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Sökning: WFRF:(Plaven Sigray P)

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1.
  • Plaven-Sigray, Pontus, et al. (författare)
  • Dopamine D1 receptor availability is related to social behavior : A positron emission tomography study
  • 2014
  • Ingår i: NeuroImage. - : Elsevier. - 1053-8119 .- 1095-9572. ; 102, s. 590-595
  • Tidskriftsartikel (refereegranskat)abstract
    • Dysfunctional interpersonal behavior is thought to underlie a wide spectrum of psychiatric disorders; however, the neurobiological underpinnings of these behavioral disturbances are poorly understood. Previous molecular imaging studies have shown associations between striatal dopamine (DA) D2-receptor binding and interpersonal traits, such as social conformity. The objective of this study was to explore, for the first time, the role of DA D1-receptors (D1-Rs) in human interpersonal behavior. Twenty-three healthy subjects were examined using positron emission tomography and the radioligand [C-11] SCH23390, yielding D1-R binding potential values. Striatal D1-R binding was related to personality scales selected to specifically assess one dimension of interpersonal behavior, namely a combination of affiliation and dominance (i.e., the Social Desirability, Verbal Trait Aggression and Physical Trait Aggression scales from Swedish Universities Scales of Personality). An exploratory analysis was also performed for extrastriatal brain regions. D1-R binding potential values in the limbic striatum(r= .52; p= .015), associative striatum(r= .55; p= .009), and sensorimotor striatum(r= .67; p= .001) were positively related to Social Desirability scores. D1-R binding potential in the limbic striatum (r= -.51; p = .019) was negatively associated with Physical Trait Aggression scores. For extrastriatal regions, Social Desirability scores showed positive correlations in the amygdala (r = .60; p = .006) and medial frontal cortex (r= .60; p = .004). This study provides further support for the role of DA function in the expression of disaffiliative and dominant traits. Specifically, D1-R availability may serve as a marker for interpersonal behavior in humans. Associations were demonstrated for the same dimension of interpersonal behavior as for D2-R, but in the opposite direction, suggesting that the two receptor subtypes are involved in the same behavioral processes, but with different functional roles.
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2.
  • Svensson, Jonas E., et al. (författare)
  • Serotonin transporter availability increases in patients recovering from a depressive episode
  • 2021
  • Ingår i: Translational Psychiatry. - : Springer. - 2158-3188 .- 2158-3188. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Molecular imaging studies have shown low cerebral concentration of serotonin transporter in patients suffering from depression, compared to healthy control subjects. Whether or not this difference also is present before disease onset and after remission (i.e. a trait), or only at the time of the depressive episode (i.e. a state) remains to be explored. We examined 17 patients with major depressive disorder with positron emission tomography using [C-11]MADAM, a radioligand that binds to the serotonin transporter, before and after treatment with internet-based cognitive behavioral therapy. In all, 17 matched healthy control subjects were examined once. Cerebellum was used as reference to calculate the binding potential. Differences before and after treatment, as well as between patients and controls, were assessed in a composite cerebral region and in the median raphe nuclei. All image analyses and confirmatory statistical tests were preregistered. Depression severity decreased following treatment (p<0.001). [C-11]MADAM binding in patients increased in the composite region after treatment (p=0.01), while no change was observed in the median raphe (p=0.51). No significant difference between patients at baseline and healthy controls were observed in the composite region (p=0.97) or the median raphe (p=0.95). Our main finding was that patients suffering from a depressive episode show an overall increase in cerebral serotonin transporter availability as symptoms are alleviated. Our results suggest that previously reported cross-sectional molecular imaging findings of the serotonin transporter in depression most likely reflect the depressive state, rather than a permanent trait. The finding adds new information on the pathophysiology of major depressive disorder.
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3.
  • Laurell, Gjertrud L, et al. (författare)
  • Nondisplaceable Binding Is a Potential Confounding Factor in 11C-PBR28 Translocator Protein PET Studies.
  • 2021
  • Ingår i: Journal of Nuclear Medicine. - 0161-5505 .- 1535-5667. ; 62:3, s. 412-417
  • Tidskriftsartikel (refereegranskat)abstract
    • The PET ligand 11C-PBR28 (N-((2-(methoxy-11C)-phenyl)methyl)-N-(6-phenoxy-3-pyridinyl)acetamide) binds to the 18-kDa translocator protein (TSPO), a biomarker of glia. In clinical studies of TSPO, the ligand total distribution volume, VT, is frequently the reported outcome measure. Since VT is the sum of the ligand-specific distribution volume (VS) and the nondisplaceable-binding distribution volume (VND), differences in VND across subjects and groups will have an impact on VTMethods: Here, we used a recently developed method for simultaneous estimation of VND (SIME) to disentangle contributions from VND and VS Data from 4 previously published 11C-PBR28 PET studies were included: before and after a lipopolysaccharide challenge (8 subjects), in alcohol use disorder (14 patients, 15 controls), in first-episode psychosis (16 patients, 16 controls), and in Parkinson disease (16 patients, 16 controls). In each dataset, regional VT estimates were obtained with a standard 2-tissue-compartment model, and brain-wide VND was estimated with SIME. VS was then calculated as VT - VND VND and VS were then compared across groups, within each dataset. Results: A lower VND was found for individuals with alcohol-use disorder (34%, P = 0.00084) and Parkinson disease (34%, P = 0.0032) than in their corresponding controls. We found no difference in VND between first-episode psychosis patients and their controls, and the administration of lipopolysaccharide did not change VNDConclusion: Our findings suggest that in TSPO PET studies, nondisplaceable binding can differ between patient groups and conditions and should therefore be considered.
