[Development of the thalamus in anurans during metamorphosis (author's transl)]

A developmental study of the anuran diencephalon from stage 30 to 2 months after metamorphosis has been done. At stage 30 in Discoglossus pictus, the diencephalic wall is divided into a superior area and an inferior area, where two kinds of cellular migrations are described. Comparison with the urodele diencephalon suggests that the building of a new area (area dorsolateralis) in anurans, by means of an 'external migration', characterizes a level of organization which is related to the optic system in Anura. During metamorphosis, opitcal morphogenetic influences would come from the tectum opticum to the dorsal thalamus. It is possible that the dorsal thalamus could be involved in binocular vision by way of tectofugal fibres. Some typical anuran diencephalic nuclei (i.e. nucleus corpus geniculatum laterale) are missing or are not well differentiated (i.e. nucleus rotondus) in Discoglossus. This species gives a simplified pattern of the anuran diencephalon.