The Neurocognitive Effects of Total and Partial Sleep Deprivation in Younger Adults.

This study aims to examine how total and partial sleep deprivation affect brain function, cognitive performance, and biomarkers related to stress and inflammation in the same participants using a crossover design. The study will also compare the effects of total and partial sleep deprivation to determine whether these conditions affect the brain and body differently. The findings may improve our understanding of the consequences of sleep deprivation and help inform strategies to reduce its negative impact on health and society. * How does total versus partial sleep deprivation affect brain activity during rest and cognitive tasks? * How does sleep deprivation affect functional connectivity between brain networks? * How does sleep deprivation affect working memory, attention, and executive control? * How does sleep deprivation affect biomarkers of stress and inflammation, such as cortisol? * Are changes in brain activity and connectivity associated with changes in cognitive performance and biological markers? * Can combining MRI-based and non-MRI-based measures provide a more complete picture of the effects of sleep deprivation? Participants will complete three study conditions in a randomized order: Total Sleep Deprivation (TSD): 28 to 32 hours of continuous wakefulness. Partial Sleep Deprivation (PSD): sleep restricted to 4 hours per night for two consecutive nights. Normal Sleep (control condition): a night of habitual sleep without sleep restriction.