Memories evolve after encoding, and their content can be updated upon external or internal contingencies changes.
How could the brain regulate a memory’s dynamics?
Using mouse models, Professor Flavio Donato’s research group at the Biozentrum, University of Basel, investigated how the brain stores memories and how they change throughout life. Scientists found that a brain region called the hippocampus stores a single event in parallel memory copies among at least three different groups of neurons, which emerge at various stages during embryonic development.
Early-born neurons are responsible for the long-term persistence of memory. Their memory copies are too weak in the beginning and get stronger later. Also, in humans, the brain might have access to such memory only sometime after encoding.
On the contrary, the memory copy created by the late-born neurons is solid initially but fades over time. Neurons that develop between the early and late stages create a more stable memory copy.
Which memory copy is used may affect how easily it can be changed or used to create a new one. Which memory copy is used may affect how easily it can be altered or used to create a new one. Memories held briefly by late-born neurons can be updated and changed. Recalling an event soon after it happens helps late-born neurons integrate new information into the memory.
First author Vilde Kveim said, “How dynamically memories are stored in the brain is proof of the brain’s plasticity, which underpins its enormous memory capacity.”
Scientists hence found that activating specific memory copies and their timing could significantly affect how we remember, change, and use our memories.
“The challenge the brain faces with memory is quite impressive. On one hand, we must remember what happened in the past to help us make sense of the world we live in. On the other, it needs to adapt to changes happening all around us, and so must our memories, to help us make appropriate choices for our future”, says Flavio Donato.
Balancing how memories persist and change is complex, but now we might have a way to understand it better. Scientists hope that learning how memories are stored and updated in the brain could help reduce troubling memories or even recover ones we thought were lost.
Journal Reference:
- Vilde Kveim, Laurenz Salm, Talia Ulmer et al. Divergent recruitment of developmentally defined neuronal ensembles supports memory dynamics. Science. DOI: 10.1126/science.adk0997