Summary: Researchers have found that lack of sleep can mask, rather than erase, memories in mice, and that these memories can be restored using existing drugs. The study demonstrated that the asthma drug roflumilast could recover social memories, while the erectile dysfunction drug vardenafil could restore spatial memories.
These findings suggest potential new treatments for memory loss caused by sleep deprivation. This research offers hope of developing human therapies to recover lost memories.
Highlights:
- Sleep deprivation hides, rather than erases, social and spatial memories in mice.
- Roflumilast and vardenafil have been used to successfully restore these hidden memories.
- The study indicates potential for developing treatments for human memory loss.
Source: Swamps
Loss of social memories caused by lack of sleep could potentially be reversed using currently available drugs, according to a mouse study presented today (Friday) at the Federation of European Neuroscience Societies (FENS) Forum 2024.
Lack of sleep is known to affect the brain, including memory, in mice and humans, but research is beginning to show that these memories are not lost, they are simply “hidden” in the brain and difficult to get back.
The new research shows that access to these previously hidden social memories can be restored in mice using a drug currently used to treat asthma and chronic obstructive pulmonary disease. The team of researchers also showed that another drug currently used to treat erectile dysfunction can restore access to spatial memories.
The researchers say these spatial memories in mice are akin to humans remembering where they put their keys the night before, while social memories could be likened to remembering a new person they met. .
The study was presented by Dr Robbert Havekes from the University of Groningen in the Netherlands. He said: “Ever since I started my PhD many years ago, I have been intrigued by the fact that a single period of sleep deprivation can have a major impact on memory processes and the brain as a whole.
“Early work published years ago helped us identify some of the molecular mechanisms behind amnesia.
“By manipulating these pathways specifically in the hippocampus, we were able to make memory processes resilient to the negative impact of sleep deprivation.” In our new studies, we examined whether we could reverse amnesia even days after the initial learning and sleep deprivation period.
The new studies, presented at the FENS Forum and funded by the Air Force Office of Scientific Research (AFOSR), were conducted by Dr. Havekes’ doctoral students Adithya Sarma and Camilla Paraciani, who will also present their work in poster format.
To study social memory in the lab, researchers gave mice the option to choose between interacting with a mouse they had never met before or with a sibling from their own cage.
Normally, mice prefer to interact with the new mouse over the littermate mouse they already know. If given the same choice the next day, mice will interact in the same way with their littermate and with the mouse they met the day before, because both mice are now considered familiar.
However, if mice are deprived of sleep after their first encounter, the next day they still prefer to interact with the new mouse as if they had never met it before. These results suggest that they simply cannot remember their previous encounter.
The team found that they were able to permanently restore these hidden social memories, first using a technique called optogenetic engram technology. This technique allows them to identify the neurons in the brain that together form a memory (called a memory engram) for a specific experience and modify those neurons so that they can be reactivated by light.
Researchers can then use light to reactivate that specific group of neurons, resulting in the recall of the specific experience (in this case, a social memory).
They were also able to restore the mice’s social memory by treating them with roflumilast, a type of anti-inflammatory drug approved by the U.S. Food and Drug Administration that is used to treat chronic obstructive pulmonary disease.
Dr Havekes says the finding is particularly exciting because it provides a stepping stone to studies of sleep deprivation and memory in humans, and he is currently collaborating with another research group that is embarking on human studies.
In parallel, the same researchers studied the loss of spatial memory caused by lack of sleep by studying the abilities of mice to learn and memorize the location of individual objects.
A brief period of sleep deprivation after training meant that the mice could not remember the original location of the object and so they did not notice when an object was moved to a new location during a test.
As with social memories, access to these spatial memories could be restored by treating mice with another drug, vardenafil, currently used to treat erectile dysfunction. This is a second drug approved by the U.S. Food and Drug Administration that researchers have successfully used to reverse amnesia in mice.
Dr Havekes said: “We were able to show that lack of sleep causes amnesia in the case of specific spatial and social recognition memories. This amnesia can be reversed a few days later after the initial learning experience and sleep-deprived episode using medications already approved for human consumption.
“We now want to focus on understanding the processes that give rise to these accessible and inaccessible memories. In the long term, we hope that these fundamental studies will pave the way for studies in humans aimed at reversing forgetting phenomena by restoring access to otherwise inaccessible information in the brain. »
Professor Richard Roche is Chairman of the FENS Forum Communications Committee and Deputy Head of the Department of Psychology at Maynooth University, Maynooth, County Kildare, Ireland, and was not involved in the research.
He said: “This research shows that social and spatial memories apparently lost due to sleep deprivation can be recovered. Although these studies were conducted in mice, they suggest that it may be possible to recover people’s lost social and spatial memories using some drug treatments already approved for human use.”
“There are many situations in which people cannot get enough sleep, so this area of research has clear potential. However, it will take time and much more work to translate this research from mice to humans.
About this sleep, memory and neuropharmacology research news
Author: Kerry Noble
Source: Swamps
Contact: Kerry Noble – FENS
Picture: Image is credited to Neuroscience News
Original research: The results were presented at the FENS 2024 Forum