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Young AMH, Chakrabarti B, Roberts D, Lai MC, Suckling J, Baron-Cohen S. From molecules to neural morphology: understanding neuroinflammation in autism spectrum condition. Mol Autism 2016; 7:9. [PMID: 26793298 PMCID: PMC4719563 DOI: 10.1186/s13229-016-0068-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 01/04/2016] [Indexed: 12/31/2022] Open
Abstract
Growing evidence points toward a critical role for early (prenatal) atypical neurodevelopmental processes in the aetiology of autism spectrum condition (ASC). One such process that could impact early neural development is inflammation. We review the evidence for atypical expression of molecular markers in the amniotic fluid, serum, cerebrospinal fluid (CSF), and the brain parenchyma that suggest a role for inflammation in the emergence of ASC. This is complemented with a number of neuroimaging and neuropathological studies describing microglial activation. Implications for treatment are discussed.
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Affiliation(s)
- Adam M H Young
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge, UK ; School of Clinical Medicine, Addenbrookes Hospital, University of Cambridge, Cambridge, UK
| | - Bhismadev Chakrabarti
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge, UK ; Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Science, University of Reading, Reading, UK
| | - David Roberts
- School of Clinical Medicine, Addenbrookes Hospital, University of Cambridge, Cambridge, UK
| | - Meng-Chuan Lai
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge, UK ; Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, Canada ; Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
| | - John Suckling
- Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Cambridge, UK ; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
| | - Simon Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge, UK ; CLASS Clinic, Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
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102
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Callaghan BL, Tottenham N. The Neuro-Environmental Loop of Plasticity: A Cross-Species Analysis of Parental Effects on Emotion Circuitry Development Following Typical and Adverse Caregiving. Neuropsychopharmacology 2016; 41:163-76. [PMID: 26194419 PMCID: PMC4677125 DOI: 10.1038/npp.2015.204] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 12/20/2022]
Abstract
Early experiences critically shape the structure and function of the brain. Perturbations in typical/species-expected early experiences are known to have profound neural effects, especially in regions important for emotional responding. Parental care is one species-expected stimulus that plays a fundamental role in the development of emotion neurocircuitry. Emerging evidence across species suggests that phasic variation in parental presence during the sensitive period of childhood affects the recruitment of emotional networks on a moment-to-moment basis. In addition, it appears that increasing independence from caregivers cues the termination of the sensitive period for environmental input into emotion network development. In this review, we examine how early parental care, the central nervous system, and behavior come together to form a 'neuro-environmental loop,' contributing to the formation of stable emotion regulation circuits. To achieve this end, we focus on the interaction of parental care and the developing amygdala-medial prefrontal cortex (mPFC) network-that is at the core of human emotional functioning. Using this model, we discuss how individual or group variations in parental independence, across chronic and brief timescales, might contribute to neural and emotional phenotypes that have implications for long-term mental health.
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Affiliation(s)
| | - Nim Tottenham
- Department of Psychology, Columbia University, New York, NY, USA
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103
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Rätsep MT, Paolozza A, Hickman AF, Maser B, Kay VR, Mohammad S, Pudwell J, Smith GN, Brien D, Stroman PW, Adams MA, Reynolds JN, Croy BA, Forkert ND. Brain Structural and Vascular Anatomy Is Altered in Offspring of Pre-Eclamptic Pregnancies: A Pilot Study. AJNR Am J Neuroradiol 2015; 37:939-45. [PMID: 26721772 DOI: 10.3174/ajnr.a4640] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/05/2015] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND PURPOSE Pre-eclampsia is a serious clinical gestational disorder occurring in 3%-5% of all human pregnancies and characterized by endothelial dysfunction and vascular complications. Offspring born of pre-eclamptic pregnancies are reported to exhibit deficits in cognitive function, higher incidence of depression, and increased susceptibility to stroke. However, no brain imaging reports exist on these offspring. We aimed to assess brain structural and vascular anatomy in 7- to 10-year-old offspring of pre-eclamptic pregnancies compared with matched controls. MATERIALS AND METHODS Offspring of pre-eclamptic pregnancies and matched controls (n = 10 per group) were recruited from an established longitudinal cohort examining the effects of pre-eclampsia. Children underwent MR imaging to identify brain structural and vascular anatomic differences. Maternal plasma samples collected at birth were assayed for angiogenic factors by enzyme-linked immunosorbent assay. RESULTS Offspring of pre-eclamptic pregnancies exhibited enlarged brain regional volumes of the cerebellum, temporal lobe, brain stem, and right and left amygdalae. These offspring displayed reduced cerebral vessel radii in the occipital and parietal lobes. Enzyme-linked immunosorbent assay analysis revealed underexpression of the placental growth factor among the maternal plasma samples from women who experienced pre-eclampsia. CONCLUSIONS This study is the first to report brain structural and vascular anatomic alterations in the population of offspring of pre-eclamptic pregnancies. Brain structural alterations shared similarities with those seen in autism. Vascular alterations may have preceded these structural alterations. This pilot study requires further validation with a larger population to provide stronger estimates of brain structural and vascular outcomes among the offspring of pre-eclamptic pregnancies.
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Affiliation(s)
- M T Rätsep
- From the Department of Biomedical and Molecular Sciences (M.T.R., A.F.H., B.M., V.R.K., S.M., G.N.S., J.N.R., B.A.C.)
| | - A Paolozza
- Centre for Neuroscience Studies (A.P., D.B., P.W.S., M.A.A., J.N.R.), Queen's University, Kingston, Ontario, Canada
| | - A F Hickman
- From the Department of Biomedical and Molecular Sciences (M.T.R., A.F.H., B.M., V.R.K., S.M., G.N.S., J.N.R., B.A.C.)
| | - B Maser
- From the Department of Biomedical and Molecular Sciences (M.T.R., A.F.H., B.M., V.R.K., S.M., G.N.S., J.N.R., B.A.C.)
| | - V R Kay
- From the Department of Biomedical and Molecular Sciences (M.T.R., A.F.H., B.M., V.R.K., S.M., G.N.S., J.N.R., B.A.C.)
| | - S Mohammad
- From the Department of Biomedical and Molecular Sciences (M.T.R., A.F.H., B.M., V.R.K., S.M., G.N.S., J.N.R., B.A.C.)
| | - J Pudwell
- Department of Obstetrics and Gynecology (J.P., G.N.S.), Kingston General Hospital, Kingston, Ontario, Canada
| | - G N Smith
- From the Department of Biomedical and Molecular Sciences (M.T.R., A.F.H., B.M., V.R.K., S.M., G.N.S., J.N.R., B.A.C.) Department of Obstetrics and Gynecology (J.P., G.N.S.), Kingston General Hospital, Kingston, Ontario, Canada
| | - D Brien
- Centre for Neuroscience Studies (A.P., D.B., P.W.S., M.A.A., J.N.R.), Queen's University, Kingston, Ontario, Canada
| | - P W Stroman
- Centre for Neuroscience Studies (A.P., D.B., P.W.S., M.A.A., J.N.R.), Queen's University, Kingston, Ontario, Canada
| | - M A Adams
- Centre for Neuroscience Studies (A.P., D.B., P.W.S., M.A.A., J.N.R.), Queen's University, Kingston, Ontario, Canada
| | - J N Reynolds
- From the Department of Biomedical and Molecular Sciences (M.T.R., A.F.H., B.M., V.R.K., S.M., G.N.S., J.N.R., B.A.C.) Centre for Neuroscience Studies (A.P., D.B., P.W.S., M.A.A., J.N.R.), Queen's University, Kingston, Ontario, Canada
| | - B A Croy
- From the Department of Biomedical and Molecular Sciences (M.T.R., A.F.H., B.M., V.R.K., S.M., G.N.S., J.N.R., B.A.C.)
| | - N D Forkert
- Department of Radiology and Hotchkiss Brain Institute (N.D.F.), University of Calgary, Calgary, Alberta, Canada
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104
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Dougherty CC, Evans DW, Myers SM, Moore GJ, Michael AM. A Comparison of Structural Brain Imaging Findings in Autism Spectrum Disorder and Attention-Deficit Hyperactivity Disorder. Neuropsychol Rev 2015; 26:25-43. [DOI: 10.1007/s11065-015-9300-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 09/22/2015] [Indexed: 01/30/2023]
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Ohta H, Nordahl CW, Iosif AM, Lee A, Rogers S, Amaral DG. Increased Surface Area, but not Cortical Thickness, in a Subset of Young Boys With Autism Spectrum Disorder. Autism Res 2015; 9:232-48. [PMID: 26184828 DOI: 10.1002/aur.1520] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/22/2015] [Indexed: 01/22/2023]
Abstract
The Autism Phenome Project is the largest, single site, longitudinal magnetic resonance imaging (MRI) study of young children with autism spectrum disorder (ASD). Previous analyses from this cohort have shown that the children with autism have a total brain volume at time 1 (∼3 years of age) that is 6% larger than typically developing (TD) children. This finding is driven primarily by 15% of the boys with ASD that have disproportionate megalencephaly (ASD-DM) or brain size that is 1.5 standard deviations above what would be expected for the child's height. In the current study, cerebral cortical grey matter volume, thickness, and surface area were assayed from MRI scans of 112, 3-year-old boys with ASD and 50 age-matched TD boys. The boys with ASD-DM (n = 17) were analyzed separately from the boys with normal brain size (ASD-N, n = 95). Previous studies of cortical thickness and surface area for ASD children in this age range have come to diametrically different conclusions concerning the significance of cortical thickness vs. surface area. Current analyses indicate that cortical thickness was comparable across the ASD and TD groups. However, surface area was significantly greater in the ASD group compared to the TD group. This result was driven largely by the children with ASD-DM. Even in the ASD-DM group, not all cortical regions demonstrated increased surface area. These results provide strong evidence that the early cortical overgrowth associated with ASD is due primarily to increased surface area and not to increased cortical thickness.
