The performance of any cognitive task invariabley depends on the adequacy of more than one cognitive process. Recent investigations from many laboratories (including the PI's) reveal that acute and chronic alcohol use affects some specific processes in visuospatial analysis relative to control subjects but not others. In addition, the subjects under the influence of alcohol and alcoholics exhibit a pattern of performance deficits which resemble, at least superficially, those seen in patients with right hemisphere lesions but not in those with left hemispere lesions. The proposed studies will employ relatively new methods to permit an evaluation of the specific processes of visuospatial analysis that are affected in alcohol and brain damaged subjects. We can then determine if the same specific cognitive processes are affected in the different populations whose overall performance in visuospatial tasks is similar. The findings from the proposed studies will be relevant to four general questions: 1) What specific processes of visuospatial analysis are affected by long term alcohol use? 2) What specific processes of visuospatial analysis are affected in intoxicated non- alcoholic subjects? 3) What specific processes of visuospatial analysis are affected in selected brain damaged patients and are they similar to or different from those affected by alcohol? 4) To what extent, if any, can visuospatial processing deficits found with alcohol (both acute and chronic) be attributed to visuospatial functioning of specified neural systems, and are any of these associated with mechanisms of perceptual organization? The results of these experiments have implications for outcome studies, assignment of patients to treatment and for suggesting biological markers for alcoholism.