Babies, Adults Sleep Similarly
Any parent can tell you there are differences between how adults and infants sleep.
A baby who is babbling one minute can be sleeping soundly the next.
Newborns often sleep more than 16 hours a day. Normal adults usually sleep half that, or less.
Fifty percent of babies' sleep is spent in a stage characterized by rapid eye movement (REM) indicating brain activity, a lack of overall muscle tone and occasional twitching. Adults spend about 20 percent in REM sleep.
Although an electroencephalogram can indicate when the brain's neurons are firing as adults cycle in and out of the two broad stages of sleep, an EEG shows little activity in the cerebral cortex of a sleeping baby.
Because of that, scientists long believed that infants' sleep is primitive and without stages. However, a study by researchers at the University of Iowa indicates that babies and adults do not sleep so differently after all.
Mark Blumberg, of the research team that published results this month in the online journal PLoS Biology, said infants and adults have the same basic stages of sleep. As babies grow, he said, "it's more that the pattern of sleep is changing over time."
Through a series of tests on week-old rats, the researchers linked behaviors that indicate REM and non-REM sleep to specific midbrain areas also known to be crucial in the sleep of adults. From this, they concluded that the neural mechanisms of infant and adult sleep are very similar.
For the 40 million American adults who suffer from sleep disorders, such research might one day help them to sleep like babies.
-- Susan P. Williams
