Brief Research Report ARTICLE
“Switch-off” of respiratory sinus arrhythmia can occur in a minority of subjects during functional magnetic resonance imaging (fMRI)
- 1Carl-Ludwig-Institute of Physiology, Leipzig University, Germany
- 2Department of Psychology, University of Graz, Austria
- 3Institute of Medical Engineering, Graz University of Technology, Austria
A group of 23 healthy scanner naïve participants of a functional magnetic resonance imaging (fMRI) study with increased state anxiety exhibited 0.1-Hz oscillations in blood-oxygenation-level-dependent (BOLD) signals, heart rate (HR) beat-to-beat intervals (RRI) and respiration The goal of the present paper is to explore slow oscillations in respiration and RRI and their phase-coupling by applying the dynamic “wave-by-wave” analysis. Five participants with either high or moderate levels of fMRI-related anxiety (age 23.8 3.3y) were found with at least one bulk of consecutive breathing waves with a respiration rate between 6 to 9 breaths/min in a 5-minute resting state. The following results were obtained: (i) Breathing oscillations with dominant frequencies at 0.1 Hz and 0.15 Hz displayed a 1:1 coupling with RRI. (ii) Inspiration time was significantly longer than expiration time. (iii) RRI minima (start of HR decrease) coincided with the early inspiration, and RRI maxima (start of HR increase) coincided with the late inspiration. (iv) RRI rhythm led over the respiratory rhythm. This phase-coupling pattern is quite contrary to typical respiratory sinus arrhythmia where HR increases during inspiration and decreases during expiration. The results support the assumption that not only an increased respiration rate but also slow breathing may play a role in anxiety processing.
Keywords: respiratory sinus arrhythmia (RSA), Heart rate variability, ~ 0.1-Hz oscillations, state anxiety, functional magnetic resonance imaging (fMRI), Emotion Regulation
Received: 19 Sep 2018;
Accepted: 09 Nov 2018.
Edited by:Tobias Opthof, Academic Medical Center (AMC), Netherlands
Reviewed by:Milan Stengl, Charles University, Czechia
Wayne R. Giles, University of Calgary, Canada
Copyright: © 2018 Rassler, Schwerdtfeger, Aigner and Pfurtscheller. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Prof. Beate Rassler, Leipzig University, Carl-Ludwig-Institute of Physiology, Leipzig, Germany, Beate.Rassler@medizin.uni-leipzig.de
Prof. Gert Pfurtscheller, Graz University of Technology, Institute of Medical Engineering, Graz, 8010, Styria, Austria, firstname.lastname@example.org