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How The Brain Controls Sleep

How The Brain Controls Sleep post image

Weird ‘zoning out’ sensation when sleepy explained.

Parts of the brain can fall asleep while the rest of the brain stays awake, new research finds.

It might explain the weird sensation of ‘zoning out’ people get when they are trying to avoid falling asleep.

The effect is triggered by a brain structure called the thalamic reticular nucleus (TRN).

The TRN relays signals including a slow oscillating brain wave typical of sleep.

The TRN may be important in how we consolidate new memories.

Dr Laura Lewis, the study’s lead author, said:

“During sleep, maybe specific brain regions have slow waves at the same time because they need to exchange information with each other, whereas other ones don’t.”

Dr Lewis said their animal experience revealed that…

“…when you induce these slow waves across the cortex, animals start to behaviorally act like they’re drowsy.

They’ll stop moving around, their muscle tone will go down.”

The brain circuit could also be responsible for the weird sensation of ‘zoning out’ people get when they are trying to avoid falling asleep.

Dr Lewis said:

“I’m inclined to think that happens because the brain begins to transition into sleep, and some local brain regions become drowsy even if you force yourself to stay awake.”

Professor Emery Brown, a co-author, said:

“The TRN is rich in synapses — connections in the brain — that release the inhibitory neurotransmitter GABA.

Therefore, the TRN is almost certainly a site of action of many anesthetic drugs, given that a large classes of them act at these synapses and produce slow waves as one of their characteristic features.”

The study was published in the journal eLife (Lewis et al., 2015).

About the author

Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology.

He has been writing about scientific research on PsyBlog since 2004. He is also the author of the book “Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks:

Dr Dean’s bio, Twitter, Facebook and how to contact him.

Brain image from Shutterstock