Unmasking the post-expiratory pause: salience network connectivity and its link to psychological factors

Breathing not only sustains life but also interacts with emotional states. Mounting evidence suggests that subtle variations in respiratory patterns-including their neural underpinnings-may serve as sensitive indicators of affective processes, yet the specific phases of spontaneous breathing have rarely been studied in detail. Here, we present a cross-sectional, exploratory investigation combining high-temporal-resolution respiratory measures, resting-state magnetoencephalography data, and psychological assessments in 46 healthy adults. Our analysis distinguishes three distinct phases-inspiration, expiration, and the brief but functionally significant post-expiratory pause (PEP). By correlating time-averaged Salience Network connectivity with aggregate respiratory metrics, we identify trait-level associations specific to the PEP in beta and gamma frequencies. Individuals with longer and more variable PEPs show distinct connectivity patterns associated with heightened depression and reduced life satisfaction. Connectivity patterns involving the right insula, bilateral anterior cingulate cortex, and left amygdala show robust correlations with these affective parameters, suggesting that this brief respiratory interval may serve as a window into interoceptive and emotional processing. Our findings highlight the overlooked role of the PEP in capturing meaningful interactions between respiration, neural circuits, and psychological well-being.