Imagine waking up one morning and having a wonderful—albeit fuzzy—memory of a place you barely cared about when you went to bed the night before. You can’t quite explain why, but the next time you go to that place you feel terrific, as if you’re somewhere you’ve always loved, even though you know that’s never actually been the case. This, more or less, is what laboratory mice at France’s National Center for Scientific Research (CNRS) have experienced recently, after undergoing what The Guardian calls “the first demonstration of memory manipulation during sleep.”
Mouse neurology is such that when they sleep, they re-create the past day’s adventures in their head; If a mouse walks through an enclosure while awake, it will mentally do so again that night, causing specific neurons associated with location to fire as they had during the day. Through observation, those neurons can then be mapped to their real-world spacial equivalents. In “Explicit memory creation during sleep demonstrates a causal role of place cells in navigation,” a study published this month in Nature Neuroscience, researchers describe the process by which they stimulated two separate parts of a sleeping mouse’s brain: The aforementioned spatial neurons, and a cluster of nerves that deliver a “reward” sensation. By triggering the “reward” nerves in a mouse’s brain as it dream-walked through a “place” it had experienced that day, the scientists were able to create what the they call an “explicit memory trance”—A happy, but entirely artificial memory, created without waking their subjects. As the experiment progressed, the team observed the mice beginning to congregate in the real-world location associated with the rewarded neurons, in effect acting upon their artificial happy memories of that spot.
The goal, lead researcher Karim Benchenane explains, is to one day “use this as a tool for post-traumatic stress disorder” in human beings, similar to the “Eternal Sunshine” memory erasing gas being researched at Harvard Medical Schoo’s McLean Hospital. That’s a ways away, but the eventual ability to neurologically trick the brain into a happier association with what might be an otherwise traumatic place or event is potentially huge. As you might expect, there are any number of ethical pitfalls associated with manipulating memories to affect behavioral outcomes. Fortunately we’re not living in that Philip K. Dick–esque memory-dystopia just yet. Those behind this breakthrough are well aware of the risks involved in tampering with people’s memories, even with good intentions. As Benechenane told The Guardian “It might be extremely dangerous [for a human suffering from PTSD] to get a reward for something fearful.”
Still, by demonstrating it’s possible to neurologically influence how we remember things, the CNRS researchers have brought us one step closer to a world in which a lifetime of happy memories might be available at the click of a button.
