1
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Wilkes BJ, Archer DB, Farmer AL, Bass C, Korah H, Vaillancourt DE, Lewis MH. Cortico-basal ganglia white matter microstructure is linked to restricted repetitive behavior in autism spectrum disorder. Mol Autism 2024; 15:6. [PMID: 38254158 PMCID: PMC10804694 DOI: 10.1186/s13229-023-00581-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 12/23/2023] [Indexed: 01/24/2024] Open
Abstract
BACKGROUND Restricted repetitive behavior (RRB) is one of two behavioral domains required for the diagnosis of autism spectrum disorder (ASD). Neuroimaging is widely used to study brain alterations associated with ASD and the domain of social and communication deficits, but there has been less work regarding brain alterations linked to RRB. METHODS We utilized neuroimaging data from the National Institute of Mental Health Data Archive to assess basal ganglia and cerebellum structure in a cohort of children and adolescents with ASD compared to typically developing (TD) controls. We evaluated regional gray matter volumes from T1-weighted anatomical scans and assessed diffusion-weighted scans to quantify white matter microstructure with free-water imaging. We also investigated the interaction of biological sex and ASD diagnosis on these measures, and their correlation with clinical scales of RRB. RESULTS Individuals with ASD had significantly lower free-water corrected fractional anisotropy (FAT) and higher free-water (FW) in cortico-basal ganglia white matter tracts. These microstructural differences did not interact with biological sex. Moreover, both FAT and FW in basal ganglia white matter tracts significantly correlated with measures of RRB. In contrast, we found no significant difference in basal ganglia or cerebellar gray matter volumes. LIMITATIONS The basal ganglia and cerebellar regions in this study were selected due to their hypothesized relevance to RRB. Differences between ASD and TD individuals that may occur outside the basal ganglia and cerebellum, and their potential relationship to RRB, were not evaluated. CONCLUSIONS These new findings demonstrate that cortico-basal ganglia white matter microstructure is altered in ASD and linked to RRB. FW in cortico-basal ganglia and intra-basal ganglia white matter was more sensitive to group differences in ASD, whereas cortico-basal ganglia FAT was more closely linked to RRB. In contrast, basal ganglia and cerebellar volumes did not differ in ASD. There was no interaction between ASD diagnosis and sex-related differences in brain structure. Future diffusion imaging investigations in ASD may benefit from free-water estimation and correction in order to better understand how white matter is affected in ASD, and how such measures are linked to RRB.
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Affiliation(s)
- Bradley J Wilkes
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611, USA.
| | - Derek B Archer
- Vanderbilt Memory and Alzheimer's Center, Department of Neurology, Vanderbilt School of Medicine, Nashville, TN, USA
- Department of Neurology, Vanderbilt Genetics Institute, Vanderbilt School of Medicine, Nashville, TN, USA
| | - Anna L Farmer
- Department of Psychology, University of Florida, Gainesville, FL, USA
| | - Carly Bass
- Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - Hannah Korah
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - David E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, P.O. Box 118205, Gainesville, FL, 32611, USA
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
- Department of Neurology, Fixel Center for Neurological Diseases, Program in Movement Disorders and Neurorestoration, University of Florida, Gainesville, FL, USA
| | - Mark H Lewis
- Department of Psychology, University of Florida, Gainesville, FL, USA
- Department of Psychiatry, University of Florida, Gainesville, FL, USA
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2
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Abstract
Autism is often considered to reflect categorically 'different brains'. Neuropsychological research on autism spectrum disorder (ASD) however, has struggled to define this difference, or derive clear-cut boundaries between autism and non-autism. Consequently, restructuring or disbanding the ASD diagnosis is becoming increasingly advocated within research. Nonetheless, autism now exists as a salient social construction, of which 'difference' is a key facet. Clinical and educational professionals must influence this cautiously, as changes to autism's social construction may counterproductively affect the quality of life of autistic people. This paper therefore reviews ASD's value as both neuropsychological and social constructs. Although lacking neuropsychological validity, the autism label may be beneficial for autistic self-identity, reduction of stigma, and administering support. Whilst a shift away from case-control ASD research is warranted, lay notions of 'different brains' may be preserved.
