Sleep-wake-dependent brain plasticity in health and depression

Sleep insufficiency is prevalent, impairs human functioning, and causes vast negative health effects and societal costs. Sleep disturbances are also common in individuals with neurological and psychiatric disorders. In addition, one night of sleep deprivation has robust antidepressant effects in major depressive disorder (MDD), yet the majority of sleep deprivation-responders relapse after recovery sleep. We and others have recently found evidence for structural and functional brain changes after hours of wake and sleep using magnetic resonance imaging (MRI), including alterations in cerebral cortical thickness, white matter microstructure, cerebral blood flow, and functional brain connectivity. Together, the results raise the prospect of sleep-wake-dependent human brain plasticity. However, the relationship between these plasticity processes and antidepressant response to sleep deprivation in MDD remains unknown. The overall goals of this project are A) to clarify whether structural and functional brain plasticity are characteristics of the human sleep-wake cycle and B) to reveal neurobiological mechanisms underlying the acute antidepressant effects of sleep deprivation and relapse of depressive symptoms after recovery sleep in MDD. We will examine 100 healthy controls and 50 individuals with MDD using structural and functional MRI techniques before, during, and after one night of sleep deprivation and recovery sleep. By combining in vivo brain imaging with characterization of sleep and psychiatric phenomenology, this research project has the potential to provide new knowledge about sleep and wake in health and depression.