Scientists have long known that our brains are busy at work while we sleep: creating and consolidating memories, clearing out toxins and processing importation information that we might need to recall in the future.
However, there's now even more support for "sleeping on" a problem before making a decision. The brain activity patterns that consolidate memories while we sleep work at an impressive rate, according to research published last week in the journal Cell Reports.
Better understanding this process provides even more evidence for how important a good night's sleep is for a strong memory and healthy brain, said Dr. Jack Mellor, a neuroscientist at the University of Bristol in England and a co-author of the study.
"By understanding how sleep helps memory, it may be possible in the future to assist the people with memory deficits by manipulating their sleep patterns," Mellor told The Huffington Post.
For the study, the researchers recorded a rat's brain activity while it slept and while it explored a new environment during wakefulness. While analyzing their recordings, the scientists looked closely at the behavior of firing neurons in the rat's hippocampus, an area of the brain associated with memory.
They found that the same firing patterns that occurred during exploration happened again, but at fast-forward speed, during sleep.
They further examined this so-called "reactivation" of brain activity in experiments and concluded that activity from the day is often replayed while we sleep to strengthen connections between nerve cells, which provides a mechanism for consolidating memories.
"The reactivated patterns of activity found during sleep are much faster than the original patterns during waking," Mellor said.
"The surprising finding is not so much that reactivated firing patterns consolidate memory, since this has been proposed before," he added. "What is surprising is the relatively few reactivations that are required to strengthen the nerve connections. Our work shows that as few as 10 reactivations occurring in a five-minute sleep time are sufficient."
The researchers proposed that our brains can work so quickly while we sleep because they aren't constrained by real-time events.
Why do we dream when we sleep? Watch the "Talk Nerdy To Me" episode below to find out.