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Affiliation(s)
- Daniel Crawshaw
- School of Psychology, University of Nottingham, University Park, Nottingham, UK
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3
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Saure E, Castrén M, Mikkola K, Salmi J. Intellectual disabilities moderate sex/gender differences in autism spectrum disorder: a systematic review and meta-analysis. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2023; 67:1-34. [PMID: 36444668 DOI: 10.1111/jir.12989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Girls/women with autism spectrum disorder (ASD) are suggested to exhibit different symptom profiles than boys/men with ASD. Accumulating evidence suggests that intellectual disability (ID) may affect sex/gender differences in ASD. However, a systematic review and meta-analysis on this topic is missing. METHODS Two databases (MEDLINE and PsycINFO) were used to search for studies reporting sex/gender differences (girls/women versus boys/men) in social communication and interaction, restrictive and repetitive behaviour and interests (RRBIs), sensory processing, and linguistic and motor abilities in ASD. The final sample consisted of 79 studies. The meta-analysis was performed with Review Manager using a random-effects model. Participants with ASD without and with ID were analysed as separate subgroups, and the effects in these two subgroups were also compared with each other. RESULTS Girls/women with ASD without ID displayed fewer RRBIs, more sensory symptoms and less problems in linguistic abilities than their boys/men counterparts. In contrast, girls/women with ASD with ID displayed more social difficulties and RRBIs, poorer linguistic abilities and more motor problems than boys/men with ASD with ID. Comparisons of groups of participants with ASD without ID versus participants with ASD with ID confirmed differences in sex/gender effects on social difficulties, sensory processing, linguistic abilities and motor abilities. CONCLUSIONS Our results clearly suggest that the female phenotype of ASD is moderated by ID. Among individuals with ASD with ID, girls/women seem to be more severely affected than boys/men, whereas among individuals with ASD without ID, girls/women with ASD may have less symptoms than boys/men. Such phenotypic differences could be a potential cause of underrecognition of girls/women with ASD, and it is also possible that observed phenotypic differences may reflect underdiagnosing of girls/women with ASD.
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Affiliation(s)
- E Saure
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- BABA Center and Department of Clinical Neurophysiology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - M Castrén
- Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - K Mikkola
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - J Salmi
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
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4
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Zhao Y, Yang L, Gong G, Cao Q, Liu J. Identify aberrant white matter microstructure in ASD, ADHD and other neurodevelopmental disorders: A meta-analysis of diffusion tensor imaging studies. Prog Neuropsychopharmacol Biol Psychiatry 2022; 113:110477. [PMID: 34798202 DOI: 10.1016/j.pnpbp.2021.110477] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/26/2021] [Accepted: 11/11/2021] [Indexed: 01/18/2023]
Abstract
BACKGROUND Neurodevelopmental disorders (NDDs) usually present overlapping symptoms. Abnormal white matter (WM) microstructure has been found in these disorders. Identification of common and unique neural abnormalities across NDDs could provide further insight into the underlying pathophysiological mechanisms. METHODS We performed a voxel-based meta-analysis of whole-brain diffusion tensor imaging (DTI) studies in autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD) and other NDDs. A systematic literature search was conducted through March 2020 to identify studies that compared measures of WM microstructure between patients with NDDs and neurotypical controls. Peak voxel coordinates were meta-analyzed via anisotropic effect size-signed differential mapping (AES-SDM) as well as activation likelihood estimation (ALE). RESULTS Our final sample included a total of 4137 subjects from 66 studies across five NDDs. Fractional anisotropy (FA) reductions were found in the splenium of the CC in ADHD, and the genu and splenium of CC in ASD. And mean diffusivity (MD) increases were shown in posterior thalamic radiation in ASD. No consistent abnormalities were detected in specific learning disorder, motor disorder or communication disorder. Significant differences between child/adolescent and adult patients were found within the CC across NDDs, reflective of aberrant neurodevelopmental processes in NDDs. CONCLUSIONS The current study demonstrated atypical WM patterns in ASD, ADHD and other NDDs. Microstructural abnormalities in the splenium of the CC were possibly shared among ASD and ADHD.
