Trans-synaptic retrograde degeneration in the visual system of primates

Abstract

Although the first observations of trans-synaptic degeneration in the nervous system were made in the nineteenth century, the phenomenon has been some- thing of an infrequent curiosity. From an experimental point of view it is not a particularly attractive field for study due to the time required for the full effects to become evident and may entail many months or even years of waiting. Consequently the majority of the observations have been made in man. Naturally occurring human lesions, even old cerebral infarctions, which are perhaps the most useful for anatomical purposes, practically never approach the discreteness of an experimental ablation since cerebral vascular disease is seldom a localized process. Although this material is of great value, usually the neuropathologist cannot undertake a comprehensive study of the entire brain in serial section so that one is left with the somewhat un- comfortable thought that possibly significant lesions had been missed in the neuropathological sampling.