How does lack of sleep effects your brain in short term? Likewise, what happens to our brains when we don’t get adequate sleep for a prolonged period?

Everybody knows that sleep is essential for our bodies and brains to function at their best. Otherwise, why would we be spending one third of our lives doing it? Chronic sleep deprivation puts us at a higher risk of various disorders and long term health conditions such as high blood pressure, cardiovascular disease, obesity, diabetes and mental health problems such as anxiety and depression, to name just a few.

It has also been amply demonstrated that the lack of sleep has a negative affect on our cognitive performance. At the cognitive level, the lack of sleep impairs our ability to focus, make judgements, consolidate information and learn new things. In the words of Dr Michael Breus, The Sleep Doctor, “It’s difficult to identify a cognitive skill that isn’t affected by sleep, and compromised by sleep deprivation.”

Yet, while the effect of sleep and the lack of it on our cognitive performance is very well documented, much less is still known about how exactly sleep affects the brain on the cellular level.

However, as brain science rapidly advances, more and more studies appear that begin to fill that gap. Here are four of the most prominent studies of recent years and their findings that looked closely at our sleep deprived brains.

Sleep Allows Your Brain Cells To Repair Themselves

A study published earlier this year in Nature Communications found that sleep is essential for the brain’s ability to repair itself. More specifically, scientists found that during sleep essential DNA repair processes take place in the brain.

In the course of the study, the researchers from Bar-Ilan University observed zebrafish, species that are characterized by having transparent heads. With the use of a powerful microscope, the researchers were able to observe the brain of the zebrafish during sleeping and waking, and took time-lapsed images of individual neurons. They were then able to see that during sleep the process of DNA repair kicked off in their brains, reversing the DNA damage accumulated during the day.

According to the researchers, human brain cells also regularly accumulate DNA damage not only from exposure to radiation and other undesirable conditions but also as a result of the normal brain activity. Sleep allows for these cells to be repaired.

One of the study’s authors, Professor Lior Applebaum, explained why this complicated process takes place while we sleep, by comparing it to repairing potholes in the road. Speaking to Independent, he said: “Roads accumulate wear and tear, especially during daytime rush hours, and it is most convenient and efficient to fix them at night, when there is light traffic.”

The researchers think that this finding might explain the essential role of sleep for all animals with neural system including humans.

Sleep Deprivation Kills Your Brain Cells

In a study that was published in 2014 in the Journal of Neuroscience researchers from the University of Pennsylvania School of Medicine made an alarming discovery that lack of sleep can result in irreversible loss of brain neurons.

The study was conducted on mice, whose brain is known to be surprisingly similar to the human brain. The mice were put on a schedule similar to the one that is used by people who work night shifts or long hours. In each 24 hour period, the mice got only 4 to 5 hours of sleep.

The results were astounding. After just three day of this schedule, the sleep-deprived mice lost 25% of brain cells in part of the brain stem, the damage that seemed to be irreversible.

According to the study’s authors, because of the similarity between the brains of mice and humans, it is very likely that the human brain suffers from the same loss of neurons when deprived of adequate sleep. This is something that researchers planned to further investigate by conducting autopsies of shift workers.

Sleep Helps Brain ‘Detox’

Another study published in Science around the same time, found that during sleep a sort of detox process takes place in your brain, as it gets rid of harmful waste products, including some that have been linked to Alzheimer’s and dementia.

The study was conducted by researchers from the University of Rochester Medical Center (URMC) who used high-tech imaging to look into the brains of mice and found that their brains behaved very differently when awake and asleep. Specifically, the waste removal process happened ten times faster when the mice were sleeping, flushing out among other things the toxic protein amyloid-beta that is associated with Alzheimer’s.

The clean up process observed by the researchers happens with the help of the cerebrospinal fluid that flows through the spaces between neurons flushing waste into the circulatory system. During sleep, the researchers found, brain cells contract, leaving more space for the cerebrospinal fluid to do its job a lot more effectively.

Sleep Enables Brain Cells to Communicate Effectively

In a fourth study on brain and sleep published recently in Nature Medicine, researchers found neurological explanation to the mental sluggishness that is so familiar to any of us who’ve ever had to take an exam, drive a car or perform any other cognitively demanding activity while sleep deprived. Specifically, the study authors found that lack of sleep severely impairs the ability of brain cells to communicate effectively.

In the study, 12 participants who were preparing to undergo surgery for epilepsy (unrelated to the study) had electrodes implanted into their brains and were asked to stay up the entire night. Several times throughout the night, researchers asked them to categorize images of faces, places and animals as fast as possible. They noticed that as people got drowsier, their reactions got slower. The researchers monitored the brain activity at the same time, paying particular attention to neurons in the temporal lobe, which regulates visual perception and memory. They were able to see that the slowed down response time was due to the less effective communication between their brain cells.

One of the study’s authors, Dr. Itzhak Fried, a professor of neurosurgery at the University of California, Los Angeles (UCLA) explained in a statement: “We discovered that starving the body of sleep also robs neurons of the ability to function properly. This paves the way for cognitive lapses in how we perceive and react to the world around us.”

This of course has direct consequences in everyday activities such as driving, and thus can have a fatal affect. “Severe fatigue exerts a similar influence on the brain to drinking too much,” Fried said. “Yet no legal or medical standards exist for identifying overtired drivers on the road the same way we target drunk drivers.”