# Cardiac Signals Facilitate the Breakthrough to Awareness of Emotional Stimuli

## TL;DR

Heart signals help emotional stimuli, like fearful faces, become consciously visible faster when they appear during the systole phase of the heartbeat.

## Contribution

This study shows that cardiac signals enhance the perceptual salience of emotionally relevant stimuli at preconscious visual stages.

## Key findings

- Fearful faces presented during systole broke through suppression faster than during diastole.
- No cardiac modulation was observed for neutral faces or in emotion discrimination accuracy.
- Cardiac afferents selectively enhance motivationally salient stimuli during early visual processing.

## Abstract

The brain continuously integrates interoceptive signals—such as those arising from cardiac afferents—with sensory input to guide perception, emotion and awareness. Previous research has demonstrated that the timing of external stimuli relative to the cardiac cycle influences perceptual and cognitive processes. However, it remains unclear whether cardiac signals facilitate the access of emotional visual stimuli to conscious awareness. Here, we used a continuous flash suppression (CFS) paradigm to investigate whether the breakthrough of fearful and neutral faces to awareness is modulated by cardiac cycle phase. Fearful and neutral faces were presented to the non‐dominant eye in synchrony with participants' heartbeats—either during estimated‐cortical systole (ec‐systole) or diastole (ec‐diastole)—while dynamic Mondrian patterns suppressed visibility in the dominant eye. Results showed that fearful faces presented during estimated‐cortical systole (ec‐systole) broke through suppression faster and after fewer heartbeat‐synchronized presentations than those presented during ec‐diastole, suggesting facilitated processing. No significant cardiac modulation was found for neutral faces or in emotion discrimination accuracy, confidence, or response bias. These findings demonstrate that cardiac afferent signals selectively enhance the perceptual salience of motivationally salient (e.g., threat signaling) stimuli, promoting earlier access to consciousness. This study extends prior work by showing that cardiac influences on emotion processing operate even at early, preconscious stages of visual perception.

This study shows that the timing of visual stimuli relative to the cardiac cycle modulates conscious perception of emotional faces. Fearful, but not neutral, faces presented during systole broke through visual suppression more rapidly, suggesting that interoceptive signals enhance the salience of emotionally relevant stimuli. These findings show how body‐to‐brain signals can shape conscious visual awareness at early processing stages and contribute to a growing understanding of how physiological arousal modulates sensory and affective perception.