Technology Science: we know more about the activity of our brain during deep sleep

Science: we know more about the activity of our brain during deep sleep

During sleep, the brain not only sorts the information accumulated during the day, allows memorization as well as certain hormonal secretions, but in addition, while performing these sorting and regeneration tasks, it continues to analyze the surrounding noises ( the falling rain, the neighbour’s music, a barking dog). And when it comes to unfamiliar noises, it goes to sleep but doesn’t wake us up.

Austrian researchers have even just demonstrated that the brain is able to identify unknown voices around us, during the deep sleep phase.

These researchers from the Salzburg sleep laboratory made 17 sleeping adults listen to familiar voices and unfamiliar voices which pronounced several dozen times during the night, their name or that of someone else (it was check-in, there was no one in the room). At the same time, they measured the brain activity of these sleepers. And the graphs show that during deep sleep, unfamiliar voices trigger more brain waves called “K-complexes”, which are specific to a sort of sentry mode of the brain. These unknown voices also trigger more micro-awakenings. And this, whatever the name pronounced elsewhere, it is really the voice that makes the difference, not the words themselves.

This shows that, even asleep, the brain is not completely disconnected from its environment, and is ready to react in the event of a threat. Moreover, this state of vigilance is not without consequence on the quality of rest, since a greater frequency of these waves “K complexes”, at night leads to less restful sleep. Even if the person hasn’t woken up.

The recordings only contained the pronunciation of a single word. The authors indicate that if the recordings had been longer, the volunteers would have woken up: this is precisely the concept of the clock radio.

That said, the study also reminds us that the brain is also able to get used to new noises that are repeated at night and end up becoming familiar. So if listeners get used to your voice, logically it won’t be the first word heard on the radio in the morning that will disturb their brain and wake them up, but the following words.

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