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Affiliation(s)
- Yilu Zhao
- The Peking University Sixth Hospital (Institute of Mental Health), National Clinical Research Centre for Mental Disorders (Peking University Sixth Hospital), NHC Key Laboratory of Mental Health, (Peking University), Beijing, China
| | - Li Yang
- The Peking University Sixth Hospital (Institute of Mental Health), National Clinical Research Centre for Mental Disorders (Peking University Sixth Hospital), NHC Key Laboratory of Mental Health, (Peking University), Beijing, China
| | - Gaolang Gong
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China; Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China
| | - Qingjiu Cao
- The Peking University Sixth Hospital (Institute of Mental Health), National Clinical Research Centre for Mental Disorders (Peking University Sixth Hospital), NHC Key Laboratory of Mental Health, (Peking University), Beijing, China.
| | - Jing Liu
- The Peking University Sixth Hospital (Institute of Mental Health), National Clinical Research Centre for Mental Disorders (Peking University Sixth Hospital), NHC Key Laboratory of Mental Health, (Peking University), Beijing, China.
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5
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Bathelt J, Koolschijn PCM, Geurts HM. Atypically slow processing of faces and non-faces in older autistic adults. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2021; 26:1737-1751. [PMID: 34961340 PMCID: PMC9483195 DOI: 10.1177/13623613211065297] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Face recognition is a fundamental function that requires holistic processing. Differences in face processing have been consistently identified in autistic children, but it is unknown whether these differences persist across the adult lifespan. Using event-related functional magnetic resonance imaging, we measured holistic face processing with a rapid Mooney faces task in 50 autistic and 49 non-autistic participants (30–74 years). Behavioral tasks included a self-paced version of the same paradigm and a global–local processing task (Navon). Reduced detection rates for faces, but not non-faces, were found in autistic adults, including slower responses on all conditions. Without time constraints, differences in accuracy disappeared between groups, although reaction times in correctly identifying faces remained higher in autistic adults. The functional magnetic resonance imaging results showed lower activation in the left and right superior frontal gyrus in the autism group but no age-related differences. Overall, our findings point toward slower information processing speed rather than a face recognition deficit in autistic adults. This suggests that face-processing differences are not a core feature of autism across the adult lifespan.
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Affiliation(s)
- Joe Bathelt
- University of Amsterdam, The Netherlands.,Royal Holloway, University of London, UK
| | | | - Hilde M Geurts
- University of Amsterdam, The Netherlands.,Leo Kannerhuis, Youz/Parnassiagroup, The Netherlands
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6
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Mo K, Sadoway T, Bonato S, Ameis SH, Anagnostou E, Lerch JP, Taylor MJ, Lai MC. Sex/gender differences in the human autistic brains: A systematic review of 20 years of neuroimaging research. Neuroimage Clin 2021; 32:102811. [PMID: 34509922 PMCID: PMC8436080 DOI: 10.1016/j.nicl.2021.102811] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 06/25/2021] [Accepted: 08/29/2021] [Indexed: 12/01/2022]
Abstract
Our current understanding of autism is largely based on clinical experiences and research involving male individuals given the male-predominance in prevalence and the under-inclusion of female individuals due to small samples, co-occurring conditions, or simply being missed for diagnosis. There is a significantly biased 'male lens' in this field with autistic females insufficiently understood. We therefore conducted a systematic review to examine how sex and gender modulate brain structure and function in autistic individuals. Findings from the past 20 years are yet to converge on specific brain regions/networks with consistent sex/gender-modulating effects. Despite at least three well-powered studies identifying specific patterns of significant sex/gender-modulation of autism-control differences, many other studies are likely underpowered, suggesting a critical need for future investigation into sex/gender-based heterogeneity with better-powered designs. Future research should also formally investigate the effects of gender, beyond biological sex, which is mostly absent in the current literature. Understanding the roles of sex and gender in the development of autism is an imperative step to extend beyond the 'male lens' in this field.
