Heartbeat evoked potentials (HEP) capture brain activity affecting subsequent heartbeat

Abstract

Beat-to-beat heart rate variability is known to be associated with neural activity not only in areas regulating reflexes but also in higher brain areas; however, temporal aspects of involvement of higher brain functions are not clear. The temporal dynamics of brain activity in relation to heart activity can be captured by heartbeat evoked potentials (HEP). The aim of this study is to investigate whether HEP amplitudes across the cardiac cycle could reflect brain activity which contribute to the regulation of the heart rate. We present a new method to analyse the human brain–heart interactions by contrasting EEG activity with respect to relative duration of EKG R-R intervals. Healthy participants were asked to sit still and fixate their gaze on the computer screen while EEG and EKG were recorded. EKG R peaks were identified and used for splitting EEG data into epochs. All epochs were classified into two groups depending on the difference between adjacent R-R intervals (RRI), i.e., whether the epoch-related RRI was longer (shorter) than the subsequent RRI. HEPs associated with prolongation vs. shortening of RRI were compared by the permutation test. HEP amplitudes in the middle of diastole were more positive at centro-parietal scalp sites before prolongation of RRI (i.e., before deceleration of the heart rate) compared to amplitudes before shortening of RRI (i.e., before acceleration of the heart rate). We show that the method of contrasting HEPs allows capturing brain activity, which contributes to the postponement of the subsequent heartbeat.