Association between supraependymal nerve fibres and the ependymal cilia of the mammalian brain.

The ciliated ependymal cells that line the floor of the fourth ventricle in adult Wistar rats are overlaid by an immense network of supraependymal nerve fibres. This study presents morphological evidence of a characteristic association of supraependymal nerve fibres with the cilia of the ependymocytes of the ventricular surface. It is found that the supraependymal nerve fibres accumulate and/or terminate at the base of the clusters of ependymal cilia. These fibres are varicose in nature and consist of large-diameter fibres with numerous prominent varicosities and small-diameter fibres with less frequent and less prominent varicosities. The characteristic association of the supraependymal nerve fibres with the ciliated ependymocytes suggests that these nerve fibres may be involved in producing co-ordinated ciliary movements in the mammalian brain.