VMHvl-Projecting Vglut1+ Neurons in the Posterior Amygdala Gate Territorial Aggression.

Despite being innate, displays of aggression are influenced by cortical activities. Here, using Vglut1 as a marker for inputs from cortical structures, we identify a small population of excitatory neurons located in the posterior amygdala (PA) that project to the ventrolateral division of ventromedial nucleus of the hypothalamus (VMHvl), a region that critically regulates territorial aggression. Indeed, activities of PA Vglut1+ (PA) neurons, as analyzed by post hoc c-Fos expression, differentiate trials in which attacks occur, or not, during resident-intruder assays. More importantly, chemogenetic activation of VMHvl-projecting PA neurons robustly promote aggression while inhibition of these neurons reduces attacks. Finally, a connectivity map places VMHvl-projecting PA neurons at the interface between emotion regulation and aggression as they receive broad inputs from limbic structures and project collaterally to the VMHvl and other targets. Taken together, these results point to VMHvl-projecting PA neurons as a potential site for cortical gating of territorial aggression.