Lack of ingrowth of retinal axons into the visually deafferented superior colliculus in young rats: a horseradish peroxidase study

Suction lesions of the brachium of the left superior colliculus (SC) and pretectal region were made in 6-11-day-old hooded rats. Central retinal projections were examined 15-261 days later by injecting the right eye of each rat with horseradish peroxidase. Retinal fibres were found to have regrown either within glial and connective tissue membranes which formed over the lesion cavity or across the surface of the lesion itself. The axons sometimes grew up the rostral face of the remaining SC to reach the superficial tectal layers; however, there was no significant penetration into the SC neuropil.