Su-Chun Zhang, a researcher at the University of Wisconsin, Madison, discovered how to direct undifferentiated hESCs into neural precursors. To begin exploring whether these cells could serve as a source of cells for possible nervous system repair, he transplanted them into neonatal mice. The cells “were incorporated into a variety of brain regions, where they differentiated into both neurons and astrocytes” (Zhang et al. 2001, 1129).