Neuroscientists find hidden

Neuroscientists at the Friedrich Miescher Institute for Biomedical Research have discovered that forgotten memories may not disappear entirely but instead persist as a "silent memory trace" in the brain. Published in Nature Neuroscience, the study used Drosophila melanogaster (fruit flies) to demonstrate that while active neural traces associated with behavior may weaken over time, a hidden set of neurons can store the information.

In experiments, researchers trained flies to associate a specific scent with a mild electric shock. Although the avoidance behavior appeared to vanish after 24 hours, the memory was reactivated when the flies were returned to the original environmental context, including specific lighting and textures. This suggests that memory retrieval is not a simple retrieval of a record but a reconstruction triggered by environmental cues.

The research also highlighted the formation of false memories. When flies were exposed to a harmless scent tied only to the training context, they began to avoid it, suggesting the brain may use distinct neural pathways for retrieving true memories versus forming false ones. Scientists suggest these false memories might be a mechanism for flexible adaptation based on prior experience, though results from fruit flies cannot be directly applied to humans.