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Valenti M, Pino MC, Mazza M, Panzarino G, Di Paolantonio C, Verrotti A. Abnormal Structural and Functional Connectivity of the Corpus Callosum in Autism Spectrum Disorders: a Review. REVIEW JOURNAL OF AUTISM AND DEVELOPMENTAL DISORDERS 2019. [DOI: 10.1007/s40489-019-00176-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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2
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Hau J, Aljawad S, Baggett N, Fishman I, Carper RA, Müller RA. The cingulum and cingulate U-fibers in children and adolescents with autism spectrum disorders. Hum Brain Mapp 2019; 40:3153-3164. [PMID: 30941791 DOI: 10.1002/hbm.24586] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 03/11/2019] [Accepted: 03/15/2019] [Indexed: 12/12/2022] Open
Abstract
The cingulum is the major fiber system connecting the cingulate and surrounding medial cortex and medial temporal lobe internally and with other brain areas. It is important for social and emotional functions related to core symptomatology in autism spectrum disorders (ASDs). While the cingulum has been examined in autism, the extensive system of cingulate U-fibers has not been studied. Using probabilistic tractography, we investigated white matter fibers of the cingulate cortex by distinguishing its deep intra-cingulate bundle (cingulum proper) and short rostral anterior, caudal anterior, posterior, and isthmus cingulate U-fibers in 61 ASD and 54 typically developing children and adolescents. Increased mean and radial diffusivity of the left cingulum proper was observed in the ASD group, replicating previous findings on the cingulum. For cingulate U-fibers, an atypical age-related decline in right posterior cingulate U-fiber volume was found in the ASD group, which appeared to be driven by an abnormally large volume in younger children. History of repetitive and restrictive behavior was negatively associated with right caudal anterior cingulate U-fiber volume, linking cingulate motor areas with neighboring gyri. Aberrant development in U-fiber volume of the right posterior cingulate gyrus may underlie functional abnormalities found in this region, such as in the default mode network.
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Affiliation(s)
- Janice Hau
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Saba Aljawad
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Nicole Baggett
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Inna Fishman
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Ruth A Carper
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Ralph-Axel Müller
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
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Martínez K, Merchán-Naranjo J, Pina-Camacho L, Alemán-Gómez Y, Boada L, Fraguas D, Moreno C, Arango C, Janssen J, Parellada M. Atypical age-dependency of executive function and white matter microstructure in children and adolescents with autism spectrum disorders. Eur Child Adolesc Psychiatry 2017; 26:1361-1376. [PMID: 28447268 DOI: 10.1007/s00787-017-0990-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 04/17/2017] [Indexed: 11/29/2022]
Abstract
Executive function (EF) performance is associated with measurements of white matter microstructure (WMS) in typical individuals. Impaired EF is a hallmark symptom of autism spectrum disorders (ASD) but it is unclear how impaired EF relates to variability in WMS. Twenty-one male youth (8-18 years) with ASD and without intellectual disability and twenty-one typical male participants (TP) matched for age, intelligence quotient, handedness, race and parental socioeconomic status were recruited. Five EF domains were assessed and several DTI-based measurements of WMS [fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD)] were estimated for eighteen white matter tracts. The ASD group had lower scores for attention (F = 8.37, p = 0.006) and response inhibition (F = 13.09, p = 0.001). Age-dependent changes of EF performance and WMS measurements were present in TP but attenuated in the ASD group. The strongest diagnosis-by-age effect was found for forceps minor, left anterior thalamic radiation and left cingulum angular bundle (all p's ≤ 0.002). In these tracts subjects with ASD tended to have equal or increased FA and/or reduced MD and/or RD at younger ages while controls had increased FA and/or reduced MD and/or RD thereafter. Only for TP individuals, increased FA in the left anterior thalamic radiation was associated with better response inhibition, while reduced RD in forceps minor and left cingulum angular bundle was related to better problem solving and working memory performance respectively. These findings provide novel insight into the age-dependency of EF performance and WMS in ASD, which can be instructive to cognitive training programs.
