Failure of division is termed holoprosencephaly (literally "whole forebrain").
In accordance with this view there would be also some probability in favour of regarding the collar nerve-tube of the Enteropneusta as the equivalent of the cerebral vesicle only of Amphioxus and the Ascidian tadpole, and also of the primary forebrain of vertebrates.
We are interested in the molecular mechanisms involved in patterning the early mammalian forebrain.
Hypothalamus-A part of the forebrain that controls heartbeat, body temperature, thirst, hunger, body temperature and pressure, blood sugar levels, and other functions.
Differential localized changes in proliferative rates of populations of cells could play a crucial role in the patterning of the developing forebrain.