a PLI value of 0 indicates no coupling or coupling with a phase difference centered around 0±π radians. For a detailed description of PLI calculation, see Stam [23]. The PLI was calculated between all channels, resulting in a 20 by 20 channel matrix. The overall (whole grid) PLI was computed by averaging all PLI values. To visualize functional connectivity, we projected the PLI scores per channel over a schematic grid representation, showing the average synchronization of the channel with the other channels of the grid (see figure 3).
