Fig. 1.

Phenotypic identifiers of cells in the neural lineage. A diagram of human neural cell identities is shown in the style of hematopoietic immune cell identity maps. Bold labels indicate neural cell types. Protein name labels highlight markers that are proposed to define neural cell identities, including cell surface proteins (red), transcription factors (blue), and other intracellular proteins (green). Lines connect multipotent stem and progenitor cells (top) with the neural lineage cell types they can produce (middle and bottom). This diagram attempts to be cell-intrinsic and to highlight surface marker sets that distinguish each major cell type, as in traditional immunology views of cell identity where FACS separation of live cells can be used for functional testing. Thus, the diagram does not explicitly consider other features that are classically important to understanding neural cell identity, such as morphology, location, and structure [31–33]. Notably, radial glial progenitors, a type of neural stem cell, are conceptually separated from adult neural stem cells both by a key difference in potency (only radial glial progenitors are normally thought to produce ependymal cells) and by developmental time (radial glial progenitors are only observed prenatally in humans)