THE GLIAL FASCICLE - AN ONTOGENIC AND PHYLOGENIC UNIT GUIDING, SUPPLYING AND DISTRIBUTING MAMMALIAN CORTICAL-NEURONS

Neurons destined for the mammalian neocortex migrate along radial glia l cells (RGCs). This paper describes a comparative study of RGCs in th e mouse, rat, hamster, cat and human fetus, selected as representative species of mammalian evolution. The glial fascicles display constant features throughout these species: they consist of 4-10 RGCs filled wi th glycogen. The glial fascicle guides and probably supplies metabolit es to the migrating neurons and organizes the vertical lamination of t he developing neocortical plate. The neuronal-glial unit which consist s of the RGCs and their affiliated migrating neurons is conserved thro ughout the species studied, suggesting a designation as a phylogenic u nit.