This project aims to elucidate the molecular coding of meso-diencephalic dopaminergic (mdDA) neurons forming the complex meso-limbic and nigro-striatal dopaminergic system in the vertebrate central nervous system. Recent advances in molecular and developmental biology have shown that this system harbors u multitude of functional units that are defined by spatial and temporal cues and are represented by specific molecular codes. These codes are essential to understand specific mdDA neuronal pathology as Parkinson's diseases and schizophrenia. In this collaborative project we gather the expertise on early and late development, cross species molecular-coding conservation, migration and axonal pathfinding to capture the significance of the understanding of mdDA neuronal development to generate a real advance in clinical understanding and treatment of mdDA pathology.