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Affiliation(s)
- Haruhisa Ohta
- The Medical Investigation of Neurodevelopmental Disorders (MIND) Institute and Department of Psychiatry and Behavioral Sciences, University of California, Davis School of Medicine, Sacramento, California
- Department of Psychiatry, Showa University School of Medicine, Tokyo, Japan
| | - Christine Wu Nordahl
- The Medical Investigation of Neurodevelopmental Disorders (MIND) Institute and Department of Psychiatry and Behavioral Sciences, University of California, Davis School of Medicine, Sacramento, California
| | - Ana-Maria Iosif
- Department of Public Health Sciences, Division of Biostatistics, University of California, Davis, Davis, California
| | - Aaron Lee
- The Medical Investigation of Neurodevelopmental Disorders (MIND) Institute and Department of Psychiatry and Behavioral Sciences, University of California, Davis School of Medicine, Sacramento, California
| | - Sally Rogers
- The Medical Investigation of Neurodevelopmental Disorders (MIND) Institute and Department of Psychiatry and Behavioral Sciences, University of California, Davis School of Medicine, Sacramento, California
| | - David G Amaral
- The Medical Investigation of Neurodevelopmental Disorders (MIND) Institute and Department of Psychiatry and Behavioral Sciences, University of California, Davis School of Medicine, Sacramento, California
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106
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Blackmon K. Structural MRI biomarkers of shared pathogenesis in autism spectrum disorder and epilepsy. Epilepsy Behav 2015; 47:172-82. [PMID: 25812936 DOI: 10.1016/j.yebeh.2015.02.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 02/11/2015] [Accepted: 02/16/2015] [Indexed: 01/28/2023]
Abstract
Etiological factors that contribute to a high comorbidity between autism spectrum disorder (ASD) and epilepsy are the subject of much debate. Does epilepsy cause ASD or are there common underlying brain abnormalities that increase the risk of developing both disorders? This review summarizes evidence from quantitative MRI studies to suggest that abnormalities of brain structure are not necessarily the consequence of ASD and epilepsy but are antecedent to disease expression. Abnormal gray and white matter volumes are present prior to onset of ASD and evident at the time of onset in pediatric epilepsy. Aberrant brain growth trajectories are also common in both disorders, as evidenced by blunted gray matter maturation and white matter maturation. Although the etiological factors that explain these abnormalities are unclear, high heritability estimates for gray matter volume and white matter microstructure demonstrate that genetic factors assert a strong influence on brain structure. In addition, histopathological studies of ASD and epilepsy brain tissue reveal elevated rates of malformations of cortical development (MCDs), such as focal cortical dysplasia and heterotopias, which supports disruption of neuronal migration as a contributing factor. Although MCDs are not always visible on MRI with conventional radiological analysis, quantitative MRI detection methods show high sensitivity to subtle malformations in epilepsy and can be potentially applied to MCD detection in ASD. Such an approach is critical for establishing quantitative neuroanatomic endophenotypes that can be used in genetic research. In the context of emerging drug treatments for seizures and autism symptoms, such as rapamycin and rapalogs, in vivo neuroimaging markers of subtle structural brain abnormalities could improve sample stratification in human clinical trials and potentially extend the range of patients that might benefit from treatment. This article is part of a Special Issue entitled "Autism and Epilepsy".
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Affiliation(s)
- Karen Blackmon
- Comprehensive Epilepsy Center, Department of Neurology, New York University School of Medicine, New York, NY 10016, USA; Center for Mind/Brain Sciences, University of Trento, Rovereto, Trento 38068, Italy.
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107
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Lin HY, Ni HC, Lai MC, Tseng WYI, Gau SSF. Regional brain volume differences between males with and without autism spectrum disorder are highly age-dependent. Mol Autism 2015; 6:29. [PMID: 26045942 PMCID: PMC4455336 DOI: 10.1186/s13229-015-0022-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 04/21/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Neuroanatomical differences between individuals with and without autism spectrum disorder (ASD) were inconsistent in the literature. Such heterogeneity may substantially originate from age-differential effects. METHODS Voxel-based morphometry was applied in 86 males with ASD and 90 typically developing control (TDC) males (aged 7 to 29 years). Three steps of statistical modeling (model 1, multiple regression with age as a covariate; model 2, multiple regression further considering diagnosis-by-age interaction; model 3, age-stratified analyses) were performed to dissect the moderating effects of age on diagnostic group differences in neuroanatomy. RESULTS Across ages, males with and without ASD did not differ significantly in total gray matter (GM) or white matter (WM) volumes. For both groups, total GM volumes decreased and WM volumes increased with age. For regional volume, comparing with the model only held the age constant (model 1), the main effect of group altered when diagnosis-by-age interaction effects were considered (model 2). Here, participants with ASD had significantly greater relative regional GM volumes than TDC in the right inferior orbitofrontal cortex and bilateral thalamus; for WM, participants with ASD were larger than TDC in the bilateral splenium of corpus callosum and right anterior corona radiata. Importantly, significant diagnosis-by-age interactions were identified at the bilateral anterior prefrontal cortex, bilateral cuneus, bilateral caudate, and the left cerebellum Crus I for GM and left forceps minor for WM. Finally, age-stratified analyses (model 3) showed distinct patterns in GM and WM volumetric alterations in ASD among subsamples of children, adolescents, and adults. CONCLUSIONS Our findings suggest that the heterogeneous reports on the atypical neuroanatomy of ASD may substantially originate from age variation in the study samples. Age variation and its methodological and biological implications have to be carefully delineated in future studies of the neurobiology of ASD.
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Affiliation(s)
- Hsiang-Yuan Lin
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, No. 7 Chung-Shan South Road, Taipei, 10002 Taiwan
| | - Hsing-Chang Ni
- Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, No. 1, Jen-Ai Road Section 1, Taipei, 10051 Taiwan.,Department of Child Psychiatry, Chang Gung Memorial Hospital at Linkou, No. 5 Fu-Hsing St., Taoyuan, 33305 Taiwan
| | - Meng-Chuan Lai
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, No. 7 Chung-Shan South Road, Taipei, 10002 Taiwan.,Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18b Trumpington Road, Cambridge, CB2 8AH UK.,Centre for Addiction and Mental Health, Hospital for Sick Children, and Department of Psychiatry, University of Toronto, 250 College St., Toronto, M5T 1R8 Canada
| | - Wen-Yih Isaac Tseng
- Graduate Institute of Brain and Mind Sciences, National Taiwan University College of Medicine, No. 1, Jen-Ai Road Section 1, Taipei, 10051 Taiwan.,Center for Optoelectronic Medicine, National Taiwan University College of Medicine, No. 1, Jen-Ai Road Section 1, Taipei, 10051 Taiwan
| | - Susan Shur-Fen Gau
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, No. 7 Chung-Shan South Road, Taipei, 10002 Taiwan.,Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, No. 1, Jen-Ai Road Section 1, Taipei, 10051 Taiwan.,Graduate Institute of Brain and Mind Sciences, National Taiwan University College of Medicine, No. 1, Jen-Ai Road Section 1, Taipei, 10051 Taiwan
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108
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Olde Loohuis NFM, Kole K, Glennon JC, Karel P, Van der Borg G, Van Gemert Y, Van den Bosch D, Meinhardt J, Kos A, Shahabipour F, Tiesinga P, van Bokhoven H, Martens GJM, Kaplan BB, Homberg JR, Aschrafi A. Elevated microRNA-181c and microRNA-30d levels in the enlarged amygdala of the valproic acid rat model of autism. Neurobiol Dis 2015; 80:42-53. [PMID: 25986729 DOI: 10.1016/j.nbd.2015.05.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 04/14/2015] [Accepted: 05/10/2015] [Indexed: 11/17/2022] Open
Abstract
Autism spectrum disorders are severe neurodevelopmental disorders, marked by impairments in reciprocal social interaction, delays in early language and communication, and the presence of restrictive, repetitive and stereotyped behaviors. Accumulating evidence suggests that dysfunction of the amygdala may be partially responsible for the impairment of social behavior that is a hallmark feature of ASD. Our studies suggest that a valproic acid (VPA) rat model of ASD exhibits an enlargement of the amygdala as compared to controls rats, similar to that observed in adolescent ASD individuals. Since recent research suggests that altered neuronal development and morphology, as seen in ASD, may result from a common post-transcriptional process that is under tight regulation by microRNAs (miRs), we examined genome-wide transcriptomics expression in the amygdala of rats prenatally exposed to VPA, and detected elevated miR-181c and miR-30d expression levels as well as dysregulated expression of their cognate mRNA targets encoding proteins involved in neuronal system development. Furthermore, selective suppression of miR-181c function attenuates neurite outgrowth and branching, and results in reduced synaptic density in primary amygdalar neurons in vitro. Collectively, these results implicate the small non-coding miR-181c in neuronal morphology, and provide a framework of understanding how dysregulation of a neurodevelopmentally relevant miR in the amygdala may contribute to the pathophysiology of ASD.
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Affiliation(s)
- N F M Olde Loohuis
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - K Kole
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - J C Glennon
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - P Karel
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - G Van der Borg
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Y Van Gemert
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - D Van den Bosch
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - J Meinhardt
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - A Kos
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - F Shahabipour
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - P Tiesinga
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - H van Bokhoven
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - G J M Martens
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Nijmegen Centre for Molecular Life Sciences (NCMLS), Radboud University Nijmegen, Nijmegen, The Netherlands
| | - B B Kaplan
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - J R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - A Aschrafi
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands.
