New research suggests that the brain stores at least three separate copies of every memory, upending the long-held belief that only one, adaptable version exists. The study, conducted in rodents, focused on the hippocampus, a brain region crucial to memory and learning. Researchers found that neurons in this region 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 copy of long-term memory. This copy is initially weak, but becomes stronger as time passes. After this, middle-path neurons form a more stable version from the beginning. Finally, late-born neurons encode a memory that starts out strong, but fades faster than the others. This process suggests that the brain has a built-in mechanism for managing the evolution of memories as we grow older and continue to learn.
How Memories Are Encoded
The study highlights the complexity of memory formation in the hippocampus. Early-born neurons are responsible for the long-term retention of memories, forming a foundational copy that is crucial for lasting memory. Middle-ground neurons ensure the stability of memory, while late-born neurons, though strong at first, contribute to the more malleable aspects of memory that can be reshaped by new experiences or information.
The findings have important implications for understanding and treating memory-related disorders. For example, in conditions such as PTSD, where memories can be painful and intrusive, therapies could target late-born neurons to reduce the emotional impact of traumatic memories. Conversely, for people with dementia, stimulating early-born neurons could help improve memory, potentially slowing the progression of memory loss.
Future possibilities
Understanding how different neuron groups contribute to memory storage opens up new avenues for potential therapies. By selectively targeting the type of neuron involved in encoding a memory, researchers may eventually be able to develop treatments that can enhance memory retention or enable the rewriting of painful memories.
This study not only changes our understanding of memory, but also lays the foundation for future treatments that could revolutionize the treatment of memory-related disorders.
