Effects of Sleep Deprivation and Adrenergic Inhibition on Glymphatic Flow in Humans

The project is aimed at identifying how the adrenergic antagonist 'carvedilol' modulates the effects of sleep deprivation in healthy volunteers. The study is a double-blind, randomized, placebo-controlled, cross-over study. Investigators will include 20 healthy volunteers who will undergo three functional magnetic resonance (fMRI) imaging sessions, one at baseline, and two after sleep deprivation (one night without sleep). The two sleep-deprivation scans are performed in a randomized order where subjects receive placebo or carvedilol, in a within-subject, cross-over study design. The following domains will be described: 1) fMRI imaging of cerebrospinal fluid (CSF) pulsations (glymphatic flow) in the human brain, performed by a combination of fMRI protocols that includes structural (T1, T2, diffusion weighted) and functional (multiband/fast imaging, spectroscopy) imaging. 2) fMRI imaging during wakefulness and sleep are determined by simultaneous electroencephalographic (EEG) recordings. 3) The effects of sleep deprivation on the fMRI derived glymphatic flow signal. 4) The effects of the adrenergic antagonist carvedilol on fMRI measurements and sleep intensity. 5) Quantification of cognitive performance before and after a nap in the MRI. Cognitive testing includes: assessments of visual attention, reaction time, paired-associative memory, working memory, emotional recognition and subjective ratings of sleepiness and mood.