Loss of ganglion cells in fetal retina transplanted to rat cortex.

Fetal retina survived and differentiated when placed into the cortex of newborn host rats. Two months after transplantation, anterograde tract tracing techniques failed to reveal any projections from these transplants into the host brain. Soma-size analysis of the cells in the ganglion cell layer of the transplants suggested that only displaced amacrine cells remained and that the ganglion cells had degenerated. The basis for these results is considered relative to trophic maintenance of ganglion cells, retinal axon guidance, and specificity of connections.