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Affiliation(s)
- Kenia Martínez
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain. .,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain. .,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain. .,Universidad Europea de Madrid, Madrid, Spain. .,Hospital Gregorio Marañón, Edificio prefabricado, entrada por Máiquez 9, 28009, Madrid, Spain.
| | - Jessica Merchán-Naranjo
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain
| | - Laura Pina-Camacho
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain.,Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Yasser Alemán-Gómez
- Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain
| | - Leticia Boada
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain
| | - David Fraguas
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain
| | - Carmen Moreno
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain
| | - Celso Arango
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain.,Universidad Complutense de Madrid, Madrid, Spain
| | - Joost Janssen
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain.,Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mara Parellada
- Department of Child and Adolescent Psychiatry, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain.,Ciber del área de Salud Mental (CIBERSAM), Madrid, Spain.,Universidad Complutense de Madrid, Madrid, Spain
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Wilkinson M, Wang R, van der Kouwe A, Takahashi E. White and gray matter fiber pathways in autism spectrum disorder revealed by ex vivo diffusion MR tractography. Brain Behav 2016; 6:e00483. [PMID: 27247853 PMCID: PMC4864276 DOI: 10.1002/brb3.483] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/01/2016] [Accepted: 03/23/2016] [Indexed: 01/20/2023] Open
Abstract
INTRODUCTION The goal of this project was to study the white and gray matter brain pathways of young children with autism spectrum disorder (ASD) and investigate how ASD brains differ from those of typically developing children of the same age. METHODS High angular resolution resolution diffusion imaging tractography and diffusion tensor imaging tractography were used to analyze the brains of two 3-year-old children with ASD and two age-matched controls. RESULTS In the ASD brains, the callosal and corticopontine pathways were thinner overall and terminal areas in the cortical gray matter were significantly smaller. The ASD brains had more short-range u-fibers in the frontal lobe compared to the control brains. Gray matter pathways were found disorganized with less coherency in the ASD brain, specifically the lateral aspects of the middle part of the brain including motor areas, and both medial and lateral surfaces of the anterior frontal brain regions. CONCLUSION These findings show our tractography technique is useful for identifying differences in brain pathways between the ASD and control groups. Given that scanning the brain of 3-year-old children with or even without ASD is challenging, postmortem scanning may offer valuable insights into the connectivity in the brain of young children with ASD.
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Affiliation(s)
- Molly Wilkinson
- Department of Behavioral Neuroscience Northeastern University Boston Massachusetts; Division of Newborn Medicine Department of Medicine Boston Children's Hospital Harvard Medical School Boston Massachusetts
| | - Rongpin Wang
- Division of Newborn Medicine Department of Medicine Boston Children's Hospital Harvard Medical School Boston Massachusetts
| | - Andre van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital Harvard Medical School Charlestown Massachusetts
| | - Emi Takahashi
- Division of Newborn Medicine Department of Medicine Boston Children's Hospital Harvard Medical School Boston Massachusetts; Fetal-Neonatal Neuroimaging and Developmental Science Center Boston Children's Hospital Harvard Medical School Boston Massachusetts
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Simard I, Luck D, Mottron L, Zeffiro TA, Soulières I. Autistic fluid intelligence: Increased reliance on visual functional connectivity with diminished modulation of coupling by task difficulty. NEUROIMAGE-CLINICAL 2015; 9:467-78. [PMID: 26594629 PMCID: PMC4596928 DOI: 10.1016/j.nicl.2015.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/18/2015] [Accepted: 09/09/2015] [Indexed: 11/16/2022]
Abstract
Different test types lead to different intelligence estimates in autism, as illustrated by the fact that autistic individuals obtain higher scores on the Raven's Progressive Matrices (RSPM) test than they do on the Wechsler IQ, in contrast to relatively similar performance on both tests in non-autistic individuals. However, the cerebral processes underlying these differences are not well understood. This study investigated whether activity in the fluid “reasoning” network, which includes frontal, parietal, temporal and occipital regions, is differently modulated by task complexity in autistic and non-autistic individuals during the RSPM. In this purpose, we used fMRI to study autistic and non-autistic participants solving the 60 RSPM problems focussing on regions and networks involved in reasoning complexity. As complexity increased, activity in the left superior occipital gyrus and the left middle occipital gyrus increased for autistic participants, whereas non-autistic participants showed increased activity in the left middle frontal gyrus and bilateral precuneus. Using psychophysiological interaction analyses (PPI), we then verified in which regions did functional connectivity increase as a function of reasoning complexity. PPI analyses revealed greater connectivity in autistic, compared to non-autistic participants, between the left inferior occipital gyrus and areas in the left superior frontal gyrus, right superior parietal lobe, right middle occipital gyrus and right inferior temporal gyrus. We also observed generally less modulation of the reasoning network as complexity increased in autistic participants. These results suggest that autistic individuals, when confronted with increasing task complexity, rely mainly on visuospatial processes when solving more complex matrices. In addition to the now well-established enhanced activity observed in visual areas in a range of tasks, these results suggest that the enhanced reliance on visual perception has a central role in autistic cognition. Reasoning network is less modulated by problem complexity in autism. Autistic individuals rely more extensively on visuospatial processes to solve complex problems. Results support the central role of visual perception in autistic cognition.
