Emotions are a central part of our mental self and health, playing a crucial role in guiding behaviors essential for survival. For instance, threats evoke fear and avoidance behaviors; conversely, rewards induce reward-states and approach behaviors. Resolving how the variety of emotions emerges in the brain remains a major challenge for modern neuroscience. The main objective of the proposed research is to investigate how opposite emotions like fear and reward are differentially processed in the limbic system. We hypothesize that these basic emotional states are encoded by interactions of neural circuits specific for negative or positive emotional valence and circuits for arousal. To address this problem, we will first aim to develop a novel genetic tagging approach for differential brain-wide screening for emotional valence and arousal circuits in a combined Pavlovian fear and reward conditioning task. Second, we will investigate how fear and reward are encoded in selected hotspots within this circuitry: by pharmaco- and optogenetic manipulations, we will test whether emotional states require the activity of, and can be induced by, a combination of valence and arousal circuits. This research will provide a circuit mechanistic framework for understanding the neural organization of emotions in health and disease and establishes a novel imaging method which will be useful for investigating other brain functions in a similar fashion.This postdoctoral project will significantly contribute to my career development by complementing my expertise in behavioral neuroscience with training in circuit neuroscience and by reinforcing my professional maturity and leadership qualities. Moreover, the reciprocal transfer of my expertise in behavioral neuroscience to the host laboratory and, in turn, my training in cutting-edge technologies in preparation for a position in my home country, is a tremendous opportunity for the diffusion of knowledge within the European Research Area.