Alterations in precision of the crossed retinotectal projection during chick development.

Chick embryos received partial eye lesions. Examination of the embryos early in development showed the partial retina projecting across the entire tectum. At later stages the partial retina projected only to the appropriate portion of the tectum. The results suggest that the retina initially projects diffusely to the tectum and that the topographically aberrant projections are eliminated during subsequent development.