Boston.Com (January 16, 2014): MIT Researchers Find a Drug that Helps Erase Traumatic Memories in Mice

Publication Date: 
Thu, 01/16/2014

For years, neuroscientist Li-Huei Tsai has been unraveling the brain circuits that underlie memory, searching for approaches that might be helpful in treating Alzheimer’s disease. In 2007, the Massachusetts Institute of Technology scientist identified an experimental drug that could restore lost memories in mice. Lately, she has been wondering whether that kind of drug might be useful to help people forget traumatic events that cause fear and anxiety.

In a study published Thursday in the journal Cell, Tsai and colleagues used a single dose of the drug, called an HDAC inhibitor, to help mice extinguish a fearful memory of a traumatic event that took place in the distant past.

The idea is simple: one therapy for post-traumatic stress disorder is to re-expose people to the trigger in a safe setting. The hope is that patients will rewrite the memory and learn not to fear the experience. But such therapies don’t always work and the effects may not last, so Tsai wondered if perhaps a dose of a drug that made the brain more malleable and plastic could help people learn the new association and permanently replace the fearful memory.

In studies with mice, Tsai and colleagues first repeatedly exposed the animals to a sound followed by a foot shock, until the mice began to freeze with fear in response to the tone alone. Then, researchers began to try and erase the memory by exposing the mice to the tone without the shock.

With one group of mice, researchers tried to extinguish the memories a day after the fearful memory was made, while in another they waited a month—with very different results. In mice that had only recently learned the association, the re-exposure regime successfully extinguished the memory. But in mice for whom the initial memory was in the distant past, it didn’t work very well.

When they paired the re-exposure therapy with an injection of the HDAC inhibitor drug that they showed helped prime their brains to lea

In studies with mice, Tsai and colleagues first repeatedly exposed the animals to a sound followed by a foot shock, until the mice began to freeze with fear in response to the tone alone. Then, researchers began to try and erase the memory by exposing the mice to the tone without the shock.

www.boston.com/news/science/blogs/science-in-mind/2014/01/16/mit-researchers-find-drug-that-helps-erase-traumatic-memories-mice/knw12fkPQLyAAizT82M56O/blog.html