Organisms evolved biological mechanisms that maintain an individual's body weight within a narrow range of variation. For that purpose, different organs such as brain, fat, liver, bone, pancreas, and even the immune system, integrate nutrient-related and hormonal signals to control weight homeostasis. Our laboratory is interested in the function of the nervous system in weight control, aiming at identifying neurons that play a fundamental role in eating behaviour and metabolism. We rely on newly developed targeted mouse strains that enable the application of state-of-the-art neuro-genetic techniques: we use optogenetics to establish the role of molecularly identified populations of neurons, and Translational Ribosome Affinity Purification – TRAP – to identify molecular targets with neuromodulatory activity enriched in those key neurons. We believe that our experimental approach will pave the way for the identification of novel molecular targets with potential in the treatment of obesity.