Amygdala and prefrontal cortex anatomo-functional dialogue in supporting behavioral adaptation in primates

My thesis aims to explore how two crucial brain regions, the amygdala (AMG), a collection of subcortical nuclei, and the medial prefrontal cortex (mPFC), dialogue to guide behavioral adaptations in primates. Based on the literature, I highlighted three important points: 1) an expansion of one nucleus of the AMG, the lateral nucleus, in humans compared to others non-human primates, 2) the complex anatomo-functional dialogue between the heterogenous subdivisions of mPFC regions and AMG nuclei, 3) the absence of comparative studies on the functional dialogue within the AMG-mPFC network functional dialogue across primate species. The available evidence led me to hypothesized the possible existence of two distinct routes within the AMG-mPFC network that sustains behavioral adaptation and that may have diverged between macaques and humans. To test this hypothesis, I first carried out resting-state functional magnetic resonance imaging (fMRI) in humans and macaques using a similar experimental strategy to investigate the interplay between mPFC and AMG nuclei activity. My work revealed that indeed the functional connectivity of the AMG-mPFC network in macaques and humans display critical divergences that might relate to differential behavioral and emotional control abilities in line with the constraints in their respective ecological niches. Second, by means of fMRI and the development of a new adaptive task in humans, I demonstrated the engagement/disengagement of two distinct and complementary routes that sustained specific behavioral adaptation features, in line with the interplay observed at rest in the AMG-mPFC network. This thesis thus provides critical information of the nature of the dialogue in the AMG-mPFC network and its similarity and divergence between the human brain and its closest model, i.e., the macaque brain.