The Neuropathology Core (NP Core) of the Udall Center for Excellence in Parkinson's Disease Research at Mayo Clinic will perform postmortem evaluation of brains of participants in the Udall Center and provide neuropathologic support for research projects. The characterization of brain tissue will employ routine neurohistologic methods, as well as immunohistochemistry, image analysis, biochemistry (fractionation and immunoblot analyses of synuclein and tau) and unbiased stereology. The specific aims are as follows: 1.) Perform standardized diagnostic neuropathologic evaluations and data collection for all brains harvested locally or sent to the Udall Center by referring physicians. As part of this process, the NP Core will perform immunostaining of cortical, hippocampal and basal forebrain sections with alpha-synuclein antibodies to record density of Lewy bodies in multiple cortical regions, as well as presence and sevedty of Lewy neurites in hippocampus, basal forebrain, striatum and amygdala. It will characterize non-Lewy body Parkinsonian degenerative disorders with immunocytochemistry and semiquantitative assessment of the density and distribution of neuronal and glial lesions. On all cases it will also assess concurrent Alzheimer type pathology with quantitative indices for senile plaque and neurofibrillary tangles in multiple cortical and subcortical areas, as well as assign a Braak neurofibrillary tangle stage. It will use validated neuropathologic research criteria for those disorders for which such criteria have been established and "best clinical practice" criteria for uncommon disorders for which research criteria do not yet exist. 2.) Provide human tissue samples to Projects by Farrer, Dickson, and Yen. 3.) The NP Core will provide fixed and frozen brain samples to qualified investigators studying Parkinson's disease and other parkinsonian disorders as approved by the Executive Committee of the Administration, Data Management and Statistics Core. 5.) The NP Core will provide data to a possible future national database linking a minimal dataset from the various Udall Centers.