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Earthquake brain: A neuroimaging investigation of the long-term impacts of exposure to the Canterbury earthquakes in healthy adults DR NADIA BORLASE, PHD There are only two previous studies that have examined the neuro-correlates of trauma exposure in a non-clinical population. Three years after an earthquake in China, those exposed to trauma showed hyperactivation between the amygdala and hippocampus and greater grey matter in the prefrontal-limbic systems, suggesting an over-active fear processing response 2 . Three years after the 9/11 terror attack, those in close proximity to the site had lower grey matter volume in several subcortical regions. In the amygdala, the brain’s emotion processing centre, grey matter volume was associated with total number of lifetime trauma incidences - suggesting the more trauma that is experienced, the greater change to your brain. Participants had no evidence of any psychiatric symptoms 3 . This area of research is very new and the neural mechanisms of the effects of trauma remain poorly understood. In 2019 we received funding from the Neurological Foundation to look at brain structure and function of 60 of the 89 resilient control participants in the University of Otago study. We are aiming to compare the brain function of this Canterbury resilient group with a group in Dunedin who did not experience the earthquakes. Participants are asked to complete a functional magnetic resonance imaging (fMRI) scan that uses a series of validated pictures from the International Affective Picture System (IAPS) 4 that are confronting and designed to elicit an emotional response. We are then able to compare the brains response to the unpleasant images in people who have experienced the earthquake with those who have not. We think, that due to the prolonged exposure to stress in the Canterbury participants, their fear processing frontal cortex – amygdala – hippocampus circuity is strengthened and the Canterbury participants will show a greater neurological response to the unpleasant images compared to people who have not experienced the earthquakes. This is a fascinating area of research and we are very excited to be among the first groups who have examined a group of psychologically healthy people looking for brain changes. The Canterbury Earthquake Sequences were a traumatic ongoing series of events. Nine years later we are still unclear of the long-term neurological impact of these events. The majority of people who survive a traumatic event will experience a period of distress but will not go on to develop mental health disorders. These people are often described as “resilient”. As these resilient groups do not have post-traumatic stress disorder (PTSD) they are likely to be overlooked for treatment and less likely to engage in health-seeking behaviour. There is evidence to suggest that the neurological function of these resilient groups is altered even when no psychological symptoms are present. The Department of Psychological Medicine, University of Otago, Christchurch, assessed a group of 89 resilient Canterbury participants 2-3 years after the earthquakes. Despite having no clinically significant psychological difficulties, researchers identified that the resilient group was more likely to incorrectly classify neutral facial expressions as threatening compared to a group who were tested prior to the earthquakes 1 . Research in trauma survivors suggests psychological distress after exposure to a traumatic event is associated with strengthening of neural circuitry involved in the threat processing system. During a stressful event the frontal cortex processes the event information (eg: sound and sights), the amygdala then provides the appropriate emotional response (flight or freeze). The hippocampus remembers the frontal lobe processing and the response of the amygdala. For every aftershock, the neurons involved in this system fire, strengthening the remembered emotional response to the earthquakes. 1 Bell, C.J., et al., Earthquake Brain: Altered Recognition and Misclassification of Facial Expressions Are Related to Trauma Exposure but Not Posttraumatic Stress Disorder. Front Psychiatry, 2017. 8(278) 2 Li, Y., et al., Long-Term Effects of Acute Stress on the Prefrontal-Limbic System in the Healthy Adult. PLoS One, 2017. 12(1): p. e0168315 3 Ganzel, B.L., et al., Resilience after 9/11: multimodal neuroimaging evidence for stress-related change in the healthy adult brain. Neuroimage, 2008. 40(2): p. 788-795. 4 Lang, P.J., M.M. Bradley, and B.N. Cuthbert, International affective picture System (IAPS): Affective ratings of pictures and instruction manual, in Technical Report A-8. 2008: University of Florida, Gainesville. 12 Headlines