Further insight was provided by Qi et al., who evaluated the effect of LiCl-treated NSCs on the ventral tegmental area (VTA) of PD model rats; the proportion of TH-positive neurons was 51 ± 9% in the LiCl-treated group, compared with 46 ± 5% in the untreated group, indicating a modest benefit of pre-conditioning strategies [28]. Here, TH is linked to Parkinson disease.