Brain: what is the real purpose of sleep?

Israeli researchers have found that sleep is necessary to repair brain damage accumulated during waking hours. Explanations.

We know that it is essential to sleep regularly to maintain good health. According to several studies, six to eight hours of sleep would be the ideal time for adults. The scientific literature has shown that adequate sleep helps protect against cardiovascular disease, stimulates the immune system and protects against metabolic diseases such as diabetes.

A new study conducted by scientists at Bar-Ilan University in Ramat-Gan, Israel, uncovered a key factor that may be central to the essential nature of sleep: its restorative effect on individual brain cells.

Led by Professor Lior Appelbaum, the research was published in the journal Nature Communications. The work focused on zebrafish, a species that scientists often use in research because it is surprisingly similar to humans. In fact, about 70% of human genes are also found in this freshwater fish.

The brain recovers from the stress stored up during the day

Using 3D imaging at regular intervals, Pr Appelbaum's team examined how sleep can affect brain cells. Their observations revealed that during sleep, the neurons were able to perform maintenance work on the nucleus, the central element of each cell that contains most of its genetic material.

When the nucleus begins to deteriorate, the genetic information it contains is also damaged, which can lead to aging, disease and general malfunction in an organ or tissue. However, it is during sleep that neurons have the opportunity to recover from the stress they have accumulated during the day and "repair" the damage they may have suffered.

During the waking phase, chromosome dynamics levels are lower than during sleep, which is why brain cells are unable to perform good DNA maintenance. Professor Applebaum likens this situation to that of "potholes on the road". "Roads accumulate potholes, especially during peak hours during the day, and it is more practical and efficient to repair them at night, when there is little traffic," he says.

A bulwark against neurodegenerative diseases?

Scientists who questioned the reasons that drove animals to sleep, especially predators or wild animals whose environment involves staying alert to ensure their survival. They deduce that cell repair could be a probable cause.

Scientists also speculate that it is possible that lack of sleep over time can harm the brain in the long term and promote neurodegenerative diseases such as Alzheimer's or Parkinson's.

Although the link between sleep deprivation and neurodegenerative diseases is still only a suggestion, Pr Appelbaum and his team wish to explore this path by observing the sleep of mammals.

Video: What a Good Night's Sleep Does for the Brain (December 2019).