Matrix area activity in the regenerating optic tectum of Rana esculenta.

After keeping specimens of Rana esculenta at 4 degrees C for 24 hrs., the Authors removed a plug of right optic tectum. Thirty days later they injected 6-H3 thymidine and on the 200th day after surgery sacrificed the animals. With this technique it is possible to show the high regenerative capacity of the optic tectum; in fact, it is possible to observe reconstruction of the typical cellular and fibre layers of the removed nervous area. The origin of the cellular elements which supported this regenerative process and the possible connection between these results and restoration of the hemotrophic embryonic conditions due to absence of the blood-brain barrier, consequent on the cold treatment, is discussed.