Do you want to erase memories from your brain? There are already people working on the solution

It doesn’t work the same as in science fiction movies. There is no Neuralizer as in Men in Blacknor implantation of memories of an imaginary life as in Total Recall. But the possibility of manipulating memory, erasing or implanting new memories already exists. At least in mice. So: do you want to erase your mouse’s memories?

A little over a decade ago, a group of neuroscientists at the MIT Center for Learning and Memory, led by Nobel laureate Susumu Tonegawa, demonstrated, in fact, that it is possible to identify and subsequently manipulate an engram; You know, of course, the memory trace that forms in the brain after a certain type of experience. In this case, a painful one, since it was an electric shock that hit the guinea pigs every time they were in a certain area of ​​a container created especially for the experiment. The rats, aware of the pain, froze with fear every time they were about to approach the point of shock. And until then, everything was normal. But the researchers, once they identified the neurons corresponding to that bad memory, managed to activate them, obtaining the same reaction of terror in the animals that had never received the shock. In other words, the guinea pigs were reacting to an artificially “implanted” memory.

They are the miracles of optogenetics

This is just one of the memory alterations that allows optogenetics. A technique that combines genetic and optical engineering. With the first, the nerve cells on which you want to act, in this case those of memory, become distinguishable from the others. With the second, light beams are used to activate or deactivate them.

Optogenetics is the field of research in which Steve Ramírez, a neuroscientist at Boston University, works. “It consists of using genetic engineering to make the brain cells that we believe store memories acquire a different color. At that time a microscope is used to get closer to these cells and try to find out how they are different from other cells that do not participate in processes. related to memory or how they have differentiated when they participated in the process of preserving memories. Microscopes so small they can implant directly in the brain of guinea pigs. This procedure, called engram mappinghas also allowed us to discover how, at a neuronal level, memories associated with negative or painful events seem different from positive ones. And subsequently artificially alter its valence, from negative to positive, or “turn off” the cells corresponding to the “bad” memories.

An invasive technique that is obviously not applicable to human beings. “But otherwise it is probable, if not inevitable, that within a few decades similar results can be obtained in humans to treat disorders such as post-traumatic stress syndrome or depression,” says Ramírez.

forget about it

Aurelio Cortese, group leader and principal investigator at the International Computational Neuroscience Laboratories at the ATR Institute in Kyoto, is experimenting with another method to modify memories in humans. Decoded Neurofeedback, abbreviated DecNef, combines two technologies: on the one hand, brain scanning using functional magnetic resonance imaging and, on the other, a machine learning algorithm that processes the data in real time. “A technique that began to be developed about ten years ago,” he explains. “At first, it was about modifying an aspect of visual perception, for example by accelerating the memorization of information related to orientation in space, reinforcing the corresponding neural activity. A revolutionary result at the time. But, over time, we were capable of modifying memories related to objects, animals, that is, something much more complex than a simple visual stimulus. The reason this was possible is that the way of accessing the neural representation is the same: in both cases, the algorithm. of machine learning learns to recognize the neural representation corresponding to the stimulus, in the first case, and the image presented to the participants in the test, in the second. Having learned the pattern of activity to calculate the probability that it corresponds to our target, participants are asked to undergo a series of tests to remodel their neural activity so that it matches the desired pattern of activity. Every time this happens, they receive a small monetary reward“.

Basically, it is about learning to control the impact of negative, stressful or painful memories. A procedure that is repeated hundreds of times, taking advantage of the brain’s ability to learn by reinforcement. The objective: to act on the memory to “erase” the phobias regarding certain animals. “To avoid any type of bias, we carried out double-blind tests, which means that both participants and experimenters are unaware of the objective of the manipulation. We have already shown that the physiological reaction to memories linked to negative emotions is diminished by the DecNef. The memory chosen as the target is ultimately modified. What was previously considered terrifying, for example, becomes neutral.” And he adds: “Machine learning systems and artificial intelligence are acquiring a fundamental role in these types of studies because neural activity is extremely complex.”