Do you think that we sleep only because we need to replenish our energy? If you do, you are wrong. The main reason why we need to sleep is that the brain is, in fact, changing states during the sleep to clear the toxic neural activity that was left during the day.
Researchers have found that losing sleep causes a loss of a significant amount of brain neurons along with synaptic connections – and this damage cannot be reversed with recovering sleep. In other words, when you skip sleep your brain cells die and cannot be recovered.
Michele Bellesi, a neuroscientist from the Marche Polytechnic University in Italy, together with his team examined the brain’s response of the mammals to poor sleeping habits and discovered that there is a weird similarity between the sleepless and the well-rested mice.
Like every cell in our body, the neurons in the brain are constantly replenished and refreshed by two different glial cells (support cells which are known as the glue of the nervous system).
The microglial cells, on one hand, are there to clear out the worn-out cells during phagocytosis – a process that in Greek means “to devour.” The astrocytes’ job, on the other hand, is to reshape and refresh the brain’s unnecessary connections (synapses).
It is known that this process happens when we sleep in order to clear the neurological waste of the day, and this same process happens when we lose sleep as well. However, this is a bad thing because during the sleepless nights the brain tends to go overboard and instead of clearing begins to harm itself.
In layman’s terms, think of the brain as the garbage that is cleared out when you are sleeping versus someone violently coming to your house after many sleepless nights and tossing your tv, fridge, and all your furniture away.
“We show for the first time that portions of synapses are literally eaten by astrocytes because of sleep loss,” Bellesi said.
To prove this theory, the researchers studied the brains of mice. They have divided them into 4 groups: one group of mice was well-rested sleeping for 6-8 hours; the second group was woken up periodically from their sleep; the third one was sleep-deprived being kept awake for plus 8 hours, and the final group was chronically sleep-deprived being kept awake for 5 days.
When they compared the results of the astrocytes’ activity in the four group of mice, they found it in 5.7% in the synapses of the well-rested brains, as opposed to 7.3% of the spontaneously awaken mice.
However, in the sleep-deprived mice and the chronically sleep-deprived mice, the researchers noticed something unusual. Namely, there was an increased astrocytes activity which led to eaten synapses parts or a process called astrocytic phagocytosis.
In other words, their brains literally ate themselves.
“We find that astrocytic phagocytosis, mainly of presynaptic elements in large synapses, occurs after both acute and chronic sleep loss, but not after spontaneous wake, suggesting that it may promote the housekeeping and recycling of worn components of heavily used, strong synapses,” the researchers said.
So, try not to lose sleep if you want to keep your brain whole!