The developmental plasticity of the dopamine systems in the rodent basal ganglia

Abstract

rently emphasize activation with blood flow measures. However, there is lack of data on carefully screened unmedicated patients compared to socio-demographieally balanced healthy control subjects, with reliable q~'nitative measure of resting baseline metabolism. Thus, there is still debate on whether hypofrontality exists under this condition, or whether there are lateralized abnormalities. We measured glucose utilization using mF-fluoro-deoxyglucose (FIX;) and positron emission tornography (PET) in 42 unmedicated patients and 42 socio-demographitally balanced healthy controls. Subjects were screened for medical conditions affecting brain metabolism and controls were also screened for psychopathology in first-degree relatives. Measures were obtained during a standard resting baseline condition (eyes open, ears unoccluded). MRIs were also obtained. ROls for anatomically co-registered PET images ineluded caudate, insula, globus pallidus, lenticular rtu¢leus, thalamus, parahippoeampal gyms, uncus, hippocampus, amygdala, mammiilary bodies, ant.crier a ~ pose ~rjor ¢~ngulum (subcortical regions), midfrontal, dorsolateral prefrontal, inferior frontal, orbitofrontal, rect. ! gyms, superior temporal, midtemporal, inferotemporal, parietal, sensorimotor, occipitotemporal, and occipital (cortical regions), and anterior and posterior corpus callosum, cerebellum and midbrain. Results showed a remarkable similarity of topography when regions were averaged between the two hemisphere. Indeed, the means for patients and controls were entirely overlapping. However, a laterality index (L-R) showed higher left hemispheric metabolism in patients for the superior temporal (p<,05) and mid. temporal cortex (p<,001), and lower left than right activity in thalamus and midbrain (p<.01). Thus, patients with schizophrenia have normal to. pography of resting brain activity, with no suggestion of hypofrontality. The laterality fndings indicate relatively higher left hemispheric activation in cortical regions and a reverse effect for subeortical regions. This pattern will be related to clinical and neuropsychological data.