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109
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Nordahl CW, Iosif AM, Young GS, Perry LM, Dougherty R, Lee A, Li D, Buonocore MH, Simon T, Rogers S, Wandell B, Amaral DG. Sex differences in the corpus callosum in preschool-aged children with autism spectrum disorder. Mol Autism 2015; 6:26. [PMID: 25973163 PMCID: PMC4429319 DOI: 10.1186/s13229-015-0005-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 02/02/2015] [Indexed: 11/29/2022] Open
Abstract
Background Abnormalities in the corpus callosum have been reported in individuals with autism spectrum disorder (ASD), but few studies have evaluated young children. Sex differences in callosal organization and diffusion characteristics have also not been evaluated fully in ASD. Methods Structural and diffusion-weighted images were acquired in 139 preschool-aged children with ASD (112 males/27 females) and 82 typically developing (TD) controls (53 males/29 females). Longitudinal scanning at two additional annual time points was carried out in a subset of these participants. Callosal organization was evaluated using two approaches: 1) diffusion tensor imaging (DTI) tractography to define subregions based on cortical projection zones and 2) as a comparison to previous studies, midsagittal area analysis using Witelson subdivisions. Diffusion measures of callosal fibers were also evaluated. Results Analyses of cortical projection zone subregions revealed sex differences in the patterns of altered callosal organization. Relative to their sex-specific TD counterparts, both males and females with ASD had smaller regions dedicated to fibers projecting to superior frontal cortex, but patterns differed in callosal subregions projecting to other parts of frontal cortex. While males with ASD had a smaller callosal region dedicated to the orbitofrontal cortex, females with ASD had a smaller callosal region dedicated to the anterior frontal cortex. There were also sex differences in diffusion properties of callosal fibers. While no alterations were observed in males with ASD relative to TD males, mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were all increased in females with ASD relative to TD females. Analyses of Witelson subdivisions revealed a decrease in midsagittal area of the corpus callosum in both males and females with ASD but no regional differences in specific subdivisions. Longitudinal analyses revealed no diagnostic or sex differences in the growth rate or change in diffusion measures of the corpus callosum from 3 to 5 years of age. Conclusions There are sex differences in the pattern of altered corpus callosum neuroanatomy in preschool-aged children with ASD. Electronic supplementary material The online version of this article (doi:10.1186/s13229-015-0005-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christine Wu Nordahl
- The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA
| | - Ana-Maria Iosif
- The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Public Health Sciences, School of Medicine, University of California at Davis, Davis, CA 95616 USA
| | - Gregory S Young
- The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA
| | - Lee Michael Perry
- Department of Psychology, Stanford University, Stanford, CA 94305 USA
| | - Robert Dougherty
- Center for Cognitive and Neurobiological Imaging, Stanford University, Stanford, CA 94305 USA
| | - Aaron Lee
- The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA
| | - Deana Li
- The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA
| | - Michael H Buonocore
- Department of Radiology, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA
| | - Tony Simon
- The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA
| | - Sally Rogers
- The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA
| | - Brian Wandell
- Department of Psychology, Stanford University, Stanford, CA 94305 USA
| | - David G Amaral
- The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA
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110
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Neuroimaging in autism spectrum disorder: brain structure and function across the lifespan. Lancet Neurol 2015; 14:1121-34. [PMID: 25891007 DOI: 10.1016/s1474-4422(15)00050-2] [Citation(s) in RCA: 268] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 03/25/2015] [Accepted: 04/13/2015] [Indexed: 12/22/2022]
Abstract
Over the past decade, in-vivo MRI studies have provided many invaluable insights into the neural substrates underlying autism spectrum disorder (ASD), which is now known to be associated with neurodevelopmental variations in brain anatomy, functioning, and connectivity. These systems-level features of ASD pathology seem to develop differentially across the human lifespan so that the cortical abnormalities that occur in children with ASD differ from those noted at other stages of life. Thus, investigation of the brain in ASD poses particular methodological challenges, which must be addressed to enable the comparison of results across studies. Novel analytical approaches are also being developed to facilitate the translation of findings from the research to the clinical setting. In the future, the insights provided by human neuroimaging studies could contribute to biomarker development for ASD and other neurodevelopmental disorders, and to new approaches to diagnosis and treatment.
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Cheng W, Rolls ET, Gu H, Zhang J, Feng J. Autism: reduced connectivity between cortical areas involved in face expression, theory of mind, and the sense of self. Brain 2015; 138:1382-93. [PMID: 25795704 PMCID: PMC4407191 DOI: 10.1093/brain/awv051] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 01/04/2015] [Indexed: 12/27/2022] Open
Abstract
Whole-brain voxel-based unbiased resting state functional connectivity was analysed in 418 subjects with autism and 509 matched typically developing individuals. We identified a key system in the middle temporal gyrus/superior temporal sulcus region that has reduced cortical functional connectivity (and increased with the medial thalamus), which is implicated in face expression processing involved in social behaviour. This system has reduced functional connectivity with the ventromedial prefrontal cortex, which is implicated in emotion and social communication. The middle temporal gyrus system is also implicated in theory of mind processing. We also identified in autism a second key system in the precuneus/superior parietal lobule region with reduced functional connectivity, which is implicated in spatial functions including of oneself, and of the spatial environment. It is proposed that these two types of functionality, face expression-related, and of one's self and the environment, are important components of the computations involved in theory of mind, whether of oneself or of others, and that reduced connectivity within and between these regions may make a major contribution to the symptoms of autism.
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Affiliation(s)
- Wei Cheng
- 1 Centre for Computational Systems Biology, Fudan University, Shanghai, PR China
| | - Edmund T Rolls
- 2 Department of Computer Science, University of Warwick, Coventry CV4 7AL, UK 3 Oxford Centre for Computational Neuroscience, Oxford, UK
| | - Huaguang Gu
- 4 School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, PR China
| | - Jie Zhang
- 1 Centre for Computational Systems Biology, Fudan University, Shanghai, PR China
| | - Jianfeng Feng
- 1 Centre for Computational Systems Biology, Fudan University, Shanghai, PR China 2 Department of Computer Science, University of Warwick, Coventry CV4 7AL, UK
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Lainhart JE. Brain imaging research in autism spectrum disorders: in search of neuropathology and health across the lifespan. Curr Opin Psychiatry 2015; 28:76-82. [PMID: 25602243 PMCID: PMC4465432 DOI: 10.1097/yco.0000000000000130] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW Advances in brain imaging research in autism spectrum disorders (ASD) are rapidly occurring, and the amount of neuroimaging research has dramatically increased over the past 5 years. In this review, advances during the past 12 months and longitudinal studies are highlighted. RECENT FINDINGS Cross-sectional neuroimaging research provides evidence that the neural underpinnings of the behavioral signs of ASD involve not only dysfunctional integration of information across distributed brain networks but also basic dysfunction in primary cortices.Longitudinal studies of ASD show abnormally enlarged brain volumes and increased rates of brain growth during early childhood in only a small minority of ASD children. There is evidence of disordered development of white matter microstructure and amygdala growth, and at 2 years of age, network inefficiencies in posterior cerebral regions.From older childhood into adulthood, atypical age-variant and age-invariant changes in the trajectories of total and regional brain volumes and cortical thickness are apparent at the group level. SUMMARY There is evidence of abnormalities in posterior lobes and posterior brain networks during the first 2 years of life in ASD and, even in older children and adults, dysfunction in primary cortical areas.
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Affiliation(s)
- Janet E. Lainhart
- Waisman Laboratory for Brain Imaging and Behavior, and Autism & Developmental Disorders Clinic, Waisman Center, and Department of Psychiatry, University of Wisconsin-Madison, Wisconsin, USA
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113
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Lai MC, Lombardo MV, Auyeung B, Chakrabarti B, Baron-Cohen S. Sex/gender differences and autism: setting the scene for future research. J Am Acad Child Adolesc Psychiatry 2015; 54:11-24. [PMID: 25524786 PMCID: PMC4284309 DOI: 10.1016/j.jaac.2014.10.003] [Citation(s) in RCA: 552] [Impact Index Per Article: 61.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 10/10/2014] [Accepted: 10/13/2014] [Indexed: 12/22/2022]
Abstract
OBJECTIVE The relationship between sex/gender differences and autism has attracted a variety of research ranging from clinical and neurobiological to etiological, stimulated by the male bias in autism prevalence. Findings are complex and do not always relate to each other in a straightforward manner. Distinct but interlinked questions on the relationship between sex/gender differences and autism remain underaddressed. To better understand the implications from existing research and to help design future studies, we propose a 4-level conceptual framework to clarify the embedded themes. METHOD We searched PubMed for publications before September 2014 using search terms "'sex OR gender OR females' AND autism." A total of 1,906 articles were screened for relevance, along with publications identified via additional literature reviews, resulting in 329 articles that were reviewed. RESULTS Level 1, "Nosological and diagnostic challenges," concerns the question, "How should autism be defined and diagnosed in males and females?" Level 2, "Sex/gender-independent and sex/gender-dependent characteristics," addresses the question, "What are the similarities and differences between males and females with autism?" Level 3, "General models of etiology: liability and threshold," asks the question, "How is the liability for developing autism linked to sex/gender?" Level 4, "Specific etiological-developmental mechanisms," focuses on the question, "What etiological-developmental mechanisms of autism are implicated by sex/gender and/or sexual/gender differentiation?" CONCLUSIONS Using this conceptual framework, findings can be more clearly summarized, and the implications of the links between findings from different levels can become clearer. Based on this 4-level framework, we suggest future research directions, methodology, and specific topics in sex/gender differences and autism.
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Affiliation(s)
- Meng-Chuan Lai
- National Taiwan University Hospital and College of Medicine, Taipei, Taiwan and the Autism Research Centre, University of Cambridge, Cambridge, UK.
| | - Michael V Lombardo
- University of Cyprus, Nicosia, Cyprus and the Autism Research Centre, University of Cambridge
| | - Bonnie Auyeung
- University of Edinburgh and the Autism Research Centre, University of Cambridge
| | - Bhismadev Chakrabarti
- Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK and the Autism Research Centre, University of Cambridge
| | - Simon Baron-Cohen
- Cambridge Lifespan Asperger Syndrome Service (CLASS) Clinic, Cambridgeshire and Peterborough National Health Service Foundation Trust, Cambridge, and the Autism Research Centre, University of Cambridge
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Autism spectrum disorder as early neurodevelopmental disorder: evidence from the brain imaging abnormalities in 2-3 years old toddlers. J Autism Dev Disord 2014; 44:1633-40. [PMID: 24419870 PMCID: PMC4057630 DOI: 10.1007/s10803-014-2033-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition that occurs within the first 3 years of life, which is marked by social skills and communication deficits along with stereotyped repetitive behavior. Although great efforts have been made to clarify the underlying neuroanatomical abnormalities and brain-behavior relationships in adolescents and adults with ASD, literature is still limited in information about the neurobiology of ASD in the early age of life. Brain images of 50 toddlers with ASD and 28 age, gender, and developmental quotient matched toddlers with developmental delay (DD) (control group) between ages 2 and 3 years were captured using combined magnetic resonance-based structural imaging and diffusion tensor imaging (DTI). Structural magnetic resonance imaging was applied to assess overall gray matter (GM) and white matter (WM) volumes, and regional alterations were assessed by voxel-based morphometry. DTI was used to investigate the white matter tract integrity. Compared with DD, significant increases were observed in ASD, primarily in global GM and WM volumes and in right superior temporal gyrus regional GM and WM volumes. Higher fractional anisotropy value was also observed in the corpus callosum, posterior cingulate cortex, and limbic lobes of ASD. The converging findings of structural and white matter abnormalities in ASD suggest that alterations in neural-anatomy of different brain regions may be involved in behavioral and cognitive deficits associated with ASD, especially in an early age of 2-3 years old toddlers.
