Why do babies sleep so much? It turns out, a good night’s sleep, especially early in life, can have profound implications for the brain’s ability to form important social bonds throughout life, according to new research.
The research was published Jan. 30, 2019, in the journal Science Advances.
“Results from these studies may ultimately inform our understanding of modifiable factors that shape social development through sensory processing,” the researchers conclude. Their results suggest that early sleep disruption could lead to impaired sensory processing of social cues, a relevant feature of neurodevelopmental disorders including autism.
Juvenile mammals, including humans, sleep more than adults. During this time, rapid eye movement, or REM, sleep is at a lifetime maximum. Because this early period of life corresponds to rapid changes in the cortical area of the brain, researchers wanted to test the role of REM sleep in shaping the development of complex social behaviors later in life.
Researchers focused on prairie voles, a social rodent species that forms lifelong pair bonds. The researchers discovered that early life reduction of REM sleep by just 25% caused lifelong changes in the balance of excitation and inhibition within brain regions involved in sensory integration, as well as long-lasting impairments in social huddling among prairie voles.
In this study, researchers used an unobtrusive method to disrupt the sleep of juvenile voles for one week during a time period roughly corresponding to the human first year of life. “Our method of REM sleep disruption doesn’t cause stress or disturb parental care, which are common hurdles in developmental sleep research,” said lead author Carolyn Jones, Ph.D., a post-doctoral researcher in neurology and behavioral neuroscience in the OHSU School of Medicine. Other authors included OHSU faculty Deborah Finn, Ph.D., and Florida State University faculty Elizabeth Hammock, Ph.D.
“It’s a novel finding that may provide an answer to one of biology’s greatest mysteries,” said senior author Miranda Lim, M.D., Ph.D., staff physician and investigator at the VA Portland Health Care System and assistant professor of neurology in the OHSU School of Medicine. “The finding has profound implications for examining sleep as a modifiable risk factor in neurodevelopmental disorders, and our hope is that this will lead to more awareness of how well human infants sleep.”
“Together, our results support the hypothesis that one of the conserved functions of early life sleep is to shape the developing brain.” the researchers wrote. “When sleep is disrupted during sensitive periods of sensory development, long-lasting changes in social behavior may result.”
This project was supported by Portland VA Research Foundation, Brain & Behavior Foundation, Collins Medical Trust, NIH, VA Office of Research and Development, and The Florida State University and the Good Nature Institute.