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Newborns spend most of their time sleeping -- between 16 and 18 hours a day, on average. But those hours don’t go wasted. Neuroscientist William Fifer, of Columbia University in New York, and colleagues found that newborns learn while they sleep.

“Sleeping newborns are better learners, better ‘data sponges’ than we knew,” said Dana Byrd, a University of Florida researcher who contributed to the study, in a written statement.

The study, published online in Proceedings of the National Academy of Sciences, looked at how a group of sleeping newborns reacted when a "gentle" tone was followed by a puff of air to the eyelids. The newborns responded by squeezing their eyelids together.

The procedure was repeated several times, and by the end of the training period 24 of the 26 newborns involved with the study squeezed their eyelids shut when the tone sounded without the puff of air.

“This ability of newborns is clearly reflecting a maturing of their brain capabilities,” Fifer said. “Babies, in fact, are able to demonstrate learning -- that is, to associate a response with a particular kind of stimulation and be able to remember that in a way that demonstrates they both are taking in information and are able to formulate associations between things.”

Past research has demonstrated the ability of newborns to learn while awake, but Byrd said this study is the first to look at how they learn while sleeping. Newborns’ sleep patterns are much different from those of older children or adults, she added.

“[Newborns] show more active sleep where heart and breathing rates are very changeable,” Byrd said. “It may be this sleep state is more amenable to experiencing the world in a way that facilitates learning.”

The act of squeezing shut one’s eyelids is reliant on a functioning cerebellum, the study explained. The cerebellum is located in the back of the brain, just above the brain stem, and is responsible for coordinating sensory input with muscular responses. This technique could therefore be used to monitor newborns’ cerebellar function and possibly identify those babies who might be at risk for neurodevelopmental disorders in the future, Fifer said.

“[The cerebellum] has been found to be deficient or act abnormally in other neurobehavioral disorders, such as autism and attention deficit disorder,” Fifer said. The technique could serve as a screen or early marker to spot these disorders earlier, he added.

During the procedure, researchers were also able to monitor the newborns’ brain activity via an electroencephalograph (EEG) net. The 24 infants who demonstrated learned behavior also registered a change in their brainwave patterns.

“When infants first hear the tones, they behave as if it is just a sound – they don’t blink  - and the brain’s auditory system responds as it would to any repeated sound,” Fifer said. “However, after the puff of air is paired many times with the tone, the brain reacts and processes the sound as something else, a signal that something is going to happen – in this case, a puff of air. So now, a tone is not just a tone.”

Fifer suggested this research could be used in the future as another technique for assessing a newborn’s brain development.

“It’s embarrassing how few tools we really have to assess early brain development in newborn infants,” Fifer said. “This could be part of another group of tools that would help ask better questions about how it is that a babies’ brain is developing.”