| 41. |
- Hall, Hakan, et al.
(författare)
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Potential genetic variants in schizophrenia : A Bayesian analysis
- 2007
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Ingår i: World Journal of Biological Psychiatry. - : Informa UK Limited. - 1562-2975 .- 1814-1412. ; 8:1, s. 12-22
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Tidskriftsartikel (refereegranskat)abstract
- A number of different gene polymorphisms have been found to dispose for the development of schizophrenia. However, no single gene polymorphism is sufficient for the precipitation of schizophrenia. Swedish psychosis patients (n = 103) and control subjects (n = 89) were analyzed for 36 single nucleotide polymorphisms in 30 candidate genes for schizophrenia. Evidence of association was analyzed with Bayesian statistical methods. Variants in the genes coding for dopamine-D-2 receptor, brain-derived neurotrophic factor (BDNF), neuropeptide Y (NPY), neuregulin 1, reelin and synapsin 3 showed association with schizophrenia, although few subjects were found in the minority allele for the two latter variants. The six gene variants, all with suspected connection to schizophrenia, were found to be risk factors when considered in combination, but not separately. The results indicate that the Bayesian statistical method gives additional possibilities in the search for risk factors for schizophrenia or other complex disorders.
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| 42. |
- Haukvik, Unn Kristin, et al.
(författare)
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An exploratory model for G x E interaction on hippocampal volume in schizophrenia; obstetric complications and hypoxia-related genes
- 2010
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Ingår i: Progress in Neuro-Psychopharmacology and Biological Psychiatry. - : Elsevier BV. - 0278-5846 .- 1878-4216. ; 34:7, s. 1259-1265
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Forskningsöversikt (refereegranskat)abstract
- Background Smaller hippocampal volume has repeatedly been reported in schizophrenia patients Obstetric complications (OCs) and single nucleotide polymorphism (SNP) variation in schizophrenia susceptibility genes have independently been related to hippocampal volume We investigated putative independent and interaction effects of severe hypoxia-related OCs and variation in four hypoxia-regulated schizophrenia susceptibility genes (BDNF, DTNBP1, GRM3 and NRG1) on hippocampal volume in schizophrenia patients and healthy controls. Methods Clinical assessment, structural MRI scans, and blood samples for genotyping of 32 SNPs were obtained from 54 schizophrenia patients and 53 control subjects Information on obstetric complications was collected from original birth records Results Severe OCs were related to hippocampal volume in both patients with schizophrenia and healthy control subjects Of the 32 SNPs studied, effects of severe OCs on hippocampal volume were associated with allele variation in GRM3 rs13242038, but the interaction effect was not specific for schizophrenia. SNP variation in any of the four investigated genes alone did not significantly affect hippocampal volume. Conclusions. The findings suggest a gene-environment (G x E) interaction between GRM3 gene variants and severe obstetric complications on hippocampus volume, independent of a diagnosis of schizophrenia Due to the modest sample size, the results must be considered preliminary and require replication in independent samples. (C) 2010 Elsevier Inc All rights reserved
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| 43. |
- Haukvik, Unn Kristin, et al.
(författare)
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Cerebral cortical thickness and a history of obstetric complications in schizophrenia
- 2009
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Ingår i: Journal of Psychiatric Research. - : Elsevier BV. - 1879-1379 .- 0022-3956. ; 43:16, s. 1287-1293
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Magnetic resonance imaging (MRI) studies have demonstrated that patients with schizophrenia have thinner brain cortices compared with healthy control subjects. Neurodevelopment is vulnerable to obstetric complications (OCs) such as hypoxia and birth trauma, factors that are also related to increased risk of developing schizophrenia. With the hypothesis that OCs might explain the thinner cortices found in schizophrenia, we studied patients with schizophrenia and healthy controls subjects for association between number and severity of OCs and variation in cortical thickness. Methods: MRI scans of 54 adults with schizophrenia or schizoaffective disorder and 54 healthy controls were acquired at Karolinska Institutet, Stockholm, Sweden. Measures of brain cortical thickness were obtained using automated computer processing (FreeSurfer). OCs were assessed from obstetric records and scored blindly according to the McNeil-Sjostrom scale. At numerous cortical locations, putative effects of OCs on cortical thickness variation were tested for each trimester, for labour, for composite OC scores, severe OC scores, and hypoxia scores among patients and controls separately. Results: Number and severity of OCs varied among both patient and control subjects but were not associated with cortical thickness in either of the groups. Patients demonstrated thinner brain cortices but there were no significant differences in number and severity of OC scores across groups. Conclusion: In the present study, number and severity of obstetric complications were not associated with brain cortical thickness, in patients with schizophrenia or in healthy control subjects. The thinner brain cortices found in patients with schizophrenia were not explained by a history of OCs. (C) 2009 Elsevier Ltd. All rights reserved.
