Year: 2026
Type: preprint
Study design: Observational Study
Abstract: ABSTRACT Introduction The heartbeat-evoked potential (HEP) is widely interpreted as an EEG/MEG marker of cortical processing of cardiac afferent signals. A central methodological challenge in HEP research is separating genuine cortical responses to cardiac afferent signals from heartbeat-related cardiac field artefact (CA). Because both neural HEP activity and cardiac artefact are time-locked to the same heartbeat, conventional averaging and blind-source correction methods lack an observable cardiac-only reference, making their separation difficult to validate. Methods Individuals with isoelectric-appearing cerebral activity i.e. those with significant brain injury leading to a lack of detectable brain activity at the scalp, have an absence of recordable HEP signal yet preserved cardiac field artifact in brain. We used clinically acquired EEGs with isoelectric-appearing cerebral activity and preserved cardiac activity as a negative control for non-neural heartbeat-locked scalp signal. Thirty-nine isoelectric participants were compared with 118 heart-rate-matched participants whose clinical EEGs were reported as normal. Participant-level heartbeat averages were analysed using covariate-adjusted spatiotemporal permutation tests. We characterised interindividual cardiac-artefact morphology and tested the primary group contrast across average-reference, surface-Laplacian and cardiac-artefact-directed ICA analyses, with pseudotrial correction for heartbeat-independent EEG activity. Results Cardiac-artefact morphology varied markedly across isoelectric participants, was predominantly posterior or posterolateral, and was not predicted by ECG morphology. We attempted delineation of the HEP from the CA by comparing the two groups, revealing a negative frontocentral cluster that persisted in control participants at 90–365 ms, p=0.16 and a posterior cluster at 145–310 ms, p=0.03. The topography of the first cluster aligns with the spatiotemporal characteristics of the early window of the HEP as identified in the literature. This cluster was negative in polarity at the scalp. After independent component analysis, the same comparison produced a less prominent cluster. There was no significant group difference in ECG. Conclusion These findings provide an important first empirical scalp-level dissociation of the early HEP from CA using an inversion-of-ground-truth approach. A cluster of difference consistent with typical distributions of the early HEP, suggests that this part of the HEP is a distinct, frontocentral, negative cortical response. The effects of conventional independent component analysis for removing the CA suggest a risk of also removing veridical HEP signal with standard correction methods. SIGNIFICANCE STATEMENT This study uses an inversion of ground truth approach to characterise the cardiac artefact seen in EEG in the absence of brain activity, and thereby better characterise the heartbeat-evoked potential. This is of benefit for future interoceptive research as characterisation of the artefact can future approaches to preprocessing, and knowledge of the polarity of an evoked potential allows inference about whether a change in the amplitude represents more or less event-related activity. HIGHLIGHTS Heartbeat-related artefact varies in distribution between individuals. The heartbeat evoked potential is distinct from the cardiac artefact. The early part of the heartbeat evoked potential is negative.
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7171359867