0211 Sleep-Preparatory Behaviors Modulate Sleep Physiology in Mice

Abstract

Abstract Introduction Prior to sleep, animals perform various sleep-preparatory behaviors, yet little is known about their contribution to sleep physiology. Sleep hygiene, which involves proper sleep preparation, is an effective treatment for insomnia in humans. The high prevalence of sleep disorders and drawbacks of available pharmacological interventions necessitate a better understanding of the ecological and evolutionary contexts of sleep. Nest-building is a sleep-preparatory behavior performed by many species. In this study, we aimed to determine whether the presence of a nest modulates sleep. Specifically, we investigated the effects of a nest on sleep/wake architecture and activity in wake-promoting neurons in mice. Methods To examine the role of nesting in sleep/wake architecture, we recorded EEG/EMG activity over 24 hrs (n=14, 7 males and 7 females) in the presence/absence of a nest. To determine whether the lack of a nest activates wake-promoting neurons, we utilized TRAP (targeted recombination in active populations) technology to label neurons activated by nest removal (n=4 mice per experimental group). Results Mice without nests exhibited increased latencies to NREM and REM sleep and spent less time asleep during the inactive/light phase. Mice without nests also exhibited shorter episodes of NREM and REM sleep and more transitions between arousal states. Additionally, our preliminary results suggest that nest removal significantly increases population activity in multiple brain regions, including several cortical and thalamic regions. Conclusion Our findings support the hypothesis that the presence of a nest facilitates and consolidates sleep. The causal role of specific neuronal populations in sleep fragmentation in the absence of a nest remains to be elucidated. Taken together, our findings provide the first evidence for a role of sleep-preparatory behaviors in the facilitation and consolidation of sleep and could shape the development of novel treatments for sleep disorders. Support This work is supported by the Sloan Alfred P. Foundation, the Brain and Behavior Research Foundation, and the Eisenberg Translational Research Award.