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Lange N, Travers BG, Bigler ED, Prigge MBD, Froehlich AL, Nielsen JA, Cariello AN, Zielinski BA, Anderson JS, Fletcher PT, Alexander AA, Lainhart JE. Longitudinal volumetric brain changes in autism spectrum disorder ages 6-35 years. Autism Res 2014; 8:82-93. [PMID: 25381736 DOI: 10.1002/aur.1427] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 09/22/2014] [Indexed: 01/01/2023]
Abstract
Since the impairments associated with autism spectrum disorder (ASD) tend to persist or worsen from childhood into adulthood, it is of critical importance to examine how the brain develops over this growth epoch. We report initial findings on whole and regional longitudinal brain development in 100 male participants with ASD (226 high-quality magnetic resonance imaging [MRI] scans; mean inter-scan interval 2.7 years) compared to 56 typically developing controls (TDCs) (117 high-quality scans; mean inter-scan interval 2.6 years) from childhood into adulthood, for a total of 156 participants scanned over an 8-year period. This initial analysis includes between one and three high-quality scans per participant that have been processed and segmented to date, with 21% having one scan, 27% with two scans, and 52% with three scans in the ASD sample; corresponding percentages for the TDC sample are 30%, 30%, and 40%. The proportion of participants with multiple scans (79% of ASDs and 68% of TDCs) was high in comparison to that of large longitudinal neuroimaging studies of typical development. We provide volumetric growth curves for the entire brain, total gray matter (GM), frontal GM, temporal GM, parietal GM, occipital GM, total cortical white matter (WM), corpus callosum, caudate, thalamus, total cerebellum, and total ventricles. Mean volume of cortical WM was reduced significantly. Mean ventricular volume was increased in the ASD sample relative to the TDCs across the broad age range studied. Decreases in regional mean volumes in the ASD sample most often were due to decreases during late adolescence and adulthood. The growth curve of whole brain volume over time showed increased volumes in young children with autism, and subsequently decreased during adolescence to meet the TDC curve between 10 and 15 years of age. The volume of many structures continued to decline atypically into adulthood in the ASD sample. The data suggest that ASD is a dynamic disorder with complex changes in whole and regional brain volumes that change over time from childhood into adulthood.
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Affiliation(s)
- Nicholas Lange
- Department of Psychiatry, Harvard School of Medicine, Boston, Massachusetts; Neurostatistics Laboratory, McLean Hospital, Belmont, Massachusetts
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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: 200] [Impact Index Per Article: 20.0] [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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Morgan JT, Barger N, Amaral DG, Schumann CM. Stereological study of amygdala glial populations in adolescents and adults with autism spectrum disorder. PLoS One 2014; 9:e110356. [PMID: 25330013 PMCID: PMC4201518 DOI: 10.1371/journal.pone.0110356] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/06/2014] [Indexed: 11/23/2022] Open
Abstract
The amygdala undergoes aberrant development in autism spectrum disorder (ASD). We previously found that there are reduced neuron numbers in the adult postmortem amygdala from individuals with ASD compared to typically developing controls. The current study is a comprehensive stereological examination of four non-neuronal cell populations: microglia, oligodendrocytes, astrocytes, and endothelial cells, in the same brains studied previously. We provide a detailed neuroanatomical protocol for defining each cell type that may be applied to other studies of the amygdala in neurodevelopmental and psychiatric disorders. We then assess whether cell numbers and average volumes differ between ASD and typically developing brains. We hypothesized that a reduction in neuron numbers in ASD might relate to altered immune function and/or aberrant microglial activation, as indicated by increased microglial number and cell body volume. Overall, average non-neuronal cell numbers and volumes did not differ between ASD and typically developing brains. However, there was evident heterogeneity within the ASD cohort. Two of the eight ASD brains displayed strong microglial activation. Contrary to our original hypothesis, there was a trend toward a positive correlation between neuronal and microglial numbers in both ASD and control cases. There were fewer oligodendrocytes in the amygdala of adult individuals with ASD ages 20 and older compared to typically developing controls. This finding may provide a possible sign of altered connectivity or impaired neuronal communication that may change across the lifespan in ASD.
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Affiliation(s)
- John T. Morgan
- Department of Psychiatry and Behavioral Sciences and the M. I. N. D. Institute, University of California Davis, Sacramento, California, United States of America
| | - Nicole Barger
- Department of Psychiatry and Behavioral Sciences and the M. I. N. D. Institute, University of California Davis, Sacramento, California, United States of America
| | - David G. Amaral
- Department of Psychiatry and Behavioral Sciences and the M. I. N. D. Institute, University of California Davis, Sacramento, California, United States of America
| | - Cynthia M. Schumann
- Department of Psychiatry and Behavioral Sciences and the M. I. N. D. Institute, University of California Davis, Sacramento, California, United States of America
- * E-mail:
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Schore AN. Early interpersonal neurobiological assessment of attachment and autistic spectrum disorders. Front Psychol 2014; 5:1049. [PMID: 25339916 PMCID: PMC4184129 DOI: 10.3389/fpsyg.2014.01049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/02/2014] [Indexed: 12/18/2022] Open
Abstract
There is now a strong if not urgent call in both the attachment and autism literatures for updated, research informed, clinically relevant interventions that can more effectively assess the mother infant dyad during early periods of brain plasticity. In this contribution I describe my work in regulation theory, an overarching interpersonal neurobiological model of the development, psychopathogenesis, and treatment of the early forming subjective self system. The theory models the psychoneurobiological mechanisms by which early rapid, spontaneous and thereby implicit emotionally laden attachment communications indelibly impact the experience-dependent maturation of the right brain, the “emotional brain.” Reciprocal right-lateralized visual-facial, auditory-prosodic, and tactile–gestural non-verbal communications lie at the psychobiological core of the emotional attachment bond between the infant and primary caregiver. These affective communications can in turn be interactively regulated by the primary caregiver, thereby expanding the infant’s developing right brain regulatory systems. Regulated and dysregulated bodily based communications can be assessed in order to determine the ongoing status of both the infant’s emotional and social development as well as the quality and efficiency of the infant–mother attachment relationship. I then apply the model to the assessment of early stages of autism. Developmental neurobiological research documents significant alterations of the early developing right brain in autistic infants and toddlers, as well profound attachment failures and intersubjective deficits in autistic infant–mother dyads. Throughout I offer implications of the theory for clinical assessment models. This work suggests that recent knowledge of the social and emotional functions of the early developing right brain may not only bridge the attachment and autism worlds, but facilitate more effective attachment and autism models of early intervention.
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Affiliation(s)
- Allan N Schore
- David Geffen School of Medicine, University of California Los Angeles Northridge, CA, USA
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119
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Gliga T, Jones EJH, Bedford R, Charman T, Johnson MH. From early markers to neuro-developmental mechanisms of autism. DEVELOPMENTAL REVIEW 2014; 34:189-207. [PMID: 25187673 PMCID: PMC4119302 DOI: 10.1016/j.dr.2014.05.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 05/19/2014] [Indexed: 02/06/2023]
Abstract
Studies of infants at-risk could reveal the developmental origin of autism. Behavioral and brain markers differentiate infants that develop autism symptoms from controls, during the first year of life. Little evidence for decreased social orienting or social motivation. Some evidence for multiple developmental pathways to autism.
A fast growing field, the study of infants at risk because of having an older sibling with autism (i.e. infant sibs) aims to identify the earliest signs of this disorder, which would allow for earlier diagnosis and intervention. More importantly, we argue, these studies offer the opportunity to validate existing neuro-developmental models of autism against experimental evidence. Although autism is mainly seen as a disorder of social interaction and communication, emerging early markers do not exclusively reflect impairments of the “social brain”. Evidence for atypical development of sensory and attentional systems highlight the need to move away from localized deficits to models suggesting brain-wide involvement in autism pathology. We discuss the implications infant sibs findings have for future work into the biology of autism and the development of interventions.
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Affiliation(s)
- T Gliga
- Centre for Brain and Cognitive Development, Birkbeck College, University of London, United Kingdom
| | - E J H Jones
- Centre for Brain and Cognitive Development, Birkbeck College, University of London, United Kingdom
| | - R Bedford
- Biostatistics Department, Institute of Psychiatry, King's College London, United Kingdom
| | - T Charman
- Psychology Department, Institute of Psychiatry, King's College London, United Kingdom
| | - M H Johnson
- Centre for Brain and Cognitive Development, Birkbeck College, University of London, United Kingdom
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120
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Kushki A, Brian J, Dupuis A, Anagnostou E. Functional autonomic nervous system profile in children with autism spectrum disorder. Mol Autism 2014; 5:39. [PMID: 25031832 PMCID: PMC4099494 DOI: 10.1186/2040-2392-5-39] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 06/18/2014] [Indexed: 12/28/2022] Open
Abstract
Background Autonomic dysregulation has been recently reported as a feature of autism spectrum disorder (ASD). However, the nature of autonomic atypicalities in ASD remain largely unknown. The goal of this study was to characterize the cardiac autonomic profile of children with ASD across four domains affected in ASD (anxiety, attention, response inhibition, and social cognition), and suggested to be affected by autonomic dysregulation. Methods We compared measures of autonomic cardiac regulation in typically developing children (n = 34) and those with ASD (n = 40) as the children performed tasks eliciting anxiety, attention, response inhibition, and social cognition. Heart rate was used to quantify overall autonomic arousal, and respiratory sinus arrhythmia (RSA) was used as an index of vagal influences. Associations between atypical autonomic findings and intellectual functioning (Weschler scale), ASD symptomatology (Social Communication Questionnaire score), and co-morbid anxiety (Revised Children’s Anxiety and Depression Scale) were also investigated. Results The ASD group had marginally elevated basal heart rate, and showed decreased heart rate reactivity to social anxiety and increased RSA reactivity to the social cognition task. In this group, heart rate reactivity to the social anxiety task was positively correlated with IQ and task performance, and negatively correlated with generalized anxiety. RSA reactivity in the social cognition task was positively correlated with IQ. Conclusions Our data suggest overall autonomic hyperarousal in ASD and selective atypical reactivity to social tasks.
