OBJECTIVE: This study reports the first paired measurements of glucose
metabolism and size of thalamic regions in never-medicated schizophrenic
patients using coregistered magnetic resonance imaging (MRI) templates.
METHOD: Positron emission tomography with [18F]fluorodeoxyglucose and
matching MRI scans were obtained in 20 never-medicated patients with
schizophrenia and 15 normal volunteers. Methods for thalamic edge finding,
statistical testing of shape differences with chi-square maps, and MRI
localization of major thalamic subregions were developed. RESULTS: Patients
with schizophrenia showed a diminished metabolic rate in the right
thalamus, with a loss of the normal pattern of right greater than left
asymmetry. Division into anterior/posterior segments revealed that the left
anterior and right posterior showed the decrease. Differences were greater
for metabolism in the weighted thalamic area (ratexarea) than for rate per
unit area, a finding consistent with reported greater decreases in total
neuron number than of neuron density in the thalami of schizophrenic
patients. The area of the thalamus was smaller in the patients than in the
volunteers, and this difference was greatest in the left anterior region.
CONCLUSIONS: The reduced thalamic activity observed in this study lends
further support to the concept of deficits in sensory filtering in
schizophrenia.Abstract Teaser