Methods and Results: Study of Prosencephalic Connectivity and Structural Organization

Abstract

The subjects used for this study were from one of the subspecies of Xenopus laevis. Animals were either bred and reared in captivity according to Nieuwkoop and Faber (1975) (30 individuals) or obtained from the Herpetological Institute in Den Dolder, the Netherlands (80 individuals), from where animals were sent to us in batches of 10–20 by fast train, in cushioned crates (15 x 30 x 50 cm) filled with moistened foam plastic. Until they were used the animals were kept in our laboratory in a white plastic opaque tank (40 x 40 x 60 cm) half filled with tap water at room temperature. The water was aerated, filtered continuously, and refreshed regularly. The animals were fed with beef or pork heart and occasionally vitamins were added to the water. Excrement was removed daily. Basalt plates obtained from a nearby extinct volcano (Barterode) provided shelter on the bottom and a brown plastic lid (15 x 30 cm) floating on the surface provided cover at the higher level. Without these hiding places the animals swim wildly around the tank when approached, bumping into the sides and into each other.