Many of us are the bearers of “bad” memories that, to this day, continue to affect our lives. Now, scientists say they have discovered a gene essential for “memory extinction,” the process by which our brain replaces older memories with new experiences.
Researchers from the Massachusetts Institute of Technology (MIT) say the discovery could help people suffering from post-traumatic stress disorder (PTSD) by replacing “fearful” memories with more positive associations.
The gene, Tet1, has been found to play a critical role in memory extinction by controlling a small group of other genes that are necessary for the process. For the study, published in the journal Neuron, the research team experimented on mice who had the Tet1 gene “knocked out,” as well as on mice who had normal levels of the gene.
In order to measure the mice’s ability to abolish memories, the mice were “conditioned” to fear a certain cage in which they received a small electric shock. Once the memory of the “cage shock” was formed, the mice were placed into the cage, but the researchers did not give them the shock.
The researchers found that after a period of time, mice with normal Tet1 levels appeared to lose their fear of the cage, indicating that new memories replaced the old ones.
Li-Huei Tsai, director of MIT’s Picower Institute for Learning and Memory, explains:
“What happens during memory extinction is not erasure of the original memory. The old trace of memory is telling the mice that this place is dangerous. But the new memory informs the mice that this place is actually safe. There are two choices of memory that are competing with each other.” View full article »