"There's new evidence that the brain's activity during sleep isn't random. And the findings could help explain why the brain consumes so much energy even when it appears to be resting."

"'There is something that's going on in a very structured manner during rest and during sleep,' says Stanford neurologist Dr. Josef Parvizi, 'and that will, of course, require energy consumption.'"

"For a long time, scientists dismissed the brain's electrical activity during rest and sleep as meaningless 'noise.' But then studies using fMRI began to reveal patterns suggesting coordinated activity."