Figure 1.

Schematic of potential sources of dopaminergic neurons for transplantation in PD patients. (i) Human fetal mesencephalic tissue, rich in dopaminergic neuroblasts, made into a cell suspension; (ii) neural stem/progenitor cells from human fetal mesencephalon, expanded and differentiated to dopaminergic neuroblasts; (iii) pluripotent cells generated from human blastocysts (ES cells) or fibroblasts (iPS cells), expanded and differentiated to dopaminergic neuron precursors/neuroblasts; (iv) human fibroblasts directly converted to dopaminergic neuron precursors/neuroblasts. The dopaminergic cells are implanted stereotaxically into the striatum, primarily putamen.