Breathing is a fundamental, life-sustaining function. Rhythmic respiratory behaviour originates from the network activity of the ventrolateral medulla and contributes to a variety of homeostatic processes, particularly to the maintenance of pH and blood O2/CO2 levels. While extensive research has been carried out on the generation of breathing rhythms by pacemaking networks in medullary respiratory centers, and on their reflexive control for gas homeostasis, little is known about the neuronal mechanisms that mediate the forebrain control over breathing oscillators. I propose to dissect the function of the PBL in orchestrating the voluntary control of sniffing using different complementary behavioural approaches. In the first aim of the project, I will elucidate the involvement of specific subsets of neurons in the PBL in driving exploratory sniffs, a robust and innate behaviour that requires an up-modulation in the respiratory frequency. In the second part, I will develop an operant conditioning task where the mouse learns to voluntarily pace its breathing to obtain a reward. I will investigate the activity of neurons in the PBL while the animal carries out the different tasks, and I will interfere with neuronal activity in the PBL to causally probe its involvement in the ongoing behaviour. Finally, I will identify upstream forebrain regions that might modulate the activity of respiratory PBL neurons. Together, my experiments will shed light into the role of the PBL as a gateway for the central modulation of respiration and provide new insights into how forebrain regions can recruit and control autonomic circuitry.