Retino-geniculate axons regenerating in adult hamsters are able to form morphologically distinct terminals

Adult mammalian retinal ganglion cells (RGCs) can regenerate through peripheral nerve (PN) grafts and innervate central nervous system (CNS) targets. Previous studies have demonstrated a basic level of differentiation of such projections. To further assess the specificity and functionality of regenerated CNS connections we have developed a new model in which RGCs are directed through a PN graft into the dorsolateral geniculate body (LGBd) while preserving the visual cortex and radiations. We also describe by light microscopy that regenerating RGC axons which enter the LGBd differentiate and form subtypes of RGC terminals reminiscent of those seen in the normal LGBd. Thus the adult CNS contains cues that permit phenotypic differentiation of terminal types during regeneration.