But despite major progress in the understanding of the neurobiology of sleep and the consequences of sleep deprivation, Frank said the reason the brain needs sleep has remained a mystery. Michael Stryker, who heads the university's department of physiology, said the study may shed some light on the matter. Stryker said in an interview. The enhancement and refinement of neural circuitry continues to a lesser extent in the adult brain, they added. The process of growth, known as plasticity, is believed to underlie the brain's capacity to control behavior, including learning and memory.
Plasticity occurs when neurons are stimulated by events, or information, from the environment.
The study represented strong evidence that one function of sleep is to help consolidate the effects of waking experience on cortical plasticity, putting memories into permanent storage, Stryker said. While the study examined sleep's effect on young cats, sleep may play a similar role in older animals and people, he added. The researchers measured in cats the response of neurons of the brain's visual cortex to the six hours of blocked vision. They said the visual deprivation triggered a rapid remodeling of neural circuitry known as ocular dominance plasticity. The researchers then examined the impact of sleep on the long-term effects of those changes by using brain imaging and making electrical recordings from brain cells.