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Affiliation(s)
- Isabelle Simard
- Department of Psychology, University of Montreal, Pavillon Marie-Victorin, C.P. 6128, Succursale Centre-ville, Montréal, Québec H3C 3J7, Canada ; Research Center, Institut universitaire en santé mentale de Montréal, 7401, rue Hochelaga, Montréal, Québec H1N 3M5, Canada
| | - David Luck
- Research Center, Institut universitaire en santé mentale de Montréal, 7401, rue Hochelaga, Montréal, Québec H1N 3M5, Canada ; Department of Psychiatry, University of Montreal, Pavillon Roger-Gaudry, Faculté de Medicine, C.P. 6128, Succursale Centre-ville, Montreal, Québec H3C 3J7, Canada
| | - Laurent Mottron
- Research Center, Institut universitaire en santé mentale de Montréal, 7401, rue Hochelaga, Montréal, Québec H1N 3M5, Canada ; Department of Psychiatry, University of Montreal, Pavillon Roger-Gaudry, Faculté de Medicine, C.P. 6128, Succursale Centre-ville, Montreal, Québec H3C 3J7, Canada
| | - Thomas A Zeffiro
- Neural Systems Group, Massachusetts General Hospital, 149 13th St, Psychiatry, Rm 2651, Charlestown, MA 02129, USA
| | - Isabelle Soulières
- Research Center, Institut universitaire en santé mentale de Montréal, 7401, rue Hochelaga, Montréal, Québec H1N 3M5, Canada ; Department of Psychology, University of Quebec in Montreal (UQAM), C.P. 8888, Succ. Centre-Ville, Montreal, Quebec H3C 3P8, Canada
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Kirkovski M, Enticott PG, Maller JJ, Rossell SL, Fitzgerald PB. Diffusion tensor imaging reveals no white matter impairments among adults with autism spectrum disorder. Psychiatry Res 2015; 233:64-72. [PMID: 26032898 DOI: 10.1016/j.pscychresns.2015.05.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 12/22/2014] [Accepted: 05/06/2015] [Indexed: 12/20/2022]
Abstract
Abnormalities within white matter (WM) have been identified in autism spectrum disorder (ASD). Although there is some support for greater neurobiological deficits among females with ASD, there is little research investigating sex differences in WM in ASD. We used diffusion tensor imaging (DTI) to investigate WM aberration in 25 adults with high-functioning ASD and 24 age-, sex- and IQ-matched controls. Tract-based spatial statistics (TBSS) was used to explore differences in WM in major tract bundles. The effects of biological sex were also investigated. TBSS revealed no differences in fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), or axial diffusivity (AD) between groups. There were no effects of biological sex. We consider whether methodological differences between past studies have contributed to the highly heterogeneous findings in the literature. Finally, we suggest that, among a high-functioning sample of adults with ASD, differences in WM microstructure may not be related to clinical impairment.
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Affiliation(s)
- Melissa Kirkovski
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, Victoria, Australia; Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia.
| | - Peter G Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia; Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Jerome J Maller
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Susan L Rossell
- Brain and Psychological Science Research Centre, Faculty Health, Arts and Design, Swinburne University, Hawthorn, Victoria, Australia; Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, Victoria, Australia
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Abstract
Autism spectrum disorder (ASD) affects 1 in 50 children between the ages of 6 and 17 years. The etiology of ASD is not precisely known. ASD is an umbrella term, which includes both low- (IQ < 70) and high-functioning (IQ > 70) individuals. A better understanding of the disorder and how it manifests in individual subjects can lead to more effective intervention plans to fulfill the individual's treatment needs.Magnetic resonance imaging (MRI) is a non-invasive investigational tool that can be used to study the ways in which the brain develops or deviates from the typical developmental trajectory. MRI offers insights into the structure, function, and metabolism of the brain. In this article, we review published studies on brain connectivity changes in ASD using either resting state functional MRI or diffusion tensor imaging.The general findings of decreases in white matter integrity and in long-range neural coherence are well known in the ASD literature. Nevertheless, the detailed localization of these findings remains uncertain, and few studies link these changes in connectivity with the behavioral phenotype of the disorder. With the help of data sharing and large-scale analytic efforts, however, the field is advancing toward several convergent themes, including the reduced functional coherence of long-range intra-hemispheric cortico-cortical default mode circuitry, impaired inter-hemispheric regulation, and an associated, perhaps compensatory, increase in local and short-range cortico-subcortical coherence.
