A LONGITUDINAL STUDY OF CHRONIC AND TOTAL SLEEP DEPRIVATION EFFECTS ON BRAIN FUNCTIONAL CONNECTIVITY

Sleep loss disrupts cognition and emotions, however, the neural effects of different sleep deprivation types remain unclear. Using a longitudinal, resting-state fMRI design, we examined how total sleep deprivation (TSD) and chronic sleep restriction (CSR) alter brain functional organization. Twenty-eight healthy adults were scanned under three conditions: rested wakefulness (RW), after one night of TSD, and after five nights of CSR. We applied a within-subject Hub Disruption Index, a novel graph-based method, to characterize individual disruptions in functional connectivity. Moreover, we used Covariate-Constrained Manifold Learning (CCML) to further characterize the effects of TSD and CSR. Finally, to compare neural changes with subjective experiences, we used psychometric assessment of sleep quality, sleepiness and circadian traits. We observed that both TSD and CSR led to the reorganization of functional connectivity compared to RW, but each form of sleep loss perturbed distinct brain hubs. Regional changes in graph measures were prominent within subsystems of the default mode, frontoparietal, and cerebellar networks. These differences were further reflected in CCML embeddings, supporting the hypothesis that TSD and CSR exert divergent effects on brain connectivity. Moreover, subjective reports strengthen these findings: greater sleepiness correlated with reduced network integration in RW, and circadian phenotype emerged as a key factor shaping individual vulnerability to sleep loss. We demonstrated that TSD and CSR induce distinct alterations in brain functional organization, providing new insights into how different forms of sleep deprivation impact the human brain.
​Funding: Polish National Science Centre No.: 2018/29/B/HS6/01934