Formation of the myelinated nerve fiber layer in the chicken retina.

Oligodendrocytes in the ganglion cell layer, the myelinating cells in the chicken retina, were investigated morphologically and quantitatively. Oligodendroblasts divided in the inner retinal layer around the 14th day of incubation and differentiated into oligodendrocytes. The oligodendrocytes started sheathing an axon in the nerve fiber layer at the 14th day of incubation. The number of myelin lamellae increased rapidly during the first week after chicks had hatched. An immunological reaction of anti-myelin basic protein was observed on the myelin sheaths in the nerve fiber layer and on the oligodendrocytes in the ganglion cell layer. These results suggest that the oligodendrocytes form the myelinated nerve fiber layer of the chicken and that they act independently of the Muller cells during myelination.