Conférence CRNL Pierre Gagnepain "Plasticity of brain resilience mechanisms associated with memory control"

Abstract

The expression and persistence of vivid and distressing intrusive memories, is a central feature of Post-Traumatic Stress Disorder (PTSD). It remains largely unknown why these traumatic memories persist in some individuals, and fade away in others. Current understanding of PTSD links this persistence to the disruption of memory functions involved in the formation and updating of the memory trace, a deficit rooted in the alteration of hippocampal structural integrity. During this talk, I will present an alternative (and complementary) hypothesis, rooted in the idea that the variation across individuals in the response to trauma may additionally depend on the disruption of the brain system that normally allows the inhibitory control over memory, a central mechanism of active forgetting (Mary et al., Science, 2020). After introducing the neural bases of memory inhibition and how this mechanism could be integrated with current models of resilience to trauma and PTSD, I will then present the findings of a longitudinal neuroimaging study realized in a cohort of 120 individuals exposed to the 11/13 Paris terrorist attacks. This research program is centered on the Think/No-Think task developed to study the suppression of intrusive memories, but also includes MRI sequences to delineate hippocampal subfields at high-resolution, providing a unique opportunity to observe the structural and functional plasticity in memory and control circuits following a severe psychological trauma.