Resting-State Functional Connectivity during Controlled Respiratory Cycles using Functional Magnetic Resonance Imaging

Abstract

This study aimed to assess the effect of controlled mouth breathing during the resting-state using functional magnetic resonance imaging (fMRI). Eleven subjects participated in this experiment in which the controlled “Nose” and “Mouth” breathings of 6 seconds respiratory cycle were performed with a visual cue at 3T MRI. Voxel-wise seed-to-voxel maps and whole-brain region of interest (ROI)-to-ROI connectome maps were analyzed in both “Nose>Mouth” and “Mouth>Nose” contrasts. As the result, there were more connection pairs in the “Mouth” breathing condition, that is, 14 seeds and 14 connecting pairs in the “Mouth>Nose” contrast, compared to 7 seeds and 4 connecting pairs in the “Nose>Mouth” contrast (false discovery rate (FDR) of P < 0.05). The present study demonstrated that mouth breathing with controlled respiratory cycles could significantly induce alterations in functional connectivity in the resting-state network, suggesting that it can differently affect the resting brain function; in particular, the brain can hardly rest during mouth breathing, as opposed to conventional nasal breathing.