University of Oulu

Raitamaa, L., Huotari, N., Korhonen, V., Helakari, H., Koivula, A., Kananen, J., & Kiviniemi, V. (2021). Spectral analysis of physiological brain pulsations affecting the BOLD signal. Human Brain Mapping, 42( 13), 4298– 4313.

Spectral analysis of physiological brain pulsations affecting the BOLD signal

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Author: Raitamaa, Lauri1,2; Huotari, Niko1,2; Korhonen, Vesa1,2;
Organizations: 1Oulu Functional Neuro Imaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu
2Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.4 MB)
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Language: English
Published: John Wiley & Sons, 2021
Publish Date: 2021-10-26


Physiological pulsations have been shown to affect the global blood oxygen level dependent (BOLD) signal in human brain. While these pulsations have previously been regarded as noise, recent studies show their potential as biomarkers of brain pathology. We used the extended 5 Hz spectral range of magnetic resonance encephalography (MREG) data to investigate spatial and frequency distributions of physiological BOLD signal sources. Amplitude spectra of the global image signals revealed cardiorespiratory envelope modulation (CREM) peaks, in addition to the previously known very low frequency (VLF) and cardiorespiratory pulsations. We then proceeded to extend the amplitude of low frequency fluctuations (ALFF) method to each of these pulsations. The respiratory pulsations were spatially dominating over most brain structures. The VLF pulsations overcame the respiratory pulsations in frontal and parietal gray matter, whereas cardiac and CREM pulsations had this effect in central cerebrospinal fluid (CSF) spaces and major blood vessels. A quasi-periodic pattern (QPP) analysis showed that the CREM pulsations propagated as waves, with a spatiotemporal pattern differing from that of respiratory pulsations, indicating them to be distinct intracranial physiological phenomenon. In conclusion, the respiration has a dominant effect on the global BOLD signal and directly modulates cardiovascular brain pulsations.

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Series: Human brain mapping
ISSN: 1065-9471
ISSN-E: 1097-0193
ISSN-L: 1065-9471
Volume: 42
Issue: 13
Pages: 4298 - 4313
DOI: 10.1002/hbm.25547
Type of Publication: A1 Journal article – refereed
Field of Science: 3112 Neurosciences
217 Medical engineering
Funding: Academy of Finland/Aivosäätiö TERVA 1-2, Grant/Award Numbers: 275342, 314497, 335720; Instrumentariumin Tiedesäätiö; Jane ja Aatos Erkon Säätiö; Maire Taposen Säätiö; Medical Research Center Oulu; Pohjois-Suomen Terveydenhuollon Tukisäätiö; Suomen Aivosäätiö; Suomen Lääketieteen Säätiö; The University of Oulu Scholarship Foundation; VTR grants from Oulu University Hospital.
Academy of Finland Grant Number: 314497
Detailed Information: 314497 (Academy of Finland Funding decision)
335720 (Academy of Finland Funding decision)
Copyright information: © 2021 The Authors. Human Brain Mapping published by Wiley Periodicals LLC. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.