Research redefines synaptic plasticity's role in memory

New research suggests that our understanding of how memories are formed in the brain may be more complex than previously thought. Traditionally, scientists believed that synaptic plasticity, the process by which connections between neurons change, operated under simple rules. The idea was that when two neurons fire together, their connection becomes stronger, while separate firing weakens it. However, a study from the University of Chicago focused on the hippocampus, a key area for memory, reveals more complicated dynamics. Scientists observed patterns of neural activity in mice as they navigated familiar and new environments. They expected this activity to remain stable once the mice learned a location, but instead found that these patterns continued to shift even after learning. Mark Sheffield, a leading researcher, noted that this ongoing change in neuronal activity suggests a different set of rules governing synaptic plasticity. The study highlighted a new concept called Behavioral Timescale Synaptic Plasticity (BTSP), which appears to better account for how and why these neuronal representations evolve over time. The researchers recorded how "place cells," neurons that respond to specific locations, acted as mice explored different settings. Contrary to expectations, the data showed continuous changes in activity, even in known spaces. These variations reflected the dynamic nature of synaptic plasticity during learning. By modeling how hippocampal neurons might work, the team found that BTSP could explain a wider range of neuronal behavior compared to traditional models. This finding suggests that BTSP might play a significant role in the brain's ability to form memories during familiarization. While this research shows that memory formation involves more dynamic processes than realized, the exact purpose of these shifting representations remains uncertain. One theory is that they could help the brain differentiate between similar memories occurring in the same location but at different times. Overall, these insights provide a new perspective on how memories are encoded in our brains and emphasize the complexity of neuronal activity in learning and memory formation.