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The classical dopamine hypothesis of schizophrenia postulates a hyperactivity of dopaminergic transmission at the D(2) receptor. We measured in vivo occupancy of striatal D(2) receptors by dopamine in 18 untreated patients with schizophrenia and 18 matched controls, by comparing D(2) receptor availability before and during pharmacologically induced acute(More)
The dopamine hypothesis of schizophrenia proposes that hyperactivity of dopaminergic transmission is associated with this illness, but direct observation of abnormalities of dopamine function in schizophrenia has remained elusive. We used a newly developed single photon emission computerized tomography method to measure amphetamine-induced dopamine release(More)
CONTEXT A long-standing version of the dopamine hypothesis of schizophrenia postulates that hyperactivity of dopaminergic transmission at D(2) receptors in the limbic striatum is associated with the illness and that blockade of mesolimbic D(2) receptors is responsible for the antipsychotic action of D(2) receptor antagonists. OBJECTIVE To localize(More)
OBJECTIVE The authors previously observed an increase in striatal dopamine transmission following amphetamine challenge in 15 untreated patients with schizophrenia compared to 15 matched healthy subjects. The purpose of this study was to replicate this finding in a new cohort of schizophrenic patients and healthy subjects. METHOD Fifteen patients with(More)
CONTEXT Postmortem studies have found evidence of γ-aminobutyric acid (GABA) deficits in fast-spiking, parvalbumin-positive interneurons in the prefrontal cortex in schizophrenia. Magnetic resonance spectroscopy studies in unmedicated patients have reported glutamine or glutamate-glutamine (Glx) elevations in this region. Abnormalities in these transmitters(More)
Studies in nonhuman primates documented that appropriate stimulation of dopamine (DA) D1 receptors in the dorsolateral prefrontal cortex (DLPFC) is critical for working memory processing. The defective ability of patients with schizophrenia at working memory tasks is a core feature of this illness. It has been postulated that this impairment relates to a(More)
BACKGROUND A decrease in dopamine type 2 receptors (D2) and mesolimbic dopamine transmission predisposes animals to consume alcohol. This study measured D2 receptors and dopamine transmission in human alcohol-dependent (AD) subjects using positron emission tomography (PET) and [11C]raclopride. METHODS Fifteen AD and 15 healthy control (HC) subjects were(More)
BACKGROUND Several lines of evidence derived from imaging and postmortem studies suggest that schizophrenia is associated with hyperactivity of dopamine function and deficiency in serotonin (5-HT) function. The aim of this study was to investigate potential alterations of striatal dopamine transporters (DAT) and brainstem serotonin transporters (SERT)(More)
We previously reported a preserved 'old-new effect' (enhanced parietal positivity 300-800 ms following correctly-recognized repeated words) in schizophrenia over mid-parietal sites using 31-channel nose-referenced event-related potentials (ERP) and reference-free current source densities (CSD). However, patients showed poorer word recognition memory and(More)
BACKGROUND The amino acid glycine, modulates neurotransmission via actions at GLY-A receptor and GLY-B receptor. The latter are coagonist sites associated with N-Methyl-D-Aspartate (NMDA) glutamate receptors. The central bioavailability of peripherally administered glycine has not been adequately characterized in humans. METHODS Healthy human subjects(More)