DRD1 and Parkinson disease: For example, using promoter-driven retrograde adeno-associated virus (AAV) and a chemogenetic effector for selective targeting and activation of DRD1-expressing MSNs, the motor signs were rescued in a primate model of PD.54 The single cell techniques we demonstrate here have the potential to take us deeper, both with regard to cell type specific neuroanatomy and with the development of targeted therapies to ameliorate the symptoms of PD and the numerous other disorders associated with circuit dysfunction in the BG.