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OBJECTIVE Attentional deficits are a prominent aspect of cognitive dysfunction in schizophrenia. The anterior cingulate gyrus is proposed to be an important component of frontal attentional control systems. Structural and functional abnormalities have been reported in this region in schizophrenia, but their relationship to attentional deficits is unknown.(More)
The role of serotonin in CNS function and in many neuropsychiatric diseases (e.g., schizophrenia, affective disorders, degenerative dementias) support the development of a reliable measure of serotonin receptor binding in vivo in human subjects. To this end, the regional distribution and intrasubject test-retest variability of the binding of [18F]altanserin(More)
Conscious recall of past events that have specific temporal and spatial contexts, termed episodic memory, is mediated by a system of interrelated brain regions. In Alzheimer's disease (AD) this system breaks down, resulting in an inability to recall events from the immediate past. Using subtraction techniques with PET-acquired images of regional cerebral(More)
Alzheimer's disease (AD) patients show normal patterns of regional cerebral blood flow during performance of subspan verbal memory tasks, but appear to allocate new brain regions when performing supraspan recall tasks. To understand the relationships among these interconnected brain regions, their functional connectivity was considered using principal(More)
This pilot study examined the hypothesis that magnetic resonance imaging T2 relaxation times of specific brain regions increase after electroconvulsive therapy (ECT) and that these increases are related to the cognitive side effects of ECT. Six depressed patients undergoing unilateral ECT were studied. The results demonstrate significant post-ECT T2(More)
BACKGROUND Patient financial incentives ("incentives") have been widely used to promote chlamydia screening uptake amongst 15-24 year olds in England, but there is scarce evidence of their effectiveness. The objectives of the study were to describe incentives used to promote chlamydia screening in Primary Care Trusts (PCTs) in England and to evaluate their(More)
UNLABELLED Because of limitations of spatial resolution, quantitative PET measurements of cerebral blood flow, glucose metabolism and neuroreceptor binding are influenced by partial-volume averaging among neighboring tissues with differing tracer concentrations. METHODS Two MR-based approaches to partial-volume correction of PET images were compared using(More)
Serotonergic system abnormalities have been implicated in major depression, suicide, violence, alcoholism, and other psychopathologies. The prolactin response to fenfluramine has been widely used as a neuroendocrine probe to study brain serotonin responsivity. We have extended this methodology by using the positron emission tomography (PET)(More)
Changes in regional cerebral blood flow (rCBF), associated with performance of an auditory verbal supraspan memory task, were studied in eight remitted DSM-III-R schizophrenic patients and eight pair-wise matched normal controls. Four positron emission tomography (PET) scans, using the [15O]-H2O technique, were acquired: two while subjects fixated a cross(More)
Based on recent functional brain imaging studies of healthy human REM sleep, we hypothesized that alterations in REM sleep in mood disorder patients reflect a functional dysregulation within limbic and paralimbic forebrain structures during that sleep state. Six unipolar depressed subjects and eight healthy subjects underwent separate(More)