A recent study from the University of Chicago offers new insights into how the brain forms and modifies memories of places. This research, published in Nature Neuroscience, explores how neurons adjust their activity as animals navigate familiar environments, suggesting that memory processing is more dynamic than previously believed.
Associate Professor Mark Sheffield, senior author of the study, explains: “When you go into a room, it’s new at first but it quickly becomes familiar to you every time you come back. You might expect that neuronal activity representing that room would settle and become stable, but it continues to change.”
The study focuses on "place cells," which are neurons in the hippocampus that activate when an animal is in a specific area. These cells form a cognitive map by covering different locations within an environment. Understanding this process could be crucial for addressing memory-related disorders like Alzheimer’s disease and schizophrenia.
Postdoctoral researcher Antoine Madar examined place cell activity in mice navigating various environments. Contrary to expectations, he found that neuronal activity patterns varied even in familiar settings. Some changes were subtle while others were more pronounced.
“These changes in representation, during learning and after, must be driven by synaptic plasticity—but what kind of plasticity exactly? It’s hard to know because we don’t have the technology to measure that directly in behaving animals,” Sheffield said.
Madar developed a computational model to test different plasticity rules against mouse data. The research challenges traditional views by suggesting Behavioral Timescale Synaptic Plasticity better explains how memories are recorded.
Sheffield proposes these shifts may encode slight experiential changes: “One idea is that these dynamics in memory representations are encoding slight changes in the experience... They’re not just encoding the environment; they’re encoding the entire experience that occurs there.”
The study was funded by several organizations including the National Institutes of Health and involved contributions from Anqi Jiang and Can Dong at UChicago.