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White Matter Integrity Dissociates Verbal Memory and Auditory Attention Span in Emerging Adults with Congenital Heart Disease. J Int Neuropsychol Soc 2015; 21:22-33. [PMID: 26304056 DOI: 10.1017/s135561771400109x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
White matter disruptions have been identified in individuals with congenital heart disease (CHD). However, no specific theory-driven relationships between microstructural white matter disruptions and cognition have been established in CHD. We conducted a two-part study. First, we identified significant differences in fractional anisotropy (FA) of emerging adults with CHD using Tract-Based Spatial Statistics (TBSS). TBSS analyses between 22 participants with CHD and 18 demographically similar controls identified five regions of normal appearing white matter with significantly lower FA in CHD, and two higher. Next, two regions of lower FA in CHD were selected to examine theory-driven differential relationships with cognition: voxels along the left uncinate fasciculus (UF; a tract theorized to contribute to verbal memory) and voxels along the right middle cerebellar peduncle (MCP; a tract previously linked to attention). In CHD, a significant positive correlation between UF FA and memory was found, r(20)=.42, p=.049 (uncorrected). There was no correlation between UF and auditory attention span. A positive correlation between MCP FA and auditory attention span was found, r(20)=.47, p=.027 (uncorrected). There was no correlation between MCP and memory. In controls, no significant relationships were identified. These results are consistent with previous literature demonstrating lower FA in younger CHD samples, and provide novel evidence for disrupted white matter integrity in emerging adults with CHD. Furthermore, a correlational double dissociation established distinct white matter circuitry (UF and MCP) and differential cognitive correlates (memory and attention span, respectively) in young adults with CHD.
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Ameis SH, Catani M. Altered white matter connectivity as a neural substrate for social impairment in Autism Spectrum Disorder. Cortex 2014; 62:158-81. [PMID: 25433958 DOI: 10.1016/j.cortex.2014.10.014] [Citation(s) in RCA: 202] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 01/01/2023]
Abstract
BACKGROUND Autism Spectrum Disorder (ASD) symptoms have been hypothesized to result from altered brain connectivity. The 'disconnectivity' hypothesis has been used to explain characteristic impairments in socio-emotional function, observed clinically in ASD. Here, we review the evidence for impaired white matter connectivity as a neural substrate for socio-emotional dysfunction in ASD. A review of diffusion tensor imaging (DTI) studies, and focused discussion of relevant post-mortem, structural, and functional neuroimaging studies, is provided. METHODS Studies were identified using a sensitive search strategy in MEDLINE, Embase and PsycINFO article databases using the OvidSP database interface. Search terms included database subject headings for the concepts of pervasive developmental disorders, and DTI. Seventy-two published DTI studies examining white matter microstructure in ASD were reviewed. A comprehensive discussion of DTI studies that examined white matter tracts linking socio-emotional structures is presented. RESULTS Several DTI studies reported microstructural differences indicative of developmental alterations in white matter organization, and potentially myelination, in ASD. Altered structure within long-range white matter tracts linking socio-emotional processing regions was implicated. While alterations of the uncinate fasciculus and frontal and temporal thalamic projections have been associated with social symptoms in ASD, few studies examined association of tract microstructure with core impairment in this disorder. CONCLUSIONS The uncinate fasciculus and frontal and temporal thalamic projections mediate limbic connectivity and integrate structures responsible for complex socio-emotional functioning. Impaired development of limbic connectivity may represent one neural substrate contributing to ASD social impairments. Future efforts to further elucidate the nature of atypical white matter development, and its relationship to core symptoms, may offer new insights into etiological mechanisms contributing to ASD impairments and uncover novel opportunities for targeted intervention.
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Affiliation(s)
- Stephanie H Ameis
- The Hospital for Sick Children, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Child, Youth and Family Program, Research Imaging Centre, The Campbell Family Mental Health Institute, The Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada.
| | - Marco Catani
- NATBRAINLAB, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry PO50, King's College London, London, UK.
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Mevel K, Fransson P, Bölte S. Multimodal brain imaging in autism spectrum disorder and the promise of twin research. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2014; 19:527-41. [PMID: 24916451 DOI: 10.1177/1362361314535510] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Current evidence suggests the phenotype of autism spectrum disorder to be driven by a complex interaction of genetic and environmental factors impacting onto brain maturation, synaptic function, and cortical networks. However, findings are heterogeneous, and the exact neurobiological pathways of autism spectrum disorder still remain poorly understood. The co-twin control or twin-difference design is a potentially powerful tool to disentangle causal genetic and environmental contributions on neurodevelopment in autism spectrum disorder. To this end, monozygotic twins discordant for this condition provide unique means for the maximum control of potentially confounding factors. Unfortunately, only few studies of a rather narrow scope, and limited sample size, have been conducted. In an attempt to highlight the great potential of combining the brain connectome approach with monozygotic twin design, we first give an overview of the existing neurobiological evidence for autism spectrum disorder and its cognitive correlates. Then, a special focus is made onto the brain imaging findings reported within populations of monozygotic twins phenotypically discordant for autism spectrum disorder. Finally, we introduce the brain connectome model and describe an ongoing project using this approach among the largest cohort of monozygotic twins discordant for autism spectrum disorder ever recruited.
