A determined team of scientists from the French National Center for Scientific Research has pulled off the impossible, instilling false memories in living animals, and in this case, sleeping mice. Even more remarkable is the fact that these implanted recollections not only stayed with the mice once they woke up, but also affected their behavior well into the future.
The idea of manipulating our minds and implanting false memories has long been the stuff of science fiction. Films like Total Recall, The Eternal Sunshine of the Spotless Mind and Vanilla Sky have all sought to explore the consequences of such technology. Although these films offer mostly cautionary tales, the obliteration of traumatic experiences and the implantation of happy memories will nonetheless someday become reality.
Snoozing mice awake to false memories
In order to generate artificial memories, researchers implanted electrodes in the brains of 40 mice designed to stimulate two regions of the brain: the medial forebrain bundle (MFB), an area responsible for creating feelings of reward, and a specific part of the hippocambus called the CA1 that deals with spatial navigation. It’s best to think of the latter as our inner-GPS, helping us and animals remember places visited that are either to be desired or avoided. Whenever we discover a new place or visit a familiar one (known scientifically as the “place field”), these hippocambus CA1 nerve cells activate and fire away.
The process of identifying these “place cells” involved letting the electrode-fitted mice roam to their hearts content. Whenever the mice reached a special place that activated these place cells, scientists also stimulated the MFB region of the mice’s brains, effectively creating a false associative memory. As a result, these mice would subsuequently spend significantly more time seeking out these same places.
To test the limits of their research, the scientists conducted another experiment with five sleeping mice in which they paired the firing of previously identified place cells (that are known to “replay” during sleep to forge new synaptic connections) with MFB stimulation. When the mice woke up, they also showed a significantly increased preference to visit the place fields.
The study sheds light on how memories (and in this case false memories) are strengthened during sleep, and offers clues into the process of memory formation. Although these procedures were highly invasive to the mice and as a result will most likely not be replicated in humans, scientists are getting closer to being able to manipulate our memories and someday, perhaps, even our thoughts.