Fig. 7: High-gamma signal coupled with a traveling wave of theta oscillations.

a Phase-amplitude coupling (PAC) of the perisaccadic period from an example electrode. High-gamma signal amplitude correlated best with the phase of theta and alpha oscillations (6–12 Hz). b High-gamma signal relative to the phase of theta oscillations (8 Hz) in the same electrodes as in (a). The High-gamma signal is highest at ±π rad and lowest at 0 rad. c Perisaccadic theta phase–high-gamma amplitude coupling across areas. Each column represents the average PAC from multiple electrodes belonging to the same cortical region. The solid black line is saccade onset. d, e Phase of theta oscillations at 90 and 110 ms from saccade onset. The phase of theta oscillations showed a gradient across adjacent electrodes. The phase of two adjusted time points shows the direction in which the phase moved along the cortical surface. f Directionality of traveling wave propagation. The black thick lines represent the direction of the traveling wave (the direction in which the same phase appeared at the next time point). The pattern of wave propagation was comparable to that of a high-gamma signal trajectory.