Embryonic stem cells. Computer-enhanced confocal light micrograph of dividing stem cells from the ventricular zone of the retina of a developing embryo. The ventricular zone is the site of cell division during retinal development. It is the part of the neural retina (left) adjacent to the pigment epithelium layer (right). Dividing cells have bright pink nuclei, while the nuclei of non-dividing cells are blue/pink. Stem cells are undifferentiated cells that have yet to become specialized for their position in the body. In the mature retina, neural cells carry information from the photoreceptors to the optic nerve. Magnification unknown.