Project Summary/Abstract Acute severe stress plays a pivotal role in shaping mental health, predisposing individuals to an array of debilitating conditions, including post-traumatic stress disorder and anxiety disorders. These conditions are difficult to treat and available pharmaceuticals are of limited efficacy. There is therefore a great need to discover novel treatments. Understanding how the brain processes the valence (i.e., magnitude) of stressful experiences is critical for identifying new biological points of intervention. This is because the valence of stressful events strongly influences their lasting consequences on disease-related behavior. Here, we propose to explore the contribution of the anterior hypothalamic nucleus (AHN) – a brain region that has previously received little attention – to the perceived valence and lasting impacts of stressful experiences.