- Toxic memories are the basis of pathologies from phobias to pain. Legions of neuroscientists have tried to marshal our understanding of how memories form in the brain to try to reverse this process in patients who need to escape the legacy of psychological or physical trauma.
- ZIP, an eponymous biochemical, wipes a rat’s memory but is incapable of selecting only “bad” memories for removal.
- Turning down the level of pain associated with anticipated trauma or a just experienced ordeal may come about from administration of drugs that decrease the levels of stress-related norepinephrine.
- A rewrite of personal history may represent yet another strategy. When old memories are recalled, drugs or behavioral therapies might alter the tainted emotional coloration surrounding them.
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The rat is on a carousel with clear plastic sides, rotating slowly in a small room. As it looks out through the plastic, it sees markings on the walls of the room from which it can determine its position. At a certain location it receives a foot shock—or, in experimenters’ jargon, a negative reinforcement.* When that happens, the rat turns sharply around and walks tirelessly in the opposite direction, so it never reaches that same place in the room again. It will do this to the point of exhaustion.
Question: How do you get the rat to stop walking? Note that just turning off the shock will not suffice, because the rat will not allow itself to enter the danger zone. The rat needs an intervention that helps it forget its fear or that overrides its response with a competing signal of safety.
This article was originally published with the title Erasing Painful Memories.