Fear built by experience lingers in genes
While almost no-one is comfortable with the surprise presence of spiders or other creepy-crawlies, for some people a deep-held phobia can seriously affect lives.
Hardcore phobias that can lead to crippling anxiety are the subject of research by neuroscientists from the University of Queensland.
They are part of an international project which may have found a way to silence the gene that feeds fear.
Queensland Brain Institute (QBI)fellow Dr Timothy Bredy says the team has shed new light on processes for loosening the grip of fear-related memories, particularly those implicated in conditions such as phobia and post-traumatic stress disorder.
A breakthrough came when the team discovered a new mechanism for gene regulation associated with fear extinction - an inhibitory learning process critical for controlling fear when the response is no longer required.
“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,” Dr Bredy said.
By understanding the way DNA functions without a change in the underlying sequence, 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,” he said.
Mr Xiang Li, a PhD candidate and the study’s lead author, said fear extinction was a clear example of rapid behavioural adaptation, and that impairments in this process were critically involved in the development of fear-related anxiety disorders.
“What is most exciting is that we have revealed an epigenetic state that appears to be quite specific for fear extinction,” Mr Li said.
“It highlights the adaptive significance of experience-dependent changes in the chromatin landscape in the adult brain,” Dr Bredy added.
The study was published this month in the Proceedings of the National Academy of Sciences of the United States of America.