Monocular visual discrimination in the goldfish after unilateral ablation of the optic tectum.

Goldfish with unilateral ablation of the optic tectum and trained to the ablated side failed to learn or to transfer interocularly a differential classically conditioned color discrimination. The direct ipsilateral retinal projection to the intact/naive side is therefore shown to contribute little to engram formation. Evidence is also presented demonstrating that the absence of one tectum does not affect the learning of a differential bar discrimination task when trained via the intact brain side.