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Affiliation(s)
- Kelly Mo
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada; Margaret and Wallace McCain Centre for Child, Youth & Family Mental Health and Azrieli Adult Neurodevelopmental Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Canada
| | - Tara Sadoway
- Department of Paediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Canada
| | - Sarah Bonato
- Margaret and Wallace McCain Centre for Child, Youth & Family Mental Health and Azrieli Adult Neurodevelopmental Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Canada
| | - Stephanie H Ameis
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada; Margaret and Wallace McCain Centre for Child, Youth & Family Mental Health and Azrieli Adult Neurodevelopmental Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Canada; Department of Psychiatry, Hospital for Sick Children, Toronto, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Evdokia Anagnostou
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada; Holland Bloorview Kids Rehabilitation Hospital, Toronto, Canada; Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Jason P Lerch
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada; Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom; Neurosciences & Mental Health Program, SickKids Research Institute, Toronto, Canada
| | - Margot J Taylor
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada; Neurosciences & Mental Health Program, SickKids Research Institute, Toronto, Canada; Diagnostic Imaging, Hospital for Sick Children, Toronto, Canada
| | - Meng-Chuan Lai
- Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada; Margaret and Wallace McCain Centre for Child, Youth & Family Mental Health and Azrieli Adult Neurodevelopmental Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Canada; Department of Psychiatry, Hospital for Sick Children, Toronto, Canada; Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, Canada; Neurosciences & Mental Health Program, SickKids Research Institute, Toronto, Canada; Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan.
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7
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Walsh MJM, Wallace GL, Gallegos SM, Braden BB. Brain-based sex differences in autism spectrum disorder across the lifespan: A systematic review of structural MRI, fMRI, and DTI findings. Neuroimage Clin 2021; 31:102719. [PMID: 34153690 PMCID: PMC8233229 DOI: 10.1016/j.nicl.2021.102719] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 12/12/2022]
Abstract
Females with autism spectrum disorder (ASD) have been long overlooked in neuroscience research, but emerging evidence suggests they show distinct phenotypic trajectories and age-related brain differences. Sex-related biological factors (e.g., hormones, genes) may play a role in ASD etiology and have been shown to influence neurodevelopmental trajectories. Thus, a lifespan approach is warranted to understand brain-based sex differences in ASD. This systematic review on MRI-based sex differences in ASD was conducted to elucidate variations across the lifespan and inform biomarker discovery of ASD in females We identified articles through two database searches. Fifty studies met criteria and underwent integrative review. We found that regions expressing replicable sex-by-diagnosis differences across studies overlapped with regions showing sex differences in neurotypical cohorts. Furthermore, studies investigating age-related brain differences across a broad age-span suggest distinct neurodevelopmental patterns in females with ASD. Qualitative comparison across youth and adult studies also supported this hypothesis. However, many studies collapsed across age, which may mask differences. Furthermore, accumulating evidence supports the female protective effect in ASD, although only one study examined brain circuits implicated in "protection." When synthesized with the broader literature, brain-based sex differences in ASD may come from various sources, including genetic and endocrine processes involved in brain "masculinization" and "feminization" across early development, puberty, and other lifespan windows of hormonal transition. Furthermore, sex-related biology may interact with peripheral processes, in particular the stress axis and brain arousal system, to produce distinct neurodevelopmental patterns in males and females with ASD. Future research on neuroimaging-based sex differences in ASD would benefit from a lifespan approach in well-controlled and multivariate studies. Possible relationships between behavior, sex hormones, and brain development in ASD remain largely unexamined.