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4.
  • Matheson, Granville J, et al. (författare)
  • Dopamine D1 receptor availability is not associated with delusional ideation measures of psychosis proneness
  • 2020
  • Ingår i: Schizophrenia Research. - : Elsevier BV. - 0920-9964 .- 1573-2509. ; 222, s. 175-184
  • Tidskriftsartikel (refereegranskat)abstract
    • The dopamine D1 receptor (D1R) is thought to play a role in psychosis and schizophrenia, however positron emission tomography studies comparing patients and controls have been inconsistent. To circumvent some of the limitations of clinical studies, such as antipsychotic exposure, an alternative approach is to examine subclinical psychotic symptoms within the general population, i.e. psychosis proneness traits. In this study, we investigated whether D1R availability is associated with delusional ideation in healthy controls, in four experiments, using [11C]SCH23390 PET (n = 76) and psychometric questionnaires (n = 217). We performed exploratory analyses, direct self-replication, and confirmatory analyses using Bayesian statistical modelling. Collectively, we found strong evidence that there is little to no linear association between delusional ideation and D1R. If hypothesised changes in D1R in drug-naive psychosis patients can be confirmed, our results suggest that they may either occur at disease onset, or that they are associated with specific aspects of psychosis other than delusional ideation.
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5.
  • Matheson, Granville J, et al. (författare)
  • Reliability of volumetric and surface-based normalisation and smoothing techniques for PET analysis of the cortex : A test-retest analysis using [11C]SCH-23390
  • 2017
  • Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 155, s. 344-353
  • Tidskriftsartikel (refereegranskat)abstract
    • Parametric voxelwise analysis is a commonly used tool in neuroimaging, as it allows for identification of regions of effects in the absence of a strong a-priori regional hypothesis by comparing each voxel of the brain independently. Due to the inherent imprecision of single voxel measurements, spatial smoothing is performed to increase the signal-to-noise ratio of single-voxel estimates. In addition, smoothing compensates for imprecisions in anatomical registration, and allows for the use of cluster-based statistical thresholding. Smoothing has traditionally been applied in three dimensions, without taking the tissue types of surrounding voxels into account. This procedure may be suitable for subcortical structures, but is problematic for cortical regions for which grey matter often constitutes only a small proportion of the smoothed signal. New methods have been developed for cortical analysis in which voxels are sampled to a surface, and smoothing is restricted to neighbouring regions along the cortical grey matter in two dimensions. This procedure has recently been shown to decrease intersubject variability and bias of PET data. The aim of this study was to compare the variability, bias and test-retest reliability of volumetric and surface-based methods as they are applied in practice. Fifteen healthy young males were each measured twice using the dopamine D1 receptor radioligand [11C]SCH-23390, and analyses were performed at the level of individual voxels and vertices within the cortex. We found that surface-based methods yielded higher BPND values, lower coefficient of variation, less bias, better reliability and more precise estimates of parametric binding. All in all, these results suggest that surface-based methods exhibit superior performance to volumetric approaches for voxelwise analysis of PET data, and we advocate for their use when a ROI-based analysis is not appropriate.
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6.
  • Plaven-Sigray, Pontus, et al. (författare)
  • Extrastriatal dopamine D2-receptor availability in social anxiety disorder
  • 2017
  • Ingår i: European Neuropsychopharmacology. - : Elsevier BV. - 0924-977X .- 1873-7862. ; 27:5, s. 462-469
  • Tidskriftsartikel (refereegranskat)abstract
    • Alterations in the dopamine system are hypothesized to influence the expression of social anxiety disorder (SAD) symptoms. However, molecular imaging studies comparing dopamine function between patients and control subjects have yielded conflicting results. Importantly, while all previous investigations focused on the striatum, findings from activation and blood flow studies indicate that prefrontal and limbic brain regions have a central role in the pathophysiology. The objective of this study was to investigate extrastriatal dopamine D2-receptor (D2-R) availability in SAD. We examined 12 SAD patients and 16 healthy controls using positron emission tomography and the high-affinity D2-R radioligand [C-11]FLB457. Parametric images of D2-R binding potential were derived using the Logan graphical method with cerebellum as reference region. Two-tailed one-way independent ANCOVAs, with age as covariate, were used to examine differences in D2-R availability between groups using both region-based and voxel-wise analyses. The region-based analysis showed a medium effect size of higher D2-R levels in the orbitofrontal cortex (OFC) in patients, although this result did not remain significant after correction for multiple comparisons. The voxel-wise comparison revealed elevated D2-R availability in patients within OFC and right dorsolateral prefrontal cortex after correction for multiple comparisons. These preliminary results suggest that an aberrant extrastriatal dopamine system may be part of the disease mechanism in SAD.
