Appendix 1—figure 1. Analysis of periodic and aperiodic features of the prestimulus power spectrum.

(A) Group-average prestimulus aperiodic-adjusted power spectrum shown separately for the five bins sorted from weak ($Q_1$) to strong ($Q_5$) total-band power. (B) Group-average offset (dark) and slope (light) of the aperiodic signal sorted from weak ($Q_1$) to strong ($Q_5$) total-band power. The results in A and B are shown for the frequencies and electrodes of most positive/negative t-statistics, collapsed across the significant clusters of Figure 3. (C) Group-average normalized ERP amplitude on trials sorted by total-band power, aperiodic-adjusted power, offset and slope. ERP amplitudes were compared across most extreme bins ($Q_{5-1}$) at the ERP time point and the prestimulus-power electrode and frequency of most positive/negative t-statistics, separately for each component and trial type. $***$, $**$, $*$ indicate FDR-corrected p-values<0.001, 0.01, 0.05, respectively. $cs$ indicates significant p-values based on cluster-level statistics (see Figure 3).