Brain caught 'filing' memories during rest

April 18, 2016, University College London
Credit: Wikimedia Commons

Memories formed in one part of the brain are replayed and transferred to a different area of the brain during rest, according to a new UCL study in rats.

The finding suggests that replay of previous experiences during rest is important for , a process whereby the brain stabilises and preserves memories for quick recall in the future. Understanding the physiological mechanism of this is essential for tackling amnesiac conditions such as Alzheimer's disease, where memory consolidation is affected.

Lead researcher, Dr Freyja Ólafsdóttir (UCL Cell & Developmental Biology), said: "We want to understand how a healthy brain stores and accesses memories as this will give us a window into how conditions such as Alzheimer's disease disrupt the process. We know people with Alzheimer's have difficulty recalling the recent past but can often readily remember childhood memories, which seem more resilient. The parts of the brain we studied are some of the first regions affected in Alzheimer's and now we know they are also involved in memory consolidation."

The study, published today in Nature Neuroscience and funded by the Wellcome Trust and Royal Society, investigated the role of sleep in memory consolidation by simultaneously studying two areas of the brain as the rats rested following activity.

Six rats each ran for 30 minutes on a six metre long track before resting for 90 minutes. During , the team studied the responses of place cells in the hippocampus, where memories are formed, and grid cells in the entorhinal cortex, where the memories were found to transfer to.

The response of the place cells showed that the rats re-ran the track in their minds as they rested but did so at speeds 10-20 times faster than they experienced in reality. The same replay happened almost simultaneously, with a 10 millisecond delay, in grid cells located in a different part of the brain, suggesting that the rats' memories transferred from one part of the brain to another.

Study supervisor, Dr Caswell Barry (UCL Cell & Developmental Biology), said: "This is the first time we've seen coordinated replay between two areas of the brain known to be important for memory, suggesting a filing of memories from one area to another. The hippocampus constantly absorbs information but it seems it can't store everything so replays the important memories for long term storage and transfers them to the entorhinal cortex, and possibly on to other areas of the brain, for safe-keeping and easy access."

The scientists plan to investigate memory transfer to other areas of the and replay in with Alzheimer's disease to better understand the consolidation mechanism and the link between quality of sleep and amnesiac conditions.

Explore further: Brain activity patterns during sleep consolidate memory

More information: H. Freyja Ólafsdóttir, Francis Carpenter & Caswell Barry, 'Coordinated grid and place cell replay during rest' Nature Neuroscience, Monday April 18, 2016. DOI: 10.1038/nn.4291

Related Stories

Brain activity patterns during sleep consolidate memory

February 19, 2016
Why does sleeping on it help? This is the question tackled by new research at the University of Bristol, which reveals how brain activity during sleep sorts through the huge number of experiences we encounter every day, filing ...

Brain study reveals how long-term memories are erased

March 31, 2016
Vital clues about how the brain erases long term memories have been uncovered by researchers.

How the brain consolidates memory during deep sleep

April 14, 2016
Research strongly suggests that sleep, which constitutes about a third of our lives, is crucial for learning and forming long-term memories. But exactly how such memory is formed is not well understood and remains, despite ...

'Brain GPS' network allows brain to track location when at rest

March 3, 2016
UC San Francisco scientists have discovered a network of brain cells that allows animals to keep track of where they are when they are not moving through space, such as when they are eating, engaged in social interactions, ...

'Lost' memories can be found

March 16, 2016
In the early stages of Alzheimer's disease, patients are often unable to remember recent experiences. However, a new study from MIT suggests that those memories are still stored in the brain—they just can't be easily accessed.

When memories age

March 15, 2016
To the brain, it makes a great difference whether we remember experiences from long ago, or if we recollect recent events. RUB neuroscientists have shown that distinct brain networks are involved.

Recommended for you

In a break with dogma, myelin boosts neuron growth in spinal cord injuries

May 23, 2018
Recovery after severe spinal cord injury is notoriously fraught, with permanent paralysis often the result. In recent years, researchers have increasingly turned to stem cell-based therapies as a potential method for repairing ...

Memory molecule limits plasticity by calibrating calcium

May 23, 2018
The brain has an incredible capacity to support a lifetime of learning and memory. Each new experience fundamentally alters the connections between cells in the brain called synapses. To accommodate synaptic alterations, ...

New type of vertigo identified

May 23, 2018
Neurologists have identified a new type of vertigo with no known cause, according to a study published in the May 23, 2018, online issue of Neurology, the medical journal of the American Academy of Neurology.

Changes to specific MicroRNA involved in development of Lou Gehrig's disease

May 23, 2018
A new Tel Aviv University study identifies a previously unknown mechanism involved in the development of Lou Gehrig's disease, or amyotrophic lateral sclerosis (ALS). The research focuses on a specific microRNA whose levels ...

Study confirms that men and women tend to adopt different navigation strategies

May 23, 2018
When navigating in a known environment, men prefer to take shortcuts to reach their destination more quickly, while women tend to use routes they know. This is according to Alexander Boone of UC Santa Barbara in the US who ...

Mechanisms of harmful overhydration and brain swelling

May 22, 2018
We are all familiar with the drawbacks of dehydration, but we rarely hear about the harmful effects of overhydration. For one, excess fluid accumulation can lead to dangerously low sodium levels in the blood or hyponatremia—a ...

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.