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Stauffer EM, Bethlehem RAI, Warrier V, Murray GK, Romero-Garcia R, Seidlitz J, Bullmore ET. Grey and white matter microstructure is associated with polygenic risk for schizophrenia. Mol Psychiatry 2021; 26:7709-7718. [PMID: 34462574 PMCID: PMC8872982 DOI: 10.1038/s41380-021-01260-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/26/2021] [Accepted: 07/30/2021] [Indexed: 02/07/2023]
Abstract
Recent discovery of approximately 270 common genetic variants associated with schizophrenia has enabled polygenic risk scores (PRS) to be measured in the population. We hypothesized that normal variation in PRS would be associated with magnetic resonance imaging (MRI) phenotypes of brain morphometry and tissue composition. We used the largest extant genome-wide association dataset (N = 69,369 cases and N = 236,642 healthy controls) to measure PRS for schizophrenia in a large sample of adults from the UK Biobank (Nmax = 29,878) who had multiple micro- and macrostructural MRI metrics measured at each of 180 cortical areas, seven subcortical structures, and 15 major white matter tracts. Linear mixed-effect models were used to investigate associations between PRS and brain structure at global and regional scales, controlled for multiple comparisons. Polygenic risk was significantly associated with reduced neurite density index (NDI) at global brain scale, at 149 cortical regions, five subcortical structures, and 14 white matter tracts. Other microstructural parameters, e.g., fractional anisotropy, that were correlated with NDI were also significantly associated with PRS. Genetic effects on multiple MRI phenotypes were co-located in temporal, cingulate, and prefrontal cortical areas, insula, and hippocampus. Post-hoc bidirectional Mendelian randomization analyses provided preliminary evidence in support of a causal relationship between (reduced) thalamic NDI and (increased) risk of schizophrenia. Risk-related reduction in NDI is plausibly indicative of reduced density of myelinated axons and dendritic arborization in large-scale cortico-subcortical networks. Cortical, subcortical, and white matter microstructure may be linked to the genetic mechanisms of schizophrenia.
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Affiliation(s)
- Eva-Maria Stauffer
- Department of Psychiatry, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
| | - Richard A I Bethlehem
- Department of Psychiatry, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Varun Warrier
- Department of Psychiatry, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Graham K Murray
- Department of Psychiatry, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
- Cambridgeshire and Peterborough NHS Trust, Elizabeth House, Fulbourn Hospital, Cambridge, UK
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia
| | - Rafael Romero-Garcia
- Department of Psychiatry, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Jakob Seidlitz
- Department of Child and Adolescent Psychiatry and Behavioral Science, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | - Edward T Bullmore
- Department of Psychiatry, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
- Cambridgeshire and Peterborough NHS Trust, Elizabeth House, Fulbourn Hospital, Cambridge, UK
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Kyriakopoulos M, Bargiotas T, Barker GJ, Frangou S. Diffusion tensor imaging in schizophrenia. Eur Psychiatry 2020; 23:255-73. [DOI: 10.1016/j.eurpsy.2007.12.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 11/19/2007] [Accepted: 12/03/2007] [Indexed: 12/12/2022] Open
Abstract
AbstractDiffusion tensor imaging (DTI) is a magnetic resonance imaging technique that is increasingly being used for the non-invasive evaluation of brain white matter abnormalities. In this review, we discuss the basic principles of DTI, its roots and the contribution of European centres in its development, and we review the findings from DTI studies in schizophrenia. We searched EMBASE, PubMed, PsychInfo, and Medline from February 1998 to December 2006 using as keywords ‘schizophrenia’, ‘diffusion’, ‘tensor’, and ‘DTI’. Forty studies fulfilling the inclusion criteria of this review were included and systematically reviewed. White matter abnormalities in many diverse brain regions were identified in schizophrenia. Although the findings are not completely consistent, frontal and temporal white matter seems to be more commonly affected. Limitations and future directions of this method are discussed.
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Jo YT, Lee J, Joo SW, Kim H, Shon SH, Yoon W, Hong Y. Additive Burden of Abnormal Diffusivity in the Brain with Schizophrenia: A Diffusion Tensor Imaging Study with Public Neuroimaging Data. Psychiatry Investig 2020; 17:341-349. [PMID: 32252513 PMCID: PMC7176571 DOI: 10.30773/pi.2019.0200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 01/20/2020] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Diffusion tensor imaging has been extensively applied to schizophrenia research. In this study, we counted the number of abnormal brain regions with altered diffusion measures in patients with schizophrenia to enumerate the burden of abnormal diffusivity in the brain. METHODS The public neuroimaging data of the COBRE project from SchizConnect were used for the study. The studied dataset consisted of data from 57 patients with schizophrenia and 71 healthy participants. FreeSurfer and FSL were applied for image processing and analysis. After verifying 161 regions of interest (ROIs), mean diffusion measures in every single ROI in all study participants were measured and normalized into Z-scores. Each ROI was then defined as normal or abnormal on the basis of a cutoff absolute Z-score of 1.96. The number of abnormal ROIs was obtained by each diffusion measure. RESULTS The numbers of ROIs with increased radial diffusivity and increased trace were significantly larger in the patient group than in healthy participants. CONCLUSION Thus, the patient group showed a significant increase in abnormal ROIs, strongly indicating that schizophrenia is not caused by the pathology of a single brain region, but is instead attributable to the additive burden of structural alterations within multiple brain regions.
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Affiliation(s)
- Young Tak Jo
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jungsun Lee
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sung Woo Joo
- Republic of Korea Navy, Donghae, Republic of Korea
| | - Harin Kim
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Seung-Hyun Shon
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Woon Yoon
- Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Youjin Hong
- Department of Psychiatry, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Republic of Korea
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Kim H, Shon SH, Joo SW, Yoon W, Lee JH, Hur JW, Lee J. Gray Matter Microstructural Abnormalities and Working Memory Deficits in Individuals with Schizophrenia. Psychiatry Investig 2019; 16:234-243. [PMID: 30934191 PMCID: PMC6444097 DOI: 10.30773/pi.2018.10.14.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/12/2018] [Accepted: 10/14/2018] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Working memory impairments serve as prognostic factors for patients with schizophrenia. Working memory deficits are mainly associated with gray matter (GM) thickness and volume. We investigated the association between GM diffusivity and working memory in controls and individuals with schizophrenia. METHODS T1 and diffusion tensor images of the brain, working memory task (letter number sequencing) scores, and the demographic data of 90 individuals with schizophrenia and 97 controls were collected from the SchizConnect database. T1 images were parcellated into the 68 GM Regions of Interest (ROI). Axial Diffusivity (AD), Fractional Anisotropy (FA), Radial Diffusivity (RD), and Trace (TR) were calculated for each of the ROIs. RESULTS Compared to the controls, schizophrenia group showed significantly increased AD, RD, and TR in specific regions on the frontal, temporal, and anterior cingulate area. Moreover, working memory was negatively correlated with AD, RD, and TR in the lateral orbitofrontal, superior temporal, inferior temporal, and rostral anterior cingulate area on left hemisphere in the individuals with schizophrenia. CONCLUSION These results demonstrated GM microstructural abnormalities in the frontal, temporal, and anterior cingulate regions of individuals with schizophrenia. Furthermore, these regional GM microstructural abnormalities suggest a neuropathological basis for the working memory deficits observed clinically in individuals with schizophrenia.
