The relationship between interoception of breathing, anxiety, and resting-state functional connectivity in the brain.

Impaired breathing-related interoceptive abilities have been associated with adverse outcomes, including higher levels of anxiety. However, brain connectivity patterns related to poor interoception, and how these may be modulated by anxiety, are poorly understood. This exploratory study investigated connectivity profiles associated with breathing-related interoceptive abilities in 65 volunteers who underwent ultrahigh-field (7 Tesla) "resting-state" magnetic resonance imaging (rs-fMRI), as well as completed a breathing-related interoceptive task and an anxiety questionnaire. The breathing task measured four aspects of interoceptive ability (sensitivity, decision bias, metacognitive bias, and insight), which served alongside anxiety to explain amygdala connectivity in the rs-fMRI data. We observed that connectivity between bilateral amygdala and insula cortex was linked to the level of confidence ascribed to respiratory-related interoceptive judgements (metacognitive bias), while left-lateralised connectivity between amygdala and insula cortex was associated with a worsened ability to detect inspiratory resistances (interoceptive sensitivity). Both reductions in confidence and sensitivity correlated weakly with heightened anxiety levels at a behavioural level. By contrast, the connectivity differences across levels of metacognitive bias and interoceptive sensitivity were not accounted for by anxiety. Our findings could suggest that, in the general population, connectivity between amygdala and insula cortex is linked to breathing-related interoceptive processes in a manner that is largely independent of anxiety.