University of Oulu

Infraslow fluctuations and respiration are driving cortical neurophysiological oscillations during sleep

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Author: Väyrynen, Tommi1
Organizations: 1University of Oulu, Faculty of Science, Physics
Format: ebook
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.6 MB)
Pages: 53
Persistent link:
Language: English
Published: Oulu : T. Väyrynen, 2022
Publish Date: 2022-04-20
Thesis type: Master's thesis
Tutor: Korhonen, Vesa
Heimonen, Kyösti
Reviewer: Korhonen, Vesa
Heimonen, Kyösti


Recently sleep has been linked to increased brain clearance through perivascular spaces from blood-brain barrier (BBB) externa limitans, facilitated by physiological pulsations such as cardiovascular and respiratory pulsations. Infraslow fluctuations (ISFs) characterize both fMRI BOLD signals and scalp EEG potentials. They are associated with both permeability fluctuations of BBB and the amplitude dynamics of faster (> 1Hz) neuronal oscillations. ISF together with respiration are though to synchronize with neural rhythms, however the directionality of these interactions has not been studied before. I used non-invasive measures which are necessary not to interfere the pressure sensitive CSF convection and BBB permeability combined with directional metrics to fully evaluate these relationships. I recorded full-band resting state EEG (fbEEG) during wakefulness and sleep and investigated whether recently shown increased brain clearance during sleep is followed by increased drive of neural amplitudes by the ISF and respiration phases. I show that ISF power increases during non-REM sleep, possibly reflecting altered BBB status. Furthermore, I show that ISF and respiration phase-amplitude couple and predict neuronal brain rhythms seen especially during sleep. These results pave the way for understanding the mechanisms how neuronal activity is modulated by the slow oscillations in human brain during wakefulness and sleep.

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Copyright information: © Tommi Väyrynen, 2022. Except otherwise noted, the reuse of this document is authorised under a Creative Commons Attribution 4.0 International (CC-BY 4.0) licence ( This means that reuse is allowed provided appropriate credit is given and any changes are indicated. For any use or reproduction of elements that are not owned by the author(s), permission may need to be directly from the respective right holders.