Almost a third of our lives is spent sleeping. It is an important activity for our health and well-being. However, why we need to sleep is still not exactly clear. We know that it re-energizes us and improves our mood, but what’s really happening in the brain and body while we sleep? Recent studies have been aimed towards these questions. When we sleep, the brain is extremely active. In fact, neurons in the brain fire as much as they do during the day, so it’s really no surprise that what happens during sleeping is very important to the brain and cognitive functions.

Here are the five most amazing thing our brain does while we’re asleep:

Makes decisions

The brain makes decisions while we sleep, a new research has showed. The study found out that the brain processes complex stimuli during sleeping, and uses that information to make decisions while awake. The researchers asked subjects in the study to categorize some spoken words separated in different categories referring to animals or objects or real vs. fake words. They were asked to indicate the category of the word they heard by pressing a left or right button. When the responses became automatic, the subjects were told that they could fall asleep (they were already in a dark room). When they fell asleep, new words were introduced from the same categories. The brain monitoring devices showed that even during sleeping, the brain makes left or right responses based on the meaning of the words that were heard. When the subjects woke up, they had no memory of the words.

Researchers Thomas Andrillon and Sid Koudier wrote in the Washington Post: “Not only did they process complex information while completely asleep, but they did it unconsciously. Our work sheds new light about the brain’s ability to process information while asleep but also while being unconscious”.

Creates and stores memories

The brain creates new memories while you sleep, consolidates old ones and links recent with earlier memories during REM and non-REM sleep. Not getting enough rest can affect the hippocampus, the area of the brain involved in memory and consolidation. That’s why sleep has an important role in learning – it helps us reinforce the new information we take in for better recall later.

“We’ve learned that sleep before learning helps prepare your brain for initial formation of memories”, Dr. Matthew Walker tells the National Institutes of Health. He is a sleep researcher at the University of California, Berkeley. “And then, sleep after learning is essential to help save and cement that new information into the architecture of the brain, meaning you’re less likely to forget it”. The next time you have an exam, rest well the night before. If you don’t sleep the ability to learn new information is reduced about 40% according to Dr. Walker.

Makes creative links

Sleep can boost creativity, as the mind can make new connections in an unconscious resting state. A study at the University of California, Berkeley in 2007 found that sleep can foster “remote associates” – unusual connections in the brain, which could lead to a major enlightening moment later. After waking up, people are 33% more likely to make connections between unrelated ideas.

Clears toxins

A series of studies in 2013 found out that the important function of sleep may be to give the brain a chance of some housekeeping. Scientists at the University of Rochester found out that during sleeping, the brains of mice tested in the research clear out the damaging molecules linked to neurodegeneration. The space between the cells was increased when the mice were unconscious, allowing the brain to remove toxic molecules build-up from the waking hours.  Dr. Nedergaard, head of the research told the National Institutes of Health: “We need sleep. It cleans up the brain”. If we don’t sleep as much as we need to, the brain doesn’t have time to remove toxins, which in turn accelerates neurodegenerative disorders like Alzheimer’s.

Learns and recalls how to perform mental tasks

Information is stored in the brain’s long-term memory through the sleep spindles, short bursts of brain waves at strong frequencies that occur during REM sleep. This process helps in storing information related to motor tasks like driving or dance moves. That’s why these tasks are automatic and never forgotten. During REM sleep, the brain transfers the short-term memories from the motor cortex to the temporal lobe, where they are transformed into long-term memories.

“Practice during sleep is essential for later performance,” James B. Maas, a sleep scientist at Cornell University told the American Psychological Association. He continues: “If you want to improve your golf game, sleep longer”.