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Conférence mensuelle (PhD seminar series) – Aline Desmedt

6 novembre 2020 / 11:30 - 12:30

Séminaire en ligne.

L’adresse pour la visioconférence sera diffusé par email environ une semaine avant.


Aline Desmedt
Team “Pathophysiology of declarative memory”
Neurocentre Magendie

The hippocampus at the core of PTSD-like memory

Post-traumatic stress disorder (PTSD) is characterized by a paradoxical memory alteration with hypermnesia for salient traumatic cues and amnesia for the traumatic context. Clinical studies strongly suggest that a deficit in trauma contextualization would leave traumatic memory out of control and thus prone to be automatically reactivated upon trauma-related cues in any context through flashbacks. In this view, recovery from PTSD-related hypermnesia would thus depend on recovery from contextual amnesia. Yet, preclinical research focuses exclusively on the emotional hypermnesia, leaving unexplored the putative causal role of a deficit in the hippocampus-dependent trauma contextualization in PTSD.

Using the first animal model that precisely recapitulates PTSD-related hypermnesia and amnesia, we first show that compared to normal fear memory, PTSD-like fear memory is specifically associated with hippocampal hypoactivation and neuronal alterations. Second, we show that optogenetic inhibition of the hippocampus (dCA1) during stress can produce PTSD-like memory in mice, whereas activating the dCA1 prevents its formation and promotes normal contextual fear memory. Finally, trauma re-contextualization normalizes PTSD-like memory, promoting the expression of a long-lasting normal fear memory.

These findings indicate that PTSD-like memory depends on contextual amnesia and that promoting the hippocampal function promotes a switch from PTSD-like to normal fear memory via trauma contextualization. Therefore, these data call for promoting therapeutic approaches of PTSD centered on trauma contextualization and its underlying hippocampal mechanisms.

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Détails

Date :
6 novembre 2020
Heure :
11:30 - 12:30
Catégories d’Évènement:
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