From Sensorimotor to Transmodal Cortex: Sleep Quality Aligns Brain Entropy with the Cortical Functional Gradient

Sleep is fundamental to brain health, yet the mechanisms by which habitual sleep quality shapes large-scale neural dynamics during wakefulness remain unclear. This work aims at determining whether habitual sleep quality is associated with systematic alterations in regional and cross-regional temporal complexity of spontaneous neural activity.

Regional brain entropy (BEN) and cross-regional brain entropy (CRBEN) were estimated from resting-state fMRI data of the UK Biobank, with replication in the Human Connectome Project (HCP) and in a randomized total sleep deprivation experiment. Temporal complexity of spontaneous neural activity was correlated to self-reported habitual sleep quality and sleep amount in observational cohorts and experimental total sleep deprivation in the laboratory study.

Better sleep quality was associated with increased BEN in sensory and sensorimotor cortices and decreased BEN in frontoparietal control regions. High-quality sleep enhanced differentiation of temporal complexity among sensory networks while strengthening coordination within higher-order control systems. In the independent HCP cohort, sleep amount predicted increased BEN in visual and somatomotor regions. Moreover, the strength of the association between sleep measures and BEN was strongly and negatively correlated with the major cortical functional gradient. Exploratory results suggest convergent effects following total sleep deprivation. Habitual sleep quality is associated with systematic reconfiguration of the brain's temporal complexity architecture at both regional and network levels.

These findings position sleep as a fundamental determinant of the brain's dynamic operating regime and identify temporal complexity as a mechanistically informative neural signature linking sleep health to cognitive function and neuropsychiatric vulnerability.