Abstract
Previous research has shown that laboratory-controlled sleep deprivation leads to cognitive impairments, including low vigilance and deficits in working memory. However, the robustness of sleep effects on behavior and brain dynamics in naturalistic settings remains underexplored. In this study, we investigated the impact of naturalistic, unfettered variations in sleep on behavioral performance and brain network dynamics in 39 healthy adults. Using a dynamic networks approach combined with ordinal regression, we show a significant increase in flexibility, a measure of rapid reconfigurations within the brain modules, with decreasing sleep time, particularly in the fronto-parietal control network, during a psychomotor vigilance (PVT) and visual working memory (VWM) task. This change in network flexibility was not observed during the resting state. Critically, performance itself did not change as a function of sleep, providing preliminary evidence that brain networks may compensate for having a poor night's sleep by recruiting the necessary resources to complete the task. Additional analysis assessing the regularity of sleep indicates a wider change in flexibility during PVT for irregular sleepers in networks including the limbic system, ventral attention network, and somatomotor system. These results provide new insights into the neural and behavioral correlates of naturalistic sleep modulations.