A 3H-thymidine autoradiographic study of the development of the cerebellum of the White Leghorn (Gallus domesticus): "evidence for longitudinal neuroblast generation patterns".

Dynamic aspects of the development of the cerebellum of the white Leghorn (Gallus domesticus) were examined using 3H-thymidine autoradiography. A single dose of 25 microCi 3H-thymidine was given to embryos varying in age from 0-18 days. The embryos were all studied before hatching, either after short or after long survival times. It appeared that the superficial part of the outer mantle layer (OML-s, or called external granular layer, egl) is histologically present at day 6, but starts its activity as a secondary matrix at day 7, probably due to activation by a secondary influx of cells from the ventricular neuro-epithelium. It was also demonstrated that Purkinje cells and cells of the central cerebellar nuclei are produced by the ventricular neuro-epithelium mainly at days 3, 4 and 5. No birth of these cells was observed beyond day 5. In addition, a relationship was found between the birth patterns of Purkinje cells and cells of the central cerebellar nuclei and the longitudinal cytoarchitectonic patterns as observed in normal Nissl stained material. It was concluded that these birth patterns are an early contribution to the establishment of the longitudinal organization of the cerebellum.