Sleep is essential for both cognition and maintenance of healthy brain function. A study used accelerated neuroimaging to measure physiological and neural dynamics in the human brain. They discovered a coherent pattern of oscillating electrophysiological, hemodynamic, and CSF dynamics that appears during non–rapid eye movement sleep. Large oscillations of fluid inflow to the brain appeared during sleep and were tightly coupled to functional magnetic resonance imaging signals and entrained to electroencephalogram slow waves.
These results demonstrate that the sleeping brain exhibits waves of CSF flow on a macroscopic scale, and these CSF dynamics are interlinked with neural and hemodynamic rhythms.
Fultz NE, Bonmassar G, Setsompop K, Stickgold RA, Rosen BR, Polimeni JR, Lewis LD: Coupled electrophysiological, hemodynamic, and cerebrospinal fluid oscillations in human sleep. Science 2019, 366(6465):628-631.