The co-modulograms of group-level PAC during rest standing, freezing and non-freezing trials were shown in Fig. 2A. We observed the highest PAC during rest standing (PBonferroni for standing versus non-freezing < 0.001, for standing versus freezing = 0.042; signed-rank test, Fig. 2B), and a significantly higher PAC during freezing trials than during non-freezing trials in the M1 (P = 0.013, signed-rank test, Fig. 2B), but not the postcentral gyrus area (P = 0.375, signed-rank test, Supplementary Fig. 2A–C). Consistent results were also revealed when PAC was computed using a 30 s window (Supplementary Fig. 1C). Taking Patient Sub8 as an example, the preferred phases of coupling were similar, but the intensities of coupling went down from standing to freezing and non-freezing trials (Fig. 2C). Notably, we did not observe significant differences in cortical beta and gamma power between freezing and non-freezing trials, while higher beta power (P = 0.007, signed-rank test) and lower gamma power (P = 0.016, signed-rank test) were indeed observed during the rest standings compared to that during walking (Supplementary Fig. 3A and B).
