Maintenance of transient occipitospinal axons in the rat

A developmentally transient occipitospinal projection arising from the visual association cortex persists if a fetal tectum is transplanted to the spinal cord at birth and at the same time, the host tectum is removed. The pathway is not sustained if the transplant is placed in the cord without a tectal lesion or if the tectum alone is damaged. Thus the tectal transplant promotes the survival of normally transient occipitospinal axons as long as another regular target of these axons is removed.