Is forgetting a form of learning?

Of the neuroscientists Trinity College Dublin argue that forgetting information is not necessarily a bad thing, but rather a form of learning. Instead of being a brain bug, forgetting is, according to them, a functional characteristic of the brain, allowing it to dynamically interact with the environment, facilitating decision-making and mental flexibility. Researchers have developed tests to explore this idea. And the first results seem to prove them right.

Forgetting is a form of learning for the brain

In order to test this theory, Irish scientists conducted experiments on mice focusing on a form of forgetting, called feedback interference. It occurs when multiple experiences occur close together in time and can cause newly formed memories to be forgotten. During the experiments set up, the mice were trained to associate a specific object with a particular context or room. Next, the scientists observed that when other competing experiences interfered with the first memory, the mice seemed to forget these associations.

To study the impact of this form of forgetting on the brain, neuroscientists have genetically marked a group of brain cells, called an engram, which stores a specific memory. “Basically, using a technique called optogenetics, they found that stimulating engram cells with light recovered memories seemingly lost in a behavioral situation. Additionally, when the mice had new experiences related to the forgotten memories, the “lost” engrams could be naturally rejuvenated.”specifies the communicated.

These results suggest that forgetting can be viewed as a brain feature that helps reorganize and update memories based on new information.

Forgotten: implications for neurodegenerative diseases

“Memories are stored in sets of neurons called ‘engram cells’ and successful recall of these memories involves the reactivation of these sets. By logical extension, forgetting occurs when engram cells cannot be reactivated. However, it becomes increasingly clear that the memories themselves are still there, but the specific sets are not activated and therefore the memory is not recalled. It’s like the memories are stored in a safe, but you can’t remember the code to unlock it”explains Dr. Tomás Ryan, professor at the School of biochemistry and Immunology and at Trinity College Institute of Neuroscience did Trinity College Dublin and the lead author of the article published in Cell Postponement.

His colleague Dr Livia Author adds: “Our findings here support the idea that competition between engrams affects recall and that the forgotten memory trace can be reactivated by natural and artificial cues as well as bet updated with new information. The continuous stream of environmental changes leads to the encoding of multiple engrams competing for consolidation and expression. So while some may persist undisturbed, some will be subject to interference by new incoming and dominant information. However, disrupted memories can still be reactivated by environmental cues leading to memory expression or by misleading or novel experiences resulting in an updated behavioral outcome.”

By demonstrating that “natural forgetting” is reversible under certain circumstances, the team believe their work is likely to have important implications for the understanding and management of disease states such as Alzheimer’s disease where these daily forgetting processes can be mistakenly activated by brain disease.