Sleep is essential for cognition and maintenance of healthy brain function. Sleep changes diverse aspects of brain physiology, and exhibits unique behavioral states, electrophysiological oscillations, vascular dynamics, and waste clearance properties. Our research integrates multiple neuroimaging technologies to understand the neural circuits controlling sleep and the consequences of sleep for brain physiology. To investigate how these multiple aspects might be coupled during sleep, we used simultaneous fast fMRI and EEG to measure fluid and neural dynamics in the human brain. We found a coherent pattern of coupled electrophysiological, hemodynamic, and cerebrospinal fluid (CSF) dynamics that appears during non-rapid eye movement sleep. Our results demonstrate that the sleeping brain exhibits waves of CSF flow on a macroscopic scale, and suggests a neural mechanism that can regulate CSF flow. Next, using fast fMRI at ultra-high field (7 Tesla), we tracked subsecond dynamics throughout thalamocortical networks across transitions between sleep and wakefulness. We identified a temporal sequence of activity across individual thalamic nuclei that appears at the moment of awakening from sleep and predicts subsequent behaviour. Together, these studies develop multimodal imaging approaches for tracking human brain physiology at fast timescales, and identify neural and fluid dynamics unique to the sleeping brain.

Zoom Link: https://umich.zoom.us/j/97723483179