Figure 6.

Prestimulus alpha power differences between illusion and nonillusion trials. A, Time-frequency representation of alpha power differences at parietal sources. B, Time courses of alpha power (IAF ±1.5 Hz) for illusion (dashed lines) and nonillusion (solid lines) trials at occipital and parietal alpha sources, demonstrating that alpha power differences were present at parietal, but not occipital, alpha sources. Gray shaded area represents the time interval where statistically significant differences between the two trial groups was observed (corrected for multiple comparisons using cluster-based permutation testing).