To succeed in forgetting a memory, our first reflex could be to stop paying attention to it. However, a new study suggests the opposite: to forget something, it should be rethought. Forgetting would be an active process that would require a greater mental effort than the creation of the memory itself.
Memory can be very difficult to control. Sometimes important information or a memory will be out of reach, no matter how hard you try to remember it. In other cases, some events that we would rather forget are engraved in our minds.
If research on memory has helped to understand the basics of its training, we know less about the mechanisms that manage forgetting. It is often perceived as a weakness, or a tragic consequence of neurodegenerative diseases, but more and more, forgetting is considered an essential element of the proper functioning of the brain.
Although we may think that forgetting is a simpler process than the formation of memory, American researchers wanting to better understand its operation have discovered that this process is more complex than it seems (New window) and that he would even ask for more brain activity than the formation of memories.
This observation would help to better understand the mechanisms of forgetfulness and possibly help people suffering from post-traumatic stress.
Memory the faculty that forgets
For many researchers, the ability to forget is necessary, and allows our brain to keep only essential information and use it more flexibly in different contexts. Many of the mechanisms involved in memory enhancement or degradation are active during sleep phases.
However, if certain memories passively fade, that is to say that the neurons involved will degrade or lose certain connections with each other, other more active processes are also present in the brain.
Some can even be used consciously. For example, several studies have shown that it is possible to interfere with the creation of a memory by quickly focusing on something else after the event.
The creation of an active memory and reorganizes neurons at the level of the hippocampus, an area of the brain that manages many of our new experiences. There will then be a gradual reorganization of multilevel neurons in the cerebral cortex.
However, during the first hours after its acquisition, a memory can be very fragile. Focusing attention on a demanding task can interfere with the process and prevent short-term memory from becoming a long-term memory.
Remember in moderation
However, it is not only the hippocampus or the prefrontal cortex that are involved in the formation of memory. Here, researchers focused on the temporal lobe, an important area for image interpretation and visual memory formation.
To see if this region has a role in oblivion, the researchers placed 24 volunteers in a magnetic resonance imaging machine. Once inside, participants saw a series of images representing objects, landscapes or faces and each time they were instructed to remember the image or to forget it quickly. .
Surprisingly, the researchers noticed that the temporal lobe had a greater overall activity when the participant was instructed not to remember the image. In addition, the best “forgetfulness” occurred during moderate activation of temporal lobe neurons, while stronger activations contributed to its enhancement. For the researchers, these less intense signals made the process of memorization sensitive to interference, and they could contribute to the weakening of the memory, then to its forgetfulness.
Researchers have also noticed that some neutral images, such as landscapes, are easier to forget than images associated with emotions, such as faces.
The researchers themselves say that the forgetting of images in the laboratory is very different from the forgetting of real events experienced by a person. However, the mechanisms involved could be similar, opening the way to a better understanding of the regions of the brain and the mechanisms involved in oblivion as well as the possibility of blurring traumatic memories.