paper: new versions of its record, its map's validation, discussions and reproductions. It opens with sign-in.