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Affiliation(s)
- Azadeh Kushki
- Bloorview Research Institute, 150 Kilgour Road, M4G 1R8 Toronto, Canada ; The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, M5S 3G9 Toronto, Canada
| | - Jessica Brian
- Bloorview Research Institute, 150 Kilgour Road, M4G 1R8 Toronto, Canada
| | - Annie Dupuis
- The Hospital for Sick Children, 555 University Avenue, M5G 1X8 Toronto, Canada
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The effect of age, diagnosis, and their interaction on vertex-based measures of cortical thickness and surface area in autism spectrum disorder. J Neural Transm (Vienna) 2014; 121:1157-70. [PMID: 24752753 DOI: 10.1007/s00702-014-1207-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 03/26/2014] [Indexed: 12/26/2022]
Abstract
Autism spectrum disorder (ASD) is a lifelong neurodevelopmental condition that is accompanied by an atypical development of brain maturation. So far, brain development has mainly been studied during early childhood in ASD, and using measures of total or lobular brain volume. However, cortical volumetric measures are a product of two distinct biological neuroanatomical features, cortical thickness, and surface area, which most likely also have different neurodevelopmental trajectories in ASD. Here, we therefore examined age-related differences in cortical thickness and surface area in a cross-sectional sample of 77 male individuals with ASD ranging from 7 to 25 years of age, and 77 male neurotypical controls matched for age and FSIQ. Surface-based measures were analyzed using a general linear model (GLM) including linear, quadratic, and cubic age terms, as well as their interactions with the main effect of group. When controlling for the effects of age, individuals with ASD had spatially distributed reductions in cortical thickness relative to controls, particularly in fronto-temporal regions, and also showed significantly reduced surface area in the prefrontal cortex and the anterior temporal lobe. We also observed significant group × age interactions for both measures. However, while cortical thickness was best predicted by a quadratic age term, the neurodevelopmental trajectory for measures of surface area was mostly linear. Our findings suggest that ASD is accompanied by age-related and region-specific reductions in cortical thickness and surface area during childhood and early adulthood. Thus, differences in the neurodevelopmental trajectory of maturation for both measures need to be taken into account when interpreting between-group differences overall.
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122
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Kodish I, Rockhill CM, Webb SJ. ASD: Psychopharmacologic Treatments and Neurophysiologic Underpinnings. Curr Top Behav Neurosci 2014; 21:257-75. [PMID: 24683058 PMCID: PMC4180816 DOI: 10.1007/7854_2014_298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Autism Spectrum Disorder encompasses a range of neurodevelopmental disorders characterized by early deficits in social communication in addition to restricted and repetitive behaviors. Symptoms are increasingly understood to be associated with abnormalities in the coordination of neuronal assemblies responsible for processing information essential for early adaptive behaviors. Pharmacologic treatments carry evidence for clinically significant benefit of multiple impairing symptoms of ASD, yet these benefits are limited and range across a broad spectrum of medication classes, making it difficult to characterize associated neurochemical impairments. Increasing prevalence of both ASD and its pharmacologic management calls for greater understanding of the neurophysiologic basis of the disorder. This paper reviews underlying alterations in local brain regions and coordination of brain activation patterns during both resting state and task-related processes. We propose that new pharmacologic treatments may focus on realigning trajectories of network specialization across development by working in combination with behavioral treatments to enhance social and emotional learning by bolstering the impact of experience-induced plasticity on neuronal network connectivity.
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Affiliation(s)
- Ian Kodish
- University of Washington Department of Psychiatry and Behavioral Sciences, Seattle, United States of America
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Abstract
Autism is a set of heterogeneous neurodevelopmental conditions, characterised by early-onset difficulties in social communication and unusually restricted, repetitive behaviour and interests. The worldwide population prevalence is about 1%. Autism affects more male than female individuals, and comorbidity is common (>70% have concurrent conditions). Individuals with autism have atypical cognitive profiles, such as impaired social cognition and social perception, executive dysfunction, and atypical perceptual and information processing. These profiles are underpinned by atypical neural development at the systems level. Genetics has a key role in the aetiology of autism, in conjunction with developmentally early environmental factors. Large-effect rare mutations and small-effect common variants contribute to risk. Assessment needs to be multidisciplinary and developmental, and early detection is essential for early intervention. Early comprehensive and targeted behavioural interventions can improve social communication and reduce anxiety and aggression. Drugs can reduce comorbid symptoms, but do not directly improve social communication. Creation of a supportive environment that accepts and respects that the individual is different is crucial.
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Affiliation(s)
- Meng-Chuan Lai
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK; Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan.
| | - Michael V Lombardo
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK; Department of Psychology, University of Cyprus, Nicosia, Cyprus
| | - Simon Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK; Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
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Anderson G, Maes M. Redox Regulation and the Autistic Spectrum: Role of Tryptophan Catabolites, Immuno-inflammation, Autoimmunity and the Amygdala. Curr Neuropharmacol 2014; 12:148-67. [PMID: 24669209 PMCID: PMC3964746 DOI: 10.2174/1570159x11666131120223757] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Revised: 08/18/2013] [Accepted: 11/02/2013] [Indexed: 12/12/2022] Open
Abstract
The autistic spectrum disorders (ASD) form a set of multi-faceted disorders with significant genetic, epigenetic and environmental determinants. Oxidative and nitrosative stress (O&NS), immuno-inflammatory pathways, mitochondrial dysfunction and dysregulation of the tryptophan catabolite (TRYCATs) pathway play significant interactive roles in driving the early developmental etiology and course of ASD. O&NS interactions with immuno-inflammatory pathways mediate their effects centrally via the regulation of astrocyte and microglia responses, including regional variations in TRYCATs produced. Here we review the nature of these interactions and propose an early developmental model whereby different ASD genetic susceptibilities interact with environmental and epigenetic processes, resulting in glia biasing the patterning of central interarea interactions. A role for decreased local melatonin and N-acetylserotonin production by immune and glia cells may be a significant treatment target.
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Affiliation(s)
| | - Michael Maes
- Department of Psychiatry, Chulalongkorn University, Bangkok, Thailand
- Department of Psychiatry, Deakin University, Geelong, Australia
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Neurobiological abnormalities in the first few years of life in individuals later diagnosed with autism spectrum disorder: a review of recent data. Behav Neurol 2014; 2014:210780. [PMID: 24825948 PMCID: PMC4006615 DOI: 10.1155/2014/210780] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 06/23/2013] [Indexed: 02/07/2023] Open
Abstract
Background. Despite the widely-held understanding that the biological changes that lead to autism usually occur during prenatal life, there has been relatively little research into the functional development of the brain during early infancy in individuals later diagnosed with autism spectrum disorder (ASD). Objective. This review explores the studies over the last three years which have investigated differences in various brain regions in individuals with ASD or who later go on to receive a diagnosis of ASD. Methods. We used PRISMA guidelines and selected published articles reporting any neurological abnormalities in very early childhood in individuals with or later diagnosed with ASD. Results. Various brain regions are discussed including the amygdala, cerebellum, frontal cortex, and lateralised abnormalities of the temporal cortex during language processing. This review discusses studies investigating head circumference, electrophysiological markers, and interhemispheric synchronisation. All of the recent findings from the beginning of 2009 across these different aspects of defining neurological abnormalities are discussed in light of earlier findings. Conclusions. The studies across these different areas reveal the existence of atypicalities in the first year of life, well before ASD is reliably diagnosed. Cross-disciplinary approaches are essential to elucidate the pathophysiological sequence of events that lead to ASD.
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126
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Barnea-Goraly N, Frazier TW, Piacenza L, Minshew NJ, Keshavan MS, Reiss AL, Hardan AY. A preliminary longitudinal volumetric MRI study of amygdala and hippocampal volumes in autism. Prog Neuropsychopharmacol Biol Psychiatry 2014; 48:124-8. [PMID: 24075822 PMCID: PMC8655120 DOI: 10.1016/j.pnpbp.2013.09.010] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/03/2013] [Accepted: 09/16/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Previous studies suggest that amygdala volume, when compared with healthy controls, is increased in young children with autism, is unchanged in cohorts of older youth, and is smaller in adults. Hippocampal volume, however, does not appear to have age-related changes, and it is unclear whether individuals with autism have volumetric differences in this structure. The goal of this pilot investigation is to characterize the developmental trajectories of the amygdala and hippocampus in children with autism between the ages of 8 and 14years and to examine clinical correlates of volume change. METHODS Twenty-three children with autism and 23 controls between the ages of 8 and 12 underwent a magnetic resonance imaging procedure of the brain (T1-weighted) at two time points. Nine children with autism and 14 controls had good quality scans from both time points; however, all usable scans from all subjects (15 children with autism and 22 controls) were included in a mixed effect analysis. Regression models were used to estimate group differences in amygdala and hippocampal volumes. Changes in amygdala and hippocampal volumes (Time 2-Time 1) were correlated with clinical severity measures. RESULTS Amygdala volume changes with time were similar between the two groups. Within the autism group, right amygdala volume change was correlated with the ability to establish appropriate eye contact. Right hippocampal volume was significantly increased in the autism group when compared with controls. Differences in right hippocampal volume change with time between the two groups approached significance. CONCLUSION This study provides preliminary evidence of normalization of amygdala volumes in late childhood and adolescence. It also suggests that hippocampal volumetric differences may exist in autism in late childhood and adolescence.
