Determination events in the nervous system of the vertebrate embryo.

Molecular and functional data suggest that the regionalization of the caudal portion of the vertebrate embryonic brain (hindbrain) is set up through a process of segmentation. In contrast, the more rostrally located met-mesencephalic domain (mid-hindbrain junction) appears to follow a mode of specification that relies on long-range inducing and organizing activities originating from the central region of the domain. Recent studies addressing this mode of anterior/posterior determination point to Wnt-1 as a key player in this process.