Not being able to fall asleep because your eyes caught a harmless eight-legged creature run beneath your bed can be debilitating, especially because it's fear-driven. An international collaboration of neuroscientists may have found a way to silence one’s fear on a microscopic level.

The team of researchers, which include those from Queensland Brain Institute at University of Queensland, said they’ve discovered the mechanism that controls the gene associated with fear. It’s akin to finding the right light switch in a room full of unlabeled switches. The study is the first of its kind and examines how fear is controlled by genes, and if the gene that feeds fear can really be controlled.

 “What is most exciting is that we have revealed an epigenetic state that appears to be quite specific for fear extinction,” said Xiang Li, a Ph.D. candidate and the study’s lead author.

Epigenetics is the study of long-term alterations to hereditary genes. It’s not the study of the actual DNA, but instead how modifications affect how cells “read” genes. Epigenetic changes will alter the physical structure of DNA. For example, they could turn off or silence a gene that controls tumor development so that cancerous tumor will slow its growth.  

It’s a field that has yet to be fully explored and recent research has led scientists one step closer to loosening the grip of fear-inducing memories. Post-traumatic stress disorder (PTSD) and phobias, such as crippling fear of the dark and heights, might be a problem of the past eventually.

“It highlights the adaptive significance of experience-dependent changes in the chromatin landscape in the adult brain,” said Queensland Brain Institute Senior Research Fellow Dr. Timothy Bredy.

Chromatin is a complex combination of DNA and proteins, which has the role of preventing DNA damage and also controlling how genes are expressed. The mechanism they found controls the brain activity associated with fear extinction, and Bredy says with therapeutic learning processes the fear response could be turned off when it is no longer needed.

“This may be achieved through the selective enhancement of memory for fear extinction by targeting genes that are subject to this novel mode of epigenetic regulation,” he said.

If a person has genuphobia, for example, they have a fear of knees. Phobias are an overwhelming and unreasonable fear of an object or situation that can disrupt a person’s daily life and require extensive therapy, according to Mayo Clinic. Now, a person with an irrational fear of knees may avoid summer attire, beaches, and looking down in the shower all together, unless they can turn off the unnecessary fear response.

Studies have been published on the fear-feeding gene before, but no one has found it until now. In 2009, researchers at McLean Hospital, the largest psychiatric branch of Harvard Medical School, found a protein in the brain that could trigger the body’s knee-jerk fear response.

Researchers found mice that lacked a specific receptor gene, where not as sensitive to a hormone released in the brain during situations of innate fear. This observed lack of anxiety could help the 6.8 million Americans that suffer from a generalized anxiety disorder, which causes exaggerated worry for little or no reason.

Harvard University, along with the University of California, Irvine, are working collaboratively with the Queensland Brain Institute to understand how exactly they can influence fear by customizing genetic makeup.

 

Source: Bredy T, Li X, Wei W, et al. Neocortical Tet3-Mediated Accumulation Of 5-hydroxymethylcytosine Promotes Rapid Behavioral Adaptation. Proceedings of the National Academy of Sciences of the United States of America. 2014.