Neural stem cells, fluorescence light micrograph. These neural stem cells have been stained using Tuj 1 to highlight a neuron-specific form of beta-tubulin (green). Beta-tubulin is a form of the cytoskeletal protein tubulin. The cells were cultured in neuronal differentiation medium (NDM). Stem cells are able to differentiate into the many cell types in the human body. The type of cell they mature into depends upon the biochemical signals received. This culture is from human tissue.