New pathway to extinguish fearful memories discovered

24 Apr 2018



New fear pathway in the brain found

A new brain pathway involved in extinguishing fearful memories has been discovered by QBI researchers.

The new-found circuit within the prefrontal cortex enhances the forgetting of triggers to traumatic events and could lead to future drug treatments for anxiety disorders like PTSD (post-traumatic stress disorder).

“Fear extinction is the process by which someone becomes less responsive to a traumatic stimulus as a result of exposure over time,” said Dr Roger Marek.

“For example, the sound of gunfire or images of battle may trigger a fear response in a soldier who has returned from combat.”

Fear extinction pathway could help treat anxiety disorders

Exposure therapy, which is used to treat anxiety disorders including PTSD, aims to extinguish these fears by exposing a person to triggering stimuli in the absence of potential danger or harm.

“We identified a new circuit by which fear extinction is regulated in an animal model.

“In future, if we can find a specific target site in the pathway, it could form a potential drug target for treating fear disorders including anxiety and PTSD.”

Lead researcher and QBI director Professor Pankaj Sah said the finding was critical for understanding the complexity of the brain circuits regulating fear and anxiety disorders.

“Fear researchers previously thought that two distinct subregions in the prefrontal cortex regulate the development and extinction of fears: the prelimbic and infralimbic regions, respectively,” said Professor Sah.

Known fear pathways linked

“Our research overturns this belief," said Professor Sah. "We found that the two are linked via the circuit we discovered, and this connection was found to enhance fear extinction“

"The next step for us will be to study the circuitry between the prefrontal cortex and the amygdala, a region of the brain important for emotional responses, to understand how these connections differentially regulate fearful memories.”

The study is published in Nature Neuroscience.


Image: Getty