STUDIES ON THE RETINAL PROJECTION TO THE VISUAL CENTERS IN THE FROG——A COMPARISON BETWEEN AUTORADIOGRAPHIC AND DEGENERATING METHOD / 解剖学报

ABSTRACT

The projection of the optic nerve to the visual centers of the frog was studied by means of autoradiographic and terminal degenerating method. The results obtained from the two methods were essentially identical in the distribution of the optic term inals in the lateral geniculate body and the pretectum neuropile contralateral to the [~3H]-leucine injected or enucleated eye. There are also some differences1. In autoradiographic cross sections at certain level of diencephalon, the Bellonci nucleus contralateral to injected eye has a circular outline. It is filled with the optic terminals. Within the Bellonci nucleus and the lateral geniculate body ipsilateral to the injected eye, the distribution of the optic terminals is clear. The Bellonci nucleus contralateral to enucleated eye, revealed by degenerating technique, has a circular outline too, but the optic terminals mainly concentrate on the peripheral of the nucleus. In the central area of the nucleus there are only few degenerating optic terminals. And the Bellonci nucleus and the lateral geniculate body ipsilateral to enucleated eye have only few degenerating optic terminals. The outlines of the two nuclei can hardly be recognized.2. The optic terminals of the superficial layers of the tectum contralateral to injected eye appear to have random distribution revealed by autoradiographic method, while in the sections of the preparation with degenerating method, the optic terminals have a laminar distribution which is very similar to that obtained with modified Cajal's method.3. The appearance of the midbrain tegmental nucleus revealed by autoradiographic method was much clearer than that revealed by degenerating methodIn addition, it has been observed that the number and distribution of degenerating terminals varied with the animal's survival time after the operation.The causes which bring about the differences, the advantages and disadvantages of the two techniques were discussed.