How Many Copies of Your Memories Does Your Brain Hold?

Have you ever wished you could erase the memory of a toxic relationship, wiping away every trace from your mind? Imagine—how many memories of an ex would LaCunaInc from Eternal Sunshine of the Spotless Mind need to delete for you to truly forget them? And, once a memory is lost, is there any way to bring it back, or is it gone for good?

In a groundbreaking study, neuroscientists at the University of Basel have made strides in understanding how our brains preserve memories that last for years while remaining adaptable to constantly changing environments. Their research has revealed one of the most significant discoveries in neuroscience this year: multiple copies of memories exist in hippocampal cells, each dedicated to storing and modifying memories uniquely.

### The Three Types of Memory-Storing Neurons

The researchers discovered that the hippocampus stores memories across three types of cells, each distinguished by its age and its role in memory persistence and adaptability:

1. **Long-lived cells**: These neurons store a stable, but often harder-to-access, copy of memories. While difficult to modify, these long-term memories are crucial for recalling events over extended periods.

2. **Intermediate-aged cells**: Bridging the gap, these neurons possess some characteristics of both long-lived and newly formed cells. They store memories that are more stable yet retain some flexibility, allowing them to be modified within certain limits.

3. **Newly formed cells**: These cells hold memories that are easily accessible in the short term but fade with time. Memories in these neurons can be updated or rewritten based on new or previous experiences, making them ideal for recent memories that may still adapt to new information.

### A Potential for Therapeutic Advances

This discovery offers hope for developing therapies that target these distinct cell types, potentially leading to treatments that could help individuals recover lost memories or reduce the impact of unwanted ones. By further exploring how memories are encoded and adjusted, researchers aim to one day soften memories that are intrusive or painful or bring back memories once thought lost.

This research opens new avenues in our understanding of memory's persistence and plasticity, laying the groundwork for future advancements that could reshape our ability to engage with the past.

Reference:

Kveim, V. A., Salm, L., Ulmer, T., Lahr, M., Kandler, S., Imhof, F., & Donato, F. (2024). Divergent recruitment of developmentally defined neuronal ensembles supports memory dynamics. Science (New York, N.Y.), 385(6710), eadk0997. https://doi.org/10.1126/science.adk0997