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Affiliation(s)
- Naama Barnea-Goraly
- Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford,Corresponding author
| | | | - Lucia Piacenza
- Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford
| | - Nancy J. Minshew
- Department of Psychiatry and Neurology, University of Pittsburgh
| | | | - Allan L. Reiss
- Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford,Department of Pediatrics Stanford University, Stanford, CA,Department of Pediatrics, Stanford University, Stanford, CA, United States
| | - Antonio Y. Hardan
- Department of Psychiatry and Behavioral Science, Stanford University School of Medicine, Stanford, United States
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127
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What We Have Learned about Autism Spectrum Disorder from Valproic Acid. PATHOLOGY RESEARCH INTERNATIONAL 2013; 2013:712758. [PMID: 24381784 PMCID: PMC3871912 DOI: 10.1155/2013/712758] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 10/16/2013] [Accepted: 10/17/2013] [Indexed: 12/29/2022]
Abstract
Two recent epidemiological investigations in children exposed to valproic acid (VPA) treatment in utero have reported a significant risk associated with neurodevelopmental disorders and autism spectrum disorder (ASD) in particular. Parallel to this work, there is a growing body of animal research literature using VPA as an animal model of ASD. In this focused review we first summarize the epidemiological evidence linking VPA to ASD and then comment on two important neurobiological findings linking VPA to ASD clinicopathology, namely, accelerated or early brain overgrowth and hyperexcitable networks. Improving our understanding of how the drug VPA can alter early development of neurological systems will ultimately improve our understanding of ASD.
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128
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Abstract
This brief review encompasses the key findings of structural Magnetic Resonance Imaging (sMRI) research on amygdala volume in autism spectrum disorders (ASD). We also highlight the possible correlation between the autistic behavioural phenotype and amygdala alteration.
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129
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Johnson RT, Yeatman JD, Wandell BA, Buonocore MH, Amaral DG, Nordahl CW. Diffusion properties of major white matter tracts in young, typically developing children. Neuroimage 2013; 88:143-54. [PMID: 24269274 DOI: 10.1016/j.neuroimage.2013.11.025] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/01/2013] [Accepted: 11/14/2013] [Indexed: 11/30/2022] Open
Abstract
Brain development occurs rapidly during the first few years of life involving region-specific changes in both gray matter and white matter. Due to the inherent difficulties in acquiring magnetic resonance imaging data in young children, little is known about the properties of white matter in typically developing toddlers. In the context of an ongoing study of young children with autism spectrum disorder, we collected diffusion-weighted imaging data during natural nocturnal sleep in a sample of young (mean age=35months) typically developing male and female (n=41 and 25, respectively) children. Axial diffusivity, radial diffusivity, mean diffusivity and fractional anisotropy were measured at 99 points along the length of 18 major brain tracts. Influences of hemisphere, age, sex, and handedness were examined. We find that diffusion properties vary significantly along the length of the majority of tracks. We also identify hemispheric and sex differences in diffusion properties in several tracts. Finally, we find the relationship between age and diffusion parameters changes along the tract length illustrating variability in age-related white-matter development at the tract level.
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Affiliation(s)
- Ryan T Johnson
- M.I.N.D. Institute, Department of Psychiatry and Behavioral Sciences, University of California at Davis, 2825 50th Street, Sacramento, CA 95817, USA
| | - Jason D Yeatman
- Department of Psychology, Jordan Hall, Stanford University, 450 Serra Mall, Stanford, CA 94305, USA
| | - Brian A Wandell
- Department of Psychology, Jordan Hall, Stanford University, 450 Serra Mall, Stanford, CA 94305, USA
| | - Michael H Buonocore
- Department of Radiology, UC Davis School of Medicine, University of California, Sacramento, CA 95817, USA
| | - David G Amaral
- M.I.N.D. Institute, Department of Psychiatry and Behavioral Sciences, University of California at Davis, 2825 50th Street, Sacramento, CA 95817, USA
| | - Christine Wu Nordahl
- M.I.N.D. Institute, Department of Psychiatry and Behavioral Sciences, University of California at Davis, 2825 50th Street, Sacramento, CA 95817, USA.
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Johnson RT, Breedlove SM, Jordan CL. Androgen receptors mediate masculinization of astrocytes in the rat posterodorsal medial amygdala during puberty. J Comp Neurol 2013; 521:2298-309. [PMID: 23239016 DOI: 10.1002/cne.23286] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 12/03/2012] [Accepted: 12/11/2012] [Indexed: 11/07/2022]
Abstract
Astrocytes in the posterodorsal portion of the medial amygdala (MePD) are sexually dimorphic in adult rats: males have more astrocytes in the right MePD and more elaborate processes in the left MePD than do females. Functional androgen receptors (ARs) are required for masculinization of MePD astrocytes, as these measures are demasculinized in adult males carrying the testicular feminization mutation (Tfm) of the AR gene, which renders AR dysfunctional. We now report that the number of astrocytes is already sexually dimorphic in the right MePD of juvenile 25-day-old (P25) rats. Because Tfm males have as many astrocytes as wild-type males at this age, this prepubertal sexual dimorphism is independent of ARs. After P25, astrocyte number increases in the MePD of all groups, but activation of ARs augments this increase in the right MePD, where more astrocytes are added in males than in Tfm males. Consequently, by adulthood, females and Tfm males have equivalent numbers of astrocytes in the right MePD. Sexual dimorphism in astrocyte arbor complexity in the left MePD arises after P25, and is entirely AR-dependent. Thus, masculinization of MePD astrocytes is a result of both AR-independent processes before the juvenile period and AR-dependent processes afterward.
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Affiliation(s)
- Ryan T Johnson
- Neuroscience Program, Michigan State University, East Lansing, Michigan 48824-1101, USA.
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131
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Zettergren A, Jonsson L, Johansson D, Melke J, Lundström S, Anckarsäter H, Lichtenstein P, Westberg L. Associations between polymorphisms in sex steroid related genes and autistic-like traits. Psychoneuroendocrinology 2013; 38:2575-84. [PMID: 23867117 DOI: 10.1016/j.psyneuen.2013.06.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 05/24/2013] [Accepted: 06/07/2013] [Indexed: 01/27/2023]
Abstract
Sex differences in psychiatric disorders are common, which is particularly striking in autism spectrum disorders (ASDs) that are four times more prevalent in boys. High levels of testosterone during early development have been hypothesized to be a risk factor for ASDs, supported by several studies showing fetal testosterone levels, as well as indirect measures of prenatal androgenization, to be associated with ASDs and autistic-like traits (ALTs). Further, the importance of sex steroid related genes in ASDs is supported by studies reporting associations between polymorphisms in genes involved in sex steroid synthesis/metabolism and ASDs and ALTs. The aim of the present study was to investigate possible associations between 29 single nucleotide polymorphisms (SNPs) in eight genes related to sex steroids and autistic features. Individuals included in the study belong to a subset (n=1771) from The Child and Adolescent Twin Study in Sweden (CATSS), which are all assessed for ALTs. For two SNPs, rs2747648 located in the 3'-UTR of ESR1 encoding the estrogen receptor alpha and rs523349 (Leu89Val) located in SRD5A2 encoding 5-alpha-reductase, type 2, highly significant associations with ALTs were found in boys and girls, respectively. The results of the present study suggest that SNPs in sex steroid related genes, known to affect gene expression (rs2747648 in ESR1) and enzymatic activity (Leu89Val in SRD5A2), seem to be associated with ALTs in a general population. In conclusion, the current findings provide further support for a role of sex steroids in the pathophysiology of ASDs.
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Affiliation(s)
- Anna Zettergren
- Institute of Neuroscience and Physiology, Department of Pharmacology, University of Gothenburg, Sweden.
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132
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Lenroot RK, Yeung PK. Heterogeneity within Autism Spectrum Disorders: What have We Learned from Neuroimaging Studies? Front Hum Neurosci 2013; 7:733. [PMID: 24198778 PMCID: PMC3812662 DOI: 10.3389/fnhum.2013.00733] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/13/2013] [Indexed: 11/13/2022] Open
Abstract
Autism spectrum disorders (ASD) display significant heterogeneity. Although most neuroimaging studies in ASD have been designed to identify commonalities among affected individuals, rather than differences, some studies have explored variation within ASD. There have been two general types of approaches used for this in the neuroimaging literature to date: comparison of subgroups within ASD, and analyses using dimensional measures to link clinical variation to brain differences. This review focuses on structural and functional magnetic resonance imaging studies that have used these approaches to begin to explore heterogeneity between individuals with ASD. Although this type of data is yet sparse, recognition is growing of the limitations of behaviorally defined categorical diagnoses for understanding neurobiology. Study designs that are more informative regarding the sources of heterogeneity in ASD have the potential to improve our understanding of the neurobiological processes underlying ASD.
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Affiliation(s)
- Rhoshel K Lenroot
- School of Psychiatry, University of New South Wales , Sydney, NSW , Australia ; Neuroscience Research Australia , Sydney, NSW , Australia
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133
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Abstract
Autism spectrum conditions (ASCs) are defined behaviorally, but they also involve multileveled disturbances of underlying biology that find striking parallels in the physiological impacts of electromagnetic frequency and radiofrequency radiation exposures (EMF/RFR). Part I (Vol 776) of this paper reviewed the critical contributions pathophysiology may make to the etiology, pathogenesis and ongoing generation of behaviors currently defined as being core features of ASCs. We reviewed pathophysiological damage to core cellular processes that are associated both with ASCs and with biological effects of EMF/RFR exposures that contribute to chronically disrupted homeostasis. Many studies of people with ASCs have identified oxidative stress and evidence of free radical damage, cellular stress proteins, and deficiencies of antioxidants such as glutathione. Elevated intracellular calcium in ASCs may be due to genetics or may be downstream of inflammation or environmental exposures. Cell membrane lipids may be peroxidized, mitochondria may be dysfunctional, and various kinds of immune system disturbances are common. Brain oxidative stress and inflammation as well as measures consistent with blood-brain barrier and brain perfusion compromise have been documented. Part II of this paper documents how behaviors in ASCs may emerge from alterations of electrophysiological oscillatory synchronization, how EMF/RFR could contribute to these by de-tuning the organism, and policy implications of these vulnerabilities. It details evidence for mitochondrial dysfunction, immune system dysregulation, neuroinflammation and brain blood flow alterations, altered electrophysiology, disruption of electromagnetic signaling, synchrony, and sensory processing, de-tuning of the brain and organism, with autistic behaviors as emergent properties emanating from this pathophysiology. Changes in brain and autonomic nervous system electrophysiological function and sensory processing predominate, seizures are common, and sleep disruption is close to universal. All of these phenomena also occur with EMF/RFR exposure that can add to system overload ('allostatic load') in ASCs by increasing risk, and can worsen challenging biological problems and symptoms; conversely, reducing exposure might ameliorate symptoms of ASCs by reducing obstruction of physiological repair. Various vital but vulnerable mechanisms such as calcium channels may be disrupted by environmental agents, various genes associated with autism or the interaction of both. With dramatic increases in reported ASCs that are coincident in time with the deployment of wireless technologies, we need aggressive investigation of potential ASC-EMF/RFR links. The evidence is sufficient to warrant new public exposure standards benchmarked to low-intensity (non-thermal) exposure levels now known to be biologically disruptive, and strong, interim precautionary practices are advocated.