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Affiliation(s)
- Katell Mevel
- Department of Women's and Children's Health, Karolinska Institutet, Sweden CNRS UMR 8240, University of Caen Basse-Normandie and University of Paris Descartes - Sorbonne Paris Cité, France
| | - Peter Fransson
- Department of Clinical Neuroscience, Karolinska Institutet, Sweden
| | - Sven Bölte
- Department of Women's and Children's Health, Karolinska Institutet, Sweden Division of Child and Adolescent Psychiatry, Stockholm County Council, Sweden
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Eierud C, Craddock RC, Fletcher S, Aulakh M, King-Casas B, Kuehl D, LaConte SM. Neuroimaging after mild traumatic brain injury: review and meta-analysis. NEUROIMAGE-CLINICAL 2014; 4:283-94. [PMID: 25061565 PMCID: PMC4107372 DOI: 10.1016/j.nicl.2013.12.009] [Citation(s) in RCA: 330] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 12/02/2013] [Accepted: 12/22/2013] [Indexed: 11/28/2022]
Abstract
This paper broadly reviews the study of mild traumatic brain injury (mTBI), across the spectrum of neuroimaging modalities. Among the range of imaging methods, however, magnetic resonance imaging (MRI) is unique in its applicability to studying both structure and function. Thus we additionally performed meta-analyses of MRI results to examine 1) the issue of anatomical variability and consistency for functional MRI (fMRI) findings, 2) the analogous issue of anatomical consistency for white-matter findings, and 3) the importance of accounting for the time post injury in diffusion weighted imaging reports. As we discuss, the human neuroimaging literature consists of both small and large studies spanning acute to chronic time points that have examined both structural and functional changes with mTBI, using virtually every available medical imaging modality. Two key commonalities have been used across the majority of imaging studies. The first is the comparison between mTBI and control populations. The second is the attempt to link imaging results with neuropsychological assessments. Our fMRI meta-analysis demonstrates a frontal vulnerability to mTBI, demonstrated by decreased signal in prefrontal cortex compared to controls. This vulnerability is further highlighted by examining the frequency of reported mTBI white matter anisotropy, in which we show a strong anterior-to-posterior gradient (with anterior regions being more frequently reported in mTBI). Our final DTI meta-analysis examines a debated topic arising from inconsistent anisotropy findings across studies. Our results support the hypothesis that acute mTBI is associated with elevated anisotropy values and chronic mTBI complaints are correlated with depressed anisotropy. Thus, this review and set of meta-analyses demonstrate several important points about the ongoing use of neuroimaging to understand the functional and structural changes that occur throughout the time course of mTBI recovery. Based on the complexity of mTBI, however, much more work in this area is required to characterize injury mechanisms and recovery factors and to achieve clinically-relevant capabilities for diagnosis. mTBI neuroimaging literature review and meta-analyses of fMRI and DTI. fMRI meta-analysis revealed differences between mTBI and controls in 13 regions. mTBI anisotropy findings are statistically more frequently reported in anterior regions. Anisotropy is elevated in acute mTBI, but depressed in chronic mTBI. We hypothesize a statistical interaction between anisotropy, cognitive score, and time.
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Affiliation(s)
- Cyrus Eierud
- Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA, USA ; Structural and Computational Biology & Molecular Biophysics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - R Cameron Craddock
- Child Mind Institute, 445 Park Avenue, New York, NY, USA ; Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Sean Fletcher
- Virginia Tech Carilion School of Medicine, 2 Riverside Circle, Roanoke, VA, USA
| | - Manek Aulakh
- Virginia Tech Carilion School of Medicine, 2 Riverside Circle, Roanoke, VA, USA
| | - Brooks King-Casas
- Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA, USA ; Department of Psychology, Virginia Tech, Blacksburg, VA, USA
| | - Damon Kuehl
- School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Stephen M LaConte
- Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA, USA ; Structural and Computational Biology & Molecular Biophysics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA ; School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA ; Department of Emergency Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA ; Department of Emergency Radiology, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
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