Part of the brain is dormant while we are awake and awake when we are sleeping.
Until recently, it was believed that dolphins have a higher good, in the form of alternate sleep for the hemispheres. However, the brain's work is somewhat more subtle. And we, too, may have a small area that behaves abnormally both in wakefulness and during sleep.
For the first time, scientists have discovered that a small region of the brain switches off to take a nap for microseconds while we are awake. What’s more, these same regions are activated and awake when we sleep. This is key to understanding neurodegenerative diseases and diseases associated with sleep regulation disorders. More about the brain, consciousness and behavioral features – read in telegram channel. Subscribe to stay up to date with new articles!
The root cause of interest in the mysterious area
Scientists from Washington University in St. Louis (WashU) and the University of California, Santa Cruz (UCSC) accidentally noticedhow activity in one tiny area of the brain suddenly disappears for just milliseconds while we're awake. And then activity in that same area suddenly reappears for the same amount of time while we're asleep.
Sleep state and its features
With powerful tools and new computational methods, there is much to be gained by challenging our most basic assumptions and rethinking the question “what is a dream state?” Sleep or wakefulness are the two key factors that determine our behavior, and everything else follows from that. So if we don’t understand what sleep and wakefulness really are, then it seems we’ve missed our chance to understand the nature of the brain.
Keith Hengen, associate professor of biology at the University of Washington.
Until now, sleep and wakefulness have been defined by common patterns of brain waves. Alpha, beta, and theta waves define our state when we are awake, and delta waves indicate that we are asleep. So the abnormal “flickering” flies in the face of everything scientists have known about brain states. It seems to be another approach to neurohacking?
It was a surprise to us scientists to discover that various parts of the brain actually doze a little while we are awake.
David Haussler, professor of biomolecular engineering at the University of California, Santa Cruz.
The essence of sleep research
In a four-year study that collected massive amounts of electrophysiological data, the scientists recorded brain activity in 10 different brain regions in mice. Over the course of several months, they tracked the activity of small groups of neurons down to the microsecond. They then trained a neural network on petabytes of data to spot patterns and highlight microsecond anomalies that human studies had missed.
We are now seeing information at an unprecedented level of detail. Previously, there was a sense that there was nothing interesting in this area and that all the important information was in the lower frequency waves. Now, if you ignore the usual measurements and just look at the details of the high frequency measurement lasting a thousandth of a second, you get enough information to know whether the tissue is asleep or not. This tells us that something is happening in our brains at an extremely small scale. This is a new hint about what might be happening in sleep.
Keith Hengen, associate professor of biology at the University of Washington.
Diving into the details of how the brain works
Using machine learning, the scientists focused on millisecond-long chunks of brain activity data and found that rapid activity between a pair of neurons in the same region seemed to run counter to previously observed patterns. But it was typical of sleep, which is typically characterized by slow-moving delta waves. However, the activity between these neurons changed during wakefulness. The team called this specific activity during normal sleep “flickers.”
Eternal Sunshine of the Bright Mind
We looked at the individual moments in time when the neurons were firing, and it was very clear that the neurons were changing their state. In some cases, these flickerings could be limited to just a small region of the brain, perhaps the size of a few neurons.
Aidan Schneider, a researcher at the University of Washington.
Just a couple of weeks ago, an article was published about how our brain exists in a certain phase state. They say he is at a critical point, and perhaps being between sleep and wakefulness somewhat determines this state.
We took all the information that neuroscience has used to understand, define, and analyze sleep over the last hundred years and asked, “Can this model work with this new data?” This allowed us to look at signals that we hadn’t understood before. Essentially, the data showed that even when we’re awake, in this small region of the brain, a few neurons switch to sleep mode while the rest of the brain continues to function normally.
David Parks, a researcher at the University of California, Santa Cruz.
Transition between states
The researchers then looked for physical responses to the micro-naps, which last for a split second. They were surprised to see that the awake mice briefly “switched off,” while the animals twitched at the same “flickering” moments during sleep.
We see these flickers as we go from wakefulness to REM sleep, from REM sleep to deep sleep — we see all these possible combinations, and they go against the model that has been built around the last hundred years of research. I think these flickers are the macro separation between sleep and wakefulness at the level of the whole animal, and the fundamental unit of states in the brain — fast and local patterns of activity.
Aidan Schneider, a researcher at the University of Washington.
The findings may provide new insights into conditions associated with sleep dysregulation and, as a result, may become a new target for the treatment of neurodevelopmental and neurodegenerative diseases.
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