An electron-microscope study of centrioles in differentiating motor neuroblasts

Abstract

Mature neurons with centrioles were first described at the end of the nine-teenth century and have been observed in many animals (see Cajal, 1911; Ariens Kappers, Huber & Crosby, 1936). As mitosis rarely, if ever, occurs after morphological differentiation of the neuroblast begins, the function of the centrioles in nerve cells posed a problem which has yet to be resolved. Held (1909) described centrosomes in differentiating neuroblasts as being associated with the ‘fibrillogenous zone’, which suggests a role for the centriole in the differen-tiation of neurofibrils.