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Regional brain glucose metabolism in drug free schizophrenic patients and clinical correlates

Regional brain glucose metabolism was investigated in healthy volunteers (n= 10) and in drug free schizophrenic patients (n= 20). The metabolism was determined by positron emission tomography (PET) with 11C‐glucose as the tracer. Diagnosis of schizophrenia was made according to RDC and DSM III. Eight patients had their first psychotic episode, four patients had a subchronic course and eight patients had a chronic course with an exacerberation of their illness. Computed tomography (CT) of the brain were made in all the subjects. Regions of interest (n= 35) were drawn on displayed CT images and the marked regions were transferred to the corresponding slice of the PET examination. The PET investigation was made in a dimly lit, quiet room with the eyes of the subject covered. The time course of the 11C‐glucose uptake was measured by a four ring PET scanner (PC‐384‐7B).

A functional cerebral response to frightening visual stimulation

The defense reaction, a fundamental reflex in the human behavioral response to threat, is characterized by anxiety and increased activity of the sympathetic nervous system. To study changes in regional cerebral blood flow (rCBF) related to the defense reaction, volunteers with snake phobia were investigated with positron emission tomography. The relative rCBF during phobogenic visual stimulation was increased in the secondary visual cortex but reduced in the hippocampus, orbitofrontal, prefrontal, temporopolar, and posterior cingulate cortex compared with that observed during neutral visual stimulation. The relative rCBF under aversive stimulation was intermediate between phobic and neutral stimulation. The rCBF patterns observed are suggested to represent a functional cerebral correlate to the visually elicited defense reaction and its associated emotions.

Functional anatomy of hypnotic analgesia: a PET study of patients with fibromyalgia.

Hypnosis is a powerful tool in pain therapy. Attempting to elucidate cerebral mechanisms behind hypnotic analgesia, we measured regional cerebral blood flow with positron emission tomography in patients with fibromyalgia, during hypnotically‐induced analgesia and resting wakefulness. The patients experienced less pain during hypnosis than at rest. The cerebral blood‐flow was bilaterally increased in the orbitofrontal and subcallosial cingulate cortices, the right thalamus, and the left inferior parietal cortex, and was decreased bilaterally in the cingulate cortex. The observed blood‐flow pattern supports notions of a multifactorial nature of hypnotic analgesia, with an interplay between cortical and subcortical brain dynamics.

Extraversion, neuroticism and brain function : A pet study of personality

The personality dimensions Extraversion and Neuroticism seem associated with differences in central nervous system function. We used positron emission tomographic (PET) measures of regional cerebral blood flow (rCBF) to investigate central neural differe

PET determination of regional cerebral glucose metabolism in alcohol-dependent men and healthy controls using 11C-glucose

Regional brain glucose metabolism was determined in 9 male alcohol‐dependent inpatients and 12 male healthy controls. All the patients were socially impaired by the alcohol abuse. All the subjects had abstained from alcohol and drugs for more than four weeks before entering the study. Brain glucose metabolism was determined by positron emission tomography (PET) with 11C‐glucose as the tracer. Regions of interest were drawn on displayed computed tomographic (CT) images of the brain. Regions were transferred to corresponding PET slices, allowing the determination of regional glucose metabolism. In the healthy volunteers there was a reduction in glucose metabolism with age. In 11 of the 19 brain regions examined, the alcoholics had a 20% to 30% lower glucose metabolism than the controls. This was true for both cortical and subcortical structures. The distribution of relative regional metabolic rates indicated that parietal cortical areas were most affected. Atrophic changes as shown by CT were not correlated to the reduced metabolism in the alcohol‐dependent patients.

Effects of sulpiride and chlorpromazine on regional cerebral glucose metabolism in schizophrenic patients as determined by positron emission tomography.

