EEG segments synchronized to be temporally farthest from the R-waves in ECG are more informative during listening to music

Listening to music affects synchronization between electroencephalograms (EEGs) and cardiac rhythmic activity. This interaction between cardiac and electrical responses led us to investigate whether EEG segments extracted during different portions of the cardiac cycle can better reveal the effects produced while listening to music. We used three portions of cardiac-synchronized EEGs: Pre-R-peak, post-R-peak, and mid-R-peak. In addition, tempo, cognition of music, and different frequency bands of EEGs were considered to find whether these effects were more localized within certain regions of the cardiac cycle. Responses were investigated using eigen decomposition of autocovariance of EEG segments. Results showed an increase in complexity of brain response by increase in the tempo of music, specifically in the parietal lobe, and triggering the smallest changes by slow tempo song (compared to other played songs), possibly explaining the calming effects of slow music. A stronger effect of cognition of music was observed in frequencies >38 Hz, particularly in the temporal lobe, and a stronger response to slower tempo music was observed in frequencies<38 Hz. Larger sensitivity of EEGs to cardiac phases was in frequency bands <38 Hz. Alpha and Beta bands were the most sensitive bands to auditory stimuli and to cardiac phases, respectively, and in both of them, effects of tempo were larger than cognition of music. Overall, we observed that the mid-R-peak portion, which is temporally farthest from R-waves, showed the effects of music in a much more significant way than the other two portions.