Abstract
Neuroimage. 2026 Oct 19:122301. doi: 10.1016/j.neuroimage.2026.122301. Online ahead of print.
ABSTRACT
Sleep and circadian rhythms both influence human brain function, but their distinct contributions to large-scale network organization remain unclear. We quantified the effect of brain state (wake, NREM, REM), sleep-wake history, and circadian phase on functional connectivity using over 1,200 hours of artifact-free EEG recorded during a 10-day forced-desynchrony protocol. We derived principal components of functional connectivity and found that both sleep-wake history and circadian phase significantly modulated functional connectivity, with sleep-wake history exerting a broader influence. Complementary cosinor analyses further demonstrated circadian rhythmicity in several NREM and REM connectivity measures. Across sleep, global connectivity increased progressively during NREM sleep, particularly in the delta and sigma bands, but declined during REM sleep. During controlled resting wakefulness, increasing time awake was associated with higher global alpha-band connectivity, which was associated with poorer concurrent cognitive performance. Connectivity during NREM sleep was also associated with subsequent cognitive performance, with lower global theta and, to a lesser extent, higher sigma connectivity linked to better performance. REM connectivity was not associated with these cognitive measures. Together, these findings reveal opposing NREM and REM trajectories in large-scale EEG functional connectivity and show that these brain-state-specific network dynamics are shaped by both sleep-wake history and circadian phase and are associated with cognitive performance.
PMID:42896690 | DOI:10.1016/j.neuroimage.2026.122301
UK DRI Authors