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Affiliation(s)
- HyunJung Kim
- Department of Clinical & Counseling Psychology, Graduate School of Psychological Service, Chung-Ang University, Seoul, Republic of Korea
| | - Seung-Hyun Shon
- Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Sung Woo Joo
- Republic of Korea Marine Corps Education and Training Center, Pohang, Republic of Korea
| | - Woon Yoon
- Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Jang-Han Lee
- Department of Psychology, Chung-Ang University, Seoul, Republic of Korea
| | - Ji-Won Hur
- Department of Psychology, Chung-Ang University, Seoul, Republic of Korea
| | - JungSun Lee
- Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
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Seitz J, Rathi Y, Lyall A, Pasternak O, Del Re EC, Niznikiewicz M, Nestor P, Seidman LJ, Petryshen TL, Mesholam-Gately RI, Wojcik J, McCarley RW, Shenton ME, Koerte IK, Kubicki M. Alteration of gray matter microstructure in schizophrenia. Brain Imaging Behav 2018; 12:54-63. [PMID: 28102528 PMCID: PMC5517358 DOI: 10.1007/s11682-016-9666-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuroimaging studies demonstrate gray matter (GM) macrostructural abnormalities in patients with schizophrenia (SCZ). While ex-vivo and genetic studies suggest cellular pathology associated with abnormal neurodevelopmental processes in SCZ, few in-vivo measures have been proposed to target microstructural GM organization. Here, we use diffusion heterogeneity- to study GM microstructure in SCZ. Structural and diffusion magnetic resonance imaging (MRI) were acquired on a 3 Tesla scanner in 46 patients with SCZ and 37 matched healthy controls (HC). After correction for free water, diffusion heterogeneity as well as commonly used diffusion measures FA and MD and volume were calculated for the four cortical lobes on each hemisphere, and compared between groups. Patients with early course SCZ exhibited higher diffusion heterogeneity in the GM of the frontal lobes compared to controls. Diffusion heterogeneity of the frontal lobe showed excellent discrimination between patients and HC, while none of the commonly used diffusion measures such as FA or MD did. Higher diffusion heterogeneity in the frontal lobes in early SCZ may be due to abnormal brain maturation (migration, pruning) before and during adolescence and early adulthood. Further studies are needed to investigate the role of heterogeneity as potential biomarker for SCZ risk.
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Affiliation(s)
- Johanna Seitz
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Harvard Medical School, Brigham and Women's Hospital, 1249 Boylston St, Boston, MA, 02215, USA
- Department of Child and Adolescent Psychiatry, Psychosomatic and Psychotherapy, Ludwig- Maximilians- Universität, Munich, Germany
| | - Yogesh Rathi
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Harvard Medical School, Brigham and Women's Hospital, 1249 Boylston St, Boston, MA, 02215, USA
| | - Amanda Lyall
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Harvard Medical School, Brigham and Women's Hospital, 1249 Boylston St, Boston, MA, 02215, USA
- Department of Psychiatry, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
| | - Ofer Pasternak
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Harvard Medical School, Brigham and Women's Hospital, 1249 Boylston St, Boston, MA, 02215, USA
- Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, USA
| | - Elisabetta C Del Re
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Harvard Medical School, Brigham and Women's Hospital, 1249 Boylston St, Boston, MA, 02215, USA
- Clinical Neuroscience Division, Laboratory of Neuroscience, VA Boston Healthcare System, Brockton, MA, USA
| | - Margaret Niznikiewicz
- Clinical Neuroscience Division, Laboratory of Neuroscience, VA Boston Healthcare System, Brockton, MA, USA
| | - Paul Nestor
- Clinical Neuroscience Division, Laboratory of Neuroscience, VA Boston Healthcare System, Brockton, MA, USA
- Department of Psychology, University of Massachusetts, Boston, MA, USA
| | - Larry J Seidman
- Department of Psychiatry, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
- Beth Israel Deaconess Medical Center Public Psychiatry Division at the Massachusetts Mental Health Center Harvard Medical School, Boston, MA, USA
| | - Tracey L Petryshen
- Psychiatric and Neurodevelopmental Genetic Unit, Department of Psychiatry and Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Raquelle I Mesholam-Gately
- Beth Israel Deaconess Medical Center Public Psychiatry Division at the Massachusetts Mental Health Center Harvard Medical School, Boston, MA, USA
| | - Joanne Wojcik
- Beth Israel Deaconess Medical Center Public Psychiatry Division at the Massachusetts Mental Health Center Harvard Medical School, Boston, MA, USA
| | - Robert W McCarley
- Clinical Neuroscience Division, Laboratory of Neuroscience, VA Boston Healthcare System, Brockton, MA, USA
- VA Boston Healthcare System, Brockton Division, Brockton, MA, USA
| | - Martha E Shenton
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Harvard Medical School, Brigham and Women's Hospital, 1249 Boylston St, Boston, MA, 02215, USA
- Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, USA
- VA Boston Healthcare System, Brockton Division, Brockton, MA, USA
| | - Inga K Koerte
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Harvard Medical School, Brigham and Women's Hospital, 1249 Boylston St, Boston, MA, 02215, USA
- Department of Child and Adolescent Psychiatry, Psychosomatic and Psychotherapy, Ludwig- Maximilians- Universität, Munich, Germany
| | - Marek Kubicki
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Harvard Medical School, Brigham and Women's Hospital, 1249 Boylston St, Boston, MA, 02215, USA.
- Department of Psychiatry, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA.
- Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, USA.
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Ramirez-Carmona R, Garcia-Lazaro HG, Dominguez-Corrales B, Aguilar-Castañeda E, Roldan-Valadez E. Main effects and interactions of cerebral hemispheres, gender, and age in the calculation of volumes and asymmetries of selected structures of episodic memory. FUNCTIONAL NEUROLOGY 2017; 31:257-264. [PMID: 28072386 DOI: 10.11138/fneur/2016.31.4.257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The aim of this study was to clarify the influence of anatomical (cerebral hemisphere) and demographic (age and gender) variables on the gray matter (GM) volumes and volumetric asymmetry indices (VAIs) of selected structures involved in episodic memory. A cross-sectional study was performed in 47 healthy volunteers. Neuropsychological evaluation revealed similar IQs across the sample. Using SPM-based software, brain segmentation, labeling and volume measurements of the hippocampus, amygdala, middle temporal gyrus and parahippocampal gyrus were performed in each cerebral hemisphere. A two-way between-groups multivariate analysis of covariance (MANCOVA) was applied to GM volumes and VAIs. The main effects of gender and cerebral hemisphere on GM volumes were significant (p < .001), while there was no significant interaction effect between gender and cerebral hemisphere. VAI measurements showed a nonsignificant effect of gender, but a significant influence of age (p = .015). The linear model of interactions and main effects explained 33% of the variance influencing the GM volume quantification. While cerebral hemisphere and gender were found to affect the volumes of brain structures involved in episodic memory, the calculation of VAIs was affected only by age. A comprehensive understanding of the main effects and interaction effects of cerebral hemisphere, gender and age on the volumes and asymmetries of structures related to episodic memory might help neurologists, psychiatrists, geriatricians and other neuroscientists in the study of degenerative brain diseases.
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Park JY, Park HJ, Kim DJ, Kim JJ. Positive symptoms and water diffusivity of the prefrontal and temporal cortices in schizophrenia patients: a pilot study. Psychiatry Res 2014; 224:49-57. [PMID: 25106804 DOI: 10.1016/j.pscychresns.2014.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 07/17/2013] [Accepted: 07/09/2014] [Indexed: 10/25/2022]
Abstract
The development of diffusion tensor imaging (DTI) has provided information about microstructural changes in the brain. Most DTI studies have focused on white matter (WM). Few DTI studies have examined the gray matter (GM) in schizophrenia and, to date, there has been no attempt to identify the relationship between water diffusivity and symptom severity in schizophrenia. The present study aimed to examine microstructural deficits in the dorsal prefrontal cortex (DPFC) and temporal cortex in schizophrenia patients using fractional anisotropy (FA) and water diffusivity. This study also explored the relationship between DTI measurements and psychotic symptoms. Magnetic resonance imaging (MRI) and DTI were used to study 19 schizophrenia patients and 19 healthy controls. Fractional anisotropy, axial diffusivity, radial diffusivity, and regional volumes were measured in the prefrontal cortex and temporal cortex. On DTI measurements, patients showed increased axial and radial diffusivities in the prefrontal cortex and temporal cortex, but they did not demonstrate any difference in fractional anisotropy and regional volumes. Additionally, axial and radial diffusivities were significantly correlated with positive symptom scores in all regions of interest. These results indicate that water diffusivity measurements, including axial and radial diffusivities, can be used to identify microstructural changes in the gray matter in schizophrenia that may be related to symptom severity.