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Affiliation(s)
- Melissa J M Walsh
- College of Health Solutions, Arizona State University, 975 S. Myrtle Ave, Tempe, AZ 85281, USA
| | - Gregory L Wallace
- Department of Speech, Language, and Hearing Sciences, The George Washington University, 2115 G St. NW, Washington, DC 20052, USA.
| | - Stephen M Gallegos
- College of Health Solutions, Arizona State University, 975 S. Myrtle Ave, Tempe, AZ 85281, USA
| | - B Blair Braden
- College of Health Solutions, Arizona State University, 975 S. Myrtle Ave, Tempe, AZ 85281, USA.
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8
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Kirkovski M, Fuelscher I, Hyde C, Donaldson PH, Ford TC, Rossell SL, Fitzgerald PB, Enticott PG. Fixel Based Analysis Reveals Atypical White Matter Micro- and Macrostructure in Adults With Autism Spectrum Disorder: An Investigation of the Role of Biological Sex. Front Integr Neurosci 2020; 14:40. [PMID: 32903660 PMCID: PMC7438780 DOI: 10.3389/fnint.2020.00040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022] Open
Abstract
Atypical white matter (WM) microstructure is commonly implicated in the neuropathophysiology of autism spectrum disorder (ASD). Fixel based analysis (FBA), at the cutting-edge of diffusion-weighted imaging, can account for crossing WM fibers and can provide indices of both WM micro- and macrostructure. We applied FBA to investigate WM structure between 25 (12 males, 13 females) adults with ASD and 24 (12 males, 12 females) matched controls. As the role of biological sex on the neuropathophysiology of ASD is of increasing interest, this was also explored. There were no significant differences in WM micro- or macrostructure between adults with ASD and matched healthy controls. When data were stratified by sex, females with ASD had reduced fiber density and cross-section (FDC), a combined metric comprised of micro- and macrostructural measures, in the corpus callosum, a finding not detected between the male sub-groups. We conclude that micro- and macrostructural WM aberrations are present in ASD, and may be influenced by biological sex.
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Affiliation(s)
- Melissa Kirkovski
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia.,Monash Alfred Psychiatry Research Centre, Monash University, Melbourne, VIC, Australia
| | - Ian Fuelscher
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Christian Hyde
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Peter H Donaldson
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Talitha C Ford
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia.,Centre for Human Psychopharmacology, Swinburne University, Melbourne, VIC, Australia
| | - Susan L Rossell
- Centre for Mental Health, Swinburne University, Melbourne, VIC, Australia
| | - Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, Monash University, Melbourne, VIC, Australia.,Epworth Centre for Innovation in Mental Health, Epworth Health Care and Central Clinical School Monash University, Melbourne, VIC, Australia
| | - Peter G Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia.,Monash Alfred Psychiatry Research Centre, Monash University, Melbourne, VIC, Australia
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9
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Haigh SM, Keller TA, Minshew NJ, Eack SM. Reduced White Matter Integrity and Deficits in Neuropsychological Functioning in Adults With Autism Spectrum Disorder. Autism Res 2020; 13:702-714. [PMID: 32073209 DOI: 10.1002/aur.2271] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 12/06/2019] [Accepted: 01/15/2020] [Indexed: 12/31/2022]
Abstract
Autism spectrum disorder (ASD) is currently viewed as a disorder of cortical systems connectivity, with a heavy emphasis being on the structural integrity of white matter tracts. However, the majority of the literature to date has focused on children with ASD. Understanding the integrity of white matter tracts in adults may help reveal the nature of ASD pathology in adulthood and the potential contributors to cognitive impairment. This study examined white matter water diffusion using diffusion tensor imaging in relation to neuropsychological measures of cognition in a sample of 45 adults with ASD compared to 20 age, gender, and full-scale-IQ-matched healthy volunteers. Tract-based spatial statistics were used to assess differences in diffusion along white matter tracts between groups using permutation testing. The following neuropsychological measures of cognition were assessed: processing speed, attention vigilance, working memory, verbal learning, visual learning, reasoning and problem solving, and social cognition. Results indicated that fractional anisotropy (FA) was significantly reduced in adults with ASD in the anterior thalamic radiation (P = 0.022) and the right cingulum (P = 0.008). All neuropsychological measures were worse in the ASD group, but none of the measures significantly correlated with reduced FA in either tract in the adults with ASD or in the healthy volunteers. Together, this indicates that the tracts that are the most impacted in autism may not be (at least directly) responsible for the behavioral deficits in ASD. Autism Res 2020, 13: 702-714. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: White matter tracts are the data cables in the brain that efficiently transfer information, and damage to these tracts could be the cause for the abnormal behaviors that are associated with autism. We found that two long-range tracts (the anterior thalamic radiation and the cingulum) were both impaired in autism but were not directly related to the impairments in behavior. This suggests that the abnormal tracts and behavior are the effects of another underlying mechanism.
