Neural circuit mechanism of sensory induced arousal

Abstract

Animals keep surveillance during sleep and wakeup in response to external stimuli. While the thalamus has been known to relay sensory information to the cortex, but this function for surveillance is mostly unknown. Here, we report that mediodorsal (MD) thalamic neurons show a higher sensitivity to sound-induced wakeup episode from non-rapid eye movement (NREM) compared to natural waking. Inhibition of MD neurons or the glutamatergic brainstem-MD inputs efficiently prevents sound-induced wakeup from NREM sleep. These results explain how brains respond to potential dangers using specialized thalamic pathways during sleep. Also we made a behavioral model of vigilance fluctuation through head nodding.