Human memory alteration has received renewed attention with recent evidence that memories, when recalled, become mutable. Scientists have long known that short-term memories needed to be “consolidated” into long-term storage, but once there, they were assumed to be fairly fixed. In recent years, scientists like McGill’s Karim Nader have called that into question, arguing that “reactivating” memories opens neurochemical space to change or even erases the recollection. Over the last few years, researchers have begun the search for drug therapies that would exploit this second chance at remembering. The new Cambridge research suggests that, at least in rats, administering a drug that blocks the action of a key memory-forming brain chemical can disrupt memory reconsolidation.
Everitt’s team conditioned rats to associate the switching on of a light with cocaine. Then the rats learned behaviors that would get the light switched on and cocaine administered. The light, in that way, became a “drug-associated memory.” Switching on the light allowed the researchers to activate that memory, causing the rats to launch into their cocaine-craving behavior. But when the researchers administered a single dose of the brain chemical blocker and then flipped on the light, the rats’ drug-seeking behaviors were reduced for up to a month. Though the memory alteration appears temporary, if the results can be translated to humans, it could open up a wide variety of new treatments for memory-linked psychological conditions. Drugs that work like the one used in the study already exist and are FDA approved including the cough suppressant dextramethorphan and memantine, an Alzheimer’s drug.