Researchers have linked a neurotransmitter to blocking fears

Bad memories taking their toll? A new research study has found a link between a glutamate receptor and the ability to "unlearn" bad memories. This could have major implications in future treatment for anxiety, phobias and PTSD.

Although seemingly pretty terrifying at the time, a bad memory is more than just that one night stand from the college party days. Distressing memories can essentially tear people apart from the inside out, causing them both physical and mental harm throughout the course of their lives, not to mention the suffering of those close to them. Researchers have unveiled a receptor on one of the most prominent neurotransmitters in the brain that is believed to play a major role in the process of 'unlearning.' This area? The receptor for glutamate. At the Salk Institute for Biological Studies, the study used mice that had been conditioned to fear a tone after having been shocked simultaneously for their basis and as explained in a scientific publication:

When researchers put mice lacking the gene for mGluR5 through the fear extinction-drill, they were unable to shake off their fear of the now harmless tone.

“We could train the mice to be afraid of the tone but they were unable to erase the association between the tone and the negative experience,” said the author of the study.

Then, the researchers tested whether deleting mGluR5 also affected animals’ ability to learn new spatial information.

For this, they first trained mice to find a hidden platform placed in a fixed location in the water maze.

Although it took mutant mice slightly longer than control animals to remember the position of the submerged platform, after several days of training the mutants got used to it and were able to find it almost as quickly as the control animals.

These findings open doors for possible drug therapy studies that could help treat many fear-based disorders, phobias and anxieties that manifest themselves through negative memories, such as post-traumatic stress disorder (PTSD), which affects over 5 million Americans such as rape and molestation victims as well as those who experience war scenarios. Previously, studies focused on learning how to deal with negative memories, but this study is different in that it works on the "unlearning" process. Study lead, Stephen F. Heinemann, Ph.D. said of the unlearning process that "Most people agree that failure to ‘unlearn’ is a hallmark of post-traumatic stress disorders and if we had a drug that affects this gene it could help soldiers coming back from the war to ‘unlearn’ their fear memories.” When traumatic memories continue over time, sometimes not even on a conscious level, they can trigger sensory cues that bring up the offending memories and a correlative negative response. Sometimes, this negative response can be seen as having a strong temper or through patterns of control. The study can be found in the most recent publication of the Journal of Neuroscience.