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OBJECTIVE This study sought to describe brain regions associated with the personality dimension of introversion/extraversion. METHOD Measures of cerebral blood flow (CBF) were obtained from 18 healthy subjects by means of [150]H20 positron emission tomography. Correlations of regional CBF with introversion/extraversion were calculated, and a(More)
BACKGROUND There have been reports that patients with schizophrenia have decreased metabolic activity in prefrontal cortex. However, findings have been confounded by medication effects, chronic illness, and difficulties of measurement. We aimed to address these problems by examination of cerebral blood flow with positron emission tomography (PET). METHODS(More)
It is uncertain whether frequent marijuana use adversely affects human brain function. Using positron emission tomography (PET), memory-related regional cerebral blood flow was compared in frequent marijuana users and nonusing control subjects after 26+ h of monitored abstention. Memory-related blood flow in marijuana users, relative to control subjects,(More)
OBJECTIVE Whether chronicity of illness produces progressive neural abnormality is an important question in current schizophrenia research. Positron emission tomography (PET) offers an opportunity to visualize and measure blood flow in vivo to address this issue. The authors previously compared healthy volunteers with neuroleptic-naive patients experiencing(More)
The accurate determination of cerebrovascular reserve (CVR), especially in elderly subjects, entails several technical issues. From a review of the literature, the optimal technique employs quantitative 15O-water PET imaging determinations of cerebral blood flow (CBF) and acetazolamide (ACZ) (1 g iv with measurements at 10- to 20-min post-administration) as(More)
OBJECTIVE This study explored the neural circuitry used during recall of unstructured verbal material in schizophrenic patients and healthy volunteer subjects. METHOD The subjects were 13 healthy volunteers and 14 schizophrenic patients. All patients were free of medication, and all subjects were right-handed. Two experimental cognitive conditions were(More)
Positron emission tomography ([(15)O] water PET) was used to examine the relationship between age and regional cerebral blood flow (rCBF) in schizophrenia. Forty-nine unmedicated male patients, ages 20-51, underwent imaging during an eyes-closed resting condition. Negative correlations were observed between age and rCBF in the anterior cingulate, as well as(More)
We examined regional cerebral blood flow (rCBF) during a long-term recognition memory task for words in schizophrenic patients and in healthy subjects using positron emission tomography (PET). The task was designed so that performance scores were similar in the patient and control subjects. This memory retrieval task did not increase rCBF in the patients'(More)
The level of familiarity of a given stimulus plays an important role in memory processing. Indeed, the novelty/familiarity of learned material has been proven to affect the pattern of activations during recognition memory tasks. We used visually presented words to investigate the neural basis of recognition memory for relatively novel and familiar stimuli(More)
OBJECTIVES Although electroconvulsive therapy (ECT) is a very effective treatment of depression and psychosis, the mechanisms by which this occurs are not fully delineated. The objective of this study was to investigate the functional alterations in brain metabolism in response to ECT through the use of positron emission tomography assessment of cerebral(More)