Cell proliferation and migration in tectum opticum in the Xenopus laevis tadpoles and adults in the norm and upon brain trauma. I. Cell proliferation and migration in tectum opticum in tadpoles
Cell proliferation and migration in tectum opticum has been studied in the Xenopus laevis tadpoles under the normal conditions and upon the tectum trauma by means of autoradiography. The same types of cells were shown to be capable of proliferation in both cases; cambial cells of the ventricle zone and scarce weakly differentiated cells in all other tectum layers. The trauma enhances cell proliferation in the damaged region of the ventricle zone. A study of the migration of 3H-thymidine labelled cells has shown the presence of vertical zones of neuronogenesis within the limits of which neurons are formed in all the tectum layers simultaneously. The completeness of tectum regeneration depends on the mutual position of the zones of trauma and neuronogenesis: the integrity of tectum layers is not restored in that part of tectum where the neuronogenesis has been already completed.