Bad memories, characteristic of some disorders such as post-traumatic stress , are a very difficult burden to bear for individuals who suffer from it. That is why it would be perfect to be able to erase or deactivate them and enhance positive memories . Well, a team of researchers from Stony Brook University (New York) has published a study in Neuron according to which it is possible to tune memory at will by manipulating the neurotransmitters involved in the memory process. Specifically, they targeted a specific neurotransmitter, acetylcholine, a molecule that serves as a messenger at the brain level.
All the mechanisms involved in the formation of memories are not yet fully known, but the hypothesis that currently carries the most weight is that feelings are found in the amygdala, an area of the brain related to the processing and storage of emotional reactions such as fear . Acetylcholine would reach the amygdala, where cholinergic neurons would be in charge of forming memories. These neurons are the first to be affected in the early stages of dementia and other cognitive impairment processes, and they are also the ones that activate and reinforce emotional memories.
“Memories of emotionally intense experiences, both negative and positive, are especially strong and long-lasting. The goal of our research is to discover the mechanisms that magnify those memories,” according to Lorna Role, professor of Neurobiology and Behavior at the Institute of Neurosciences of said. college. To learn about the functioning of this type of neurons, the researchers activated fear reactions in laboratory mice, since this feeling is one of those that produces the most powerful memories. They did so using the technique of optogenetics , a method that consists of applying light to genetically modified neurons so that they respond to light stimuli. Thus they managed to alter the memories at will.
It is not the first time optogenetic files used to erase the memory, but can be used whenever light more precisely and as specific neuronal modification method. According to the researchers, the more they increased the dose of the neurotransmitter acetylcholine in the amygdala during the formation of a traumatic memory, the more it lasted twice as long as a normal memory. And if acetylcholine was lowered in the amygdala during a traumatic experience, even memory formation was prevented.
This finding could lead to the creation of mice that lacked fear by manipulating a single brain messenger. In the long term, in humans, if the release of acetylcholine is prevented during a memory formed based on fear, it would be possible to avoid and even erase the bad memories in some diseases such as post-traumatic stress disorder. At the moment, the cholinergic neurons responsible for receiving the neurotransmitter acetylcholine are difficult to study, as they are connected with many other types of neurons and are not very numerous in the brain compared to others. On the other hand, acetylcholine acts as a messenger for various processes and is essential for memory in general. But this is an important step to achieve in the future the goal of erasing bad memories and strengthening positive ones.
Crédito: Image courtesy of Stony Brook University.
Caption : Li Jiang, Lorna Role and David Talmage, neuroscientists at Stony Brook University in New York, have developed a method to manipulate the neurotransmitter acetylcholine and alter memories in mice.
