Neuroscientist Michele Bellesi of the Marche Polytechnic University in Italy studied the mammalian brain's response to sleep problems and found strange similarities between well-rested and sleepless mice. It boils down to the fact that in both cases the brain triggers the same self-cleaning reaction, but with insomnia, it proceeds uncontrollably. And instead of removing the "garbage", the brain begins to damage itself.
Under normal conditions, during sleep, microglia and astrocytes are activated in the brain. The former devour, utilize old and worn-out cells, the latter remove obsolete synapses and renew the neural network. In a sleeping organism, the activity of astrocytes affects less than 5.7% of synapses, but if sleep was interrupted, it increases to 7.3%. This was shown by experiments on mice, which were forced to various forms of insomnia.
It turned out that with a single skip of sleep, the activity of astrocytes increases and affects 8, 4% of synapses, and with chronic sleep deprivation, as much as 13, 5%. The so-called astrocytic phagocytosis develops, in which initially relatively calm astrocyte cells become like aggressive microglia and begin to devour neurons. What is most annoying is that they attack primarily old, stable synapses, from which the fundamental structure of memory and thinking is built.
The activity of microglia also increases in the absence of sleep, but scientists have not yet figured out why. It is possible that they enter into a competitive struggle with astrocytes, which, instead of comrades-in-arms, are recorded as enemies. And this form of activity has many negative consequences. Since 1999, the number of cases of Alzheimer's disease has increased by 50%, and more and more people are complaining of problems with sleep - there is probably an indirect or even direct connection.