Gabrielle Girardeau: Understanding Emotional Processing During Sleep

Gabrielle Girardeau's research deciphers the neuronal mechanisms that enable the brain to consolidate emotional memory during sleep. Supported by funding from the Atip-Avenir Program, the young researcher's work focuses on in vivo analysis of interactions between two areas of the brain, the hippocampus and the amygdala, which are involved in spatial and episodic memory and in the emotion processing network respectively. Ultimately, her research could advance our understanding of the normal and pathological functioning of this overnight processing of emotions, and of the development of anxiety.

A focused, dazzling early career in neuroscience and a huge determination to understand the inner workings of memory: these are the qualities that led to Girardeau joining Inserm and securing funding from the Atip-Avenir Program. With 180,000 euros at her disposal and the ability to recruit a postdoctoral researcher on a 2-year contract, in October 2018 the researcher was able to set up her own research group within the Fer à Moulin Institute (IFM) in Paris. "My group is studying the neuronal activity that conditions the normal or abnormal reinforcement of emotional memory during sleep," she explains. "Specifically, we want to characterize the role of dialogue between two areas of the brain: the hippocampus, which is necessary for episodic and spatial memory, and the amygdala, which is central to the emotion processing network." Her research involves carrying out experiments in rats, in particular using a specialist "closed-loop" system.

"This is a method that records the signal emitted by the brain using surgically implanted electrodes and which, following automated detection of a neural pattern, triggers disruption of the neuronal network in real time," Girardeau explains. She mastered this demanding technique during her graduate studies, during which she analyzed the link between memory and the hippocampus. Using this technology, she then showed that the rapid oscillations detected in the hippocampus during deep sleep are necessary for spatial and contextual memory: a piece of research that remains seminal in this area.

Manipulating the amygdala during different stages of sleep

The idea for her current research project came to her when she began her postdoctoral post. "The literature hypothesizes that there is a link between sleep, particularly REM sleep, and the emotional aspect of memory, but at present we have very limited physiological and mechanistic data for this," the researcher explains. While working as a postdoctoral researcher at New York University, Girardeau developed skills in programming (MATLAB) and in analyzing data from neuron populations recorded in waking and sleep stages, creating a large body of open access data, "a type of data that is increasingly valued." She also began to explore the links between the hippocampus and the amygdala. "I showed that this dialogue between the two structures does exist. The first phase of the project for which I won Atip-Avenir funding aims to move from correlation to intervention: using the closed-loop system, we will be able to see the effect of manipulating the amygdala during the oscillations of the hippocampus in deep sleep or REM sleep on learning and emotional memory."

Studying anxiety disorders

Subsequently, the young researcher plans to develop an animal model of post-traumatic stress in order to analyze how such dialogue is disrupted in this condition, as well as in anxiety disorders. In the longer term, she will eventually attempt to restore its normal function.

The IFM, which focuses on psychiatric research and has an animal unit with a surgery room and excellent IT infrastructure for analyzing large quantities of data, is the ideal place for the researcher to pursue her objectives. Her funding from the Atip-Avenir Program, which supports young researchers who do not yet hold accreditation to supervise research ("habilitation à diriger des recherches" or HDR), has recently made it possible for Girardeau to recruit a postdoctoral researcher and begin supervising her first graduate student. "The Atip-Avenir funding really launched my career, by identifying me as a promising young researcher and thus establishing my profile in the French research community," she notes.

Gabrielle Girardeau is head of the "Sleep and Emotional Memory" group at the Fer à Moulin Institute (Unit 1270 Inserm/Sorbonne Université).