June 9 (HealthDay News) -- Next time you need to solve a problem, sleep on it, researchers suggest.
In a study from the medical school at the University of California, San Diego, researchers say that rapid eye movement (REM) sleep boosts creative problem solving, possibly by forming new associative networks in the brain.
"We found that -- for creative problems that you've already been working on -- the passage of time is enough to find solutions," Sara Mednick, an assistant professor of psychiatry, said in a news release from the university. "However, for new problems, only REM sleep enhances creativity."
The study findings are reported June 8 in the online edition of the Proceedings of the National Academy of Sciences.
During the study, participants were tested in the morning and again in the afternoon after a nap with REM sleep, after a nap without REM sleep or after a quiet rest period. Those who had REM sleep showed greater improvement in answering test questions than those who experienced other sleep or wake states, the study found.
"Participants grouped by REM sleep, non-REM sleep and quiet rest were indistinguishable on measures of memory," study co-author Denise Cai, a graduate student in psychology at the University of California, San Diego, said in the news release. "Although the quiet rest and non-REM sleep groups received the same prior exposure to the task, they displayed no improvement on the Remote Associates Test. Strikingly, however, the REM sleep group improved by almost 40 percent over their morning performances."
The researchers are unsure why REM sleep increases problem-solving skills. One hypothesis is that changes to neurotransmitter systems during REM sleep help the brain make those new associations between unrelated ideas.
SOURCE: University of California, San Diego, news release, June 8, 2008