[Autoradiography of neurogenesis and morphogenesis in the regio cingularis of the rat. III. Migration and lamination in the regions of the cingulate cortex and the area postcentralis].

The migration has been investigated in 171 embryonic and neonatal rats by means of autoradiographs, after injection of tritiated thymidine from E 18 to P 12 in 4 regions of the brain (Mesoarchicortex, Regio cingularis mesoneocorticalis, Area praecentralis angranularis, Area postcentralis). The migration begins at the third day after the injection. The localization of labeled cells was found in the cortical plate after injection in the early embryonic period and in the L II after injection in the late phasis always at the third day, the speed of migration increases in the course of embryonic development. The migration indicates in all regions an inside-out sequence. Cells from the last division migrates to the surface of the cortical plate. The cortical plate is a transitory element of the brain development. The lamination is possible earlier by means of the distribution pattern of labeled cells than with cytoarchitectonics and also the observation of areas.