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7.
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8.
  • Plaven-Sigray, Pontus, et al. (författare)
  • Positron Emission Tomography Studies of the Glial Cell Marker Translocator Protein in Patients With Psychosis : A Meta-analysis Using Individual Participant Data
  • 2018
  • Ingår i: Biological Psychiatry. - : Elsevier BV. - 0006-3223 .- 1873-2402. ; 84:6, s. 433-442
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Accumulating evidence suggests that the immune system may be an important target for new treatment approaches in schizophrenia. Positron emission tomography and radioligands binding to the translocator protein (TSPO), which is expressed in glial cells in the brain including immune cells, represents a potential method for patient stratification and treatment monitoring. This study examined whether patients with first-episode psychosis and schizophrenia had altered TSPO levels compared with healthy control subjects.METHODS: PubMed was searched for studies comparing patients with psychosis with healthy control subjects using second-generation TSPO radioligands. The outcome measure was total distribution volume (V-T), an index of TSPO levels, in frontal cortex, temporal cortex, and hippocampus. Bayes factors (BFs) were applied to examine the relative support for higher, lower, or no difference in patients' TSPO levels compared with healthy control subjects.RESULTS: Five studies, with 75 participants with first-episode psychosis or schizophrenia and 77 healthy control subjects, were included. BFs showed strong support for lower VT in patients relative to no difference (all BFs > 32), or relative to higher V-T (all BFs > 422), in all brain regions. From the posterior distributions, mean patient-control differences in standardized V-T values were -0.48 for frontal cortex (95% credible interval [CredInt] = -0.88 to 0.09), -0.47 for temporal cortex (CredInt = -0.87 to -0.07), and -0.63 for hippocampus (CredInt = -1.00 to -0.25).CONCLUSIONS: The lower levels of TSPO observed in patients may correspond to altered function or lower density of brain immune cells. Future studies should focus on investigating the underlying biological mechanisms and their relevance for treatment.
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9.
  • Caravaggio, Fernando, et al. (författare)
  • Trait impulsivity is not related to post-commissural putamen volumes : A replication study in healthy men
  • 2018
  • Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:12
  • Tidskriftsartikel (refereegranskat)abstract
    • High levels of trait impulsivity are considered a risk factor for substance abuse and drug addiction. We recently found that non-planning trait impulsivity was negatively correlated with post-commissural putamen volumes in men, but not women, using the Karolinska Scales of Personality (KSP). Here, we attempted to replicate this finding in an independent sample using an updated version of the KSP: the Swedish Universities Scales of Personality (SSP). Data from 88 healthy male participants (Mean Age: 28.16 +/- 3.34), who provided structural T1-weighted magnetic resonance images (MRIs) and self-reported SSP impulsivity scores, were analyzed. Striatal sub-region volumes were acquired using the Multiple Automatically Generated Templates (MAGeT-Brain) algorithm. Contrary to our previous findings trait impulsivity measured using SSP was not a significant predictor of post-commissural putamen volumes (beta = .14, df = 84, p = .94). A replication Bayes Factors analysis strongly supported this null result. Consistent with our previous findings, secondary exploratory analyses found no relationship between ventral striatum volumes and SSP trait impulsivity (beta = -.05, df = 84, p = .28). An exploratory analysis of the other striatal compartments showed that there were no significant associations with trait impulsivity. While we could not replicate our previous findings in the current sample, we believe this work will aide future studies aimed at establishing meaningful brain biomarkers for addiction vulnerability in healthy humans.
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10.
  • Farde, Lars, et al. (författare)
  • Brain neuroreceptor density and personality traits : towards dimensional biomarkers for psychiatric disorders.
  • 2018
  • Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - 0962-8436 .- 1471-2970. ; 373:1744
  • Forskningsöversikt (refereegranskat)abstract
    • Positron emission tomography has, for 30 years, been used in numerous case-control studies searching for hypothesized differences in the density of neuroreceptor or transporter proteins in psychiatric disorders such as schizophrenia and depression. In most cases, the results have not been conclusive. One reason could be the sizeable interindividual variability in biochemical markers, which in twin studies have shown to emanate from both environmental and genetic factors, leading to low statistical power for the detection of group effects. On the other hand, the same interindividual variability has served as an opportunity for correlative studies on the biological underpinning of behaviour. Using this approach, a series of studies has linked markers for the dopamine and serotonin system to personality traits associated with psychiatric conditions. Based on increasing evidence for the view that many psychopathological states represent extremes of a continuum rather than distinct categories, this research strategy may lead to new biological insights about the vulnerability to and pathophysiology of major psychiatric disorders.This article is part of the theme issue 'Diverse perspectives on diversity: multi-disciplinary approaches to taxonomies of individual differences'.
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  • [1]234Nästa

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