Recollections are saved in all totally different areas all through the mind as networks of neurons are referred to as engrams. Along with gathering details about incoming stimuli, these engrams seize emotional data. In a brand new research, Steve Ramirez, a neuroscientist at Boston College, found the place the mind shops optimistic and destructive recollections and located a whole lot of markers that distinguish optimistic reminiscence neurons from destructive reminiscence neurons.
In 2019, Ramirez discovered proof that good and dangerous recollections are saved in numerous areas of the hippocampus, a cashew-shaped construction that shops the sensory and emotional data wanted to kind and retrieve recollections. The higher a part of the hippocampus is activated when the rats have a nice expertise, however the decrease half is activated after they have a destructive expertise.
His workforce additionally found that they might manipulate recollections by activating this area. When he and his workforce activated the higher a part of the hippocampus, dangerous recollections grew to become much less traumatic. In distinction, after they activated the decrease limb, the mice confirmed indicators of long-lasting anxiety-related behavioral modifications. Ramirez suspects this distinction in impact is as a result of the neurons that retailer good and dangerous recollections have totally different capabilities past merely sustaining optimistic and destructive feelings. Nonetheless, earlier than he can unravel these variations, he must determine which cells retailer good and dangerous recollections. The outcomes are revealed within the journal Communication Biology.
Constructive and destructive recollections
To find out the place optimistic and destructive recollections are saved, Ramirez and his workforce genetically modified mouse neurons to glow purple or inexperienced when activated. When the mice had a traumatic expertise (that’s, creating a nasty reminiscence), the researchers blocked the inexperienced protein from being expressed, and when the mice had a optimistic expertise (that’s, creating a very good reminiscence), the researchers blocked the purple protein. This manner, neurons that retailer dangerous recollections will glow purple, and neurons that retailer good recollections will glow inexperienced.
They discovered that some mind areas (primarily the prefrontal cortex, the area chargeable for organizing ideas and actions in accordance with inner objectives) contained purple and inexperienced fluorescent alerts, indicating that they host optimistic and destructive reminiscence storage neurons. Notably, different areas solely host one kind. For instance, some elements of the amygdala (concerned in emotional data processing) primarily host neurons that retailer optimistic recollections, whereas different areas of the amygdala primarily host neurons that retailer destructive recollections.
“That is fairly wild as a result of it reveals that these optimistic and destructive recollections have their very own properties within the mind,” Ramirez stated in a press release.
Good and dangerous reminiscence cells work in another way
Since optimistic and destructive engrams retailer various kinds of recollections and are in numerous mind areas, the researchers suspect that they are often molecularly distinguished. To catalog these variations, they in contrast the RNA of neurons activated whereas creating optimistic and destructive recollections to neurons activated when storing a impartial reminiscence. Damaging reminiscence neurons expressed 212 genes that weren’t expressed by optimistic or impartial reminiscence cells, and optimistic reminiscence neurons expressed 872 genes that weren’t expressed by both destructive or impartial reminiscence cells. This implies that optimistic and destructive reminiscence neurons have totally different molecular mechanisms.
This probably has large implications: It opens the door to exploring reminiscence manipulation. Ramirez added, “We wish a recreation changer, proper? We wish issues that can be simpler than the present therapy choices.”
This text has been reprinted with permission from Massive Suppose, the place it was initially revealed.