Structural neuroimaging of the basal ganglia in schizophrenic patients: a review

The basal ganglia structures have quickened interests in schizophrenia research for several reasons: On the one hand, schizophrenic patients are successfully treated with neuroleptics acting on dopamine receptors, which are highly concentrated in the basal ganglia structures. On the other hand, basal ganglia play an important role in higher cognitive functions such as attention, working memory and goal-directed behavior, which are impaired in schizophrenia. Magnetic resonance imaging allows non-invasive in vivo volumetric measurement of these brain structures. In this review, we studied all available papers on MRI research of the basal ganglia in schizophrenic patients. We found a possibly decreased caudate volume in first-episode schizophrenic patients, whereas studies on chronic patients mostly reveal volume increases in caudate, putamen and pallidum. Data from longitudinal studies suggest on the one hand that typical and atypical neuroleptics may produce different effects on brain morphology and on the other hand, that these changes are dynamic and might be reversible. Further studies are warranted for a better understanding of the mechanisms, which may lead to structural basal ganglia abnormalities, with medication effects demanding particular attention.