Riedner, B. | Search bioRxiv

bioRxiv2026

Neural Signatures of Conscious Experience During Sleep: A Serial Awakening Study Using High-Density EEG

Identifying neural signatures of consciousness remains a central challenge in neuroscience. Sleep offers a tractable model for comparing brain activity in the presence or absence of subjective experience while minimizing behavioral responsiveness confounds. Using overnight 256 electrode high-density EEG in 140 participants and a serial-awakening paradigm, we analyzed 699 non-rapid eye movement (NREM) sleep stage 2 and 3 awakenings (351 dreaming experience, 348 no experience). Features from the 60s preceding awakening included regional spectral power, lagged-coherence connectivity, graph-theoretic metrics and gamma-to-alpha power ratios. Dreaming experiences were associated with shifts in posterior spectral balance, particularly reduced alpha and delta power and increased gamma-related measures, together with altered large scale network organization. In participant-level cross-validated machine-learning analyses, all classifiers performed above chance, with the best ensemble model reaching an ROC-AUC of 0.80 and average precision of 0.80. These findings identify reproducible posterior electrophysiological and network-level signatures of conscious states during NREM sleep.

neuroscience↗

bioRxiv2026

Sleep-Related Respiratory Disruption is Associated with Altered Spindle Morphology and Poorer Attention in Children

Study ObjectivesTo determine whether sleep-related respiratory disruption is associated with regionally specific alterations in sleep spindle topography and whether hypopnea-sensitive spindle features are associated with attentional performance in children. MethodsWe recorded overnight high-density EEG in children across a wide range of respiratory disruption severity. Slow and fast spindle metrics were extracted per channel, and channel-wise regression models characterized topographic associations with hypopnea index (HI). Cluster-based permutation testing controlled for multiple comparisons. Hierarchically defined regions of interest were tested as predictors of attentional performance on the Test of Variables of Attention (TOVA). ResultsCanonical slow-anterior and fast-posterior spindle organization was detectable across the cohort. Two HI-related topographic effects survived cluster-based permutation correction: higher HI was associated with shortened anterior fast spindle duration and with slower anterior slow spindle peak frequency. In cognitive models, anterior fast spindle duration was the strongest and most consistent predictor of attentional performance, associated with higher signal detection sensitivity, fewer omission errors, and fewer commission errors. By contrast, slow spindle peak frequency showed no attentional associations. ConclusionsPediatric respiratory disruption is associated with regionally specific alterations in spindle morphology rather than global spindle reduction. Shortened anterior fast spindle duration showed convergent respiratory and attentional associations, suggesting that localized spindle integrity may provide a neurophysiological marker of cognitive vulnerability in pediatric sleep-disordered breathing beyond conventional clinical respiratory metrics. HighlightsO_LIHigher hypopnea index was associated with shortened anterior fast spindle duration and slower anterior slow spindle peak frequency C_LIO_LIAnterior fast spindle duration predicted attentional performance in children C_LIO_LIRespiratory disruption may impair attention by disrupting thalamocortical spindle activity C_LI Statement of SignificanceChildren with sleep-disordered breathing can show neurocognitive difficulties that are not well explained by standard respiratory indices alone. This study uses high-density EEG to show that hypopnea burden is associated with regionally specific alterations in sleep spindle morphology, particularly shortened anterior fast spindle duration, rather than a global reduction in spindle occurrence. Anterior fast spindle duration was also the spindle feature most consistently associated with attentional performance. These findings suggest that localized spindle morphology may provide a sleep-neurophysiological readout of cognitive vulnerability in pediatric sleep-disordered breathing. Longitudinal and treatment studies are needed to determine whether spindle duration changes with respiratory improvement and whether such changes track cognitive recovery.

neuroscience↗