The primary objectives of this Core are: 1) To assist in characterizing study participants, by providing information about gross brain morphology, with a particular emphasis on neuroanatomical abnormalities present late in the capabilities to studies requiring detailed regional neuroanatomic characterization; 3) To support, with consultation; 3) To support, with consultation and generation of sMRI data for pilot studies, new research initiatives employing neuroimaging techniques, such as MR Spectroscopy (MRS), MR diffusion imaging, and functional MRI (fMRI); 4) To provide a liaison between HNRC investigators and two associated neuroimaging programs: (a) the Brain Image Analysis Laboratory (BIAL), a (REAP), a multi-investigator core infrastructure and training program focusing on applications of fMRI in dementing disorders (T. Jernigan, P.I.); 5) To provide mentorship, consultation, and training in neuroimaging to students and junior investigators affiliated with the HNRC. The Core will support ongoing work investigating the nature and regional distribution of HIV-related brain abnormalities measurable in vivo (with sMRI data), as well as new work aimed at developing more sensitive and more efficient means of monitoring HIV-related CNS dysfunction with other neuroimaging modalities (e.g., fMRI, MR Spectroscopy, etc.). The Core will also focus on new method development targeting the specific abnormalities present in this population, including the development of: more fully automated image-analytic methods for assessment of brain structure from MRI volumes; maps of the distribution of brain tissue anomalies associated with CDC-C3 status and ultimately, with autopsy-verified HIV encephalitis (HIVE); and more sophisticated methods for characterizing prevalent MRI abnormalities in cerebral white matter.