Know About Suppressing Memories

There is a cashew-shaped structure inside our brains which is called the hippocampus. It stores the sensory and emotional information which makes up memories, whether they are positive or negative ones. There can’t be two similar memories, and likewise, each memory which is stored in our brain is in a unique combination of brain cells which contain all the environmental and emotional information linked with that memory. The hippocampus itself, although small, contains various different subregions all working in tandem to recall the elements of a specific memory.

Now, in a recent paper in Current Biology, Ramirez along with a team of collaborators have reflected just how pliable memory is if you know which regions of the hippocampus for stimulating. This could someday enable personalized treatment for people haunted by particularly troubling memories.

Briana Chen, first author of the paper, said that many psychiatric disorders, especially PTSD, are on the basis of the idea which after there's a really traumatic experience, the person is not able to move on as they recall their fear over and over again. He is currently a graduate researcher who is studying depression at Columbia University.

In their study, the senior author of the paper, Chen and Ramirez, show how traumatic memories like those at the root of disorders like PTSD -- can become so emotionally loaded. By artificially activating the cells of memory in the bottom part of the brain's hippocampus, negative memories can become even more debilitating. In contrast, stimulation of memory cells in the top part of the hippocampus can strip bad memories of their emotional oomph, making them less traumatic to remember.

Utilizing a methodology which is called optogenetics, Chen and Ramirez analyzed about the cells in the hippocampus which were being activated when male mice made new memories of positive, neutral, and negative experiences. For example, a positive experience could be exposure to a female mouse. On the other hand, a negative experience could be getting a startling but mild electrical zap to the feet. Then, identification of cells is a part of the memory-making process; they were capable to artificially trigger those specific memories again later, utilizing laser light for activating the memory cells.

Their studies disclosed just how different the roles of the top and bottom parts of the hippocampus are. Activating the top of the hippocampus functions like effective exposure therapy, deadening the trauma of reliving bad memories. But activation of the bottom part of the hippocampus can impart lasting fear and anxiety-related behavioral changes, hinting that this part of the brain could be overactive when memories are becoming so emotionally charged that they are debilitating.

That distinction, Ramirez said that it is critical. He added that it suggests suppressing overactivity in the bottom part of the hippocampus could potentially be used for treating PTSD and anxiety disorders. It could also be the main key for enhancing cognitive skills, "like Limitless".

By: Preeti Narula

Content: https://www.sciencedaily.com/releases/2019/05/190523143040.htm