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CONTEXT A major limitation on the development of biomarkers and novel interventions for schizophrenia is that its pathogenesis is unknown. Although elevated striatal dopamine activity is thought to be fundamental to schizophrenia, it is unclear when this neurochemical abnormality develops in relation to the onset of illness and how this relates to the(More)
In humans, 5-HT1A receptors are implicated in anxiety and depressive disorders and their treatment. However, the physiological and genetic factors controlling 5-HT1A receptor expression are undetermined in health and disease. In this study, the influence of two genetic factors on 5-HT1A receptor expression in the living human brain was assessed using the(More)
BACKGROUND Cannabis use in early adolescence may be a risk factor for development of schizophrenia. In animals, Delta9-tetrahydrocannabinol (THC) increases the rate of dopamine neuronal firing and release in the striatum. Thus cannabis use may increase dopamine release in the human striatum leading to vulnerability to psychosis. AIMS To investigate(More)
The very high-affinity position emission tomography (PET) radioligand [(11)C]FLB 457 was developed in order to study extrastriatal tissues, where the density of dopamine D(2)/D(3) receptors is one to two orders of magnitude lower than in the striatum. The present study investigated the validity of using the cerebellum as a reference region. Ten healthy(More)
UNLABELLED Head movement presents a continuing problem in PET studies. Head restraint minimizes movement but is unreliable, resulting in the need to develop alternative strategies. These include frame-by-frame (FBF) realignment or use of motion tracking (MT) during the scan to realign PET acquisition data. Here we present a comparative analysis of these 2(More)
CONTEXT Alterations in dopaminergic neurotransmission and function of the prefrontal cortex are thought to be central to the pathophysiology of schizophrenia, but the relationship between these factors in the development of psychosis is unclear. OBJECTIVE To investigate the relationship between striatal dopamine activity and prefrontal function in people(More)
Genetic factors are important in the etiology of bipolar disorder (BD). However, first-degree relatives of BD patients are at risk for a number of psychiatric conditions, most commonly major depressive disorder (MDD), although the majority remain well. The purpose of the present study was to identify potential brain structural correlates for risk and(More)
Studies in vitro suggest that the expression of the serotonin transporter (5-HTT) is regulated by polymorphic variation in the promoter region of the 5-HTT gene (5-HTTLPR); however, results from human brain imaging studies examining the relation between 5-HTT genotype and 5-HTT radioligand binding in vivo have been inconsistent. This inconsistency could(More)
Parkinson's disease is associated with slowness, especially of sequential movements, and is characterized pathologically by degeneration of dopaminergic neurons, particularly targeting nigrostriatal projections. In turn, nigrostriatal dopamine has been suggested to be critical for the execution of sequential movements. The objective of this study was to(More)
The dopamine D2 receptor antagonist sulpiride can produce a range of cognitive deficits in normal volunteers, consistent with those seen in Parkinson's disease (PD). This, together with studies in experimental animals, implies sulpiride might be acting in the striatum. However, subtle changes in prefrontal cortex (PFC) activity are seen following L-Dopa(More)