Confocal micrograph of radial glia in a coronal section of the optic tectum in a 10 day old chick embryo. The cells were labelled by injecting the fluorescent dye, DiI into the central lumen of the neural tube. During development, the radial glial cells form a scaffold which guides the migration of the neurons from the inner ventricular layers of the tectum where they undergo their final cell division, to the outer layers.