To examine the phase-angle preference of the theta-gamma PAC effect, we examined phase-sorted amplitude values based on the phase frequency, amplitude frequency, and electrodes showing significant memory-related PAC. The theta phase and gamma amplitude values were aligned and sorted into two vectors by phase angles in ascending order for each subject, collapsed across time and trials. Amplitude values were sorted based on the corresponding phase angle. Phase angles were grouped into 30 bins of 12-degree increments and the amplitudes were averaged within each phase bin (Fig. 3c shows plots of 6 bins of 60 degrees each for visualization purposes). Of note, although the phase bin number is arbitrary, the specific number does not influence PAC estimation 74. We normalized the individual amplitude distribution by the mean across all bins.