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Affiliation(s)
- Sarah M Haigh
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.,Department of Psychology, Carnegie Mellon University, Pittsburgh, Pennsylvania.,Department of Psychology and Integrative Neuroscience, University of Nevada, Reno, Nevada
| | - Timothy A Keller
- Department of Psychology, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Nancy J Minshew
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.,Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Shaun M Eack
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.,School of Social Work, University of Pittsburgh, Pittsburgh, Pennsylvania
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10
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Ruigrok ANV, Lai MC. Sex/gender differences in neurology and psychiatry: Autism. HANDBOOK OF CLINICAL NEUROLOGY 2020; 175:283-297. [PMID: 33008532 DOI: 10.1016/b978-0-444-64123-6.00020-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Autism is a heterogenous set of early-onset neurodevelopmental conditions that are more prevalent in males than in females. Due to the high phenotypic, neurobiological, developmental, and etiological heterogeneity in the autism spectrum, recent research programs are increasingly exploring whether sex- and gender-related factors could be helpful markers to clarify the heterogeneity in autism and work toward a personalized approach to intervention and support. In this chapter, we summarize recent clinical and neuroscientific research addressing sex/gender influences in autism and explore how sex/gender-based investigations shed light on similar or different underlying neurodevelopmental mechanisms of autism by sex/gender. We review evidence that may help to explain some of the underlying sex-related biological mechanisms associated with autism, including genetics and the effects of sex steroid hormones in the prenatal environment. We conclude that current research points toward coexisting quantitative and, perhaps more evidently, qualitative sex/gender-modulation effects in autism across multiple neurobiological aspects. However, converging findings of specific neurobiological presentations and sex/gender-informed mechanisms cutting across the many subgroups within the autism spectrum are still lacking. Future research should use big data approaches and new stratification methods to decompose sex/gender-related heterogeneity in autism and work toward personalized, sex/gender-informed intervention and support for autistic people.
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Affiliation(s)
- Amber N V Ruigrok
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Meng-Chuan Lai
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Centre for Addiction and Mental Health & The Hospital for Sick Children, Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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11
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Haigh SM, Eack SM, Keller T, Minshew NJ, Behrmann M. White matter structure in schizophrenia and autism: Abnormal diffusion across the brain in schizophrenia. Neuropsychologia 2019; 135:107233. [PMID: 31655160 PMCID: PMC6884694 DOI: 10.1016/j.neuropsychologia.2019.107233] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 10/14/2019] [Accepted: 10/14/2019] [Indexed: 01/23/2023]
Abstract
BACKGROUND Schizophrenia and autism share many behavioral and neurological similarities, including altered white matter tract structure. However, because schizophrenia and autism are rarely compared directly, it is difficult to establish whether white matter abnormalities are disorder-specific or are common across these disorders that share some symptomatology. METHODS In the current study, we compared white matter water diffusion using tensor imaging in 25 adults with autism, 15 adults with schizophrenia, all with IQ scores above 88, and 19 neurotypical adults. RESULTS Although the three groups evinced no statistically significant differences in measures of fractional anisotropy (FA), the schizophrenia group showed significantly greater mean diffusivity (MD; Cohen's d > 0.77), due to greater radial diffusivity (RD; Cohen's d > 0.92), compared to both the autism and control groups. This effect was evident across the brain rather than specific to a particular tract. CONCLUSIONS The greater MD and RD in schizophrenia appears to be diagnosis-specific. The altered diffusion may reflect subtle abnormalities in myelination, which could be a potential mechanism underlying the widespread behavioral deficits associated with schizophrenia.
