Some data on postnatal maturation of the cerebral cortex in cat.

This paper describes the neurons in different cortical areas and traces their postnatal changes. Rapid Golgi and Golgi--Kopsch impregnation were carried out in 1-day-old and 9-day-old kittens. The maturation of the pyramidal neurons can be observed mainly on their basal dendritic orientation and on development of the dendritic spines. The differentiation of the interneurons (non-pyramidal) also proceeds on the first postnatal days. These, though slightly less mature than the associated pyramidal neurons, are identifiable already on the first postnatal day. It is concluded that there are significant differences in the maturation of the neurons in the various cortical areas.