Enhanced structure-function coupling of the sensorimotor network following partial sleep deprivation and its...

Sleep deprivation is known to disrupt large-scale brain network organization and impair vigilance, yet its influence on the coupling between brain structure and function-and whether such neural changes help explain vigilance decline-remains insufficiently understood. In this study, we analyzed resting-state fMRI, diffusion-weighted imaging, and psychomotor vigilance task data from 54 participants of the Stockholm Sleepy Brain Project to characterize how partial sleep deprivation reshapes structure-function coupling (SFC) at both system and network levels, and how these changes relate to vigilance performance. Our findings revealed that cortical SFC significantly increases after partial sleep deprivation, predominantly driven by the sensorimotor network (SMN). Critically, enhanced SMN coupling was significantly correlated with individual differences in baseline performance: participants with more fragile vigilance exhibited a more pronounced SFC enhancement. These findings remained invariant among the younger and older adults. Overall, our results suggest that insufficient sleep is accompanied by increased structural constraints on functional connectivity in SMN. This enhancement may reflect a trait-like vulnerability, whereby individuals with lower baseline vigilance are more likely to exhibit stronger structural constraints on SMN functional activity when exposed to sleep deprivation, highlighting the potential of network-level SFC and baseline vigilance as predictive markers of vulnerability to sleep deprivation.