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Affiliation(s)
- Jin Young Park
- Department of Psychiatry, Yonsei University, College of Medicine, Gangnam Severance Hospital, 211 Eonju-ro, Gangnam-gu, Seoul 135-720, Korea; Institute of Behavioral Science in Medicine, Yonsei University, College of Medicine, Seoul, Korea
| | - Hae-Jeong Park
- Department of Radiology, Nuclear Medicine and Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea; BK21 Project for Medical Science, Yonsei University, College of Medicine, Seoul, Korea
| | - Dae-Jin Kim
- Department of Radiology, Nuclear Medicine and Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea; BK21 Project for Medical Science, Yonsei University, College of Medicine, Seoul, Korea
| | - Jae-Jin Kim
- Department of Psychiatry, Yonsei University, College of Medicine, Gangnam Severance Hospital, 211 Eonju-ro, Gangnam-gu, Seoul 135-720, Korea; Institute of Behavioral Science in Medicine, Yonsei University, College of Medicine, Seoul, Korea; BK21 Project for Medical Science, Yonsei University, College of Medicine, Seoul, Korea.
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Impaired empathic abilities and reduced white matter integrity in schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2014; 48:117-23. [PMID: 24099786 DOI: 10.1016/j.pnpbp.2013.09.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/16/2013] [Accepted: 09/27/2013] [Indexed: 11/21/2022]
Abstract
Empathic abilities are impaired in schizophrenia. Although the pathology of schizophrenia is thought to involve disrupted white matter integrity, the relationship between empathic disabilities and altered white matter in the disorder remains unclear. The present study tested associations between empathic disabilities and white matter integrity in order to investigate the neural basis of impaired empathy in schizophrenia. Sixty-nine patients with schizophrenia and 69 age-, gender-, handedness-, education- and IQ level-matched healthy controls underwent diffusion-weighted imaging. Empathic abilities were assessed using the Interpersonal Reactivity Index (IRI). Using tract-based spatial statistics (TBSS), the associations between empathic abilities and white matter fractional anisotropy (FA), a measure of white matter integrity, were examined in the patient group within brain areas that showed a significant FA reduction compared with the controls. The patients with schizophrenia reported lower perspective taking and higher personal distress according to the IRI. The patients showed a significant FA reduction in bilateral deep white matter in the frontal, temporal, parietal and occipital lobes, a large portion of the corpus callosum, and the corona radiata. In schizophrenia patients, fantasy subscales positively correlated with FA in the left inferior fronto-occipital fasciculi and anterior thalamic radiation, and personal distress subscales negatively correlated with FA in the splenium of the corpus callosum. These results suggest that disrupted white matter integrity in these regions constitutes a pathology underpinning specific components of empathic disabilities in schizophrenia, highlighting that different aspects of empathic impairments in the disorder would have, at least partially, distinct neuropathological bases.
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Abnormalities in the fatty acid composition of the postmortem entorhinal cortex of patients with schizophrenia, bipolar disorder, and major depressive disorder. Psychiatry Res 2013; 210:346-50. [PMID: 23731984 DOI: 10.1016/j.psychres.2013.05.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 04/20/2013] [Accepted: 05/07/2013] [Indexed: 11/23/2022]
Abstract
Previous studies of postmortem orbitofrontal cortex have shown abnormalities in levels of n-3 polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA), in individuals with schizophrenia, bipolar disorder, and major depressive disorder (MDD). We have previously measured PUFA levels in the postmortem hippocampus from patients with schizophrenia or bipolar disorder and control subjects; however, we found no significant differences between the groups except for small changes in n-6 PUFAs. Furthermore, our study of the postmortem amygdala showed no significant differences in major PUFAs in individuals with schizophrenia, bipolar disorder, or MDD in comparison with controls. In the present study, we investigated whether there were any changes in PUFAs in the entorhinal cortexes of patients with schizophrenia (n=15), bipolar disorder (n=15), or MDD (n=15) compared with unaffected controls (n=15) matched for characteristics including age and sex. In contrast to previous studies of the orbitofrontal cortex and hippocampus, we found no significant differences in major PUFAs. However, we found a 34.3% decrease in docosapentaenoic acid (DPA) (22:5n-3) in patients with MDD and an 8.7% decrease in docosatetraenoic acid (22:4n-6) in those with schizophrenia, compared with controls. Changes in PUFAs in patients with these psychiatric disorders may be specific to certain brain regions.
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Karnik-Henry MS, Wang L, Barch DM, Harms MP, Campanella C, Csernansky JG. Medial temporal lobe structure and cognition in individuals with schizophrenia and in their non-psychotic siblings. Schizophr Res 2012; 138:128-35. [PMID: 22542243 PMCID: PMC3372633 DOI: 10.1016/j.schres.2012.03.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 03/05/2012] [Accepted: 03/07/2012] [Indexed: 12/15/2022]
Abstract
Medial temporal lobe (MTL) structures play a central role in episodic memory. Prior studies suggest that individuals with schizophrenia have deficits in episodic memory as well as structural abnormalities of the medial temporal lobe (MTL). While correlations have been reported between MTL volume loss and episodic memory deficits in such individuals, it is not clear whether such correlations reflect the influence of the disease state or of underlying genetic influences that might contribute to risk. We used high resolution magnetic resonance imaging and probabilistic algorithms for image analysis to determine whether MTL structure, episodic memory performance and the relationship between the two differed among groups of 47 healthy control subjects, 50 control siblings, 39 schizophrenia subjects, and 33 siblings of schizophrenia subjects. High-dimensional large deformation brain mapping was used to obtain volume measures of the hippocampus. Cortical distance mapping was used to obtain volume and thickness measures of the parahippocampal gyrus (PHG) and its substructures: the entorhinal cortex (ERC), the perirhinal cortex (PRC), and the parahippocampal cortex (PHC). Neuropsychological data was used to establish an episodic memory domain score for each subject. Both schizophrenia subjects and their siblings displayed abnormalities in episodic memory performance. Siblings of individuals with schizophrenia, and to a lesser extent, individuals with schizophrenia themselves, displayed abnormalities in measures of MTL structure (volume loss or cortical thinning) as compared to control groups. Further, we observed correlations between structural measures and memory performance in both schizophrenia subjects and their siblings, but not in their respective control groups. These findings suggest that disease-specific genetic factors present in both patients and their relatives may be responsible for correlated abnormalities of MTL structure and memory impairment. The observed attenuated effect of such factors on MTL structure in individuals with schizophrenia may be due to non-genetic influences related to the development and progression of the disease on global brain structure and cognitive processing.
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Affiliation(s)
- Meghana S. Karnik-Henry
- Department of Psychology, Green Mountain College,Corresponding Author: Meghana S. Karnik-Henry, 1 Brennan Circle, Poultney, VT 05764,
| | - Lei Wang
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL
| | - Deanna M. Barch
- Department of Psychology, Washington University, St. Louis, MO,Department of Psychiatry, Washington University School of Medicine, St. Louis, MO
| | - Michael P. Harms
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO
| | | | - John G. Csernansky
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL
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11
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Jose SP, Sharma E, Narayanaswamy JC, Rajendran V, Kalmady SV, Rao NP, Venkatasubramanian G, Gangadhar BN. Entorhinal Cortex Volume in Antipsychotic-naïve Schizophrenia. Indian J Psychol Med 2012; 34:164-9. [PMID: 23162194 PMCID: PMC3498781 DOI: 10.4103/0253-7176.101787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Entorhinal cortex (ERC), a multimodal sensory relay station for the hippocampus, is critically involved in learning, emotion, and novelty detection. One of the pathogenetic mechanistic bases in schizophrenia is proposed to involve aberrant information processing in the ERC. Several studies have looked at cytoarchitectural and morphometric changes in the ERC, but results have been inconsistent possibly due to the potential confounding effects of antipsychotic treatment. MATERIALS AND METHODS In this study, we have examined the entorhinal cortex volume in antipsychotic-naïve schizophrenia patients (n=40; M:F=22:18) in comparison with age, sex, and handedness, matched (as a group) with healthy subjects (n=42; M:F=25:17) using a valid method. 3-Tesla MR images with 1-mm sections were used and the data was analyzed using the SPSS software. RESULTS Female schizophrenia patients (1.25±0.22 mL) showed significant volume deficit in the right ERC in comparison with female healthy controls (1.45±0.34 mL) (F=4.9; P=0.03), after controlling for the potential confounding effects of intracranial volume. However, male patients did not differ from male controls. The left ERC volume did not differ between patients and controls. CONCLUSIONS Consistent with the findings of a few earlier studies we found a reduction in the right ERC volume in patients. However, this was limited to women. Contextually, our study finding supports the role for ERC deficit in schizophrenia pathogenesis - perhaps mediated through aberrant novelty detection. Sex-differential observation of ERC volume deficit in schizophrenia needs further studies.
