Fig. 2: Heterogeneity of cerebral hemodynamic across the four brain regions.

a Individual example of cerebral hemodynamic cross-channel coherence: anterior–posterior (A–P); anterior–left temporal (A–L); anterior–right temporal (A–R). b Grand-averaged coherence spectrum (solid lines: mean; shaded areas: standard error). The A–P pair had lower coherence than the other two pairs, indicating greater frontal–posterior heterogeneity. c With mean coherence in wavelet scale range of s = 200–300 s, the Wilcoxon test’s with Bonferroni correction suggests that A–P pairs had the lowest mean coherence score (p = 0.02).