Post-traumatic stress disorder (PTSD) causes its victims to relive troubling memories, but a new treatment shows promise in stopping such flashbacks.

In a new study, researchers were successful in erasing fear-inducing memories from laboratory mice conditioned to have PTSD-like symptoms, the Los Angeles Times reported. By stimulating certain genes, the researchers were able to condition the brain's hippocampus, a region where memories are secured and dealt with.

Most promising of all, the fear-conditioned mice did not simply forget why they were afraid, their memory neurons were revitalized, acting healthier and stronger than before.

"We can see that this treatment can markedly increase synaptic density, and synapses are the basic unit for the communication between neurons," study author Li-Huei Tsai, a neurobiologist and director of Picower Institute for Learning and Memory at MIT, told the LAT.

About 29 percent of PTSD patients can experience horrifying or painful memories for the rest of their lives. The researchers were able to build off of a form of therapy involving the recollection of the highly emotional memories, where patients have the opportunity to overcome their fear.

This type of therapy is called exposure therapy and it generally works with patients whose problem memories are short-term. It is not so successful with patients who have old memories entrenched in their mind.

Using a compound called a histone deacetylase inhibitor, the researchers were able to lower the fear of mice conditioned with short and long term frightening memories. However, the compound only worked when preceded by a form of exposure therapy, or access to the painful memory.

The researchers found that they were not creating a new memory, but re-associating existing ones. In other words, they gave a new, non-painful meaning to an old memory causing the PTSD.

Tsai noted her team has yet to determine if the treatment is safe to test on humans, but that will certainly be the researchers' next step. They will also explore optogenetics, the use of light, and other non-pharmaceutical options to get the same results.

The researchers' study was published online in the journal Cell.