New research indicates that the brain stores at least three distinct copies of every memory, overturning the long-held belief that a single, modifiable version exists. Conducted on rodents, the study focused on the hippocampus, a critical brain region for memory and learning. Researchers discovered that neurons in this area create multiple memory copies, each varying in strength and stability, which could explain why and how memories change over time.

These memory copies are encoded by different types of neurons, each with unique characteristics. Early-born neurons are the first to create a long-term memory copy. Initially weak, this copy becomes stronger as time passes. Following this, middle-ground neurons form a more stable version from the outset. Lastly, late-born neurons encode a memory that starts strong but fades more rapidly than the others. This process suggests that the brain has a built-in mechanism for managing the evolution of memories as we age and continue to learn.

How Memories Are Encoded

The study highlights the complexity of memory formation within the hippocampus. Early-born neurons are responsible for the long-term retention of memories, forming a foundational copy that is critical for enduring recollection. Middle-ground neurons ensure the memory’s stability, while late-born neurons, although strong at first, contribute to the more malleable aspects of memory that might be reshaped by new experiences or information.

The findings carry significant implications for understanding and treating memory-related disorders. For instance, in conditions like PTSD, where memories can be distressing and intrusive, therapies could target the late-born neurons to diminish the emotional impact of traumatic memories. Conversely, for those suffering from dementia, stimulating early-born neurons might help enhance memory retention, potentially slowing the progression of memory loss.

Future Possibilities

Understanding how different neuron groups contribute to memory storage opens new avenues for potential therapies. By selectively targeting the type of neuron involved in encoding a memory, researchers may eventually develop treatments that can either strengthen memory retention or enable the rewriting of painful memories.

This study not only reshapes our understanding of memory but also lays the groundwork for future treatments that could revolutionize the management of memory-related conditions.