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134
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Schore AN. Regulation Theory and the Early Assessment of Attachment and Autistic Spectrum Disorders: A Response to Voran's Clinical Case. ACTA ACUST UNITED AC 2013. [DOI: 10.1080/15289168.2013.822741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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135
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Torres EB, Brincker M, Isenhower RW, Yanovich P, Stigler KA, Nurnberger JI, Metaxas DN, José JV. Autism: the micro-movement perspective. Front Integr Neurosci 2013; 7:32. [PMID: 23898241 PMCID: PMC3721360 DOI: 10.3389/fnint.2013.00032] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Accepted: 04/21/2013] [Indexed: 11/13/2022] Open
Abstract
The current assessment of behaviors in the inventories to diagnose autism spectrum disorders (ASD) focus on observation and discrete categorizations. Behaviors require movements, yet measurements of physical movements are seldom included. Their inclusion however, could provide an objective characterization of behavior to help unveil interactions between the peripheral and the central nervous systems (CNSs). Such interactions are critical for the development and maintenance of spontaneous autonomy, self-regulation, and voluntary control. At present, current approaches cannot deal with the heterogeneous, dynamic and stochastic nature of development. Accordingly, they leave no avenues for real time or longitudinal assessments of change in a coping system continuously adapting and developing compensatory mechanisms. We offer a new unifying statistical framework to reveal re-afferent kinesthetic features of the individual with ASD. The new methodology is based on the non-stationary stochastic patterns of minute fluctuations (micro-movements) inherent to our natural actions. Such patterns of behavioral variability provide re-entrant sensory feedback contributing to the autonomous regulation and coordination of the motor output. From an early age, this feedback supports centrally driven volitional control and fluid, flexible transitions between intentional and spontaneous behaviors. We show that in ASD there is a disruption in the maturation of this form of proprioception. Despite this disturbance, each individual has unique adaptive compensatory capabilities that we can unveil and exploit to evoke faster and more accurate decisions. Measuring the kinesthetic re-afference in tandem with stimuli variations we can detect changes in their micro-movements indicative of a more predictive and reliable kinesthetic percept. Our methods address the heterogeneity of ASD with a personalized approach grounded in the inherent sensory-motor abilities that the individual has already developed.
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Affiliation(s)
- Elizabeth B Torres
- Psychology Department, Rutgers Center for Cognitive Science, Center for Computational Biomedicine Imaging and Modeling (Computer Science), Movement Disorders, Neurology, Rutgers University School of Medicine, Rutgers University New Brunswick, NJ, USA ; Movement Disorders, Neurology Department, Indiana University School of Medicine Indianapolis, IN, USA
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136
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Torres EB, Isenhower RW, Yanovich P, Rehrig G, Stigler K, Nurnberger J, José JV. Strategies to develop putative biomarkers to characterize the female phenotype with autism spectrum disorders. J Neurophysiol 2013; 110:1646-62. [PMID: 23864377 DOI: 10.1152/jn.00059.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Current observational inventories used to diagnose autism spectrum disorders (ASD) apply similar criteria to females and males alike, despite developmental differences between the sexes. Recent work investigating the chronology of diagnosis in ASD has raised the concern that females run the risk of receiving a delayed diagnosis, potentially missing a window of opportunity for early intervention. Here, we retake this issue in the context of the objective measurements of natural behaviors that involve decision-making processes. Within this context, we quantified movement variability in typically developing (TD) individuals and those diagnosed with ASD across different ages. We extracted the latencies of the decision movements and velocity-dependent parameters as the hand movements unfolded for two movement segments within the reach: movements intended toward the target and withdrawing movements that spontaneously, without instruction, occurred incidentally. The stochastic signatures of the movement decision latencies and the percent of time to maximum speed differed between males and females with ASD. This feature was also observed in the empirically estimated probability distributions of the maximum speed values, independent of limb size. Females with ASD showed different dispersion than males with ASD. The distinctions found for females with ASD were better appreciated compared with those of TD females. In light of these results, behavioral assessment of autistic traits in females should be performed relative to TD females to increase the chance of detection.
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137
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Shen MD, Nordahl CW, Young GS, Wootton-Gorges SL, Lee A, Liston SE, Harrington KR, Ozonoff S, Amaral DG. Early brain enlargement and elevated extra-axial fluid in infants who develop autism spectrum disorder. ACTA ACUST UNITED AC 2013; 136:2825-35. [PMID: 23838695 DOI: 10.1093/brain/awt166] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Prospective studies of infants at risk for autism spectrum disorder have provided important clues about the early behavioural symptoms of autism spectrum disorder. Diagnosis of autism spectrum disorder, however, is not currently made until at least 18 months of age. There is substantially less research on potential brain-based differences in the period between 6 and 12 months of age. Our objective in the current study was to use magnetic resonance imaging to identify any consistently observable brain anomalies in 6-9 month old infants who would later develop autism spectrum disorder. We conducted a prospective infant sibling study with longitudinal magnetic resonance imaging scans at three time points (6-9, 12-15, and 18-24 months of age), in conjunction with intensive behavioural assessments. Fifty-five infants (33 'high-risk' infants having an older sibling with autism spectrum disorder and 22 'low-risk' infants having no relatives with autism spectrum disorder) were imaged at 6-9 months; 43 of these (27 high-risk and 16 low-risk) were imaged at 12-15 months; and 42 (26 high-risk and 16 low-risk) were imaged again at 18-24 months. Infants were classified as meeting criteria for autism spectrum disorder, other developmental delays, or typical development at 24 months or later (mean age at outcome: 32.5 months). Compared with the other two groups, infants who developed autism spectrum disorder (n = 10) had significantly greater extra-axial fluid at 6-9 months, which persisted and remained elevated at 12-15 and 18-24 months. Extra-axial fluid is characterized by excessive cerebrospinal fluid in the subarachnoid space, particularly over the frontal lobes. The amount of extra-axial fluid detected as early as 6 months was predictive of more severe autism spectrum disorder symptoms at the time of outcome. Infants who developed autism spectrum disorder also had significantly larger total cerebral volumes at both 12-15 and 18-24 months of age. This is the first magnetic resonance imaging study to prospectively evaluate brain growth trajectories from infancy in children who develop autism spectrum disorder. The presence of excessive extra-axial fluid detected as early as 6 months and the lack of resolution by 24 months is a hitherto unreported brain anomaly in infants who later develop autism spectrum disorder. This is also the first magnetic resonance imaging evidence of brain enlargement in autism before age 2. These findings raise the potential for the use of structural magnetic resonance imaging to aid in the early detection of children at risk for autism spectrum disorder or other neurodevelopmental disorders.
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Affiliation(s)
- Mark D Shen
- The Medical Investigation of Neurodevelopmental Disorders Institute and Department of Psychiatry and Behavioural Sciences, UC Davis School of Medicine, University of California, Davis, Sacramento, CA 95817, USA
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138
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Autism-specific maternal autoantibodies recognize critical proteins in developing brain. Transl Psychiatry 2013; 3:e277. [PMID: 23838888 PMCID: PMC3731784 DOI: 10.1038/tp.2013.50] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 04/22/2013] [Accepted: 04/23/2013] [Indexed: 11/16/2022] Open
Abstract
Autism spectrum disorders (ASDs) are neurodevelopmental in origin, affecting an estimated 1 in 88 children in the United States. We previously described ASD-specific maternal autoantibodies that recognize fetal brain antigens. Herein, we demonstrate that lactate dehydrogenase A and B (LDH), cypin, stress-induced phosphoprotein 1 (STIP1), collapsin response mediator proteins 1 and 2 (CRMP1, CRMP2) and Y-box-binding protein to comprise the seven primary antigens of maternal autoantibody-related (MAR) autism. Exclusive reactivity to specific antigen combinations was noted in 23% of mothers of ASD children and only 1% of controls. ASD children from mothers with specific reactivity to LDH, STIP1 and CRMP1 and/or cypin (7% vs 0% in controls; P<0.0002; odds ratios of 24.2 (95% confidence interval: 1.45-405)) had elevated stereotypical behaviors compared with ASD children from mothers lacking these antibodies. We describe the first panel of clinically significant biomarkers with over 99% specificity for autism risk thereby advancing our understanding of the etiologic mechanisms and therapeutic possibilities for MAR autism.
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139
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Breece E, Paciotti B, Nordahl CW, Ozonoff S, Van de Water JA, Rogers SJ, Amaral D, Ashwood P. Myeloid dendritic cells frequencies are increased in children with autism spectrum disorder and associated with amygdala volume and repetitive behaviors. Brain Behav Immun 2013; 31:69-75. [PMID: 23063420 PMCID: PMC4229011 DOI: 10.1016/j.bbi.2012.10.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Revised: 10/03/2012] [Accepted: 10/04/2012] [Indexed: 12/25/2022] Open
Abstract
The pathophysiology of autism spectrum disorder (ASD) is not yet known; however, studies suggest that dysfunction of the immune system affects many children with ASD. Increasing evidence points to dysfunction of the innate immune system including activation of microglia and perivascular macrophages, increases in inflammatory cytokines/chemokines in brain tissue and CSF, and abnormal peripheral monocyte cell function. Dendritic cells are major players in innate immunity and have important functions in the phagocytosis of pathogens or debris, antigen presentation, activation of naïve T cells, induction of tolerance and cytokine/chemokine production. In this study, we assessed circulating frequencies of myeloid dendritic cells (defined as Lin-1(-)BDCA1(+)CD11c(+) and Lin-1(-)BDCA3(+)CD123(-)) and plasmacytoid dendritic cells (Lin-1(-)BDCA2(+)CD123(+) or Lin-1(-)BDCA4(+) CD11c(-)) in 57 children with ASD, and 29 typically developing controls of the same age, all of who were enrolled as part of the Autism Phenome Project (APP). The frequencies of dendritic cells and associations with behavioral assessment and MRI measurements of amygdala volume were compared in the same participants. The frequencies of myeloid dendritic cells were significantly increased in children with ASD compared to typically developing controls (p<0.03). Elevated frequencies of myeloid dendritic cells were positively associated with abnormal right and left amygdala enlargement, severity of gastrointestinal symptoms and increased repetitive behaviors. The frequencies of plasmacytoid dendritic cells were also associated with amygdala volumes as well as developmental regression in children with ASD. Dendritic cells play key roles in modulating immune responses and differences in frequencies or functions of these cells may result in immune dysfunction in children with ASD. These data further implicate innate immune cells in the complex pathophysiology of ASD.
