Comparative microangiographic and histologic studies of the embryonal development of intracerebral capillaries.

In 69 embryos and fetuses of cattle and pigs with an age of gestation of 4 weeks to 4 months the development of intracerebral capillaries was studied comparatively by microangiography and controlled by histologic slices. The first invasion of blood vessels into the wall of the neural tube takes place in the brain stem and colliculus ganglionaris at an age of gestation of 4 weeks. After that, specific and different angioarchitectonic patterns of capillary development can be demonstrated within the telencephalon, basal ganglia, and brain stem. The telencephalic vessels show concentrically arranged areas of ramification which interrupt their longitudinal course towards the ventricular cavity. The branchings are related topographically to the projection fibers from the internal capsule and to the subependymal matrix layer. In the basal ganglia, the developing internal capsule interrupts the blood supply of the caudate nucleus from the periphery, and a new central system is established mainly running radially towards the ventricular canal. Thus, it could be shown in consecutive stages of cerebral development that the angioarchitectonic pattern of a certain embryonal stage and brain area depends on the histologic structure of the neural tissue and its specific metabolic demands.