NR4A2 and Parkinson disease: Indeed, a recent snRNAseq study used sorting with a selective dopamine neuron marker NR4A2 (rather than NEUN) to examine over 300 000 midbrain nuclei (22 000 dopamine neurons) and identified a subpopulation of dysfunctional ventral tier DA neurons associated with Parkinson’s disease.40 Complementary, we analysed high numbers of non-DA neurons in the human ventral midbrain.