Morphogenesis of the cerebellum of the frog tadpole during spontaneous metamorphosis

Abstract

The cerebellum of the frog tadpole remains in an immature state throughout the premetamorphic (growth) phase. An external granular layer is absent except for a few scattered cells. A well defined Purkinje cell zone is also lacking. Large cells, which presumably are the immature Purkinje cells, are found in the subventricular zone.During the prometamorphic period (accelerated hind leg growth) an external granular layer, several cells thick, becomes established by a migration of cells from the base of the cerebellum. A second migration involving the movement of the external granule cells toward the ventricular region begins at this time. However, the most active period of this latter migration is at the end of the prometamorphic period and during the days following fore leg emergence, viz., metamorphic climax. Concomitantly, a well defined Purkinje cell stratum is established.