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| 44. |
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| 45. |
- Haukvik, Unn Kristin, et al.
(författare)
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No effect of obstetric complications on basal ganglia volumes in schizophrenia
- 2010
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Ingår i: Progress in Neuro-Psychopharmacology and Biological Psychiatry. - : Elsevier BV. - 0278-5846 .- 1878-4216. ; 34:4, s. 619-623
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Forskningsöversikt (refereegranskat)abstract
- Background: Heterogeneous findings have been reported in studies of basal ganglia volumes in schizophrenia patients as compared to healthy controls. The basal ganglia contain dopamine receptors that are known to be involved in schizophrenia pathology and to be vulnerable to pre- and perinatal hypoxic insults. Altered volumes of other brain structures (e.g. hippocampus and lateral ventricles) have been reported in schizophrenia patients with a history of obstetric complications (005). This is the first study to explore if there is a relationship between OCs and basal ganglia volume in schizophrenia. Methods: Thorough clinical investigation (including information on medication) of 54 schizophrenia patients and 54 healthy control subjects was undertaken. MR images were obtained on a 1.5T scanner, and volumes of nucleus caudatus, globus pallidum, putamen, and nucleus accumbens were quantified automatically. Information on OCs was blindly collected from original birth records. Results: Unadjusted estimates demonstrated a relationship between increasing number of OCs and larger volume of nucleus accumbens in schizophrenia patients and healthy controls. No statistically significant relationships were found between OCs and the basal ganglia volumes when controlled for intracranial volume, age, and multiple comparisons. There were no effects of typical versus atypical medication on the basal ganglia volumes. The patients with schizophrenia had larger globus pallidum volumes as compared to healthy controls, but there were no case-control differences for accumbens, putamen, or caudate volumes. Conclusion: The present results do not support the hypothesis that OCs are related to alterations in basal ganglia volume in chronic schizophrenia. (C) 2010 Elsevier Inc. All rights reserved.
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| 46. |
- Henriksson, Karin, et al.
(författare)
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A morphometric magnetic resonance method for measuring cranial, facial and brain characteristics for application to schizophrenia : Part 1
- 2006
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Ingår i: Psychiatry Research. - : Elsevier BV. - 0925-4927 .- 1872-7506 .- 0165-1781. ; 147:2-3, s. 173-186
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Tidskriftsartikel (refereegranskat)abstract
- Serious psychopathology in adulthood may be associated with disturbed foetal brain development, which potentially shows lingering "fossil marks" in the cranial and facial regions. Several methods exist for assessing external craniofacial and internal brain distances but, to our knowledge, no method yet provides simultaneous measurement of cranial, facial and brain dimensions in live subjects. In this article we describe a method to identify landmarks on magnetic resonance images (MRI) for simultaneous measurement of cranial, facial and brain characteristics potentially associated with psychosis. To test the method itself, 30 patients with chronic schizophrenia and 31 healthy comparison subjects, mean age 41 years, were randomly selected from a larger cohort recruited at the Karolinska Hospital, Sweden. Participants were investigated with MRI, and 60 landmarks in the cranial, facial and brain regions were identified in the images. An independent anthropometric examination measured external craniofacial characteristics for study in relation to measurements produced through MRI. High inter-scorer and re-test reliabilities were obtained for two independent scorers of the landmarks in the MR images. Measurements of potentially comparable craniofacial distances showed high alignment with an established anthropometric method. This new method can provide simultaneous investigation of multiple aspects of cranial, facial and brain morphology in MR images originally collected for other purposes. In a second article we will use this method to compare 3D craniofacial measurements and shape between schizophrenia patients and healthy controls.
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| 47. |
- Henriksson, Karin, et al.
