Sleep essential for creative thinking

Rolling Stones guitarist Keith Richards said the riff in "(I Can't Get No) Satisfaction" came to him in his sleep, while the 19th-century chemist Dmitri Mendeleev literally dreamed up the periodic table of elements.

Now, for the first time, scientists say they have proved what creative minds have known all along: that our sleeping brains continue working on problems that baffle us during the day, and that the right answer may come more easily after eight hours of rest.

The German study is considered to be the first hard evidence supporting the commonsense notion that creativity and problem-solving appear to be directly linked to adequate sleep.

Some researchers said the study provides a valuable reminder for overtired workers and students that sleep is often the best medicine.

"A single study never settles an issue once and for all, but I would say this study does advance the field significantly," said Dr. Carl E. Hunt, director of the National Center on Sleep Disorders Research at the National Institutes of Health. "It's going to have potentially important results for children for school performance and for adults for work performance."

Scientists at the University of Luebeck found that volunteers taking a simple math test were three times more likely than sleep-deprived participants to figure out a hidden rule for converting the numbers into the right answer if they had eight hours of sleep. The findings appear in today's issue of the journal Nature.

Jan Born, who led the study, said the results support biochemical studies of the brain that indicate memories are restructured before they are stored. Creativity also appears to be enhanced in the process, he said.

"This restructuring might be occurring in such a way that the problem is easier to solve," Born said.

Born said the exact process in the sleeping brain for sharpening these abilities remains unclear. But it appears that memories start deep in an area of the brain called the hippocampus, and are eventually pushed outward to the neocortex to be consolidated.

The changes leading to creativity or problem-solving insight occur during "slow wave" or deep sleep, which typically occurs in the first four hours of the sleep cycle, he said.

The findings also may explain the memory problems associated with aging, because older people typically have trouble getting enough sleep, especially the kind of deep sleep needed to process memories, Born said.

History is rife with examples of artists and scientists who have awakened to make their most notable contributions. Samuel Taylor Coleridge wrote the epic poem "Kubla Khan" after a long night of rest. Robert Louis Stevenson credited a good night's sleep with helping him create scenes in "The Strange Case of Dr. Jekyll and Mr. Hyde." And Elias Howe came up with his idea for the sewing machine after waking up.

Other researchers have long suspected that sleep helps to consolidate memories and sharpen thoughts. But until now it had been difficult to design an experiment to demonstrate it.

Born and his team "have applied a clever test that allows them to determine exactly when insight occurs," Pierre Maquet and Perrine Ruby at the University of Liege said in an accompanying commentary.

Some 70 million Americans are believed to be sleep-deprived, contributing to accidents, health problems and lower test scores.

Maquet and Ruby said the study should be considered a warning to schools, employers and government agencies that sleep makes a huge difference in mental performance.

The results "give us good reason to fully respect our periods of sleep -- especially given the current trend to recklessly curtail them," they said.

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