As we go through life, we make a lot of memories, but we forget about a lot of them. Why? ‘Forgetting,’ according to popular belief, may not be a bad thing — at least, according to experts who think it is a sort of learning.
Changes in our capacity to retrieve certain memories are dependent on contextual input and predictability, according to the scientists behind the new idea, which was published today in the top international journal Nature Reviews Neuroscience. Rather than being a flaw, forgetting might be a useful characteristic of the brain, enabling it to engage with the environment in a dynamic way.
In a dynamic environment like the one humans and many other animals live in, losing certain memories might be advantageous since it allows us to be more flexible in our behavior and make better decisions. If memories were formed in conditions that are no longer relevant, forgetting them may be a beneficial move that enhances our overall well-being.
As a result, experts think that humans learn to forget certain memories while maintaining others that are critical. Of course, forgetting results in the loss of knowledge, but a growing body of evidence suggests that forgetting is caused by changed memory access rather than memory loss in certain situations.
Dr. Tomás Ryan, Associate Professor in the School of Biochemistry and Immunology at Trinity College Dublin and the Trinity College Institute of Neuroscience, and Dr. Paul Frankland, Professor in the Department of Psychology at the University of Toronto and the Hospital for Sick Children in Toronto, have proposed a new theory.
Drs. Ryan and Frankland are both fellows of CIFAR, a Canadian worldwide research institution that facilitated this cooperation via its Child & Brain Development program, which is conducting multidisciplinary research in this field.
Dr. Ryan, whose Trinity Biomedical Sciences Institute (TBSI) research team is situated, said:
“Memories are stored in ‘engram cells,’ which are neuronal ensembles, and proper recall of these memories requires the reactivation of these ensembles. The logical conclusion is that when engram cells cannot be reactivated, forgetfulness occurs. The memories themselves are still there, but they can’t be remembered until the precise ensembles can be triggered. It’s like if your memories are locked up in a safe and you don’t know how to open it.
“According to our new hypothesis, forgetting is caused by circuit remodelling, which causes engram cells to move from accessible to inaccessible states. We argue that forgetting is essentially a sort of learning that affects memory accessibility in accordance with the environment and how predictable it is, since the pace of forgetting is influenced by environmental factors.”
Dr. Frankland went on to say:
“Our brains forget in a variety of ways, but all of them make the engram — the physical embodiment of a memory — more difficult to retrieve.”
Dr. Ryan and Dr. Frankland point out the following when discussing pathological forgetfulness in disease:
“Most importantly, we think that this ‘natural forgetting’ is reversible in certain conditions, and that these normal forgetting processes are hijacked in disease states, such as Alzheimer’s disease, resulting in dramatically decreased engram cell accessibility and pathological memory loss.”