It does not wait for spring, but every night our brain is busy cleaning up to make room for new things we will do and we will learn the following day. Two Italian scientists have recently discovered that our mind eliminates unnecessary memories and information without our knowledge, but not only during sleep. Let us find out how our brain works when the sun sets and how important it is to rest well.

During the phases of deep sleep our brain gets rid of a large part of what it learned in the previous hours, eliminating with amazing ability only the information considered by the same brain, not very significant and not particularly integrated with what is locked away in the recesses of the memory each of us has filled over the years. This selection takes place not only in an unconscious state, but during the deepest stages of sleep, so it is really unbeknown to us. So, the next morning, we only have available what we really need. This is the hypothesis of the Synaptic Homeostasis formulated by Giulio Tononi and Chiara Cirelli, two Italian researchers who work at the University of Wisconsin in Madison.

Why can we not learn endlessly? The explanation would be in the energy needed because our brain consumes about 20% of the total energy of the organism, two thirds of which deplete for the activity of the synapses, since to learn in an enduring way the synapses must be continuously strengthened or even new ones must be formed. It is like a factory that must always produce new materials, but no factory can work incessantly day and night.

Likewise, researches of the past few years have shown how sleeping is important to the brain to eliminate the waste of cellular metabolism and this can be possible while resting because, unable to use the lymphatic system like the rest of the body, the alternative system to use, called glinfatico, consumes such an amount of energy to prevent it from simultaneously feeding the conscious state as well.

The need to cleanse the brain from potentially neurotoxic waste could be the definitive explanation that we all need an adequate number of hours of sleep to "work" well the next day and keep healthy. Researchers have demonstrated that sleep helps to memorize and consolidate memories and to develop better behavioral patterns. Although very important, this function would not be able to explain the evolution of sleep: the benefits that it entails do not seem sufficient to compensate the risk related to the vulnerability in which we find ourselves when sleeping, nor to adequately explain the very serious symptoms manifested in those who are deprived of sleep for a long time.

The timely removal of waste is essential to avoid the uncontrolled accumulation of toxic proteins, a phenomenon that is found almost in all neurodegenerative diseases. Thus, if we accumulate "rubbish" during the day,the darkness frees ourselves from it: that is why resting a little or badly not only causes stress, but can also cause Alzheimer's or Parkinson's.

Do not be afraid of losing something, good rest earns so much more.