Right temporal cortical hypertrophy in resilience to trauma: an MRI study

BACKGROUND: In studies employing physiological measures such as magnetic resonance imaging (MRI), it is often hard to distinguish what constitutes risk-resilience factors to posttraumatic stress disorder (PTSD) following trauma exposure and what the effects of trauma exposure and PTSD are. OBJECTIVE: We aimed to investigate whether there were observable morphological differences in cortical and sub-cortical regions of the brain, 7–8 years after a single potentially traumatic event. METHODS: Twenty-four participants, who all directly experienced the 2004 Indian Ocean Tsunami, and 25 controls, underwent structural MRI using a 3T scanner. We generated cortical thickness maps and parcellated sub-cortical volumes for analysis. RESULTS: We observed greater cortical thickness for the trauma-exposed participants relative to controls, in a right lateralized temporal lobe region including anterior fusiform gyrus, and superior, middle, and inferior temporal gyrus. CONCLUSIONS: We observed greater thickness in the right temporal lobe which might indicate that the region could be implicated in resilience to the long-term effects of a traumatic event. We hypothesize this is due to altered emotional semantic memory processing. However, several methodological and confounding issues warrant caution in interpretation of the results. HIGHLIGHTS OF THE ARTICLE: Following a traumatic event, most people do not develop long-lasting trauma-related symptoms. In a group who experienced a traumatic event 8 years prior, but showed low levels of trauma-related symptoms, we observed increased cortical thickness in the right temporal lobe. The right temporal lobe is implicated in emotional semantic memory processing, and thus might be associated with resilience to the long-term effects of a traumatic event.