Radial unit analysis of hippocampal histogenesis in the mouse.

The technique of radial unit analysis was applied to the development of the hippocampal region in the mouse. A radial unit was defined as a transect through the neural wall of sufficient size to contain a representative sample of ventricular cells together with their product of neurons. This convention allowed growth to be resolved into two components: a radial component which was a function of the productivity of an individual unit and a tangential component which was a function of the number of participating units. The sequences of cell production, accumulation and dispersal in an average radial unit of the regio superior, regio inferior and dentate gyrus were worked out, and for each area a pattern of summation of such average units into the adult structure was suggested. The approach seemed to offer a useful method for the study of ontogenetic and phylogenetic change in this part of the medical telencephalic wall.