A Bridge between the Breath and the Brain: Synchronization of Respiration, a Pupillometric Marker of the Locus Coeruleus, and an EEG Marker of Attentional Control State.

Michael Christopher Melnychuk,Ian H Robertson,Paul M Dockree,Emanuele R G Plini

doi:10.3390/brainsci11101324

Michael Christopher Melnychuk, Ian H Robertson + Show 2 more

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https://doi.org/10.3390/brainsci11101324

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Journal: Brain sciences	Publication Date: Oct 6, 2021
Citations: 8	License type: CC BY 4.0

Affiliation: Trinity College Dublin

Abstract

Yogic and meditative traditions have long held that the fluctuations of the breath and the mind are intimately related. While respiratory modulation of cortical activity and attentional switching are established, the extent to which electrophysiological markers of attention exhibit synchronization with respiration is unknown. To this end, we examined (1) frontal midline theta-beta ratio (TBR), an indicator of attentional control state known to correlate with mind wandering episodes and functional connectivity of the executive control network; (2) pupil diameter (PD), a known proxy measure of locus coeruleus (LC) noradrenergic activity; and (3) respiration for evidence of phase synchronization and information transfer (multivariate Granger causality) during quiet restful breathing. Our results indicate that both TBR and PD are simultaneously synchronized with the breath, suggesting an underlying oscillation of an attentionally relevant electrophysiological index that is phase-locked to the respiratory cycle which could have the potential to bias the attentional system into switching states. We highlight the LC’s pivotal role as a coupling mechanism between respiration and TBR, and elaborate on its dual functions as both a chemosensitive respiratory nucleus and a pacemaker of the attentional system. We further suggest that an appreciation of the dynamics of this weakly coupled oscillatory system could help deepen our understanding of the traditional claim of a relationship between breathing and attention.

Highlights

Published: 6 October 2021In this paper we investigate the extent to which key cortical and subcortical signatures of attention are synchronized with breath dynamics
To this end we examine a tripartite relationship between the respiratory cycle [1], the EEG theta-beta ratio [2], a putative marker of attentional control and mind wandering, and pupil diameter [3], a proxy measure for the locus coeruleus/noradrenergic system (Figure 1)
This analysis was similar to the methodology of van Son (2019), but with respiratory phase as the within-subject factor, and participant as between-subjects factor (RMANOVA; F(10,59) = 1.842, p = 0.0002, partial η2 = 0.137), and the results indicate a variation in thetabeta ratio (TBR) amplitude across the respiratory cycle (Figure 3A) was common across participants

Summary

Introduction

In this paper we investigate the extent to which key cortical and subcortical signatures of attention are synchronized with breath dynamics. To this end we examine a tripartite relationship between the respiratory cycle [1], the EEG theta-beta ratio [2], a putative marker of attentional control and mind wandering, and pupil diameter [3], a proxy measure for the locus coeruleus/noradrenergic system (Figure 1). Yogic philosophy clearly states that the breath and the mind are closely related. This forms a foundational premise of many ancient techniques of breath control known collectively as pranayama. While it is currently agreed that at least some neuronal activity is regulated and/or entrained by Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

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