M.S. Buchsbaum

Frontal cortex and basal ganglia metabolic rates assessed by positron emission tomography with [18F]2-deoxyglucose in affective illness.

Twenty affective disorder patients (16 bipolar and 4 unipolar) and 24 normal controls received scans with positron emission tomography (PET) using [18F]2-deoxyglucose (FDG) as a tracer. Subjects received a series of brief electrical stimuli to their right arms during FDG uptake. Patients with bipolar affective illness had significantly lower frontal to occipital glucose metabolic rate ratios (relative hypofrontality) and significantly lower metabolic rates in their basal ganglia in comparison to whole slice metabolism than normal controls. Patients with unipolar illness showed significantly higher frontal to occipital ratios, and also showed relatively decreased metabolism in the basal ganglia. All results in unipolar patients should be considered exploratory due to the small number of patients. Clinical depression ratings correlated negatively with whole slice metabolic rate.

Comparison of regional brain metabolism in bulimia nervosa and affective disorder assessed with positron emission tomography

Women with bulimia often present with symptoms of depression in addition to bingeing and purging behavior. Brain metabolism in eight women with bulimia nervosa was compared to that in eight women with major affective disorder and eight normal women, using positron emission tomography and 18-fluoro-2-deoxyglucose. Normal women have higher right than left cortical metabolic rates and active basal ganglia. Bulimics lost the normal right activation in some areas, but maintained basal ganglia activity. Depressives retained right hemisphere activation, but had decreased metabolism in basal ganglia. This suggests that although women with bulimia frequently present with symptoms of depression, the pathophysiologic changes associated with bulimia differ from major effective disorder.

Simultaneous cerebral glucography with positron emission tomography and topographic electroencephalography.

Publisher Summary This chapter presents the study that directly measured local cerebral glucose use by positron emission tomography (PET) with simultaneous recording of EEG from 16 electrodes spaced over the left hemisphere to maximize spatial resolution. Simultaneous cerebral glucography with positron emission tomography and topographic quantitative electroencephalography is carried out in six normal volunteers. The presence of resting occipital alpha activity is associated with relatively low glucose use consistent with the phenomenon of alpha blocking with visual input. Higher EEG amplitude is associated with higher glucose use in some posterior and central regions. The harmlessness, repeatability, and low cost of EEG topography give it some advantages over the high cost of PET or isotopic regional blood flow techniques. Extended studies are further necessary to define regional relationships; simultaneous PET and EEG studies are able to better characterize metabolic information available in the scalp electrical activity.

Regional Correlations in Patterns of Glucose Use in Patients with Schizophrenia and Normal Subjects During Mild Pain Stimulation

The ability to study patterns of cerebral metabolism in humans noninvasively is clearly one of the great advantages of positron tomography. The development of the 18F-labeled 2-fluorodeoxyglucose (218FDG) method has produced a powerful tool for studying cerebral energy metabolism with positron tomography (Huang et al. 1980). Given the tight coupling normally existing between cerebral function and energy metabolism (Sokoloff 1977, 1981), 218FDG has been used to study resting patterns of metabolism in resting subjects (Mazziotta et al. 1981), subjects undergoing neuropsychological activations (Greenberg et al. 1981), and schizophrenic subjects at rest and off medication (Buchsbaum et al. 1982).