(författare)
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A pilot study of facial, cranial and brain MRI morphometry in men with schizophrenia: Part 2.
- 2006
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Ingår i: Psychiatry Research. - : Elsevier BV. - 1872-7123 .- 0925-4927 .- 0165-1781. ; 147:2-3, s. 187-195
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Tidskriftsartikel (refereegranskat)abstract
- This pilot study applies a new 3D morphometric MR method to test the hypothesis that men with schizophrenia (vs. controls) have deviant facial shapes and landmark relations in cranio/facialibrain (CFB) regions. This constitutes Part 2 of paired articles in this issue of Psychiatry Research: Neuroimaging, in which Part 1 presents the new method in detail. MRI coordinates from CFB landmarks of 23 patients and 15 controls were identified and then aligned with the Procrustes model, leaving shape as the only unitless geometrical information. Men with schizophrenia had significantly longer mid- and lower-facial heights, and greater lower (left) facial depth, with a tendency toward rotation along the facial midline. This supports findings from earlier anthropometric and 3D studies of the "exterior" (face). In contrast, none of the patient-control differences for the new "interior" (cranial-brain) distances reached statistical significance. These results need to be retested on a larger sample of both sexes. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
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| 48. |
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| 49. |
- Hilland, Eva, et al.
(författare)
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Aberrant default mode connectivity in adolescents with early-onset psychosis : A resting state fMRI study
- 2022
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Ingår i: NeuroImage. - : Elsevier. - 2213-1582. ; 33
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal default mode network (DMN) connectivity has been found in schizophrenia and other psychotic disorders. However, there are limited studies on early onset psychosis (EOP), and their results show lack of agreement. Here, we investigated within-network DMN connectivity in EOP compared to healthy controls (HC), and its relationship to clinical characteristics. A sample of 68 adolescent patients with EOP (mean age 16.53 +/- 1.12 [SD] years, females 66%) and 95 HC (mean age 16.24 +/- 1.50 [SD], females 60%) from two Scandinavian cohorts underwent resting state functional magnetic resonance imaging (rsfMRI). A group independent component analysis (ICA) was performed to identify the DMN across all participants. Dual regression was used to estimate spatial maps reflecting each participant's DMN network, which were compared between EOP and HC using voxel-wise general linear models and permutation-based analyses. Subgroup analyses were performed within the patient group, to explore associations between diagnostic subcategories and current use of psychotropic medication in relation to connectivity strength. The analysis revealed significantly reduced DMN connectivity in EOP compared to HC in the posterior cingulate cortex, precuneus, fusiform cortex, putamen, pallidum, amygdala, and insula. The subgroup analysis in the EOP group showed strongest deviations for affective psychosis, followed by other psychotic disorders and schizophrenia. There was no association between DMN connectivity strength and the current use of psychotropic medication. In conclusion, the findings demonstrate weaker DMN connectivity in adolescent patients with EOP compared to healthy peers, and differential effects across diagnostic subcategories, which may inform our understanding of underlying disease mechanisms in EOP.
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| 50. |
- Hult, Roger, 1969-
(författare)
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Segmentation and Visualisation of Human Brain Structures
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis the focus is mainly on the development of segmentation techniques for human brain structures and of the visualisation of such structures. The images of the brain are both anatomical images (magnet resonance imaging (MRI) and autoradigraphy) and functional images that show blood flow (functional magnetic imaging (fMRI), positron emission tomography (PET), and single photon emission tomograpy (SPECT)). When working with anatomical images, the structures segmented are visible as different parts of the brain, e.g. the brain cortex, the hippocampus, or the amygdala. In functional images, the activity or the blood flow that be seen.Grey-level morphology methods are used in the segmentations to make tissue types in the images more homogenous and minimise difficulties with connections to outside tissue. A method for automatic histogram thresholding is also used. Furthermore, there are binary operations such as logic operation between masks and binary morphology operations.The visualisation of the segmented structures uses either surface rendering or volume rendering. For the visualisation of thin structures, surface rendering is the better choice since otherwise some voxels might be missed. It is possible to display activation from a functional image on the surface of a segmented cortex. A new method for autoradiographic images has been developed, which integrates registration, background compensation, and automatic thresholding to getfaster and more realible results than the standard techniques give.
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