Spatiotemporal gradient of astrocyte development in the chick optic tectum: evidence for multiple origins and migratory paths of astrocytes.

Astrocytes have been considered to be transformed from radial glial cells that appear at early stage of development and play a scaffold-role for neuronal cell migration. Recent studies indicate that neuroepithelial cells in the spinal cord also give rise to astrocytes. However, the mode of astroglial generation and migration in the ventricular neuroepithelium remains poorly understood.