01/11/2026
🧠 When the heart shapes perception (and doesn’t just “detect” it)
In a study published a few days ago, researchers reanalyzed data from a previously published experiment (Cobos, Alameda, Guerra & Chica) in which 25 people rapidly viewed strings of colored letters and had to report the color of a target letter while ignoring nearby distractors. Sometimes they integrated shape and color correctly; other times they reported the color of the wrong letter (an illusion). Brain activity (EEG) and heart activity (ECG) were recorded simultaneously.
Key findings:
1. Before the stimulus appeared (the string of colored letters that participants had to look at and for which they had to indicate the color of the target letter), the amplitude of the HEP (heart-evoked potential) differed depending on whether people would later integrate shape and color correctly or experience an illusion. In other words, the brain-heart signal was already different before the stimulus appeared, and this difference was associated with how the subsequent perceptual integration would turn out.
2. Heart-locked oscillations (HEO) in the alpha and low-beta bands increased before correct integration.
These effects disappear when the data are analyzed time-locked to the stimulus instead of to the heartbeat. They also remain significant when compared with “false” analyses in which the heartbeat is randomly shifted: this shows that the effects depend on the precise timing of the heartbeat itself, not merely on spontaneous differences in brain activity.
This result aligns with Park and Tallon-Baudry’s idea of the “neural subjective frame”: the first-person sense of having seen something (“I have seen X”) arises because the brain integrates information coming from the external world with information coming from the body, including the heart.
The results do not demonstrate any form of precognition or advance knowledge of the future. They only show that the brain’s state, already modulated by the heartbeat a few moments before the stimulus, is statistically associated with how that stimulus will later be integrated (correctly or as an illusion). It is an effect of predisposition of the brain state, not a prediction of the perceptual content. In other words, the system does not “already know” whether the integration will be correct or incorrect: it is simply in a more or less favorable condition for correct integration.
These findings fit naturally into the gut-heart-brain axis. It is now well established that metabolites produced by the gut microbiome influence cardiovascular function, autonomic tone, and systemic inflammation from a distance. One of the best-known of these metabolites is TMAO (trimethylamine N-oxide), a molecule generated by gut bacteria from dietary nutrients such as choline and carnitine, which has been linked to atherosclerosis and cardiovascular risk. The heartbeat is therefore not an isolated signal: it also partly reflects the metabolic and autonomic state modulated by the gut. When the heart “talks” to the brain through the HEP and heart-locked oscillations, it is in effect conveying information that may originate further upstream, in the interaction between the gut microbiome and the autonomic nervous system.
From this perspective, the pre-stimulus predisposition observed in the study by Cobos and colleagues could represent a point of integration along a broader continuum: the gut microbiome influences the heart and the autonomic system, the heart in turn modulates cortical state, and this state contributes to determining how visual features are integrated. It is a concrete example of how multiple bodily signals—from the microbiota to cardiac activity—participate together in the construction of first-person perceptual experience.
https://www.biorxiv.org/content/10.64898/2026.05.22.726192v2
This continuum is precisely the territory explored by the Bravo Microbiome Restoration System: by supporting the biodiversity and resilience of the gut ecosystem, Bravo aims to influence the very upstream signals that shape the heart-brain dialogue and, ultimately, embodied perception.
Fulvia Gianetta