Enhancement of heartbeat-related brain potentials through cardiac awareness training.

Heartbeat synchronous potentials were found to be sensitive to differences in perceptual accuracy. Since heartbeat perception can be improved using appropriate training procedures, increased ability to perceive cardiac performance should also influence heartbeat-related potentials. In the present study, subjects in either of two groups had to press a button immediately after the occurrence of a heartbeat-feedback tone. Whereas the first group was given acoustical heartbeat-feedback throughout the entire training, the second group was provided with tone signals that became fainter during the course of the training phases. The better posttraining performance in heartbeat perception of the group receiving full-intensity feedback was also reflected in the evoked potentials. They differed markedly before and after training, especially between 250 to 400 ms (after the EKG-R-wave), the biggest effect being at Fz and F7. The findings are interpreted as the brain electrical reflection of an increased perception susceptibility to a cardiovascular signal occurring at about 200 ms after the R-wave.