Fig. 4: Aperiodic and oscillatory components code task content.

A, B Decoding of task content (alphanumeric vs. colour) using (A) the aperiodic and (B) the oscillatory activity for each task. All MEG/EEG sensors were used for decoding. Each dot means one participant. Error bars represent standard errors. ^***p < 0.001 (FDR-corrected). C, D Source estimation patterns for content decoding averaged across all tasks for (C) aperiodic and (D) oscillatory signals. Coloured regions represent the 60th to 100th percentiles of activation (colour vs. alphanumeric discrimination) across the brain. Positive values (red) indicate increased activity (or a shallower slope) in the colour condition compared to the alphanumeric condition. Source estimation patterns for each task separately are shown in Figure S4. E Pearson’s correlation results between source estimation patterns (360 ROIs in source space) that coded task content from oscillatory power in different frequency bands. Left: Scatter plots using data averaged across subtasks and participants for illustration. Each dot represents a cortical ROI. Right: Correlation coefficients from within-subject analyses, each dot represents a single participant. ^***p < 0.001 with 1000 permutations. F, G Representations of task demand and task content in two-dimensional space extracted from (F) the aperiodic and the (G) oscillatory signals from all MEG/EEG sensors. Abbreviations as shown in Fig. 2.