Spectral analysis of F3, C3, T3, P3, and O1 for all RISE episodes in the corresponding PTI channels (F3-F4, C3-C4, T3-T4, P3-P4, and O1-O2) compared to previous “baseline” EEG segments without elevated synchronization levels. Frequency bands: delta 0.5–3.5 Hz, theta > 3.5–8 Hz, alpha > 8–12 Hz, sigma > 12–14.5 Hz, and beta > 14.5–25 Hz. Although the mean levels and durations of synchronization during RISE episodes are largely independent of the current state of vigilance, the spectral content of EEG segments contributing to RISE changes extensively (the significance levels of the differences to the other stages are given in Table 3 for F3). See text for further details.