Brain regionalization: of signaling centers and boundaries

Our knowledge of the general mechanisms controlling the formation of the vertebrate central nervous system has advanced tremendously in the last decade. Here, we discuss the impact of the combined use of cell manipulation, in vivo imaging and genetics in the zebrafish on recent progress in understanding how signaling processes progressively control regionalization of the central nervous system. We highlight the unresolved issues and speculate upon the fundamental role the zebrafish will continue having in answering them.Peer Reviewe