Research published in Nature Neuroscience shows that sleep deprivation triggers cleaning pulses in the brain normally seen only during deep sleep — causing attention lapses and slower reactions.
Going one night without sleep doesn’t just make you tired — it changes the way your brain operates. A new study published in Nature Neuroscience reveals that after prolonged wakefulness, the brain periodically slips into a kind of “internal maintenance mode”, even while a person appears awake.
Researchers from Boston University and the Massachusetts Institute of Technology (MIT) found that during brief lapses in attention, the brain releases a wave of cerebrospinal fluid (CSF) — the same cleansing process normally seen during deep sleep. This fluid helps remove waste and maintain the nervous system.
The study suggests that when a person is severely sleep-deprived, the brain forces itself to perform part of its nightly cleaning duties during wakefulness — and the result is a significant drop in mental performance.
Participants experienced moments where they reacted more slowly, or failed to respond to simple stimuli, as if the brain briefly “checked out” to prioritize maintenance instead of attention.
HOW THE STUDY WORKED
Scientists analyzed 26 young adults under two conditions:
- After a night of normal sleep
- After staying awake all night
The next day, participants underwent attention tests inside an MRI scanner, while also wearing EEG caps, pupil sensors, and other biometric trackers.
Researchers observed — in real time — how the brain, body, and eyes responded to tasks. Each attention lapse matched a pulse of CSF flowing into and out of the brain.
These pulses did not appear in well-rested participants.
WHAT IT MEANS
The findings show that sleep deprivation destabilizes the brain’s alertness system. To compensate, the brain intermittently slips into a state physiologically similar to sleep — even when the person is awake.
The result is a sharp decline in performance, attention, and responsiveness.
Scientists say the brain cannot postpone its recovery processes, making sufficient sleep essential for cognitive health.
