Researchers trigger sleep’s restorative effect in parts of the awake brain

Monday, June 8, 2026

Researchers trigger sleep's restorative effect in parts of the awake brain

NIH-funded study in animals offers new details about how the brain resets during sleep.

By inducing specific patterns of activity in small portions of the brain in awake mice, researchers supported by the National Institutes of Health (NIH) have triggered a recalibration of neural connections that normally only occurs during sleep. This new approach offset the effects of sleep deprivation in memory tasks and revealed features of sleep that are key to its restorative effect.

"What we're essentially doing is forcing sleep in a local region of the brain. While that part is solidifying memories and restoring learning capacity, other parts stay aware/vigilant and connected to environment," said corresponding author Chiara Cirelli, M.D., Ph.D., a professor of psychiatry at the University of Wisconsin-Madison. "Dolphins do something similar, sleeping with only one brain hemisphere at a time."

Non-rapid eye movement (NREM) sleep, which makes up about 80% of sleep for adults, is when the junctions between neurons that make memories are evaluated. During this phase, the brain protects important connections for long-term storage, prunes those that are less necessary, and makes space for new ones.

Cirelli and her colleagues previously showed that, when sleep-deprived, both rats(link is external) and humans(link is external) can exhibit local slow-wave brain activity - a hallmark of NREM sleep - while awake. These deprivation-induced dips into sleep-like activity may have been too sporadic and brief to be beneficial, but the findings raised questions about the possible effects of a longer, more systematic version of this activity.

In the new research, the authors used a combination of light-pulsing implants and genetic modifications to induce rhythmic on-and-off activity in one side of the brains of sleep deprived mice for 30 minutes at a time, mimicking patterns that occur during NREM sleep.

When mice subsequently slept, slow-wave activity was lower in the specific brain regions the authors had stimulated, indicating less need for sleep. Additional experiments suggested that this effect hinged not on the overall reduction in neuronal firing, which some scientists had suggested was critical to recover from wake-induced neuronal fatigue, but rather on the specific alternating on-and-off pattern of activity.

The researchers explored potential benefits through a behavioral test of tactile memory, for which sleep is important. Sleep-deprived mice who received stimulation in motor and sensory regions on both sides of the brain performed similarly to those who were well rested. Sleep-deprived mice who did not receive stimulation performed significantly worse.

In future studies, Cirelli aims to learn whether similar effects could be replicated in humans using less invasive, transcranial stimulation technology.

"This research further decodes why we sleep and how we learn, which brings us a step closer to understanding how to better prevent and treat cognitive decline," said Amy Bany Adams, Ph.D., acting director of the NIH's National Institute of Neurological Disorders and Stroke (NINDS), which funded the research.

About the National Institute of Neurological Disorders and Stroke (NINDS): NINDS is the nation's leading funder of research on the brain and nervous system. The mission of NINDS is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease. https://www.ninds.nih.gov(link is external).

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit https://www.nih.gov.

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Reference

Kort Driessen et al. Induction of cortical ON/OFF periods in awake mice fulfills sleep functions. Nature Neuroscience. 2026. DOI: 10.1038/s41593-026-02318-9