A new mouse study has found that the brain’s representation of places is not fixed and can change over time. Researchers believe that memories of locations are encoded by different sets of neurons in the brain, leading to a phenomenon known as “hippocampal representational drift.” This concept challenges the long-held idea that memories of specific places were encoded by specific “place cells” in the hippocampus.
The study used virtual reality and controlled environmental factors to isolate the effect of spatial memory on the brain. By monitoring the activity of hippocampal cells in real-time, researchers discovered that only a small subset of cells behaved like conventional place cells, while others showed more variability.
According to senior study author Daniel Dombeck, this drift may be a mechanism for separating similar experiences into distinct memories and tracking the passage of time. The findings suggest that the brain uses different neurons to encode memories of specific places over time, rather than relying on a single “mental map.”
While the study has limitations, including only capturing a fraction of the cells in the mouse hippocampus, Dombeck believes that similar processes may occur in humans. He speculated that maintaining the excitability of brain cells or finding ways to support it could help preserve memory.
The discovery sheds new light on how our brains process and store memories of specific places and challenges previous assumptions about spatial memory encoding.
Source: https://www.livescience.com/health/memory/memories-arent-static-in-the-brain-they-drift-over-time