Wouldn't it be nice if we could get a full eight hours of restful sleep but still have our brains working for us?
Scientists now say that may be possible. Research is beginning to show that our brains don’t go completely offline during a doze, but are actually busy organizing and storing away memories of events — and may be quite open to other activities.
In fact, a new study has shown that the brain can be started on a task just as a person is dropping off to sleep and then, during slumber, take in new auditory information and then process it, according to a report published Thursday in Current Biology.
“During sleep people are far from being totally shut down from the environment,” said the study’s lead author, Sid Kouider, a professor at the Ecole Normale Superieure in Paris. “They can continue performing what they were doing before falling asleep and this can involve understanding the meaning of what is being said around them.”
To take a look at what the brain was capable of during sleep, Kouider and his colleagues outfitted 18 volunteers with scalp sensors to detect brain waves.
While awake, the volunteers listened to a list that contained two categories of words: animals and objects. They were instructed to push a button with their left hand if the word denoted an animal and with the right for an object. All the while, the researchers monitored brain waves to determine which nerve cells were sparking during the task.
The same procedure was repeated after the volunteers were moved to a darkened room where they could lie down and drift off to sleep. Once the volunteers were fully asleep, a list of different animals and objects was read aloud to them.
Intriguingly, the same nerve cells that prompted the left or right hands to push buttons while the volunteers were awake began to fire. Because the volunteers were asleep, there was no actual movement, but the brain had gone through the same process as it had when awake.
The new findings fit in well with other recent research showing that people can indeed use their brains while sleeping, said Ken Paller, a professor of psychology and the director of cognitive neuroscience program at Northwestern University.
For example, in a study Paller performed, a group of volunteers learned to play a simple melody on a keyboard. Then, the melody was played quietly over and over for half of the group as they slept. The other half slept in complete silence. When the volunteers woke up, the ones who had been in the room with the music were able to play the melody better.
Kreigh Knerr used sleep-rehearsal to his advantage when he was back in college. “I was an opera performance major and I struggled to memorize my music,” said the 29-year-old business owner from Waukesha, Wisconsin. “I learned that if I studied my music hard just before bed that I would dwell on it and dream upon it through the night. Using that approach, I memorized my music much faster.”
Jodi Hersh, a 46-year-old graphic designer from Atlanta, often works through design problems while dozing. “In some cases I literally dreamed the design concept implemented the next day,” Hersh said. “In others I was literally clicking and designing and drawing in my sleep as I would on the computer, waking with the answer to whatever I was struggling with the night before.”
Experts aren’t sure how much work you can get your brain to do during off hours, but Kouider says he can imagine, for example, that people performing calculations on simple equations while falling asleep might then continue to work on the problem.
Like anything else that sounds too good to be true, giving after hours jobs to your brain may come at a cost, said Dr. Alon Avidan, a professor of neurology at the University of California, Los Angeles and director of the UCLA Sleep Disorders Center.
The brain already has lots of work to do during sleep, Avidan said. Like a librarian shelving new books, the brain must take memories of events that occurred during the day, decide where to store the important ones and then come up with a card catalog for accessing them later.
Giving the brain a task to do during sleep might be like distracting the librarian from shelving with a long phone call. Or, alternatively, sleep might not be as restorative, Avidan said.
That appears to be the price that Sarah Weissman seems to be paying for making her brain work overtime.
“My sleep is like a nightshift for a small business,” said the 58-year-old entrepreneur and mother of two from Highland Park, Illinois. “I solve problems for myself and others. It’s exhausting!”
Linda Carroll is a regular contributor to NBCNews.com and TODAY.com. She is co-author of "The Concussion Crisis: Anatomy of a Silent Epidemic” and the recently released “Duel for the Crown: Affirmed, Alydar, and Racing’s Greatest Rivalry.”