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Affiliation(s)
- Sam P. Jose
- Department of Psychiatry, The Schizophrenia Clinic, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
| | - Eesha Sharma
- Department of Psychiatry, The Schizophrenia Clinic, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
- Translational Psychiatry Laboratory, Cognitive Neurobiology Division, Neurobiology Research Center, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
| | - Janardhanan C. Narayanaswamy
- Department of Psychiatry, The Schizophrenia Clinic, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
- Translational Psychiatry Laboratory, Cognitive Neurobiology Division, Neurobiology Research Center, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
| | - Vishnurajan Rajendran
- Translational Psychiatry Laboratory, Cognitive Neurobiology Division, Neurobiology Research Center, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
| | - Sunil V. Kalmady
- Department of Psychiatry, The Schizophrenia Clinic, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
- Translational Psychiatry Laboratory, Cognitive Neurobiology Division, Neurobiology Research Center, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
| | - Naren P. Rao
- Department of Psychiatry, The Schizophrenia Clinic, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
- Translational Psychiatry Laboratory, Cognitive Neurobiology Division, Neurobiology Research Center, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
| | - Ganesan Venkatasubramanian
- Department of Psychiatry, The Schizophrenia Clinic, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
- Translational Psychiatry Laboratory, Cognitive Neurobiology Division, Neurobiology Research Center, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
| | - Bangalore N. Gangadhar
- Department of Psychiatry, The Schizophrenia Clinic, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
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12
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Cheung V, Chiu CPY, Law CW, Cheung C, Hui CLM, Chan KKS, Sham PC, Deng MY, Tai KS, Khong PL, McAlonan GM, Chua SE, Chen E. Positive symptoms and white matter microstructure in never-medicated first episode schizophrenia. Psychol Med 2011; 41:1709-1719. [PMID: 20809999 DOI: 10.1017/s003329171000156x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND We investigated cerebral structural connectivity and its relationship to symptoms in never-medicated individuals with first-onset schizophrenia using diffusion tensor imaging (DTI). METHOD We recruited subjects with first episode DSM-IV schizophrenia who had never been exposed to antipsychotic medication (n=34) and age-matched healthy volunteers (n=32). All subjects received DTI and structural magnetic resonance imaging scans. Patients' symptoms were assessed on the Positive and Negative Syndrome Scale. Voxel-based analysis was performed to investigate brain regions where fractional anisotropy (FA) values significantly correlated with symptom scores. RESULTS In patients with first-episode schizophrenia, positive symptoms correlated positively with FA scores in white matter associated with the right frontal lobe, left anterior cingulate gyrus, left superior temporal gyrus, right middle temporal gyrus, right middle cingulate gyrus, and left cuneus. Importantly, FA in each of these regions was lower in patients than controls, but patients with more positive symptoms had FA values closer to controls. We found no significant correlations between FA and negative symptoms. CONCLUSIONS The newly-diagnosed, neuroleptic-naive patients had lower FA scores in the brain compared with controls. There was positive correlation between FA scores and positive symptoms scores in frontotemporal tracts, including left fronto-occipital fasciculus and left inferior longitudinal fasciculus. This implies that white matter dysintegrity is already present in the pre-treatment phase and that FA is likely to decrease after clinical treatment or symptom remission.
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Affiliation(s)
- V Cheung
- Department of Psychiatry, University of Hong Kong, Pokfulam, SAR China
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13
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Waters-Metenier SL, Toulopoulou T. Putative diffusion tensor neuroimaging endophenotypes in schizophrenia: a review of the early evidence. FUTURE NEUROLOGY 2011. [DOI: 10.2217/fnl.11.16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although schizophrenia has a high heritability, the genetic effects conferring diathesis to schizophrenia are thought to be complex and underlain by multifactorial polygenic inheritance. ‘Endophenotypes’, or ‘intermediate phenotypes’, are narrowed constructs of genetic risk that are assumed to be more proximal to the gene effects in the disease pathway than clinical phenotypes. A current aim in schizophrenia research is to identify promising putative endophenotypes for use in molecular genetics studies. Recently, much of the focus has been on neurocognitive, conventional T1-weighted structural MRI, functional MRI and electrophysiological endophenotypes. Diffusion tensor imaging has emerged as another important structural neuroimaging modality in the aim to identify abnormalities in brain connectivity and diffusivity in schizophrenia, and abnormalities detected via this method may be promising candidate endophenotypes. In this article, we present the first comprehensive review of the early evidence that qualifies diffusion tensor abnormalities as potentially appropriate endophenotypes of schizophrenia.
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Affiliation(s)
- Sheena Lindsey Waters-Metenier
- Department of Psychosis Studies, King’s College London, King’s Health Partners, Institute of Psychiatry, London SE5 8AF, UK
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14
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Müller DJ, Likhodi O, Heinz A. Neural markers of genetic vulnerability to drug addiction. Curr Top Behav Neurosci 2011; 3:277-99. [PMID: 21161757 DOI: 10.1007/7854_2009_25] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
This chapter will summarize genetics findings derived from various strategies and highlight important neural markers (or correlates) in some specific and extensively studied genes. Most studies highlighted here focus on alcohol and nicotine dependence (AD and ND, respectively). AD and ND are among the most prevalent addictive disorders worldwide, are among the best studied, and are also associated globally with the largest socioeconomic impact.We describe different mechanisms through which genes can have an impact on the addictive behaviors, distinguishing between the genes that inscribe the proteins affecting the metabolism of the addictive substance (e.g., ADH/ALDH for alcohol or CYP2A6 for nicotine) and genes that code for the brain transmitter systems, such as genes involved in cerebral neurotransmission thought to be involved in addiction (e.g., brain reward system, mood regulation, opioid system). Strategies include linkage analyses, association studies, whole genome association studies as well as intermediate/endophenotype studies. Moreover, some important findings derived from animal studies and from neuroimaging studies are highlighted. In conclusion, we provide the reader with an overview of most important studies related to AD and ND and give an outlook how these findings may become useful and beneficial in the future.
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Affiliation(s)
- Daniel J Müller
- Department of Psychiatry, Charité University Medicine, Campus Charité Mitte, Schumannstrasse, Berlin, Germany
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15
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Abstract
The neurodegenerative aspect of schizophrenia presupposes gene-environmental interactions involving chromosomal abnormalities and obstetric/perinatal complications that culminate in predispositions that impart a particular vulnerability for drastic and unpredictable precipitating factors, such as stress or chemical agents. The notion of a neurodevelopmental progression to the disease state implies that early developmental insults, with neurodegenerative proclivities, evolve into structural brain abnormalities involving specific regional circuits and neurohumoral agents. This neurophysiological orchestration is expressed in the dysfunctionality observed in premorbid signs and symptoms arising in the eventual diagnosis, as well as the neurobehavioral deficits reported from animal models of the disorder. The relative contributions of perinatal insults, neonatal ventral hippocampus lesion, prenatal methylazoxymethanol acetate and early traumatic experience, as well as epigenetic contributions, are discussed from a neurodegenerative view of the essential neuropathology. It is implied that these considerations of factors that exert disruptive influences upon brain development, or normal aging, operationalize the central hub of developmental neuropathology around which the disease process may gain momentum. Nonetheless, the status of neurodegeneration in schizophrenia is somewhat tenuous and it is possible that brain imaging studies on animal models of the disorder, which may describe progressive alterations to cortical, limbic and ventricular structures similar to those of schizophrenic patients, are necessary to resolve the issue.
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Affiliation(s)
- Trevor Archer
- University of Gothenburg, Department of Psychology, Box 500, SE-40530, Gothenburg, Sweden.
