DOPAMINERGIC MODULATION OF IMPAIRED COGNITIVE ACTIVATION IN THE ANTERIOR CINGULATE CORTEX IN SCHIZOPHRENIA

DOPAMINERGIC dysregulation remains an empirical cornerstone for theori es concerning the causation of schizophrenia. Evidence for a dopamine system dysfunction in schizophrenia includes the psychosis-inducing ef fects of dopaminergic agonists(1,2) and the antipsychotic potency of d opaminergic antagonists(3'4). Here we use positron emission tomography (PET) to examine the regulatory role of dopamine on cortical function in normal subjects and unmedicated schizophrenic patients. Using a fa ctorial experimental design, we compared the effect of dopaminergic ma nipulation with apomorphine on a neural response to a cognitive task. In the schizophrenic patients, relative to controls, an impaired cogni tive activation of the anterior cingulate cortex was significantly mod ulated by a manipulation of dopaminergic neurotransmission. Thus, afte r apomorphine, the schizophrenic subjects displayed a significantly en hanced cognitive activation of the anterior cingulate cortex relative to the controls. These data provide in vivo evidence that an impaired cognitive-task-induced activation of the anterior cingulate cortex in schizophrenic patients can be significantly modulated by a dopaminergi c manipulation.