Overcoming Long-Term Trauma Can Be Facilitated

Researchers facilitated the extinction of long-term traumatic memories in mice by enhancing trauma-related activity in the nucleus reuniens.

Exploring How the Brain Handles Long-Term Trauma: Breakthrough Research on Fear Extinction

Traumatic memories are so emotionally charged that they are difficult to ‘erase’ or put an end to it. But what scientific proof do we have about the way the brain deals with short-term versus long-term traumatic memories?

EPFL scientists conducted the first study on fear extinction at the brain circuit level for long-lasting traumatic memories in mice.

EPFL scientists identified specific brain regions in mice that stabilize traumatic experiences towards safety. These regions differ depending on whether the trauma occurred recently or long ago.

In the experiment, the mice undertook ‘Pavlovian fear conditioning’, in which they received an electric shock from the ground. A traumatized mouse expresses its fear by freezing, but post therapy, the mouse regains confidence and normal movement. One group of mice received therapy 1 day after experiencing the trauma, while another group received therapy 30 days later.

The scientists found out about the brain circuits which were active in both groups of mice. They found that a direct cortico-amygdala pathway was active 1 day following the trauma, but after 30 days, fear memories depend on thalamic nucleus reuniens (NRe) inputs to the basolateral amygdala (BLA).

The results provide knowledge about the brain-circuit level as to why traumatic memories are persistent and harder to put an end on them. The study explained about the brain mechanisms involved for recovering from long-term traumatic memories.

This discovery can be helpful as therapy for people suffering from post-traumatic stress disorder or other long-term traumatic experiences that affect mental health. But it still remains a challenge. In alliance with a partner institute in the Netherlands, the scientists currently have approval to study similar brain mechanisms in humans.