And more about the dangers of lack of sleep

Scientists: with a lack of sleep, the brain begins to "devour" itself

Sergey Vasiliev, Naked Science

One of the key reasons that we are so constantly in need of sleep is the "cleaning of the brain". It has been shown that during this time, glial cells actively remove by-products that are dangerous for neurons, primarily beta-amyloids. Michele Bellesi and his colleagues from the Polytechnic University of Marche in Italy found that the same process develops with a severe lack of sleep – only in this case it completely gets out of control, destroying the brain itself. Scientists talk about this in an article published by the Journal of Neuroscience (Bellesi et al., Sleep Loss Promotes Astrocytic Phagocytosis and Microglial Activation in Mouse Cerebral Cortex).

The brain is "cleaned" by auxiliary cells of the nervous tissue: microglial absorb old and damaged cells; astrocytes clear unnecessary synapses, contacts between neurons (this process is called pruning of neurons). Bellesi and his co-authors focused on the second of these processes and studied laboratory mice by examining brain activity in different groups of animals. One group was studied immediately after 6-8 hours of full sleep ("rested"); the second – after a sleep that was interrupted from time to time ("awakened"); the third – after an extra 8 hours of wakefulness ("sleepy"); finally, the mice of the fourth group were not allowed to sleep for 5 days ("sleepless").

In "rested" animals, astrocytes were found in 5.7 percent of synapses, in "awakened" ones – in 7.3. In mice with one–time and permanent sleep deficiency - in 8.4 and as much as 13.5 percent of synapses, respectively. More importantly, in "sleepless" and simply "sleepless" mice, astrocytes showed unusual phagocytic activity, quickly destroying synapses.

According to the authors, the main target of this activity are large, old contacts between neurons – most likely performing important functions. In "sleepless" mice, the activity of microglia also jumped – and it is known that excessive zeal of these cells can lead to the development of Alzheimer's disease and other neurodegenerative processes. Exhausted by a lack of sleep, the brain literally "recycles" itself by eating its own cells and tissues.

For an increase in the likelihood of a stroke with a lack of sleep, see here – VM.

Portal "Eternal youth" http://vechnayamolodost.ru  26.05.2017