Abstract Lucid dreaming (LD) is a state of conscious awareness of the current dream state, predominantly associated with REM sleep. Research progress in uncovering the neurobiological basis of LD has been hindered by low sample sizes, diverse EEG setups, and specific artifact issues like saccadic eye movements and signal non-stationarity. To address these matters, we developed a multi-stage preprocessing pipeline that integrates standardized early-stage preprocessing, artifact subspace reconstruction, and signal-space projection. This approach enhanced data quality by precisely removing saccadic potential effects even in setups with minimal channels. To uncover the electrophysiological correlates of LD, we applied this methodology to LD data collected across laboratories and explored sensor- and source-level markers hypothesized to underlie LD. Compared to non-lucid REM sleep, in line with recent findings we observed few robust differences on the EEG sensor level. In contrast, on the source level, beta power (12-30 Hz) was reduced during LD in right central and parietal areas including the temporo-parietal junction, potentially associated with a conscious reassessment of the veridicality of the currently perceived reality. Gamma1 power (30-36 Hz) around the onset of LD eye signaling increased in right temporo-occipital regions including the right precuneus, in line with its involvement in self-referential thinking. Source-level connectivity analyses revealed alpha (8-12 Hz) mediated communication between anterior frontal and posterior areas, which are usually functionally disconnected during non-lucid REM sleep. Taken together, these findings illuminate the electrophysiological correlates of LD, laying the groundwork for decoding the mechanisms of this intriguing state of consciousness. Significance Statement Lucid dreaming (LD), the state of metacognitive insight into one’s current dream state, has fascinated humans for millennia. Despite decades of neuroscientific inquiry, the brain mechanisms underlying LD remain elusive. Leveraging a newly developed electrophysiological preprocessing pipeline to overcome signal artifacts and harmonize different recording set-ups, this study decoded the spectral nature of LD at the sensor and source levels within a high sample size dataset. Our results point to reductions in temporoparietal beta as well as increased gamma in precuneus in lucid over non-lucid REM sleep. These results enhance our understanding of LD’s mechanisms and ultimately pave the way for targeted induction protocols that will unlock LD’s full clinical potential.

Electrophysiological correlates of lucid dreaming