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Understanding traumatic memories and PTSD

Research awardFellows Award programme

Funding period2015 - 2018

InstitutionBrain Mind Institute of the Ecole Polytechnique Fédérale de Lausanne


Dr Johannes Gräff examined what exposure therapy can teach us about treating post-traumatic stress disorder (PTSD). 

The project

Almost two million people in the UK live with post-traumatic stress disorder (PTSD), which can be caused by anything from military combat to traumatic childbirth.

The condition can cause serious and lasting distress, but remains difficult to treat – often because memories of traumatic events are deeply ingrained. 

So Johannes investigated how brain cells are affected when the shadow of traumatic memories is successfully lifted.


The process

Johannes focussed on one of the most effective treatments for PTSD – exposure therapy. This involves helping people to overcome anxiety by exposing them to the source of their fears in a safe environment.

By pinpointing the brain cells involved in exposure therapy, Johannes studied how cell behaviour changes when traumatic memories are successfully targeted and reduced. 

Cross-section of the hippocampal region within the brain showing nerve cells (green and red) activated by a traumatic memory


Johannes’ study uncovered the group of cells vital for storing and reducing traumatic memories - offering hope for testing new interventions.

His results support the notion that re-writing memories – by facing fears – could be the most successful way to overcome a trauma, rather than trying to rationalise or suppress them. 

Where next?

By pinpointing the cells that are important for reducing traumatic memories, Johannes has opened the gates to test new, more refined interventions for PTSD.

With more knowledge of how traumatic memories can be reduced, Johannes' study has moved us closer to not only improving existing treatments for PTSD – but to finding new and more effective treatments, more quickly.

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