DESCRIPTION [provided by applicant]: This application for continued support of Years 16 through 20 of the Mental Retardation/Developmental Disabilities Research Center (MRDDRC) at the Kennedy Krieger Institute and Johns Hopkins University is submitted in response to RFA HD-02-014. The MRDDRC consists of the Administrative Core (Core A) with a research subdivision and five research cores (Cores B, C, D, E, and F). Core A (Administration), provides overall leadership, management, and organizational support to the Center, operates the educational component (lectures and seminars), and links users to biostatistical services (a research subdivision). Core B (Genetics) provides centralized tissue culture, amino acid/organic acid analyses, standard and molecular cytogenetics, specialized molecular genetics (DNA and RNA analyses) microarrays and bioinformatics. Core C (Neuroscience) provides synaptic neurochemistry (focusing on histology imaging and high performance liquid chromatography) and lipid biochemistry (lipid metabolism, fatty acid analysis, and mass spectrometry services). Core D (Motion Analysis) provides quantitative computer-assisted methods of documenting gaits, reaching, and learning behaviors within the motor domain. Core E (Neuroimaging) provides for acquisition and quantitative analysis of data derived from functional, volumetric, diffusion tensor, and spectroscopic MR imaging, and Core F (Behavioral Science) offers training of subjects for cooperation with research protocols, selection and administration of standardized tests (developmental, cognitive, and functional), direct observations of behavior, and design of activation paradigms for fMRI.