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Affiliation(s)
- Sarah M Haigh
- Department of Psychology, Carnegie Mellon University, USA; Center for the Neural Basis of Cognition, Carnegie Mellon University, USA; Department of Psychology and Center for Integrative Neuroscience, University of Nevada, Reno, USA.
| | - Shaun M Eack
- Department of Psychiatry, University of Pittsburgh School of Medicine, USA; School of Social Work, University of Pittsburgh, USA
| | - Timothy Keller
- Department of Psychology, Carnegie Mellon University, USA
| | - Nancy J Minshew
- Department of Psychiatry, University of Pittsburgh School of Medicine, USA; Department of Neurology, University of Pittsburgh, USA
| | - Marlene Behrmann
- Department of Psychology, Carnegie Mellon University, USA; Center for the Neural Basis of Cognition, Carnegie Mellon University, USA
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12
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Lei J, Lecarie E, Jurayj J, Boland S, Sukhodolsky DG, Ventola P, Pelphrey KA, Jou RJ. Altered Neural Connectivity in Females, But Not Males with Autism: Preliminary Evidence for the Female Protective Effect from a Quality-Controlled Diffusion Tensor Imaging Study. Autism Res 2019; 12:1472-1483. [PMID: 31347307 PMCID: PMC6851962 DOI: 10.1002/aur.2180] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 07/04/2019] [Accepted: 07/08/2019] [Indexed: 12/02/2022]
Abstract
Previous studies using diffusion tensor imaging (DTI) to investigate white matter (WM) structural connectivity have suggested widespread, although inconsistent WM alterations in autism spectrum disorder (ASD), such as greater reductions in fractional anisotropy (FA). However, findings may lack generalizability because: (a) most have focused solely on the ASD male brain phenotype, and not sex‐differences in WM integrity; (b) many lack stringent and transparent data quality control such as controlling for head motion in analysis. This study addressed both issues by using Tract‐Based Spatial Statistics (TBSS) to separately compare WM differences in 81 ASD (56 male, 25 female; 4–21 years old) and 39 typically developing (TD; 23 males, 16 females; 5–18 years old) children and young people, carefully group‐matched on sex, age, cognitive abilities, and head motion. ASD males and females were also matched on autism symptom severity. Two independent‐raters completed a multistep scan quality assurance to remove images that were significantly distorted by motion artifacts before analysis. ASD females exhibited significant widespread reductions in FA compared to TD females, suggesting altered WM integrity. In contrast, no significant localized or widespread WM differences were found between ASD and TD males. This study highlights the importance of data quality control in DTI, and outlines important sex‐differences in WM alterations in ASD females. Future studies can explore the extent to which neural structural differences might underlie sex‐differences in ASD behavioral phenotype, and guide clinical interventions to be tailored toward the unique needs of ASD females and males. Autism Res 2019, 12: 1472–1483. © 2019 The Authors. Autism Research published by International Society for Autism Research published by Wiley Periodicals, Inc. Lay Summary Previous Diffusion Tensor Imaging (DTI) studies have found atypical brain structural connectivity in males with autism, although findings are inconclusive in females with autism. To investigate potential sex‐differences, we studied males and females with and without autism who showed a similar level of head movement during their brain scan. We found that females with autism had widespread atypical neural connectivity than females without autism, although not in males, highlighting sex‐differences.
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Affiliation(s)
- Jiedi Lei
- Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut.,Centre for Applied Autism Research, Psychology Department, University of Bath, Bath, UK
| | - Emma Lecarie
- Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut.,Department of Psychology, Arizona State University, Tempe, Arizona
| | - Jane Jurayj
- Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut
| | - Sarah Boland
- Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut
| | - Denis G Sukhodolsky
- Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut
| | - Pamela Ventola
- