“…Up to 450 ms after the R wave, the HEP amplitude and the electrocardiac field partially overlap (Dirlich, Vogl, Plaschke, & Strian, ; Schandry et al., ). In the literature, there were different approaches described to overcome this possible confounding factor: in some studies, the electrocardiac field was eliminated using the Hjorth source derivation method (Pollatos et al., ; Pollatos & Schandry, ), others subtracted components possibly originating from the ECG via principal (Yuan, Yan, Xu, Han, & Yan, ) or independent component analysis (Terhaar, Viola, Bar, & Debener, ), and some newer studies limited the analysis on a time window of 455â595 ms after the R wave, during which the electrocardiac field is considered minimal (Gray et al., ; Schulz, Strelzyk et al., ). Here, we used the latter approach and analyzed HEP amplitudes during the previously established interval of R +455â595 ms. HEP amplitudes of F3 and F7, as well as F4 and F8, were collapsed to create an equalâsized 3 (frontal, central, parietal) Ă 3 (left, midline, right) electrode field on the scalp.…”