Bursts of brain activity linked to memory reactivation

May 24, 2018, Northwestern University
Credit: CC0 Public Domain

Leading theories propose that sleep presents an opportune time for important, new memories to become stabilized. And it's long been known which brain waves are produced during sleep. But in a new study, researchers set out to better understand the brain mechanisms that secure memory storage.

The team from Northwestern and Princeton universities set out to find more direct and precisely timed evidence for the involvement of one particular sleep wave—known as the "sleep ."

In the study, sleep spindles, described as bursts of brain activity typically lasting around one second, were linked to reactivation. The paper, "Sleep spindle refractoriness segregates periods of memory reactivation," will be published May 24 in the journal Current Biology.

"The most novel aspect of our study is that we found these spindles occur rhythmically—about every three to six seconds—and this rhythm is related to memory," said James W. Antony, first author of the study and a postdoctoral fellow in Princeton's Computational Memory Lab.

Three experiments explored how recent memories are reactivated during sleep. While volunteers took an afternoon nap, sound cues were surreptitiously played. Each was linked to a specific memory. The researchers' final experiment showed that if cues were presented at opportune times such that spindles could follow them, the linked memories were more likely to be retained. If they were presented when a spindle was unlikely to follow, the linked memories were more likely to be forgotten.

"One particularly remarkable aspect of the study was that we were able to monitor spindles moment by moment while people slept," said Ken A. Paller, senior author of the study and professor of psychology at Northwestern's Weinberg College of Arts and Sciences. "Therefore, we could know when the brain was most ready for us to prompt memory reactivation."

If the researchers reminded people of a recently learned fact, a spindle would likely be evident in the cerebral cortex, and memory for that information would be improved, added Paller, also director of Northwestern's Cognitive Neuroscience Program.

"In memory research, we know it's important to segregate experiences while you're awake so that everything doesn't just blend together," said Antony, who worked in Paller's lab at Northwestern as a doctoral student. "If that happens, you may have difficulty retrieving information because so many things will come to mind at once. We believe the spindle rhythmicity shown here might play a role in segregating successive memory reactivations from each other, preventing overlap that might cause later interference between memories."

Ultimately, the researchers' goal is to understand how sleep affects memory under natural conditions, and how aging or disease can impact these functions.

"With that goal in mind, we've helped elucidate the importance of sleep spindles more generally," Antony said.

Paller said they are on the trail of the physiology of memory reactivation.

"Future work will be needed to see how spindles fit together with other aspects of the physiology of memory and will involve other types of memory testing and other species," Paller said.

Explore further: Cueing newly learned information in sleep improves memory, and here's how

Related Stories

Cueing newly learned information in sleep improves memory, and here's how

March 8, 2018
Scientists have long known that sleep plays an important role in the formation and retention of new memories. That process of memory consolidation is associated with sudden bursts of oscillatory brain activity, called sleep ...

Brain wave activity associated with circadian preferences

November 3, 2017
A new study from the University of Helsinki, Finland, shows that individual circadian preference is associated with brain activity patterns during the night.

Reactivating memories during sleep: Memory rehearsal during sleep can make a big difference in remembering later

April 12, 2013
Why do some memories last a lifetime while others disappear quickly? A new study suggests that memories rehearsed, during either sleep or waking, can have an impact on memory consolidation and on what is remembered later.

New insights into how sleep helps the brain to reorganise itself

October 2, 2017
A study has given new insights into how sleep contributes to brain plasticity – the ability for our brain to change and reorganise itself – and could pave the way for new ways to help people with learning and memory disorders.

Learn that tune while fast asleep

June 24, 2012
Want to nail that tune that you've practiced and practiced? Maybe you should take a nap with the same melody playing during your sleep, new provocative Northwestern University research suggests.

'Princess Leia' brainwaves help sleeping brain store memories

November 15, 2016
Every night while you sleep, electrical waves of brain activity circle around each side of your brain, tracing a pattern that, were it on the surface of your head, might look like the twin hair buns of Star Wars' Princess ...

Recommended for you

Study on instinctive behaviour elucidates a synaptic mechanism for computing escape decisions

June 21, 2018
How does your brain decide what to do in a threatening situation? A new paper published in Nature describes a mechanism by which the brain classifies the level of a threat and decides when to escape.

Researchers find important new piece in the Huntington's disease puzzle

June 21, 2018
In a new study, researchers from the University of Copenhagen have discovered a hitherto unknown error in the transport of glutamine between astrocytes and neurons in the brain of mice with Huntington's disease. At the same ...

Rare in-vivo study shows weak brain nodes have strong influence on memory network

June 20, 2018
Our ability to learn, remember, problem solve, and speak are all cognitive functions related to different parts of our brain. If researchers can identify how those brain parts communicate and exchange information with each ...

Powerful new approach helps understand molecular alterations in neurological disease

June 20, 2018
Neurological diseases are typically associated with a multitude of molecular changes. But out of these thousands of changes in gene expression, which ones are actually driving the disease? To answer this question, a team ...

Scientists unravel DNA code behind rare neurologic disease

June 20, 2018
Scientists conducting one of the largest full DNA analyses of a rare disease have identified a gene mutation associated with a perplexing brain condition that blinds and paralyzes patients.

A dual-therapy approach to boost motor recovery after a stroke

June 20, 2018
Paralysis of an arm and/or leg is one of the most common effects of a stroke. But thanks to research carried out by scientists at the Defitech Foundation Chair in Brain-Machine Interface and collaborators, stroke victims ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.