Similarly, another study comparing the proportions of CALB1+ DaNs between control and MPTP-induced parkinsonian macaques revealed only a slight increase in CALB1+TH+ cells after MPTP treatment in the ventral tegmental area (VTA)64, indicating the restricted expression of CALB1 across PD-resistant DaNs in macaques. The gene discussed is CALB1; the disease is Parkinson disease.