Functional Connectivity Within the Central Autonomic Network Increases During Resonance Paced Breathing at 0.1 Hz.

Physiological processes such as respiration, while typically automatic, can be brought under volitional control to initiate cascading effects across the autonomic and central nervous systems. Slow breathing paced at approximately six breaths-per-minute, termed resonance paced breathing (RPB), activates the 0.1 Hz resonance frequency of the baroreflex. This slow breathing intervention has multiple health benefits, including significant reductions in anxiety, depression, and stress. Positive cardiovascular changes (e.g., reduced blood pressure, increased heart rate variability and baroreflex sensitivity) are observed during RPB, however, little is known about real-time brain response to RPB. This study examined changes in functional connectivity between 13 a priori selected regions-of-interest (ROIs) of the central autonomic brain network during RPB compared to natural breathing. Participants (N = 147) with depression, a substance use disorder, or no diagnosis were imaged using a 3 T Siemens Trio scanner during brief episodes of natural breathing and RPB. Linear mixed modeling with adaptive false discovery rate correction indicated that compared to natural breathing, RPB led to increased functional connectivity between multiple ROIs of the central autonomic network. Of the 15 ROI pairs with significantly increased connectivity, 10 pairs involved a subdivision of the insula. This pattern supports that the insular cortex may play a key role in integrating afferent viscerosensory information from lower brain areas with cognitive and emotional information relayed from higher cortical areas. Further knowledge about the interdependencies between autonomic and central nervous system processes is important to identify new and accessible intervention targets for physical and mental disorders that involve arousal modulation challenges.