In the Great East Japan Earthquake, many people remembered the trivial events before and after the earthquake, such as what they ate at lunch.Professor Kaoru Inoguchi of the Department of Biochemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, and others, in collaboration with the Jikei University School of Medicine, have long-term memories of trivial events that would normally be forgotten immediately. Elucidated the mechanism.
Memories are converted and stored in the activity of specific nerve cell populations (memory engrams) in the brain, and different memories have different memory engrams.When you have a strong experience, the phenomenon that the trivial events before and after that are saved as long-term memory is called "behavior tag", which is an interesting phenomenon in the sense that the two memories interact, but the mechanism was unknown. ..
The research group used mice to identify memory engrams that act in response to intense experiences and trivial events.As a result, the overlap rate of the two memory engrams increased in a specific area of the brain (hippocampal CA2).Furthermore, it was discovered that if the activity of the memory engram of intense experience is artificially suppressed by light irradiation (optogenetic method), it becomes impossible to remember the trivial event in which the behavior tag was established.This is said to be the first demonstration at the neural circuit level of the formation of behavioral tags due to the duplication of memory engrams of trivial events and intense experiences.
When forming knowledge and concepts, various memory information accumulated in the brain is associated with it.However, in PTSD (post-traumatic stress disorder), other less relevant memories (situations) are unnecessarily linked to traumatic memory.This time, elucidating the mechanism by which different memory engrams interact is expected to lead to the development of treatments for psychiatric disorders such as PTSD.