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Abstract
Neuroimaging studies have found evidence of altered brain structure and function in schizophrenia, but have had complex findings regarding the localization of abnormality. We applied multimodal imaging (voxel-based morphometry (VBM), functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) combined with tractography) to 32 chronic schizophrenic patients and matched healthy controls. At a conservative threshold of P=0.01 corrected, structural and functional imaging revealed overlapping regions of abnormality in the medial frontal cortex. DTI found that white matter abnormality predominated in the anterior corpus callosum, and analysis of the anatomical connectivity of representative seed regions again implicated fibres projecting to the medial frontal cortex. There was also evidence of convergent abnormality in the dorsolateral prefrontal cortex, although here the laterality was less consistent across techniques. The medial frontal region identified by these three imaging techniques corresponds to the anterior midline node of the default mode network, a brain system which is believed to support internally directed thought, a state of watchfulness, and/or the maintenance of one's sense of self, and which is of considerable current interest in neuropsychiatric disorders.
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Schultz CC, Koch K, Wagner G, Roebel M, Schachtzabel C, Nenadic I, Albrecht C, Reichenbach JR, Sauer H, Schlösser RGM. Psychopathological correlates of the entorhinal cortical shape in schizophrenia. Eur Arch Psychiatry Clin Neurosci 2010; 260:351-8. [PMID: 19898735 DOI: 10.1007/s00406-009-0083-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2009] [Accepted: 10/21/2009] [Indexed: 10/20/2022]
Abstract
Animal experiments have shown that early developmental lesions of the entorhinal cortex lead, after a prolonged interval, to an enhanced mesolimbic dopamine release and an increased locomotor activity in rats. Hence, disturbed shape of the entorhinal cortex might indicate maturational abnormalities relevant for psychotic symptoms in schizophrenia. We used an automated surface-based MRI method to perform a region of interest analysis of entorhinal cortical surface area, folding and thickness in 59 patients with schizophrenia and 59 healthy controls. We postulated the entorhinal cortical surface area, folding index, and thickness to be significantly smaller in patients with schizophrenia. Additionally, we expected the complexity of the entorhinal cortical shape to be associated with psychotic symptoms in schizophrenia. Our ROI analysis showed a significant thinner left entorhinal cortex. In addition, our data demonstrate a positive correlation between left entorhinal cortical surface area and folding index and severity of psychotic symptoms. In conclusion, we present new evidence for the involvement of the entorhinal cortex in the pathogenesis of schizophrenia. As cortical folding is a stable neuroanatomical parameter terminated in early neonatal stages, our data give reason to assume that the vulnerability to develop psychotic symptoms might be manifest at an early level of brain maturation.
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Affiliation(s)
- C Christoph Schultz
- Department of Psychiatry and Psychotherapy, Friedrich-Schiller-University Jena, Jena, Germany.
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18
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Schultz CC, Koch K, Wagner G, Roebel M, Nenadic I, Schachtzabel C, Reichenbach JR, Sauer H, Schlösser RGM. Complex pattern of cortical thinning in schizophrenia: results from an automated surface based analysis of cortical thickness. Psychiatry Res 2010; 182:134-40. [PMID: 20418074 DOI: 10.1016/j.pscychresns.2010.01.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2009] [Revised: 01/12/2010] [Accepted: 01/14/2010] [Indexed: 11/15/2022]
Abstract
A considerable body of evidence from structural brain imaging studies suggests that patients with schizophrenia have significant alterations of gray matter density. Additionally, recently developed surface-based analysis approaches demonstrate reduced cortical thickness in patients with schizophrenia. However, the number of studies employing this relatively new method is still limited. Specifically, little is known about changes in cortical thickness in schizophrenia patients whose duration of illness is relatively short. Therefore, the present study sought to examine cortical thickness in a large sample of patients with adult onset schizophrenia and an average duration of illness of 4.4 years, using an automated analysis method over the entire cortex. A significantly decreased cortical thickness in prefrontal and temporolimbic regions as well as parieto-occipital cortical areas was hypothesized. A sample of 58 patients with schizophrenia and 58 age- and sex-matched healthy controls was investigated using high-resolution magnetic resonance imaging (MRI) and an automated algorithm for extraction of the cortical surface in order to assess local cortical thinning across the entire cerebrum. Significant reduction of cortical thickness in schizophrenia was found in a spatially complex pattern of focal anatomical regions. This pattern comprised the dorsolateral prefrontal cortex as well as the medial prefrontal cortex, lateral temporal cortices, left entorhinal cortex, posterior cingulate cortex, precuneus and lingual cortex, bilaterally. A complex fronto-temporo-parietal pattern of reduced cortical thickness in schizophrenia was observed. This pattern is consistent with a disruption of neurofunctional networks previously implicated in the pathophysiology of schizophrenia.
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Affiliation(s)
- C Christoph Schultz
- Department of Psychiatry and Psychotherapy, Friedrich-Schiller-University Jena, Philosophenweg 3, Jena, Germany.
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Kumazawa S, Yoshiura T, Honda H, Toyofuku F, Higashida Y. Partial volume estimation and segmentation of brain tissue based on diffusion tensor MRI. Med Phys 2010; 37:1482-90. [DOI: 10.1118/1.3355886] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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20
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Cao Q, Sun L, Gong G, Lv Y, Cao X, Shuai L, Zhu C, Zang Y, Wang Y. The macrostructural and microstructural abnormalities of corpus callosum in children with attention deficit/hyperactivity disorder: A combined morphometric and diffusion tensor MRI study. Brain Res 2010; 1310:172-80. [DOI: 10.1016/j.brainres.2009.10.031] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 10/11/2009] [Accepted: 10/14/2009] [Indexed: 10/20/2022]
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Association between myelin basic protein expression and left entorhinal cortex pre-alpha cell layer disorganization in schizophrenia. Brain Res 2009; 1301:126-34. [DOI: 10.1016/j.brainres.2009.09.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 09/02/2009] [Accepted: 09/03/2009] [Indexed: 11/19/2022]
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Abstract
OBJECTIVES Since the development of diffusion tensor imaging (DTI) nearly a decade ago, it has been extensively applied to a number of different psychiatric disorders. Its rapid assimilation into psychiatric research has stemmed from its unique property to measure the coherence and direction of neuronal fiber tracts. The goal of this article is to provide an overview of DTI and its application to psychiatric disorders. METHODS We performed an extensive literature review of articles using DTI to study psychiatric disorders. To date, most DTI studies have been performed on individuals with schizophrenia. However, recent studies have emerged that evaluate white matter (WM) integrity in major depressive disorder, anxiety disorders, obsessive-compulsive disorder, attention deficit disorder, autism, and personality disorders. RESULTS There is tremendous heterogeneity in the results of DTI studies of patients with psychiatric disorders. In schizophrenia, which currently has more than 50 studies using DTI, brain regions such as the cingulate bundle, corpus callosum, and regions within the frontal and temporal WM have a proportionally larger number of positive findings across the studies. Studies of other psychiatric disorders have findings that overlap with those seen in schizophrenia. CONCLUSIONS There is converging evidence that a number of psychiatric disorders are associated with WM abnormalities. However, the considerable heterogeneity of results, both within and between existing studies, will require future work within and across psychiatric disorders to better delineate the neurobiological underpinnings of these white matter abnormalities.
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23
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Fischl B, Stevens AA, Rajendran N, Yeo BTT, Greve DN, Van Leemput K, Polimeni JR, Kakunoori S, Buckner RL, Pacheco J, Salat DH, Melcher J, Frosch MP, Hyman BT, Grant PE, Rosen BR, van der Kouwe AJW, Wiggins GC, Wald LL, Augustinack JC. Predicting the location of entorhinal cortex from MRI. Neuroimage 2009; 47:8-17. [PMID: 19376238 DOI: 10.1016/j.neuroimage.2009.04.033] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 03/23/2009] [Accepted: 04/07/2009] [Indexed: 11/18/2022] Open
Abstract
Entorhinal cortex (EC) is a medial temporal lobe area critical to memory formation and spatial navigation that is among the earliest parts of the brain affected by Alzheimer's disease (AD). Accurate localization of EC would thus greatly facilitate early detection and diagnosis of AD. In this study, we used ultra-high resolution ex vivo MRI to directly visualize the architectonic features that define EC rostrocaudally and mediolaterally, then applied surface-based registration techniques to quantify the variability of EC with respect to cortical geometry, and made predictions of its location on in vivo scans. The results indicate that EC can be localized quite accurately based on cortical folding patterns, within 3 mm in vivo, a significant step forward in our ability to detect the earliest effects of AD when clinical intervention is most likely to be effective.
