Figure 1.
Electrocardiography (ECG) and electroencephalography (EEG).
One cycle of ECG includes various deflections, P, Q, R, S (QRS complex) and T. All R peaks of ECG recordings were detected to obtain the RR interval (RRI) time series. Each EEG recording includes brain waves from 19 electrode sites, one ECG recording and one trace of photic stimulation (PS).
Figure 2.
Examples of RR interval (RRI), detrended EEG and the multiscale entropy (MSE) profiles of them.
One RRI time series and one detrended single-channel EEG signal are shown on the left-hand side of the figure. MSE-RRI 1-3 are examples of the MSE profiles showing the MSE values of RRI from scale 1 to scale 20, while MSE-EEG 1-3 are examples of the MSE profiles showing the MSE values of EEG from scale 1 to scale 20. All the MSE-profiles show an initial increasing before a plateau or a fall.
Figure 3.
Inverse association between the multiscale entropy (MSE) values of the awake RRI and resting-awake EEG.
(a) Regions with significant inverse correlation between the summed MSE values on the scales 11−20 of the awake RRI and the summed MSE values on the scales 6−20 of the resting-awake EEG after Bonferroni corrections (corrected p-values = original p-values19, alpha = 0.05). r and p denote the Pearson’s partial correlation coefficient and corrected significance level, respectively. (b) The brain map illustrates regions with significant association. The relative brightness is according to the sequential p-values from the smallest one (Fp2, C4, T6 and T4).
Figure 4.
Inverse association between the multiscale entropy (MSE) values of the awake RRI and fast-PS EEG.
(a) Regions with significant inverse correlation between the summed MSE values on the scales 11−20 of the awake RRI and the summed MSE values on the scales 6−20 of the photic-simulated EEG at frequency 12, 15, 18 and 24 Hz (fast-PS, duration 10 seconds and interval 10 seconds) after Bonferroni corrections (corrected p-values = original p-values19, alpha = 0.05). r and p denote the Pearson’s partial correlation coefficient and corrected significance level, respectively. (b) The brain map illustrates regions with significant association. The relative brightness is according to the sequential p-values from the smallest one (O1, O2 and C4).