All the cats in the study had one eye sewed shut and were kept awake for 6 hours, by gently moving their cages or playing tapes of meowing, to allow these modifications to begin. Then some cats were allowed to sleep, while others were kept awake for 6 more hours, some in the dark and others in the light. Frank and his colleagues used microelectrodes to measure the activity of neurons within the visual cortex and gauge the degree of neural remodeling as the brain adapted to the loss of stimulation. Cats that were allowed to sleep after the initial 6-hour period showed more than twice the degree of neural change compared to those kept awake in the dark. The results suggest that sleep enhances brain remodeling, the researchers report in the April issue of Neuron , and may explain why young mammals with growing, developing brains sleep so much.
Sleep experts are impressed.