Sleep “Resets” Neurons to Allow for New Memories
We all know what it feels like the day after not getting enough sleep. Maybe you’re irritable and slower to get things done, and it probably feels harder to stay focused and motivated. But lack of sleep affects more than our emotions and ability to perform well at school or work. A new study on mice also indicates that sleep might “reset” our neurons to help our brain take on new memories.
The Research on Sleep and Memory Formation
A team of scientists from Cornell University’s Department of Neurobiology and Behavior wanted to better understand how sleep affects memory formation. Using mouse models, they looked at neurons in the hippocampus while mice slept to determine which processes were affected.
The researchers found that during sleep, the hippocampus goes “silent” to allow neurons to “reset.” This gives the neurons the ability to create new memories the next day.
“Once we started cracking the neural processes that are important for these many different things, we could use that to reverse detrimental conditions, such as memory impairment, during sleep,” explained Cornell’s Department of Neurobiology and Behavior Department Assistant Professor Dr. Azahara Oliva. “We [spend] about a third of our life sleeping—this is a lot of time. Understanding the relation between sleep and memory will provide insights into how we can tackle detrimental memory conditions.”
Resetting Memory in the Hippocampus
There are three main regions of the hippocampus: CA1, CA2, and CA3. During daytime learning, the researchers observed that the neurons in CA1 and CA3 were very active. But the middle region, CA2, generated the silencing of those two regions during sleep to give the neurons a chance to reset.
“During our experience, a few neurons become highly active,” explained Oliva. “The same neurons ‘work hard’ during sleep to imprint this experience into memory. What we found is that for these neurons to be able to imprint these memories, they also need breaks or a ‘reset.’
Hope for potential therapies
The team hopes that this renewed understanding of sleep and memory formation will eventually lead to new interventions in memory-related diseases, such as Alzheimer’s. In addition, the research may provide insights into how clinicians might be able to remove negative or traumatic memories from people with conditions like PTSD.
“Additionally, optimizing sleep quality through interventions like cognitive-behavioral therapy for insomnia could be crucial in managing these conditions,” added Dr. Manisha Parulekar, who reviewed the study. She serves as an associate professor at Hackensack Meridian School of Medicine, as well as the director of its Division of Geriatrics and the co-director of its Center for Memory Loss and Brain Health. “Translating these findings into clinical trials to test the efficacy of interventions targeting the CA2 circuit or sleep quality in patients with dementia and Alzheimer’s disease is crucial. Developing personalized approaches based on individual sleep patterns and brain activity and conducting studies to evaluate the sustained benefits and potential risks of these interventions are essential next steps.”
The study was published in the August 15, 2024, edition of the journal Science.
MBJ
Wendy Burt-Thomas writes about the brain, mental health and parenting.
Check out the original research: