Excessive resting state PAC has also been reported in primary motor cortex and adjacent motor regions of Parkinson's disease (PD) patients in a PA domain encompassing the 10–25 Hz phase frequency by 30–200 Hz amplitude frequency range (de Hemptinne et al., 2013; López-Azcárate et al., 2010; van Wijk et al., 2016; Yin et al., 2022). Pathologically strong beta-gamma PAC seen in unmedicated Parkinson's disease patients was associated with more severe motor symptoms, both of which were dramatically reduced following levodopa treatment (López-Azcárate et al., 2010; van Wijk et al., 2016). PD patients also exhibited strong beta-gamma PAC in the motor cortex accompanying freezing of gait with gait freezing temporally aligned with increased beta-gamma PAC (Yin et al., 2022). It has been suggested that observed excessive PAC might reflect a pathological restriction of motor cortex to a monotonous pattern of coupling that make it less responsive to signals from brain regions mediating voluntary movement (de Hemptinne et al., 2013). In fact, results from a recent study have provided evidence indicating that temporal PAC dynamics may be as important as changes in
