Our Brains Take Naps While We’re Awake And Wake Up When We’re Asleep

Scientists have discovered that a small region of our brain shuts down to take microsecond-long naps while we’re awake, and these same areas ‘flicker’ awake while we’re asleep. These findings could offer pivotal insights into neurodevelopmental and neurodegenerative diseases linked to sleep dysregulation. Researchers from Washington University in St. Louis (WashU) and the University of California Santa Cruz (UCSC) made these findings by accident, noticing how brain waves in one tiny area of the brain suddenly shut down for milliseconds when we’re awake. Conversely, these brain waves jolt awake for the same duration when we’re asleep.

“With powerful tools and new computational methods, there’s so much to be gained by challenging our most basic assumptions and revisiting the question of ‘what is a state?’” said Keith Hengen, Assistant Professor of Biology at WashU. “Sleep or wake is the single greatest determinant of your behavior, and then everything else falls out from there. So if we don’t understand what sleep and wake actually are, it seems like we’ve missed the boat.”

Until now, sleeping and awake states have been defined by overall brain wave patterns – alpha, beta, and theta waves when we’re awake, delta when we’re not – so these ‘flicker’ anomalies challenge our understanding of these distinct states.

“It was surprising to us as scientists to find that different parts of our brains actually take little naps when the rest of the brain is awake, although many people may have already suspected this in their spouse,” joked David Haussler, Professor of Biomolecular Engineering at UCSC.

In a four-year study gathering massive electrophysiology data, scientists recorded brain-wave voltage in 10 brain regions in mice. They tracked activity from small groups of neurons down to the microsecond. Petabytes of data were analyzed by an artificial neural network, isolating microsecond anomalies that human studies have missed.

The findings may offer new insights into conditions associated with dysregulated sleep, providing a new target for treating neurodevelopmental and neurodegenerative diseases. “The more we understand fundamentally about what sleep and wake are, the more we can address pertinent clinical and disease-related problems,” Hengen said.