Identification of neurophysiological markers of interoceptive signals using the event-related potential technique

The paper is devoted to presentation and assessment of the algorithm for extraction of heartbeat evoked potential (HEP) using the independent component analysis (ICA). The algorithm includes simultaneous recording of electroencephalogram (EEG) and photoplethysmogram (PPG), selection the EEG-epochs, related to the peak of the PPG pulse wave, separation of cardiac and brain activity in the epochs using the independent component analysis (ICA), synchronization the epochs with the R-wave of the cardiogram. Current source density (CSD) transformation was applied to establish the localization of the extracted potential. The algorithm was tested on 21 subjects and revealed a characteristic increase in evoked potential amplitude between 0 and 400 ms after a heartbeat. Application of independent component analysis and spatial filtering to EEG epochs, synchronized with PPG recording of heartbeat, allows to extract the heartbeat evoked potential, separately from cardiac field artifact.