As our lives go by, not only do we get older, we also generate an enormous amount of memories, which most of us forget. The general belief is that memories deteriorate over time and therefore we end up forgetting details of past events. But a new study shows that “forgetting” might not be so bad, but it would represent a different way of learning.
According to new research conducted by Trinity College Dublin, Ireland and the University of Toronto, Canada, and published in Nature Reviews Neuroscience , forgetting is caused by circuitry remodeling, which changes the accessibility of engram cells and the ability to recall information. Thus, they consider the possibility that memories are preserved in engram cells and that forgetting is caused by the inability to reactivate those engram cells.
Forgetting, a functional feature of the brain
“Memories are stored in sets of neurons called ‘engram cells,’ and successful recall of these memories involves reactivation of these sets. The logical extension of this is that forgetting occurs when the engram cells cannot be reactivated. The memories themselves are still there, but if the specific sets cannot be activated, they cannot be retrieved. It is as if the memories were stored in a safe but you cannot remember the code to unlock them”, explains Tomás Ryan, co-author of the work.
The authors argue that forgetting should not be considered as a weakness of our cognitive system (and, therefore, as a negative aspect), since they have discovered that forgetting some memories could be beneficial, as it can lead to more flexible behavior and better decision making. Forgetting would be improving our well-being by making us retain important memories for our current situation and forget those that are not.
“ Our new theory proposes that forgetting is due to circuit remodeling that changes engram cells from an accessible to an inaccessible state . Because the rate of forgetting is affected by environmental conditions, we propose that forgetting is actually a form of learning that alters memory accessibility according to the environment and how predictable it is.”
Thus, taking into account the different ways in which our brain is capable of forgetting certain things, it is not a random brain event , but is orchestrated so that the physical embodiment of a memory is more difficult to access because it is no longer It is really useful for us at this time of life.
“Importantly, we believe that this ‘natural forgetting’ is reversible under certain circumstances , and that in disease states, such as in people living with Alzheimer’s disease, for example, these natural forgetting mechanisms are hijacked, which results in a great reduction of engram cells, in accessibility and pathological memory loss”, the experts conclude.
Referencia: Tomás J. Ryan, Paul W. Frankland. Forgetting as a form of adaptive engram cell plasticity. Nature Reviews Neuroscience, 2022; DOI: 10.1038/s41583-021-00548-3
