Effect of dopaminergic depletion and embryo stem cell derived dopaminergic neuron implantation. Gait parameters were assessed at 4 weeks after injection of 6-OHDA (6-OHDA) or saline (SHAM) at 8 weeks after transplantation of ES-derived dopaminergic neurons (6-OHDA-SC-8w) or injection of vehicle (6-OHDA-SA-8w) as the control. The intensity and max area (A and B) were reduced in the left paws and the swing speed (C) of all paws decreased after 6-OHDA injection. After implantation of dopaminergic neurons, the intensity, max area, and swing speed of all paws improved. The BOS between the hind paws increased after injection of 6-OHDA and partially recovered after dopaminergic neuron implantation (D). 6-OHDA-lesioning and dopaminergic neuron implantation did not lead to a significant change in step patterns and inter-limb phase dispersions (E, F, G and H). Rotational behavior in response to methamphetamine was tested at pre-transplantation (pre-TP) and at 4 and 8 weeks post-grafting. A significant decrease in absolute numbers of drug-induced turning was seen in the transplantation group compared with control animals at eight weeks (I). *P < 0.05; **P < 0.005.