The discovery of adult neural stem cells (NSCs) has broaden our view of the physiological plasticity of the nervous system,and has opened new perspectives on the possibility of tissue regeneration and repair in the brain. NSCs reside in specializedniches in the adult mammalian nervous system, where they are exposed to specific paracrine signals regulating theirbehavior. These neural progenitors are generally in a quiescent state within their niche, and they activate their proliferationdepending on tissue regenerative and growth needs. Understanding the mechanisms by which NSCs enter and exit thequiescent state is crucial for the comprehension of the physiology of the adult nervous system. In this project we will studythe behavior of a specific subpopulation of adult neural stem cells recently described by our group in the carotid body (CB).This small organ constitutes the most important chemosensor of the peripheral nervous system and has neuronal glomuscells responsible for the chemosensing, and glia-like sustentacular cells which were thought to have just a supportive role.We recently described that these sustentacular cells are dormant stem cells able to activate their proliferation in response to aphysiological stimulus like hypoxia, and to differentiate into new glomus cells necessary for the adaptation of the organ.Due to our precise experimental control of the activation and deactivation of the CB neurogenic niche, we believe the CB isan ideal model to study fundamental questions about adult neural stem cell physiology and the interaction with the niche. Wepropose to study the cellular and molecular mechanisms by which these carotid body stem cells enter and exit the quiescentstate, which will help us understand the physiology of adult neurogenic niches. Likewise, understanding this neurogenicprocess will improve the efficacy of using glomus cells for cell therapy against neurological disease, and might help usunderstand some neural tumors.