Fig. 5
Effect of the scalp location of the interpolated signal (i.e., reference-electrodes; LOCref) and its interaction with distance between electrode pairs (DISTpair), number of electrodes (Ne), and SSI parameters m and λ. The p-values in the titles or legends of each graph stands for those of repeated measure ANOVAs testing significance of LOCref effect in the corresponding condition. a Error-bars of PLV difference (dPLV) across 11 locations of reference-electrodes in near and distant pair-electrodes, depicting a significant LOCref by DISTpair interaction; dPLV was significantly different across the 11 reference electrodes in distant pair-electrodes, but not in near pair-electrodes. Two-way interactions of LOCref by Ne (b and c), LOCref by m (d and e), and LOCref by λ (f and g) depicted for near (left panels) and distant pair-electrodes (right panels) illustrate the three-way interactions among them. Significant LOCref effect in distant pair-electrodes were even larger with 128 channel electrodes, m = 4, and λ = 1e-8, which caused large interpolation errors. LOCref effect was even significant in near pair-electrodes when SSI was conducted with these levels of Ne, m and λ