The Matt Walker Podcast
The Matt Walker Podcast is all about sleep, the brain, and the body. Matt is a Professor of Neuroscience at the University of California, Berkeley. He is the author of the book, Why We Sleep and has given a few TED talks. Matt is an awkward British nerd who adores science and the communication of science to the public.
The Matt Walker Podcast
#153- Sleeping in an MRI Machine
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Today’s episode explores how scientists study the sleeping brain inside a roaring, 111-decibel MRI scanner. Despite the extreme noise and discomfort, researchers use sleep deprivation, earplugs, and clever audio-filtering tricks to capture the mind drifting off. These small but groundbreaking studies reveal that falling asleep isn't a simple "on/off" switch, but a gradual transition where humans can adapt to the world's worst bedroom.
Matt explains that our sensory gatekeeper, the thalamus, actually shuts down minutes before the conscious cortex, explaining why we never catch the exact moment we fall asleep. He also reveals that deep sleep is a highly active state where "sleep spindles" filter out noise, while REM sleep shuts down logic and boosts emotion to fuel vivid dreams. Finally, Matt highlights new MRI imaging that captures fluid washing rhythmically through the sleeping brain.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
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As always, if you have thoughts or feedback you’d like to share, please reach out to Matt:
Matt: Instagram @drmattwalker, X @sleepdiplomat,
YouTube: https://www.youtube.com/@sleepdiplomat