Introduction

Abstract

As was demonstrated in Part I of this study, hemisection of the brain stem at the level of the mesencephalon in kittens leads to a rapid disintegration of the majority of the neurons in the homolateral pontine nuclei. This reaction was interpreted as a type of transneuronal degeneration which occurs after deafferentation of immature neurons. The neuronal degeneration was accompanied by a brisk proliferation of glial cells. Similar changes have been described previously by Torvik (1956). Although no specific glial stains were used, Torvik (1956) suggested that most of the reacting cells were microglial. This type of reaction differed from the glial reaction which occurred during retrograde degeneration of the pontine nuclei of young animals, where both astrocytes and microglia appeared to proliferate.