We have established an in-vitro coculture-system of adult rat retina with fetal midbrain explants to examine whether regenerating central nervous system axons are still able to recognize appropriate target neurons. Our results show that the retinal ganglion cell axons regenerate their axons and reinnervate the retino-recipient areas of cocultured fetal midbrain slices after one to seven weeks in-vitro. Functional connections as defined by electrophysiological criteria are detected only within these areas.