 Potentially, such characteristics of the layer may act as a remainder of early developmental life or pathway for cellular migration given similarity to a homologous layer in bovine SVZ shown to have migratory cells common only to higher order mammals.The third layer (Layer III) forms a ribbon of astrocyte cell bodies that are believed to maintain a subpopulation of astrocytes able to proliferate in vivo and form multipotent neurospheres with self-renewal abilities in vitro.While some oligodendrocytes and ependymal cells have been found within the ribbon, they not only serve an unknown function, they are uncommon by comparison to the population of astrocytes that reside in the layer.