The morphological pattern of the vertebrate brain

Bergquist and Källén as well as Puelles and collaborators have presented models of the developing vertebrate brain, the basic units of which are formed by intersection of transversely oriented neuromeres and longitudinally arranged zones. These units represent initially discrete, developmentally independent compartments, but during later development some (many?) are invaded by sizable numbers of neuroblasts generated in adjacent units. No consensus exists with regard to the number and arrangement of the units involved in the formation of the telencephalon and hypothalamus.