Forgetting is learning and memory can be reactivated, say scientists

Recent research suggests that forgetting may be a form of learning and an adaptive process. Much more than just memory loss, this brain dynamic could be a response to a changing environment.

The scientific study was published in the journal Cell Reports with an analysis of this brain phenomenon. In addition, the publication presents descriptions of experiments that stimulate natural forgetfulness.

According to the researchers, forgetting can be considered a learned behavior. Therefore, it performs an "adaptive function of the brain that can contribute to learning and memory updating".

To validate the theory and select the study samples, they used rodents and a back-interference process. During the process, the mice were tested in different recent memory situations.

How was the forgetting study done?

Despite being frequently associated with the failure of

memory or disability, forgetting can be an experience that is influenced by changes that are taking place in the environment.

Therefore, the researchers organized a retroactive interference experiment, so that new specific information attenuated the memories previously encoded by the mice.

In the test, the rodents needed to create associations between objects and where they were in the environment. Afterwards, the idea was to see if they could identify an object that was displaced from its original location. The process of habituation to the contexts lasted about four days.

Part of the process also went through a moment of competing experiences that interfered with the first memory.

During the experiment, they analyzed the responses of brain cells that are responsible for storing memories. Thus, they found that the test rodents forgot the associations when they were interfered with by competing experiences.

But “the interfered memories can still be reactivated by surrounding cues that lead to the expression of the memory or by misleading or novel experiences that end in an updated behavioral outcome,” said Livia Autore, one of the authors of the study.

(Image: Freepik/Playback)

Oblivion can be retrieved

After the first round of tests, the rodents received a new round of associations that were related to forgotten memories. At that moment, the researchers realized that the cells responsible for memories were retrieved.

For Tomás Ryan, professor at the Trinity College Institute of Neuroscience, “memories are stored in sets of neurons called "engram cells" and the successful retrieval of these memories involves reactivating these sets”.

With all this, they noticed that forgotten memories are still stored in the brain, but need to be reactivated.