Positron emission tomography (PET) was used to determine regional brain glucose metabolism in schizophrenic patients (n=17) before and during neuroleptic treatment. The patients had not been treated with neuroleptics for at least 3 weeks before the first study. All suffered from acute psychotic symptoms and were hospitalized to obtain neuroleptic treatment. After determination of regional brain metabolism without neuroleptic treatment, 11 patients were treated with sulpiride (800 mg/day) and 6 patients were treated with chlorpromazine (400 mg/day) over 5–6 weeks before the second PET investigation. The control group consisted of seven healthy male volunteers, also investigated twice 5 weeks apart. The PET investigation was made with the subject in a resting state. The tracer was uniformly labelled 11C-glucose. The metabolism was determined bilaterally in 15 brain regions cortical, as well as central regions. Metabolic rates differed among the groups. The sulpiride group had lower metabolic rates than the controls and the schizophrenic patients later treated with chlorpromazine. The sulpiride group, in which absolute metabolic rates were determined, were clinically more autistic and chronic than the chlorpromazine group. It was proposed that these facts could explain the lower metabolic rates in the sulpiride group. A significant change in metabolism in relation to drug treatment was only found in one brain region. The selective D2-receptor antagonist sulpiride increased the metabolic rate in the right lentiform nucleus in comparison with the patients treated with chlorpromazine and the controls. Likewise, relative metabolic rates were increased only in the right lentiform nucleus. Negative correlations between intensity of clinical symptoms and metabolism indicated that emotional tone and drive were related to brain metabolism. No correlations were found between drug concentrations and metabolism or clinical symptoms.

Evidence of Altered Cerebral Blood-Flow Relationships in Acute Phobia

Functional cerebral guiding and integrating systems may be revealed by analyzing the covariation of regional cerebral blood flow (rCBF). Positron emission tomography (PET) was used to measure absolute rCBF in 14 volunteers with specific phobia and 6 nonphobic controls, when exposed to videos containing phobia-relevant and neutral scenes. A fear reaction and increased covariation between absolute rCBFs was observed during phobia-relevant as compared to neutral stimulation in phobics only. In controls fear was not elicited and rCBF covariation was not influenced by stimulus condition, being similar to the pattern observed in phobics during neutral stimulation. We suggest the rCBF correlative pattern during phobic fear to reflect fear-related activation of distinct neuronal pathways that involves the amygdala, the thalamus, and the striatum. We theorize that these pathways are activated also by uncontrolled emotions in diverse conditions, like posttraumatic stress disorder, panic disorder, and schizophrenia.

Dexamethasone suppression test in schizophrenic patients before and during neuroleptic treatment

Abstract— The dexamethasone suppression test (DST) was performed in 21 drug‐free schizophrenic patients. The patients satisfied DSM‐III and Research Diagnostic Criteria for schizophrenia and were in an acute phase of the disease. In 15 of the patients the DST was repeated after about 5 weeks of treatment with neuroleptics. DST compliance was checked by analysis of dexamethasone concentrations in plasma. In the acute phase 71% (at 04 pm.) of the patients were nonsuppressors. After neuroleptic treatment the frequency of abnormal responders had decreased to 20%. The decrease in nonsuppressors was not due to alteration of the dex amethasone concentration between the two test occasions. Prolactin levels were markedly increased at the second test occasion compared with the first. There were no significant relationships between cortisol levels, cortisol suppression and prolactin levels. The high frequency of nonsuppressors among schizophrenic patients in the acute phase of the disease indicates that acute stress may be a confounding factor in the outcome of DST.

Cerebral correlates of anticipated fear: A PET study of specific phobia

Cerebral correlates of anticipatory anxiety was studied in 14 women with specific snake or spider phobia, and in 6 nonphobic controls. Videofilms with neutral scenes were shown during positron emission tomographic measurements of regional cerebral blood flow (rCBF). The phobics, but not the controls, anticipated scenes with spiders or snakes to appear in the videofilms. This was reflected in higher anxiety ratings in the phobics. The primary visual cortex rCBF was lower in phobics than controls, while no rCBF differences were found in the other brain regions investigated. The results are suggested to indicate inhibition of corticogeniculate pathways, in turn representing a neurophysiological correlate of avoidant anticipatory coping.

Altered relationships between metabolic rates of glucose in brain regions of schizophrenic patients

Regional brain glucose metabolism was studied with positron emission tomography (PET) in healthy volunteers (n= 9) and schizophrenic patients (n= 15). The patients were in an acute phase of the disease and drug free. Cerebral metabolic rate with 11C‐glucose as the tracer (CMRgl) was determined in both cortical and subcortical structures. In the healthy volunteers significant correlations were found between metabolic rates of some regions, but no relationships were found between CMRgl of limbic cortical areas and that of neocortical or subcortical structures. In the patients, high and significant positive correlations were found between metabolic rates in the neocortical areas, the limbic cortical areas and the subcortical areas. The results indicate differences in the neuronal interplay between regions of healthy and schizophrenic subjects. It is proposed that neuronal systems guiding the specificity and diversity in neuronal functions between different brain regions, are abnormal in schizophrenic patients. Such a disturbance may be the basis for the diversity of psychiatric symptoms in schizophrenics.