Facteurs biologiques et environnementaux influençant l'apprentissage et la régulation de la peur

 

Marie-France Marin

CIUSSS de l'Est-de-l'Île-de-Montréal

 

Domaine : neurosciences, santé mentale et toxicomanies

Programme Chercheurs-boursiers - Junior 1

Concours 2018-2019

Fear is essential to survival. Dysregulated fear levels could however increase one's vulnerability to various psychopathologies, notably post-traumatic stress disorder (PTSD). PTSD is a memory-based psychopathology that emerges from an overconsolidation of the traumatic memory and an insufficient consolidation of the safety memory. The goal of the current program is therefore to examine the biological and environmental factors that modulate the formation and consolidation of fear and safety memories. The first research axis aims to study the role of the family environment on the intergenerational transmission of fear. In fact, it has been shown that offspring of parents suffering from PTSD have higher risk of developing such disorder.

Consequently, it is essential to study the learning processes that occur within a family environment. We will test how healthy children learn fear through the observation of their parent undergoing an associative fear learning task. Specifically, we will assess whether this differs as a function of the parent's trauma history and diagnosis of PTSD. The second research axis aims to study the interaction between stress exposure and sex hormones on the formation of fear and safety memories. Studies have shown that these factors are modulators of memory, but their respective role and their interaction have not been investigated thoroughly in the context of fear and safety learning. We will recruit healthy young adults (men, naturally cycling women at different moments of their menstrual cycle to modulate estradiol levels (a sex hormone), and women taking oral contraceptives). Participants will be either 1) exposed to a psychosocial stressor before fear learning; 2) exposed to a psychosocial stressor before safety learning, or 3) not exposed to a stressor at any point in the experiment. The results obtained through this research program will help better understand the mechanisms that could convey a heightened vulnerability to PTSD.