By a verfy different method than just cell division:-"Instead, closer inspection by the researchers has revealed that one part of the progenitor cell undergoes an abscission (where it is severed from the rest of the cell.)
 
Using a very high resolution microscope, the researchers watched neurogenesis unfold in embryonic chicken embryo cells. In its beginning stages, the progenitor cell has two main parts: the primary cilium and an apical part which is connected via a tentacle-like strand of cells. As the researchers watched, one tentacle constricted, causing the two parts of the progenitor to be severed—a process the researchers have dubbed "apical abscission." The lopped off part migrated to another location and would have slowly differentiated into a neuron had it been growing in an egg. The base section, the cilium stayed behind—because it holds the signaling part of the progenitor cell, the lopped off portion was no longer able to communicate with the rest of the system, which the researchers believe is a critical part of neurogenesis."--http://medicalxpress.com/news/2014-01-progenitor-cells-engage-apical-abscission.html