Lost And Found: After Reversing Amnesia In Rodents, Manipulating Human Memories Doesn't Sound So Far Off

memory
Researchers say they've developed a process to reverse amnesia in rats, thus paving the way to greater manipulation of human memory. Jason Eppink, CC by 2.0

If we could manipulate our memories, we could change not only our past but also our future lives. Trauma would be forgotten, while the happiness of that first connection with a new friend remains perfectly intact... forever! A new Cardiff University study demonstrates a process to reverse amnesia in rats, under conditions where the rodents’ memories were assumed to be completely lost.

The scientists say having identified a process that could help rescue what is forgotten — or bury what should go unremembered — paves the way for new treatments to help people with memory problems.

The Molecular Basis For Memory

Consolidation occurs whenever an acquired memory trace is stabilized. Essentially, this is a molecular process occurring in the brain that can be likened to placing a remembered experience into storage. Similarly, specific molecular processes accompany moments of recall, and, in conditioning studies, researchers have disrupted these molecular processes, resulting in a permanent amnesia. These experiments are considered to be a demonstration of the existence of reconsolidation.

Reconsolidation theory proposes that, under certain experimental conditions, already consolidated (and so stable) memories can enter into a labile (malleable) state on recall. Updating or strengthening of the stable memory can occur, though if it is not actively re-stabilized, the memory will disappear.

For the current study, the researchers used rats to experiment with the various processes of memory. After the rodents had acquired a contextual fear memory, the researchers disrupted the molecular processes necessary for recall — expression of the Zif268 and Arc genes and synthesis of new proteins. This should have wiped out the rodents’ fear memories completely. However, before testing the rats on their recall ability, they gave them a chemical infusion and then a reminder stimulus. Unexpectedly, the rats recalled the memory that should have been lost.

Though the researchers performed this experiment on rats, they believe the results translate to humans. In fact, they believe the animal models accurately reflect what's happening in humans.

“Our autobiographical memories, our self-histories, are clouded by new memories rather than actually lost,” Dr. Kerrie Thomas, a senior lecturer at Cardiff and lead researcher, stated in a press release. “This is an exciting prospect in terms of treating psychiatric illness associated with memory disorders such as post-traumatic stress disorder, schizophrenia and psychosis.” Though Thomas and her colleagues are hopeful, they say new treatments will not be available soon.

Source: Trent S, Barnes P, Hall J, Thomas KL. Rescue of long-term memory after reconsolidation blockade. Nature Communications. 2015.

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