UNCONSTRAINED SLEEP RESEARCH: USING MINI2P IMAGING AND ELECTROPHYSIOLOGY TO INVESTIGATE NATURAL SLEEP DYNAMICS IN MICE

Our project aims to investigate neural, glial and vascular dynamics during natural sleep in freely moving mice. To date, sleep research in mice has been bound to head-fixed setups for subcellular imaging, whilst freely moving configurations have been confined to electrophysiological recordings and imaging approaches of lower resolution. These included fiberphotometry, which is limited to bulk fluorescence signals and 1-photon miniscopes, which include cellular resolution. Mini2p achieves subcellular resolution within freely moving conditions. Although head-fixed setups provided us detailed insights into cellular and subcellular mechanisms, they do not allow mice to assume natural sleep positions or engage in preparatory behaviors such as grooming and nesting. This could have wide-ranging consequences for sleep depth and other sleep characteristics. To obtain a comprehensive yet detailed picture, we have developed an experimental setup that combines mini2p imaging with simultaneous electrophysiological recordings, providing us with exhaustive monitoring of brain activity during unconstrained stress-free sleep. Performing both measurements at the same time enables us to study sleep-state dynamics within their natural behavioral context, while capturing the interactions between neuroglial networks and vascular function throughout sleep with high temporal and spatial resolution.