Can a positive memory replace a negative one? Does our memory have healing power to stop fighting depression? The study carried out by scientists from the RIKEN-MIT Center for Neural Circuit Genetics , a joint collaboration of the RIKEN Institute of Brain Sciences in Japan and MIT (USA), which has been published in the journal Nature, began under these premises.
In their experiment carried out with laboratory mice, scientists have established that the artificial reactivation of memories stored during a positive experience is fully capable of suppressing the effects of stress-induced depression . Thus, the study shows that positive and negative memories continuously interact with mood disorders and therefore, this specific brain circuit to activate positive experiences in our memory may represent the future of clinical cure for depression among other disorders Similar.
The mice under study were genetically modified by optogenetics so that the cells of the dentate gyrus of the hippocampus (one of the areas of the adult brain capable of generating neurons throughout life) could be marked while memories were being formed, and later reactivated with an optical fiber that emits blue light implanted in the dentate gyrus .
The Nobel laureate and study leader Susumu Tonegawa, discovered that by activating only the group of neurons that contained the positive memory of the previous experiment (where the mice were trained to remember a negative, a neutral and a positive experience) they recovered from the symptoms of depression , very similar to those suffered by human beings. Five days of this positive memory activation treatment was enough to completely eliminate the effects of stress accumulated during the 10 days that the first experiment lasted. In addition, this improvement lasted over time despite stopping the stimulation of these neurons .
The in-depth study of the brain of the mice also revealed that other brain areas, apart from the hippocampus, benefited from this technique , since the amygdala (key in the feeling of fear) and the nucleus accumbens (integrated in the reward system of the brain) appeared active in this regulation or control of stress.
The mice that did not undergo neuronal stimulation and therefore did not remember the positive experience did not recover from depression even by putting them directly in the same situation that caused the positive memory, which is evidence, according to the experts, that Memories have much more healing power than experiences themselves. The authors state that it is too early to conclude that positive memories in general can mitigate the effects of stress-induced depression in humans, yet it is clear that cells of the dentate gyrus of the hippocampus are promising targets for therapeutic approaches. related to mood.
