Genetic variation in a brain-cleansing water channel affects human sleep

The reason why we sleep remains an unresolved question of the 21st century. Research by Sara Marie Ulv Larsen, Sebastian Camillo Holst and colleagues from the Neurobiology Research Unit at the University Hospital Copenhagen, published this week in open access journal PLoS Biology, now shows that the depth of non-rapid-eye-movement (nonREM) sleep in humans is associated with different genetic versions of a gene that encodes a water channel involved in fluid flow in the brain.