Magnetic resonance imaging of mediodorsal, pulvinar, and centromedian nuclei of the thalamus in patients with schizophrenia.

BACKGROUND: Postmortem and magnetic resonance imaging (MRI) data have suggested volume reductions in the mediodorsal (MDN) and pulvinar nuclei (PUL) of the thalamus. The centromedian nucleus (CMN), important in attention and arousal, has not been previously studied with MRI. METHODS: A sample of 41 patients with schizophrenia (32 men and 9 women) and 60 healthy volunteers (45 men and 15 women) underwent assessment with high-resolution 1.2-mm thick anatomical MRI. Images were differentiated to enhance the edges and outline of the whole thalamus, and the MDN, PUL, and CMN were outlined on all slices by a tracer masked to diagnostic status. RESULTS: Significantly smaller volumes of the MDN and PUL were found in patients with schizophrenia compared with controls. Volume relative to brain size was reduced in all 3 nuclei; differences in relative reduction did not differ among the nuclei. The remainder of the thalamic volume (whole thalamus minus the volume of the 3 delineated nuclei) was not different between schizophrenic patients and controls, indicating that the volume reduction was specific to these nuclei. Volume relative to brain size was reduced in all 3 nuclei and remained significant when only patients who had never been exposed to neuroleptic medication (n = 15) were considered. For the MDN, women had larger relative volumes than men among controls, but men had larger volumes than women among schizophrenic patients. CONCLUSIONS: Three association regions of the thalamus that have reciprocal connectivity to schizophrenia-associated regions of the cortex have significantly smaller volumes on MRI in patients with schizophrenia.

Kraepelinian and non-Kraepelinian schizophrenia subgroup differences in cerebral metabolic rate.

We studied two subtypes of schizophrenia. the Kraepelinian subtype (n = 10) characterized by an unremitting and severe course and the non-Kraepelinian subtype (n = 17) characterized by a remitting course and some periods of self-care. Patients were assessed with positron emission tomography (PET) with 18F-deoxyglucose (FDG) and high-resolution magnetic resonance imaging (MRI). A group of 32 age- and sex-matched normal volunteers served as comparison subjects. During the FDG tracer uptake period, patients performed a serial verbal learning task. MR images were segmented into gray, white and cerebrospinal fluid regions, and warped to average normal coordinates. PET images were coregistered to the MR images and similarly warpedfor analysis. Kraepelinian subtype patients were characterized by lower metabolic rates in the temporal lobe and cingulategyrus. and lower fronto/occipital ratios than non-Kraepelinian subtype patients. Exploratory statistical probability mapping alsorevealed lower metabolic rates in the right striatum in Kraepelinian versus non-Kraepelinian patients. These differences couldnot be attributed to differences in age, symptom severity, task performance during FDG uptake, or severity of involuntary movements. Factor analysis of the cortical surface identified significantly lower temporal lobe metabolic rates in Kraepelinian patients than non-Kraepelinian patients. A combined frontal/temporal deficit or greater cortical change may be associated with poorer longitudinal course.

FDG-PET and MRI imaging of the effects of sertindole and haloperidol in the prefrontal lobe in schizophrenia.

Sertindole, a 2nd generation antipsychotic with low movement disorder side effects, was compared with haloperidol in a 6-week crossover study. Fifteen patients with schizophrenia (mean age=42.6, range=22-59, 11 men and 4 women) received sertindole (12-24 mg) or haloperidol (4-16 mg) for 6 weeks and then received a FDG-PET scan and an anatomical MRI. Patients were then crossed to the other treatment and received a second set of scans at week 12. Dose was adjusted by a physician blind to the medication type. Brodmann areas were identified stereotaxically using individual MRI templates applied to the coregistered FDG-PET image. Sertindole administration was associated with higher dorsolateral prefrontal cortex metabolic rates than haloperidol and lower orbitofrontal metabolic rates than haloperidol. This effect was greatest for gray matter of the dorsolateral Brodmann areas 8, 9, 10, 44, 45, and 46. Patients were further contrasted with an approximately age and sex-matched group of 33 unmedicated patients with schizophrenia and with a group of 55 normal volunteers. Sertindole administration was associated with greater change toward normal values and away from the values found in the unmedicated comparison group for dorsolateral prefrontal cortex gray matter and white matter underlying medial prefrontal and cingulate cortex. These results are consistent with the low motor side-effect profile of sertindole, greater improvement on prefrontal cognitive tasks with sertindole than haloperidol, and with the tendency of 2nd generation antipsychotic drugs to have greater frontal activation than haloperidol.