Acute Stress Enhances Heartbeat-Evoked Potentials, but Does Not Affect Cardiac Interoceptive Accuracy

Area of Science:

• Neuroscience
• Psychophysiology
• Stress Research

Background:

• Acute stress is hypothesized to enhance cardiac interoceptive attention (IAt), the awareness of internal bodily sensations, specifically heartbeats.
• Heartbeat-evoked potentials (HEPs) during a heartbeat counting task (HCT) serve as a measure of cardiac IAt.
• The influence of the sympatho-adrenomedullary (SAM) and hypothalamic-pituitary-adrenocortical (HPA) axes on stress-induced IAt remains unclear.

Purpose of the Study:

• To investigate if acute stress enhances cardiac IAt.
• To explore the contribution of SAM and HPA axis activation to stress-related changes in cardiac IAt.

Main Methods:

• Sixty-six healthy individuals were randomized into a stress (socially evaluated cold pressor test/SECPT) or control group.
• Participants completed a HCT and a distraction task before and at three time points after the intervention.
• Physiological stress markers (heart rate, blood pressure, cortisol) and HEPs were measured.

Main Results:

• The SECPT successfully induced physiological stress responses, including increased heart rate, blood pressure, and cortisol levels.
• Cardiac interoceptive accuracy, measured by HCT performance, was not significantly affected by acute stress.
• Individuals in the SECPT group exhibited increased HEPs 40 minutes post-intervention, indicating enhanced cardiac IAt, with a right-hemispheric distribution.

Conclusions:

• Acute stress appears to selectively enhance cardiac IAt, potentially mediated by right-hemispheric neural networks, possibly involving the insula.
• The late enhancement of cardiac IAt post-stress may relate to parasympathetic nervous system activity during stress recovery.
• Further research is needed to elucidate the neural mechanisms and the role of cardiac afferents in stress-modulated IAt.