TAC1 and Parkinson disease: Production of an accurate and detailed description of complete SN anatomy based on histological and immunohistochemistry stainings (e.g., Perl, Luxol fast blue/Cresyl violet, substance P, and Calbindin) of PD tissue conjointly imaged with high-field MRI (i.e., MR microscopy) has proven successful (Massey et al. 2017) warranting similar examination across PD subtypes.