Sleep must be continuous to be beneficial – hence, the less it is disrupted, the better. However, birds would crash and dolphins would drown if natural sleep were not supplemented with maintained reactivity to the environment and to the body. Therefore:
Vigilance must be high enough such that potential dangers, like minor shifts in the environment or in the organism’s physiology, can disrupt sleep.
Vigilance must also be low enough so that sleep is not disrupted for nothing.
Sleep vigilance must be error-prone: as long as the sleeping princess is unable to distinguish between a snake and a pea below her pillow, it is better for her to wake up because of a pea than to keep sleeping on top of a snake.
Such elementary considerations make it natural to hypothesize that abnormal arousals from sleep, albeit diverse in pathophysiological origin and present in a wide variety of sleep disorders, arise from malfunctions of sleep’s vigilance system.
In the Luthi lab, we work on a thorough, multi-level investigation of the different branches of mammalian sleep’s vigilance system from mice to humans, demonstrating that it offers previously overseen targets for the treatment of sleep disorders.