REGIONALIZATION OF THE PROSENCEPHALIC NEURAL PLATE

Recent embryological studies are beginning to establish that the under lying organization of the forebrain may be reduced to relatively simpl e elements that are common to all vertebrates. We begin this chapter b y reviewing studies that describe the similarities in prospective fate and molecular organization of the developing neural plate in fish, fr ogs, chickens, and mice. The chapter next addresses mechanisms that re gulate regional specification in the anterior central nervous system. There is now evidence that the axial mesendoderm anterior to the notoc hord (the prechordal plate) has a central role in induction of the flo or and basal plate primordia (hypothalamus) of the forebrain. Patterni ng of the anterolateral neural plate (telencephalon) may be regulated by FGF8 produced in the anterior neural ridge. Thus, the synthesis of information from fate mapping and experimental embryological and genet ic studies is illuminating the mechanisms that generate the different components of the forebrain.