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Affiliation(s)
- Bruce Fischl
- Athinoula A Martinos Center, Department of Radiology, MGH, Harvard Medical School, Charlestown, MA 02129, USA.
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24
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Increased diffusivity in superior temporal gyrus in patients with schizophrenia: a Diffusion Tensor Imaging study. Schizophr Res 2009; 108:33-40. [PMID: 19135872 PMCID: PMC2675036 DOI: 10.1016/j.schres.2008.11.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 11/12/2008] [Accepted: 11/15/2008] [Indexed: 11/20/2022]
Abstract
BACKGROUND Superior temporal gyrus (STG) volume reduction is one of the most consistent findings in schizophrenia. The goal of this study was to conduct the first Diffusion Tensor Imaging (DTI) study to investigate altered structural integrity in STG gray and white matter in patients with chronic schizophrenia compared with healthy controls. METHODS Magnetic resonance imaging (MRI) and DTI were acquired in 21 male patients with schizophrenia and 22 age-, handedness-, and parental social economic status-matched male comparison subjects. After manual segmentation of gray and white matter, mean diffusivity and fractional anisotropy were measured within STG. Correlational analyses were also conducted to test possible associations between DTI and clinical measures, including positive and negative symptoms of schizophrenia. RESULTS Compared with controls, patients demonstrated reduced volume, bilaterally, in STG gray matter but not in white matter. For DTI measures, patients showed increased mean diffusivity, bilaterally, in STG gray matter, and in left STG white matter. In addition, mean diffusivity in left STG white matter showed statistically significant correlations with auditory hallucinations and attentional impairments in patients. CONCLUSIONS These findings suggest a disruption of tissue integrity in STG gray and white matter in schizophrenia. In addition, increased water diffusivity in left-side STG, which was associated with auditory hallucinations and attentional impairments, suggests the possibility of a disconnection among auditory/language processing regions in schizophrenia.
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25
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Valenti O, Grace AA. Entorhinal cortex inhibits medial prefrontal cortex and modulates the activity states of electrophysiologically characterized pyramidal neurons in vivo. Cereb Cortex 2008; 19:658-74. [PMID: 18632738 DOI: 10.1093/cercor/bhn114] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The prefrontal cortex receives multiple inputs from the hippocampal complex, which are thought to drive memory-guided behavior. Moreover, dysfunctions of both regions have been repeatedly associated with several psychiatric disorders. Therefore, understanding the interconnections and modulatory interactions between these regions is essential in evaluating their role in behavior and pathology. The effects of entorhinal cortex (EC) stimulation on the activity of identified medial prefrontal cortex (mPFC) pyramidal neurons were examined using single-unit extracellular recordings and sharp-electrode intracellular recordings in anesthetized rats. Single-pulse electrical stimulation of EC induced a powerful inhibition in the majority of mPFC neurons examined during extracellular recording. Intracellular recording showed that EC stimulation evoked a complex synaptic response, in which the greater proportion of neurons exhibited excitatory postsynaptic events and/or a short lasting and a prolonged inhibitory postsynaptic response. Furthermore, stimulation of EC selectively produced an augmentation of the bistable up-down state only in the type 2 regular spiking neurons and in a subclass of nonintrinsic bursting neurons. Taken together, these data suggest that the potent inhibition observed following EC stimulation may mask a direct excitatory response within the mPFC which markedly potentiates the bistable states in a select subpopulation of mPFC pyramidal neurons.
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Affiliation(s)
- Ornella Valenti
- University of Pittsburgh, Department of Neuroscience, Psychiatry and Psychology, Pittsburgh, PA 15260, USA.
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26
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Kalus P, Falkai P, Heinz A. [Structural and functional brain changes in schizophrenic disorders. Indications of early neuronal developmental disturbances?]. DER NERVENARZT 2008; 79:275-87. [PMID: 18264816 DOI: 10.1007/s00115-008-2414-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The neurodevelopmental hypothesis of schizophrenia, which was established 30 years ago and discussed controversially for a long time, postulates that pre- and perinatally acting cerebral noxae cause disturbances of corticogenesis in the developing neuronal fibre systems which are essential for later onset of the disease. During recent years the cerebral alterations of schizophrenic patients could be further characterized as area-, layer-, and cell type-specific changes in temporolimbic and frontal regions leading to specific abnormalities of intrinsic and extrinsic connectivity. Animal models allowed for realistic imitations of these structural lesions and for elucidating their functional consequences concerning transmitter systems and behaviour. With modern neuroimaging techniques microstructural changes and alterations in cerebral activation can be exactly demonstrated and related to the specific psychopathologic features of schizophrenia.
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Affiliation(s)
- P Kalus
- Psychiatrische Universitätsklinik der Charité im St. Hedwig Krankenhaus, Grosse Hamburger Strasse 5-11, 10115 Berlin.
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Cheung V, Cheung C, McAlonan GM, Deng Y, Wong JG, Yip L, Tai KS, Khong PL, Sham P, Chua SE. A diffusion tensor imaging study of structural dysconnectivity in never-medicated, first-episode schizophrenia. Psychol Med 2008; 38:877-885. [PMID: 17949516 DOI: 10.1017/s0033291707001808] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Diffusion tensor imaging (DTI) can be used to investigate cerebral structural connectivity in never-medicated individuals with first-episode schizophrenia. METHOD Subjects with first-episode schizophrenia according to DSM-IV-R who had never been exposed to antipsychotic medication (n=25) and healthy controls (n=26) were recruited. Groups were matched for age, gender, best parental socio-economic status and ethnicity. All subjects underwent DTI and structural magnetic resonance imaging (MRI) scans. Voxel-based analysis was performed to investigate brain regions where fractional anisotropy (FA) values differed significantly between groups. A confirmatory region-of-interest (ROI) analysis of FA scores was performed in which regions were placed blind to group membership. RESULTS In patients, FA values significantly lower than those in healthy controls were located in the left fronto-occipital fasciculus, left inferior longitudinal fasciculus, white matter adjacent to right precuneus, splenium of corpus callosum, right posterior limb of internal capsule, white matter adjacent to right substantia nigra, and left cerebral peduncle. ROI analysis of the corpus callosum confirmed that the patient group had significantly lower mean FA values than the controls in the splenium but not in the genu. The intra-class correlation coefficient (ICC) for independent ROI measurements was 0.90 (genu) and 0.90 (splenium). There were no regions where FA values were significantly higher in the patients than in the healthy controls. CONCLUSIONS Widespread structural dysconnectivity, including the subcortical region, is already present in neuroleptic-naive patients in their first episode of illness.
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Affiliation(s)
- V Cheung
- Department of Psychiatry, The University of Hong Kong, and Queen Mary Hospital, Pokfulam, Hong Kong, S.A.R. China
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Begré S, Kleinlogel H, Kiefer C, Strik W, Dierks T, Federspiel A. White matter anisotropy related to electrophysiology of first episode schizophrenia during NoGo inhibition. Neurobiol Dis 2008; 30:270-80. [PMID: 18356066 DOI: 10.1016/j.nbd.2008.01.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 01/24/2008] [Accepted: 01/30/2008] [Indexed: 10/22/2022] Open
Abstract
Patients with schizophrenia have reduced execution functions and white matter alterations indicating cerebral disconnectivity. Here we investigated the relationship between white matter integrity and event related potentials (ERP) during a continuous performance test (CPT). Anisotropy values were correlated with the brain electrical P300 microstate duration and P300 latency associated to the NoGo- and the Go-stimuli of the CPT in 11 patients with first episode schizophrenia and 11 matched healthy controls. Both groups showed significant positive correlations of the NoGo-microstate duration with the white matter signal in the superior frontal region, the optic radiation, the posterior cingulate, and the inferolateral fascicle. In addition, patients with first episode schizophrenia had significant correlations with the right radiation and the left genu of the corpus callosum, bilateral geniculate, and the left middle and the superior temporal regions. We interpreted these findings as a sign of functional correlates of extended circuits for the active inhibition of a motor response in the visual CPT as compared to controls.
