Post-traumatic stress disorder (PTSD) is a mental health condition caused by stressful events, affecting anxiety levels and emotional state. The Wang laboratory at the Centre for Clinical Brain Sciences (CCBS) is interested in developing a novel animal behavioural model that may provide insights into treatment for PTSD and other memory related disorders. To understand PTSD-related memories, consider that retrieval of a fear memory often involves two main processes: reconsolidation and extinction. Reconsolidation is thought to be an update mechanism during which new information is incorporated into old memories. It may be possible to permanently change a fear memory by introducing new non-fearful information during this reconsolidation period. Extinction is when a tone conditioned stimulus (CS) that predicts a shock unconditioned stimulus (US) is repeatedly presented in the absence of the US, causing conditioned fear responses to diminish. With sufficient extinction, subjects respond to the CS as if they had never been conditioned. The hypothesis posited by the Wang group is that, by combining this retrieval and extinction paradigm, fear memory could be persistently altered. Another aspect that the Wang group explores is what happens in the brain during fearful memories. To do this, functional magnetic resonance imaging (fMRI) is used in conscious animals to visualise the brain areas involved. The Wang group hopes that by combining this novel retrieval-extinction paradigm with brain imaging techniques, the neurobiology of PTSD can be better understood, potentially contributing to novel treatment strategies.