Myelinated dendrites of Purkinje cells in deafferented cerebellar cortex

Following chronical (30--60 days) isolation of cerebellar vermis in developing and in adult rats, partially myelinated primary and secondary dendrites of Purkinje cells and myelinated Golgi, basket and stellate cell bodies were observed. The dendritic myelin sheaths were not continuous with but developed independently of preexisting axonal myelin. Experiments on rats and cats have additionally revealed that this redundant myelinization of Purkinje dendrites and of interneuronal perikarya can be elicited also by selective destruction of the olivocerebellar (climbing fibre) afferents, indicating a direct influence of climbing fibre afferentation on myelinization processes in the cerebellar cortex.