The discovery of rapid eye movement sleep (REM) about 75 years ago shattered the long-held idea that sleep was a passive condition. Even while scientists weren’t sure what the brain was doing during REM sleep, it was clear that it was doing something. There is no one opinion on why humans sleep, but many sleep experts believe that REM sleep, the period in which we dream, permits our brains to encode and restructure data. Non-REM sleep, on the other hand, is primarily concerned with healing the brain from the stresses of everyday life.
Researchers from several fields have now discovered a time in early infancy when children’s REM sleep decreases dramatically. Their findings, which were published today in Science Advances, show that the function of sleep changes in youngsters between the ages of 2 and 3 from one of restructuring and learning to one of brain repair from everyday pressures and wear.
Co-author and biomathematician Van Savage of the University of California, Los Angeles said the study’s success may be attributed to bringing together experts from many fields, including mathematical physical theory, statistical data analysis and conventional sleep specialists.
Researchers from Savage’s team were keen to dissect opposing hypotheses regarding the functions of our brains and bodies while we are asleep. Because of this, they’d attempt something a little different: a quantitative approach to analysing existing data.
Savage and his colleagues combed through prior studies to find any hints as to the significance of sleep for their investigation. A total of 60 research were analysed to examine if there was a consistent pattern in the sleeping brains of adolescents and teens, as well as a few other animals, across mammal species. It was determined that the brain’s metabolic rate, the brain’s general size, and the amount of time spent in REM sleep vs non-REM sleep could be studied using a mathematical model.
Human newborns’ REM sleep (the stage linked with restructuring) declines dramatically at the age of 2.4 years, according to their data analysis. Non-REM sleep becomes more prevalent in toddlers’ sleep patterns after the age of two, implying that sleep becomes primarily for repair. Researchers also looked at how much time rats, rabbits, and Guinea pigs spend in REM sleep as they aged, but they didn’t detect this rapid shift. Human brain development is dependent on sleep, and this research shows that sleep’s role may adapt as our brains’ demands change, adds Savage.