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Affiliation(s)
- Elizabeth Breece
- Department of Medical Microbiology and Immunology, University of California, Davis, USA
- M.I.N.D Institute, University of California, Davis, USA
| | | | - Christine Wu Nordahl
- M.I.N.D Institute, University of California, Davis, USA
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, USA
| | - Sally Ozonoff
- M.I.N.D Institute, University of California, Davis, USA
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, USA
| | - Judy A. Van de Water
- M.I.N.D Institute, University of California, Davis, USA
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, USA
| | - Sally J. Rogers
- M.I.N.D Institute, University of California, Davis, USA
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, USA
| | - David Amaral
- M.I.N.D Institute, University of California, Davis, USA
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, USA
| | - Paul Ashwood
- Department of Medical Microbiology and Immunology, University of California, Davis, USA
- M.I.N.D Institute, University of California, Davis, USA
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140
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DeMaster D, Pathman T, Lee JK, Ghetti S. Structural development of the hippocampus and episodic memory: developmental differences along the anterior/posterior axis. ACTA ACUST UNITED AC 2013; 24:3036-45. [PMID: 23800722 DOI: 10.1093/cercor/bht160] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The hippocampus is critically involved in episodic memory, yet relatively little is known about how the development of this structure contributes to the development of episodic memory during middle to late childhood. Previous research has inconsistently reported associations between hippocampal volume and episodic memory performance during this period. We argue that this inconsistency may be due to assessing the hippocampus as a whole, and propose to examine associations separately for subregions along the longitudinal axis of the hippocampus. In the present study, we examined age-related differences in volumes of the hippocampal head, body, and tail, and collected episodic memory measures in children ages 8-11 years and young adults (N = 62). We found that adults had a smaller right hippocampal head, larger hippocampal body bilaterally, and smaller right hippocampal tail compared with children. In adults, but not in children, better episodic memory performance was associated with smaller right hippocampal head and larger hippocampal body. In children, but not in adults, better episodic memory was associated with larger left hippocampal tail. Overall, the results suggest that protracted development of hippocampal subregions contribute to age-related differences in episodic memory.
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141
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Nordahl CW, Braunschweig D, Iosif AM, Lee A, Rogers S, Ashwood P, Amaral DG, Van de Water J. Maternal autoantibodies are associated with abnormal brain enlargement in a subgroup of children with autism spectrum disorder. Brain Behav Immun 2013; 30:61-5. [PMID: 23395715 PMCID: PMC3641177 DOI: 10.1016/j.bbi.2013.01.084] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 12/05/2012] [Accepted: 01/28/2013] [Indexed: 11/27/2022] Open
Abstract
Autism spectrum disorder (ASD) is very heterogeneous and multiple subtypes and etiologies likely exist. The maternal immune system has been implicated in the pathogenesis of some forms of ASD. Previous studies have identified the presence of specific maternal IgG autoantibodies with reactivity to fetal brain proteins at 37 and 73kDa in up to 12% of mothers of children with ASD. The current study evaluates the presence of these autoantibodies in an independent cohort of mothers of 181 preschool-aged male children (131 ASD, 50 typically developing (TD) controls). We also investigated whether ASD children born to mothers with these autism-specific maternal IgG autoantibodies exhibit a distinct neural phenotype by evaluating total brain volume using structural magnetic resonance imaging (MRI). Of the 131 ASD children, 10 (7.6%) were born to mothers with the 37/73kDa IgG autoantibodies (ASD-IgG). The mothers of the remaining ASD children and all TD controls were negative for these paired autoantibodies. While both ASD groups exhibited abnormal brain enlargement that is commonly observed in this age range, the ASD-IgG group exhibited a more extreme 12.1% abnormal brain enlargement relative to the TD controls. In contrast, the remaining ASD children exhibited a smaller 4.4% abnormal brain enlargement relative to TD controls. Lobar and tissue type analyses revealed that the frontal lobe is selectively enlarged in the ASD-IgG group and that both gray and white matter are similarly affected. These results suggest that maternal autoantibodies associated with autism spectrum disorder may impact brain development leading to abnormal enlargement.
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Affiliation(s)
- Christine Wu Nordahl
- The M.I.N.D. Institute, University of California at Davis, School of Medicine, Sacramento, CA 95817, USA.
| | - Daniel Braunschweig
- Department of Internal Medicine, University of California at Davis, School of Medicine, Davis, CA 95616
| | - Ana-Maria Iosif
- Department of Public Health Sciences, Division of Biostatistics, University of California at Davis, Davis, CA 95616
| | - Aaron Lee
- Department of Psychiatry and Behavioral Sciences, University of California at Davis, School of Medicine, Sacramento, CA 95817
| | - Sally Rogers
- The M.I.N.D Institute, University of California at Davis, School of Medicine, Sacramento, CA 95817,Department of Psychiatry and Behavioral Sciences, University of California at Davis, School of Medicine, Sacramento, CA 95817
| | - Paul Ashwood
- The M.I.N.D Institute, University of California at Davis, School of Medicine, Sacramento, CA 95817,Department of Internal Medicine, University of California at Davis, School of Medicine, Davis, CA 95616
| | - David G. Amaral
- The M.I.N.D Institute, University of California at Davis, School of Medicine, Sacramento, CA 95817,Department of Psychiatry and Behavioral Sciences, University of California at Davis, School of Medicine, Sacramento, CA 95817
| | - Judy Van de Water
- The M.I.N.D Institute, University of California at Davis, School of Medicine, Sacramento, CA 95817,Department of Internal Medicine, University of California at Davis, School of Medicine, Davis, CA 95616
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142
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Bauman MD, Schumann CM. Is 'bench-to-bedside' realistic for autism? An integrative neuroscience approach. ACTA ACUST UNITED AC 2013; 3:159-168. [PMID: 24000295 DOI: 10.2217/npy.13.18] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Given the prevalence and societal impact of autism spectrum disorder (ASD), there is an urgent need to develop innovative treatments that will improve core social deficits, for which there is currently no reliable pharmacological treatment, prevention or cure. Development of novel biological interventions will depend upon the successful translation of basic neuroscience research into safe and effective medicines. This article outlines steps to bring neuroscience research from 'the bench' to treatment at 'bedside', from phenotyping the disorder to animal models to patient treatment. Although these steps appear simplistic, this is a daunting challenge because of the inherent complexity of the human brain, our lack of understanding of disease neurobiology underlying ASD, and the incredible heterogeneity of the disorder. For ASD, perhaps more than any other neurological or psychiatric disorder, progress will depend on integrative multidisciplinary approaches between basic scientists from varying neuroscience disciplines and clinicians to make 'bench to bedside' treatment a reality.
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Affiliation(s)
- Melissa D Bauman
- Department of Psychiatry & Behavioral Sciences, University of California, Davis, CA, USA ; The M.I.N.D. Institute, University of California, Davis, 2825 50th Street, Sacramento, CA 95817, USA
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143
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Jones RM, Lord C. Diagnosing autism in neurobiological research studies. Behav Brain Res 2012; 251:113-24. [PMID: 23153932 DOI: 10.1016/j.bbr.2012.10.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 10/18/2012] [Accepted: 10/22/2012] [Indexed: 12/27/2022]
Abstract
Autism spectrum disorder (ASD) is by definition a complex and heterogeneous disorder. Variation in factors such as developmental level, language ability and IQ further complicate the presentation of symptoms. Clinical research and basic science must continue to inform each other's questions to help address the heterogeneity inherent to the disorder. This review uses a clinical perspective to outline the common tools and best practices for diagnosing and characterizing ASD in a research setting. We discuss considerations for classifying research populations, including language ability and IQ and examine the advantages and disadvantages of different psychometric measurements. Ultimately, the contribution of multiple sources of data representing different perspectives is crucial for interpreting and understanding the ASD phenotype.
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Affiliation(s)
- Rebecca M Jones
- Weill-Cornell Medical College, Center for Autism and the Developing Brain, New York Presbyterian Hospital/Westchester Division, 21 Bloomingdale Road, White Plains, NY 10605, USA.
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144
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Ameis SH, Szatmari P. Imaging-genetics in autism spectrum disorder: advances, translational impact, and future directions. Front Psychiatry 2012; 3:46. [PMID: 22615702 PMCID: PMC3351673 DOI: 10.3389/fpsyt.2012.00046] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 04/23/2012] [Indexed: 12/29/2022] Open
Abstract
Autism Spectrum Disorder (ASD) refers to a group of heterogeneous neurodevelopmental disorders that are unified by impairments in reciprocal social communication and a pattern of inflexible behaviors. Recent genetic advances have resolved some of the complexity of the genetic architecture underlying ASD by identifying several genetic variants that contribute to the disorder. Different etiological pathways associated with ASD may converge through effects on common molecular mechanisms, such as synaptogenesis, neuronal motility, and axonal guidance. Recently, with more sophisticated techniques, neuroimaging, and neuropathological studies have provided some consistency of evidence that altered structure, activity, and connectivity within complex neural networks is present in ASD, compared to typically developing children. The imaging-genetics approach promises to help bridge the gap between genetic variation, resultant biological effects on the brain, and production of complex neuropsychiatric symptoms. Here, we review recent findings from the developing field of imaging-genetics applied to ASD. Studies to date have indicated that relevant risk genes are associated with alterations in circuits that mediate socio-emotional, visuo-spatial, and language processing. Longitudinal studies ideally focused on early development, in conjunction with investigation for gene-gene, and gene-environment interactions may move the promise of imaging-genetics in ASD closer to the clinical domain.
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Affiliation(s)
- Stephanie H Ameis
- Department of Psychiatry, The Hospital for Sick Children, University of Toronto Toronto, ON, Canada
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