EEG alpha rhythm and glucose metabolic rate in the thalamus in schizophrenia

Positron emission tomography with uptake of [F-18]fluo- rodeoxyglucose (FDG ) and quantitative EEG were simultaneously performed in 18 medication-free patients with schizophrenia and in 13 normal volunteers. Subjects performed the Continuous Performance Task (CPT) during FDG uptake. Correlations were calculated between alpha power during the CPT and glucose metabolic rate ( GMR) in thalamic regions and between alpha power during the CPT and GMR in occipital cortices. Regression analyses were used to describe the predictio n of GMR in the occipital cortices and in the thalamic regions of occipital alpha power. In normal controls, we found (1) significant negative correla tions between absolute alpha power and GMR in the left occipital cortex, (2 ) significant positive correlations between normalized alpha power and GMR in the right and left lateral thalamus and (3) combined effects of GMR in t he thalamic regions and the occipital cortices on alpha power, which accoun ted for 98% of the variance of alpha power. In patients with schizophrenia, we found no significant correlations between alpha power and GMR in the oc cipital cortices or between alpha power and GMR in the thalamic regions. Co rrelation coefficients between absolute alpha power and GMR in the left occ ipital cortex and between normalized alpha power and GMR in the left latera l thalamus were significantly different in normal subjects compared to schi zophrenic patients. The present findings provide evidence for involvement o f the thalamus in the generation of alpha rhythm in humans. Furthermore, th e present results suggest differences in thalamocortical circuits between n ormal controls and schizophrenic subjects. Copyright (C) 2001 S.Karger AG,Basel.