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Affiliation(s)
- Stefan Begré
- University Hospital/Inselspital, Department of General Internal Medicine, Division of Psychosomatic Medicine, Bern, Switzerland
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29
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Nesvåg R, Lawyer G, Varnäs K, Fjell AM, Walhovd KB, Frigessi A, Jönsson EG, Agartz I. Regional thinning of the cerebral cortex in schizophrenia: effects of diagnosis, age and antipsychotic medication. Schizophr Res 2008; 98:16-28. [PMID: 17933495 DOI: 10.1016/j.schres.2007.09.015] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 09/03/2007] [Accepted: 09/12/2007] [Indexed: 11/18/2022]
Abstract
Morphological abnormalities of the cerebral cortex have been reported in a number of MRI-studies in schizophrenia. Uncertainty remains regarding cause, mechanism and progression of the alterations. It has been suggested that antipsychotic medication reduces total gray matter volumes, but results are inconsistent. In the present study differences in regional cortical thickness between 96 patients with a DSM-IV diagnosis of schizophrenia (n=81) or schizoaffective disorder (n=15) and 107 healthy subjects (mean age 42 years, range 17-57 years) were investigated using MRI and computer image analysis. Cortical thickness was estimated as the shortest distance between the gray/white matter border and the pial surface at numerous points across the entire cortical mantle. The influence of age and antipsychotic medication on variation in global and regional cortical thickness was explored. Thinner cortex among patients than controls was found in prefrontal and temporal regions of both hemispheres, while parietal and occipital regions were relatively spared. Some hemispheric specificity was noted, as regions of the prefrontal cortex were more affected in the right hemisphere, and regions of the temporal cortex in the left hemisphere. No significant interaction effect of age and diagnostic group on variation in cortical thickness was demonstrated. Among patients, dose or type of antipsychotic medication did not affect variation in cortical thickness. The results from this hitherto largest study on the topic show that prefrontal and temporal cortical thinning in patients with schizophrenia compared to controls is as pronounced in older as in younger subjects. The lack of significant influence from antipsychotic medication supports that regional cortical thinning is an inherent feature of the neurobiological disease process in schizophrenia.
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Affiliation(s)
- Ragnar Nesvåg
- Department of Psychiatric Research, Diakonhjemmet Hospital, and Institute of Psychiatry, University of Oslo, Norway.
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Nucifora PGP, Verma R, Lee SK, Melhem ER. Diffusion-tensor MR imaging and tractography: exploring brain microstructure and connectivity. Radiology 2007; 245:367-84. [PMID: 17940300 DOI: 10.1148/radiol.2452060445] [Citation(s) in RCA: 214] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diffusion magnetic resonance (MR) imaging is evolving into a potent tool in the examination of the central nervous system. Although it is often used for the detection of acute ischemia, evaluation of directionality in a diffusion measurement can be useful in white matter, which demonstrates strong diffusion anisotropy. Techniques such as diffusion-tensor imaging offer a glimpse into brain microstructure at a scale that is not easily accessible with other modalities, in some cases improving the detection and characterization of white matter abnormalities. Diffusion MR tractography offers an overall view of brain anatomy, including the degree of connectivity between different regions of the brain. However, optimal utilization of the wide range of data provided with directional diffusion MR measurements requires careful attention to acquisition and postprocessing. This article will review the principles of diffusion contrast and anisotropy, as well as clinical applications in psychiatric, developmental, neurodegenerative, neoplastic, demyelinating, and other types of disease.
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Affiliation(s)
- Paolo G P Nucifora
- Department of Radiology, Sections of Neuroradiology and Biomedical Image Analysis, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
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Thermenos HW, Seidman LJ, Poldrack RA, Peace NK, Koch JK, Faraone SV, Tsuang MT. Elaborative verbal encoding and altered anterior parahippocampal activation in adolescents and young adults at genetic risk for schizophrenia using FMRI. Biol Psychiatry 2007; 61:564-74. [PMID: 17276751 DOI: 10.1016/j.biopsych.2006.04.044] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 04/20/2006] [Accepted: 04/21/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND First-degree relatives of persons with schizophrenia are at elevated risk for the illness, demonstrate deficits in verbal memory, and exhibit structural abnormalities in the medial temporal lobe (MTL). We used functional magnetic resonance imaging (fMRI) to assess brain activity in the MTL during novel and repeated word-pair encoding. METHODS Participants were 21 non-psychotic, first-degree relatives of persons with schizophrenia and 26 matched healthy controls (ages 13-28). fMRI signal change was measured using a Siemens 1.5T MR scanner, and data were analyzed using SPM-2. Verbal memory was assessed using the Miller Selfridge (MS) Context Memory test prior to scanning. RESULTS The groups were comparable on demographics, intelligence and post-scan word recognition. Relatives at genetic risk (GR) had significantly more psychopathology than controls and worse performance on the MS test (p < .05). GR participants exhibited greater repetition suppression of activation in the left and right anterior parahippocampus (PHA, in the region of the entorhinal cortex region), after controlling for possible confounders. Controls and GR participants with above-median MS performance showed significantly greater repetition suppression of activation in left inferior frontal gyrus than those scoring below the median. CONCLUSIONS This is the first study to demonstrate an alteration of brain activity in the PHA in persons at GR for schizophrenia.
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Affiliation(s)
- Heidi W Thermenos
- Harvard Medical School, Massachusetts Mental Health Center in the Division of Public Psychiatry, Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, USA.
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Mitelman SA, Newmark RE, Torosjan Y, Chu KW, Brickman AM, Haznedar MM, Hazlett EA, Tang CY, Shihabuddin L, Buchsbaum MS. White matter fractional anisotropy and outcome in schizophrenia. Schizophr Res 2006; 87:138-59. [PMID: 16854563 DOI: 10.1016/j.schres.2006.06.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 06/03/2006] [Accepted: 06/07/2006] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Disparate white matter fractional anisotropy (FA) findings have been reported in patients with schizophrenia in recent years. This may in part reflect heterogeneity of subjects in the studies, including differences in outcome and severity of the illness. We examined whether there is a relationship between white matter FA and outcome in patients with schizophrenia. METHOD Diffusion-tensor images were obtained in 41 normal subjects and 104 patients with schizophrenia, divided into good-outcome (n=51) and poor-outcome (Kraepelinian; n=53) subtypes based on their ability for self-care. White matter FA and its relationship to regional tissue volumes were evaluated across 40 individual Brodmann's areas using a semi-automated parcellation technique. RESULTS Overall white matter FA was lower in schizophrenia patients than normal subjects, with regional reductions in widespread temporoparietal and selected prefrontal white matter regions. In schizophrenia patients, lower regional white matter FA was associated with lower regional gray matter volumes. In comparison to normal subjects, overall white matter FA was reduced in patients with poor outcomes in both hemispheres, but to a lesser extent and only in the right hemisphere in good-outcome patients. Lower regional FA was associated with larger regional white matter volumes in good-outcome group. CONCLUSIONS Global FA reductions implicate white matter as tissue type in the pathophysiology of schizophrenia. In contrast to poor outcome, good outcome in schizophrenia patients may be associated with less extensive FA reductions, higher FA in regional frontal and cingulate white matter, and correlated increases in regional white matter volumes, particularly in the left hemisphere.
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Affiliation(s)
- Serge A Mitelman
- Department of Psychiatry, Neuroscience-PET Laboratory, Box 1505, Mount Sinai Medical Center, One Gustave L. Levy Place, New York, NY 10029, USA.
