Brain–heart dynamics during emotional processing under uncertain conditions: An index of depression risk

Recent studies have highlighted the essential role of interoception in healthy emotional processing and the pathology of major depressive disorder. However, it is unclear how individual differences in healthy people with high depression risk (HDR; i.e., individual differences in depression risk) are related to the neurophysiological underpinnings of interoception and emotional reactions under different degrees of certainty. We examined whether an individual’s depression risk mediates the relationships of heartbeat-evoked potentials (HEPs), a neurophysiological marker of cardiac interoception, with heart rate (HR) and heart rate variability (HRV), indices for cardiac reactivity. In a concurrent electroencephalogram-electrocardiogram (EEG-ECG) experiment, 26 healthy participants completed an emotion-evoking picture-evaluation task. Each trial began with a differential auditory cue that was associated with the certainty of subsequently seeing a pleasant or unpleasant picture. The results showed the following: after participants saw a cue of uncertainty, HDR was associated with 1) reduced neural activity when anticipating upcoming pictures and 2) enhanced physiological reactions to unexpected , unpleasant pictures. These results suggest that weaker predictions and augmented prediction errors for negative emotional stimuli reflect depression risk. Moreover, depression risk significantly mediated the relationships between HEPs and HR and between HEPs and HRV for unexpected, unpleasant stimuli. This study provides evidence that interoception and autonomic cardiac regulation may be altered by depression risk. This highlights the insights provided by specific indices of brain–heart interactions, such as HEPs, into the underlying activity of the autonomic nervous system and unique interoceptive disturbances associated with depression risk.