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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)
BACKGROUND Low striatal dopamine 2/3 receptor (D(2/3)) availability and low ventrostriatal dopamine (DA) release have been observed in alcoholism and cocaine and heroin dependence. Less is known about the dopaminergic system in cannabis dependence. We assessed D(2/3) availability and DA release in abstinent cannabis users compared with control subjects and(More)
3,4-Methylenedioxymethamphetamine (MDMA), the main psychoactive component of the recreational drug ecstasy, is a potent serotonin (5-HT) releaser. In animals, MDMA induces 5-HT depletion and toxicity in 5-HT neurons. The aim of this study was to investigate both presynaptic (5-HT transporter, SERT) and postsynaptic (5-HT(2A) receptor) markers of 5-HT(More)
BACKGROUND We used a positron emission tomography paradigm with the D2/3 radiotracer [¹¹C]raclopride and an alcohol challenge to examine the magnitude of alcohol-induced dopamine release and compare it between young men and women. METHODS Twenty-one nonalcohol-dependent young social drinkers completed two positron emission tomography scans on separate(More)
The amphetamine challenge, in which positron emission tomography (PET) or single photon emission computed tomography radioligand binding following administration of amphetamine is compared to baseline values, has been successfully used in a number of brain imaging studies as an indicator of dopaminergic function, particularly in the striatum. [(18)F](More)
Glutamatergic abnormalities in corticostriatal brain circuits are thought to underlie obsessive-compulsive disorder (OCD). Whether these abnormalities exist in adults with OCD is not clear. We used proton magnetic resonance spectroscopy (¹H MRS) to test our hypothesis that unmedicated adults with OCD have reduced glutamate plus glutamine (Glx) levels in the(More)
BACKGROUND An imaging method to probe glutamate levels in vivo would allow the study of glutamate transmission in disease states and in response to therapeutic interventions. Here we demonstrate the feasibility of this approach for the first time using positron emission tomography and [(11)C] ABP688, a radiotracer for an allosteric site on the metabotropic(More)
The support vector machine (SVM) has been applied to the problem of bankruptcy prediction, and proved to be superior to competing methods such as the neural network, the linear multiple discriminant approaches and logistic regression. However, the conventional SVM employs the structural risk minimization principle, thus empirical risk of misclassification(More)
Functional neuroimaging (fMRI) studies show activation in mesolimbic circuitry in tasks involving reward processing, like the Monetary Incentive Delay Task (MIDT). In voltammetry studies in animals, mesolimbic dopamine release is associated with reward salience. This study examined the relationship between fMRI activation and magnitude of dopamine release(More)