So, the last time an 11-year-old girl asked what happens in the brain when we wake up. The experts — an associate professor of Psychiatry and Behavioral Neuroscience and a medical student-answered her.
How does the brain wake itself from sleep? This question continues to baffle scientists. However, researchers find clues by studying people’s brains as they switch between sleeping and waking.
One way scientists can study brain activity is by using a tool called electroencephalography, or EEG. The EEG measures electrical signals coming from thousands of brain cells called neurons, and activity in the subject’s brain is displayed in wavy lines.
Although you may think that your brain is “off” during sleep, it is like riding a roller coaster in reality. A person cycles through four different stages of sleep, each of which manifests itself on the EEG in the form of different patterns. There is also the REM sleep phase when we usually dream.
It turns out that each stage of sleep is also associated with different chemicals in the brain. They are called neurochemicals and are a way for brain cells to interact with each other.
One of the main brain systems that wake us up is called the reticular activating system, or RAS. The RAS is a part of our brain located just above the spine that acts as a filter for the brain, making sure that it does not have to deal with more information than it can process.
RAS can perceive important information and create neurochemicals that awaken other parts of the brain. It also keeps us awake during the day.
If, for example, a person needs to go to the toilet in the middle of the night, the RAS picks up this signal from his body and flips a switch to wake up the brain. Signals coming from outside, such as the sound of an alarm clock, can also turn on our race.
But after “turning on,” it may take some time for the entire brain and body to wake up. It takes a few minutes to get all the “sleepy” neurochemicals out of the brain, so we may feel sluggish after waking up on the alarm clock.
But why do we feel sleepier on some days than others? When our brain is asleep, it switches between the “deep” and “light” phases of sleep. If the alarm goes off during a deeper sleep, all brain parts take longer to wake up. But you can use technologies that track what stage of sleep you are in to wake you up at the most appropriate moment.
But scientists still have a lot to learn about sleep. Although we spend about a third of our lives sleeping, scientists don’t quite understand this process’s purpose. Although it is now known for sure that sleep is vital for health, especially for children, whose brains and bodies are still growing, it also restores our immune system, improves memory, and supports mental health.