There is overwhelming lesion and physiological evidence in animals paralleled by focal lesions and clinical evidence in humans that suggests that the basal ganglia plays a key role in working memory. Paradoxically, imaging studies of working memory have failed to activate the basal ganglia. I have been able to show working memory activation within the basal ganglia. The present proposal builds on this pilot data in a systematic fashion. The goal of this project is to delineate areas within the basal ganglia that are important for working memory and to characterize this activation within a psychological construct. Two different aims will be followed to achieve this goal. The set of experiments proposed under specific aim 1 will utilize fMRI in order to identify neural substrates within the basal ganglia that are specific to different domains of working memory. If such neural substrates exist, then this supports the thesis that the striatum might be segregated in a domain-specific manner. The other issue that this study is aimed at resolving are the contributions of the basal ganglia to the central executive system of working memory or working memory general (WMG). This aspect of working memory is used in the widest range of cognitive performance and has been linked to reliable differences in reasoning abilities. The set of fMRI experiments proposed under specific aim 2 are aimed at identifying areas within the basal ganglia that are involved in central executive processes. The proposed study aims to identify discrete components involved in working memory within the basal ganglia that can be utilized to identify specific functional loss due to neuroanatomical lesions that occurs in clinical populations, such as in patients with Huntington's disease, Parkinson's disease, Schizophrenia, and Tourette's syndrome.
