Disrupting REM sleep in infant cats also disrupted the development of crucial brain and sensory functions affecting learning, according to a study in Science Advances. In a press release, a co-author said that the study had important implications for treating children and youth with psychiatric drugs that can disrupt REM sleep.
Led by researchers from Washington State University, the study involved awakening kittens intermittently during the rapid-eye movement portion of their sleep, and awakening controls during non-REM sleep. Using a surgical intervention, the researchers simultaneously monitored over time for particular aspects of neuroplasticity response during ocular development.
“In summary, we find that REM sleep plays an important role in enhancing experience-dependent plasticity in the developing cerebral cortex of cats,” the researchers wrote. “These findings support a long-standing hypothesis that REM sleep in early life promotes circuit formation. Our findings suggest that REM sleep achieves this function by promoting molecular and network events that reinforce neural patterns present during experience.”
“Analyses showed that normal vision did not develop in animals experiencing a REM sleep deficit,” explained the press release. “The researchers found that brain circuits change in the visual cortex as animals explore the world around them, but that REM sleep is required to make those changes ‘stick.'”
Co-author Marcos Frank said in the press release that, “REM sleep acts like the chemical developer in old-fashioned photography to make traces of experience more permanent and focused in the brain.” In the disruption of that REM process, he added, though a brain may adaptively learn and develop while engaged in daily activities, during REM-disrupted sleep “the brain basically forgets what it saw.”
“There is a lot of data accumulating that says the amount of sleep a child gets impacts his/her ability to do well in school,” Frank said. “This study helps explain why this might be — and why we should be cautious about restricting sleep in our children… We know there are different times in a child’s development when sleep needs increase — they are very high in babies but also in adolescents when their brains are changing rapidly.”
Frank commented that, “it is becoming more common for pediatricians to give compounds that affect brain activity earlier in life — not just Ritalin for attention deficit disorder, but also antidepressants and other drugs… The fact is, we have very little pre-clinical research data to tell us what these drugs are doing to developing brains in both the short and long term. Almost all of these compounds can potentially suppress sleep and REM sleep in particular. REM sleep is very fragile — it can be inhibited by drugs very easily.”
REM sleep critical for young brain development; medication interferes (Washington State University press release on ScienceDaily, July 3, 2015)
Dumoulin Bridi, Michelle C., Sara J. Aton, Julie Seibt, Leslie Renouard, Tammi Coleman, and Marcos G. Frank. “Rapid Eye Movement Sleep Promotes Cortical Plasticity in the Developing Brain.” Science Advances 1, no. 6 (July 3, 2015). doi:10.1126/sciadv.1500105. (Full text)