Modulation du comportement anxieux et de la mémoire par le contexte émotionnel : dissection des voies de projections des noyaux du raphe

 

Bénédicte Amilhon

Centre hospitalier universitaire Sainte Justine

 

Domaine : neurosciences, santé mentale et toxicomanies

Programme Chercheurs-boursiers - Junior 1

Concours 2018-2019

Memories formed in a heavy emotional context, either positive such as intense joy or negative such as highly stressful situations, leave a strong imprint in our minds. In particular, memories formed in anxiogenic contexts are vital for survival: one needs to clearly remember where, how, why danger occurred to respond appropriately to similar situations in the future. In humans, exposure to traumatic situations can lead to a dysfunction in memory formation resulting in post-traumatic stress disorder (PTSD).

The aim of this research program is to dissect the neuronal mechanisms underlying memory formation in emotional heavy context. The main part of my research program focuses on the interactions between two brain regions: on one hand the ventral hippocampus (vHP), known for its role in both anxious behavior and emotion-related memory formation; on the other hand, the raphe nuclei, and in particular neurons using the neurotransmitter serotonin (5-HT), which are involved in many aspects of emotional behavior. 5-HT neurons send dense projections to the vHP and are ideally positioned to influence the vHP neuronal network and associated behaviors. Using cutting-edge neuroscience technology, the main objective of my research program is to specifically record the activity of vHP-projecting 5-HT neurons in freely behaving mice.

This technique, called calcium imaging, will be combined with optogenetics, allowing to manipulate the activity of neurons using light. The simultaneous use of calcium imaging and optogenetics during behavioral tests of anxiety and fear-related memory will enable in depth analysis of the neural circuits involved in memory formation during anxiogenic or fearful conditions. This research will reveal factors of vulnerability to PTSD and help find new therapeutic targets to treat this anxiety disorder.