Summary: A new Northwestern Medicine study reveals that breathing rhythms during sleep coordinate hippocampal brain waves—slow waves, spindles, and ripples—critical for memory consolidation. The study suggests that disrupted breathing, such as in sleep apnea, may hinder memory consolidation. The findings emphasize the importance of proper sleep and breathing patterns for cognitive health, with implications for treating sleep disorders to improve memory and reduce the risk of conditions like Alzheimer’s disease.
Key Takeaways:
- Breathing Rhythms Influence Memory: Breathing patterns during sleep coordinate hippocampal brain waves vital for memory consolidation.
- Link to Sleep Disorders: Disrupted breathing, like in sleep apnea, can impair memory and cognitive function.
- Implications for Health: Proper sleep and breathing are crucial for brain health and memory, with potential links to Alzheimer’s and other disorders.
Just as a conductor coordinates different instruments in an orchestra to produce a symphony, breathing coordinates hippocampal brain waves to strengthen memory while we sleep, reports a new Northwestern Medicine study.
The researchers say this is the first time breathing rhythms during sleep have been linked to these hippocampal brain waves—called slow waves, spindles, and ripples—in humans. Scientists knew these waves were linked to memory, but their underlying driver was unknown.
“To strengthen memories, three special neural oscillations emerge and synchronize in the hippocampus during sleep, but they were thought to come and go at random times,” says senior study author Christina Zelano, PhD, professor of neurology at Northwestern University Feinberg School of Medicine, in a release. “We discovered that they are coordinated by breathing rhythms.”
Northwestern scientists discovered that hippocampal oscillations occur at particular points in the breathing cycle, suggesting that breathing is a critical rhythm for proper memory consolidation during sleep.
“Memory consolidation relies on orchestration of brain waves during sleep, and we show that this process is closely timed by breathing,” said corresponding author Andrew Sheriff, a postdoctoral student in Zelano’s lab.
The study is published in the Proceedings of the National Academy of Sciences.
The findings have important implications for disordered breathing during sleep—such as sleep apnea—which is linked with poor memory consolidation.
Memory Formation and the Role of Sleep
We’ve all had the experience of better memories after a night of sleep. This was noted as far back as ancient Rome, when the scholar Quintillion wrote of the “curious fact” that “the interval of a single night will greatly increase the strength of the memory,” the study authors say. He was describing what we now call memory consolidation, which is accomplished by the exquisitely tuned coordination of different brain waves in the hippocampus.
“When you’re sleeping, your brain is actively replaying experiences you had during the day,” Sheriff says in a release.
Sheriff had just returned from a conference in Reykjavik, Iceland, where he had to learn his way around a new city. “The hippocampus plays a major role in forming a map of a new area,” Sheriff says in a release. “I would wake up and feel I had a better representation of the city around me. That was facilitated by the oscillations that occurred during my sleep, which we found are coordinated by breathing.”
Disrupted Breathing and Cognitive Health
The study indicates people with disrupted breathing during sleep should seek treatment for it, Sheriff says. “When you don’t get sleep your brain suffers, your cognition suffers, you get foggy,” Sheriff says in a release. “We also know that sleep-disordered breathing is connected with stroke, dementia, and neurodegenerative disorders like Alzheimer’s Disease.
He continues, “If you listen to someone breathing, you might be able to tell when they are asleep because breathing is paced differently when you’re sleeping. One reason for that may be that breathing is performing a careful task: coordinating brain waves that are related to memory.”
Photo caption: Corresponding author Andrew Sheriff looks at a computer monitor in a lab.
Photo credit: Northwestern University
