Changes in retinotectal projection in adult Xenopus following partial retinal ablation

Abstract

The retinotectal projection was mapped electrophysiologically and autoradiographically after surgical removal of the nasal or temporal retinal quadrants in Xenopus. The immediate result of retinal ablation was a corresponding temporal or nasal scotoma in the visual field and the absence of part of the optic fibre projection from the tectum. Thirty to forty days after operation the visual field scotoma still persisted but the vacated tectal area became reinnervated by collateral sprouting of optic fibres from the fringe of the residual retinal projection. It is concluded that the retinotectal connection pattern can be altered by retinal ablations in adult toads.