For many people, fear of flying or of spiders skittering across the lounge room floor is more than just a momentary increase in heart rate and a pair of sweaty palms.

An international team led by QBI neuroscientists may have found a way to silence the gene that feeds such fears.

Group leader Dr Timothy Bredy said the team had shed new light on the processes involved in loosening the grip of fear-related memories, particularly those implicated in conditions such as phobia and post-traumatic stress disorder.

Dr Bredy said they had discovered a novel mechanism of gene regulation associated with fear extinction, an inhibitory learning process thought to be critical for controlling fear when the response was no longer required.

“This is the first comprehensive analysis of how fear extinction is influenced by modifying DNA, and highlights the adaptive significance of experience-dependent changes in the chromatin landscape in the adult brain,” Dr Bredy said.

“Rather than being static, the way genes function is incredibly dynamic and can be altered by our daily life experiences, with emotionally relevant events having a pronounced impact,” he said.

He said that epigenetic processes, including variations in the chemical tagging of DNA, can promote the activation or silencing of genes although the genome itself remains the same.

“We have shown that DNA modifications have the innate capacity to respond and adapt in an experience-dependent manner,” he said.

He explained that by understanding the fundamental relationship between the accumulation of a recently discovered DNA modification, 5-hydroxymethycytosine (5-hmC), and chromatin states that are involved in this important form of learning, future targets for therapeutic intervention in fear-related anxiety disorders could be developed.

“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.”

The collaborative research is being done by a team from QBI, the University of California, Irvine, and Harvard University.

The study was published in the Proceedings of the National Academy of Sciences of the United States of America.