MAPT and Alzheimer disease: Still, the focus on the substantia nigra in the updated PSP criteria needs to consider the fact that the involvement of this region in cases with concurrent Alzheimer's disease may be problematic since the substantia nigra is often affected by neurofibrillary pathology in aging and AD [35, 44], albeit glial tau pathology in the midbrain section is not a feature of ADNC.