DESCRIPTION (Investigator's abstract): Feasibility will be explored of establishing a great ape brain bank as a comparative neurobiology of aging resource to amplify understanding of the normal aging process and promote prevention and treatment of age-related neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. The resource would provide means of studying aging processes in the great apes, the nonhuman primates most genetically, neurobiologically, behaviorally, and cognitively similar to humans. Candidate great apes in zoological gardens and research centers would be identified, emphasizing the oldest individuals. Prospective longitudinal cognitive and behavioral assessments would be made, and data would be archived. When apes died of natural causes, their brains would be collected and preserved (both fixed and frozen) using methods currently used for human brains. Brain tissue would undergo detailed neuropathology examination and would be made available for study by qualified investigators. The prospectively archived cognitive and behavioral records would provide relevant background on each brain and allow retrospective evaluation of any neuropathologic changes identified during postmortem assessment. The neurobiology of aging research resource would enhance opportunities for direct comparison of correlates of human aging with homologous processes in the animals that most resemble humans.