University of Oulu

Borchardt, V., Korhonen, V., Helakari, H. et al. Inverse correlation of fluctuations of cerebral blood and water concentrations in humans. Eur. Phys. J. Plus 136, 497 (2021).

Inverse correlation of fluctuations of cerebral blood and water concentrations in humans

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Author: Borchardt, Viola1; Korhonen, Vesa1,2; Helakari, Heta1,2;
Organizations: 1Oulu Functional Neuroimaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu, Finland
2Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu, Finland
3Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
4Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
5Optoelectronics and Measurement Techniques Research Unit, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.9 MB)
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Language: English
Published: Springer Nature, 2021
Publish Date: 2021-06-09


Near-infrared spectroscopy (fNIRS) measures concentrations of oxygenated (HbO) and deoxygenated (HbR) hemoglobin in the brain. Recently, we demonstrated its potential also for measuring concentrations of cerebral water (cH₂O). We performed fNIRS measurements during rest to study fluctuations in concentrations of cH₂O, HbO and HbR in 33 well-rested healthy control subjects (HC) and 18 acutely sleep-deprived HC. Resting-state fNIRS signal was filtered in full-band, cardiac, respiratory, low-, and very-low-frequency bands. The sum of HbO and HbR constitutes the regional cerebral blood volume (CBV). CBV and cH₂O concentrations were analyzed via temporal correlation and phase synchrony. Fluctuation in concentrations of cH₂O and CBV was strongly anti-correlated across all frequency bands in both frontal and parietal cortices. Fluctuation in concentrations of cH₂O and CBV showed neither a completely synchronous nor a random phase relationship in both frontal and parietal cortices. Acutely sleep-deprived subjects did not show significant differences in temporal correlation or phase synchrony between fluctuations in cH₂O and CBV concentrations compared with well-rested HC. The reciprocal interrelation between fluctuations in CBV and cH₂O concentrations is consistent with the Munro–Kellie doctrine of constant intracranial volume. This coupling may constitute a functional mechanism underlying glymphatic circulation, which persists despite acutely disturbed sleep patterns.

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Series: European physical journal plus
ISSN: 2190-5444
ISSN-E: 2190-5444
ISSN-L: 2190-5444
Volume: 136
Issue: 5
Article number: 497
DOI: 10.1140/epjp/s13360-021-01480-2
Type of Publication: A1 Journal article – refereed
Field of Science: 3126 Surgery, anesthesiology, intensive care, radiology
3112 Neurosciences
Funding: Open access funding provided by University of Oulu including Oulu University Hospital. Funding was provided by Academy of Finland (Grant No. 314502).
Academy of Finland Grant Number: 314502
Detailed Information: 314502 (Academy of Finland Funding decision)
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