Fig. 2: General temporal and spectral descriptions of all the 6 inferred states.

a Temporal domain. We illustrate the steps to extract the event-related activation profiles of all the HMM states. We epoched the statewise time courses with respect to the task information, considering 200 ms before the stimulus onset and 1200 ms after the stimulus onset. Then, each trial is baseline corrected considering the [−200, −30] ms interval as baseline. Finally, we ran the generalized linear model to extract the statewise ER activations. We plotted the constant regressor for all the states, the flat lines underneath the curves represent the time window in which the correspondent state (colour-coded) is significantly different from zero (permutation test p < 0.025, number of permutations n = 1000, multiple comparison correction via maximum statistics across states and number of regressors), hence, from the baseline level. b Spectral domain. Via multitaper, we extracted the statewise power spectral density (PSD) distribution for all regions and the coherence (COH) across all pairs of regions. We plot the average PSD and COH across regions/connections per state (bold line) and the standard deviation across subjects (shaded area). Finally, we decomposed the COH into 4 components via non-negative matrix factorization (NNMF) to identify 4 data-driven frequency bands. c State-spectral mode association. Each state is associated with the spectral mode covering the frequency window where the state’s broadband PSD/COH profiles display a peak. The spectral mode represents the frequency band capturing most of the state’s spectral activity.