Retention of shape discrimination after regeneration of the optic nerves in the toad

Using a method of successive discrimination previously described by the author eight toads (Bufo bufo), were trained to discriminate first between horizontal and vertical rectangles, each 3.5 ± 7.5 cm., and second between horizontal and vertical rectangles each 5.0 ± 7.5 cm. Immediately after training, both optic nerves were severed in four animals and allowed to regenerate. After a period of 10 weeks without training both the operated and non-operated animals retained the capacity to discriminate both the large and the small rectangles at a level either not significantly different from training or significantly better than training.