We focused on in vivo measurements of two DA subpopulations that are largely non-overlapping: the Anxa1+ PD-vulnerable DLS-projecting population of DA neurons that increase activity with locomotor acceleration (Azcorra et al. 2023), compared to the Vglut2+ population of DA neurons that we and others have shown are preserved in PD animal models and resilient to neurodegeneration in human PD (Mendez et al. 2008; Shen et al. 2018; Steinkellner et al. 2018; Steinkellner et al. 2022; Buck et al. 2021; Fushiki et al. 2024). The gene discussed is ANXA1; the disease is Parkinson disease.