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Mitelman SA, Byne W, Kemether EM, Newmark RE, Hazlett EA, Haznedar MM, Buchsbaum MS. Metabolic thalamocortical correlations during a verbal learning task and their comparison with correlations among regional volumes. Brain Res 2006; 1114:125-37. [PMID: 16935269 DOI: 10.1016/j.brainres.2006.07.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 07/01/2006] [Accepted: 07/13/2006] [Indexed: 10/24/2022]
Abstract
Methods based on the analysis of metabolic and volumetric interregional correlations have been used in neuroimaging research, yet metabolic and volumetric interregional correlations for identical regions of interest have never been compared in the same group of subjects. Magnetic resonance and [18F]-fluorodeoxyglucose positron emission tomography brain images were acquired in 59 healthy subject. Correlation matrices for relative glucose metabolic rates during a verbal learning task and for relative gray matter volumes were compiled between the manually traced mediodorsal, centromedian, and pulvinar nuclei of the thalamus and 39 cortical Brodmann's areas. Metabolic correlations between the cortex and these thalamic nuclei followed the known patterns of anatomical connectivity in non-human primates. Intercorrelations of the mediodorsal nucleus were widespread with the prefrontal cortex (9 out of 10 Brodmann's areas in the left hemisphere) and temporal lobe (10 out of 11 Brodmann's areas in the left hemisphere) while the pulvinar correlated only with the parietal and occipital cortical areas. Different correlation patterns were observed for the regional gray matter volumes whereby only the pulvinar yielded extensive cortical intercorrelations, primarily with the occipital, parietal, anterior cingulate, and orbitofrontal areas in the right hemisphere. Metabolic thalamocortical correlations were much more extensive for the mediodorsal and centromedian nuclei whereas structural correlations were more extensive for the pulvinar. Therefore, metabolic and volumetric correlational methods are sensitive to different aspects of interregional relations in the brain and their comparison in the same group of subjects may render complementary and only partially overlapping connectivity information.
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Affiliation(s)
- Serge A Mitelman
- Department of Psychiatry, Neuroscience PET Laboratory, Box 1505, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
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Marenco S, Rawlings R, Rohde GK, Barnett AS, Honea RA, Pierpaoli C, Weinberger DR. Regional distribution of measurement error in diffusion tensor imaging. Psychiatry Res 2006; 147:69-78. [PMID: 16797169 PMCID: PMC1941705 DOI: 10.1016/j.pscychresns.2006.01.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 11/28/2005] [Accepted: 01/02/2006] [Indexed: 11/25/2022]
Abstract
The characterization of measurement error is critical in assessing the significance of diffusion tensor imaging (DTI) findings in longitudinal and cohort studies of psychiatric disorders. We studied 20 healthy volunteers, each one scanned twice (average interval between scans of 51 +/- 46.8 days) with a single shot echo planar DTI technique. Intersession variability for fractional anisotropy (FA) and Trace (D) was represented as absolute variation (standard deviation within subjects: SDw), percent coefficient of variation (CV) and intra-class correlation coefficient (ICC). The values from the two sessions were compared for statistical significance with repeated measures analysis of variance or a non-parametric equivalent of a paired t-test. The results showed good reproducibility for both FA and Trace (CVs below 10% and ICCs at or above 0.70 in most regions of interest) and evidence of systematic global changes in Trace between scans. The regional distribution of reproducibility described here has implications for the interpretation of regional findings and for rigorous pre-processing. The regional distribution of reproducibility measures was different for SDw, CV and ICC. Each one of these measures reveals complementary information that needs to be taken into consideration when performing statistical operations on groups of DT images.
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Affiliation(s)
- Stefano Marenco
- Genes, Cognition and Psychosis Program, Clinical Brain Disorders Branch, IRP, NIMH, Bethesda, MD 20892, USA.
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Federspiel A, Begré S, Kiefer C, Schroth G, Strik WK, Dierks T. Alterations of white matter connectivity in first episode schizophrenia. Neurobiol Dis 2006; 22:702-9. [PMID: 16624566 DOI: 10.1016/j.nbd.2006.01.015] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Revised: 12/12/2005] [Accepted: 01/22/2006] [Indexed: 11/26/2022] Open
Abstract
Cerebral disconnectivity due to white matter alterations in patients with chronic schizophrenia assessed by diffusion tensor imaging has been reported previously. The aim of this preliminary study is to investigate whether cerebral disconnectivity can be detected as early as the first episode of schizophrenia. Intervoxel coherence values were compared by voxel-based t test in 12 patients with first episode schizophrenia and 12 age- and gender-matched control groups. We detected 14 circumscribed significant clusters (P < 0.02), 3 of them with higher, and 11 of them with lower IC values for patients with schizophrenia than for healthy control groups. We interpret these white matter alterations in different regions to be disconnected fiber tracts already present early in schizophrenic disease progression.
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Affiliation(s)
- Andrea Federspiel
- University Hospital of Clinical Psychiatry, Department of Psychiatric Neurophysiology, Berne, Switzerland
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Liu T, Young G, Huang L, Chen NK, Wong STC. 76-space analysis of grey matter diffusivity: methods and applications. Neuroimage 2006; 31:51-65. [PMID: 16434215 DOI: 10.1016/j.neuroimage.2005.11.041] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Revised: 11/14/2005] [Accepted: 11/21/2005] [Indexed: 10/25/2022] Open
Abstract
Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) allow in vivo investigation of molecular motion of tissue water at a microscopic level in cerebral gray matter (GM) and white matter (WM). DWI/DTI measure of water diffusion has been proven to be invaluable for the study of many neurodegenerative diseases (e.g., Alzheimer's disease and Creutzfeldt-Jakob disease) that predominantly involve GM. Thus, quantitative analysis of GM diffusivity is of scientific interest and is promised to have a clinical impact on the investigation of normal brain aging and neuropathology. In this paper, we propose an automated framework for analysis of GM diffusivity in 76 standard anatomic subdivisions of gray matter to facilitate studies of neurodegenerative and other gray matter neurological diseases. The computational framework includes three enabling technologies: (1) automatic parcellation of structural MRI GM into 76 precisely defined neuroanatomic subregions ("76-space"), (2) automated segmentation of GM, WM and CSF based on DTI data, and (3) automatic measurement of the average apparent diffusion coefficient (ADC) in each segmented GM subregion. We evaluate and validate this computational framework for 76-space GM diffusivity analysis using data from normal volunteers and from patients with Creutzfeldt-Jakob disease.
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Affiliation(s)
- Tianming Liu
- Center for Bioinformatics, Harvard Center for Neurodegeneration and Repair, Harvard Medical School, MA 02478, USA.
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Kalus P, Slotboom J, Gallinat J, Mahlberg R, Cattapan-Ludewig K, Wiest R, Nyffeler T, Buri C, Federspiel A, Kunz D, Schroth G, Kiefer C. Examining the gateway to the limbic system with diffusion tensor imaging: the perforant pathway in dementia. Neuroimage 2005; 30:713-20. [PMID: 16337815 DOI: 10.1016/j.neuroimage.2005.10.035] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Revised: 10/25/2005] [Accepted: 10/31/2005] [Indexed: 11/22/2022] Open
Abstract
Current treatments for Alzheimer's disease (AD) are only able to slow the progression of mental deterioration, making early and reliable diagnosis an essential part of any promising therapeutic strategy. In the initial stages of AD, the first neuropathological alterations occur in the perforant pathway (PP), a large neuronal fiber tract located at the entrance to the limbic system. However, to date, there is no sensitive diagnostic tool for performing in vivo assessments of this structure. In the present bimodal magnetic resonance imaging (MRI) study, we examined 10 elderly controls, 10 subjects suffering from mild cognitive impairment (MCI), and 10 AD patients in order to evaluate the sensitivity of diffusion tensor imaging (DTI), a new MRI technique, for detecting changes in the PP. Furthermore, the diagnostic explanatory power of DTI data of the PP should be compared to high-resolution MRI volumetry and intervoxel coherences (COH) of the hippocampus and the entorhinal cortex, two limbic regions also involved in the pathophysiology of early AD. DTI revealed a marked decrease in COH values in the PP region of MCI (right side: 26%, left side: 29%, as compared to controls) and AD patients (right side: 37%, left side: 43%, as compared to controls). Reductions in COH values of the PP region were significantly correlated with cognitive impairment. DTI data of the PP zone were the only parameter differing significantly between control subjects and MCI patients, while the volumetric measures and the COH values of the hippocampus and the entorhinal cortex did not. DTI of medial temporal brain regions is a promising non-invasive tool for the in vivo diagnosis of the early/preclinical stages of AD.
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Affiliation(s)
- Peter Kalus
- Department of Psychiatry, Charité University Medicine, Campus Mitte, Berlin, Germany.
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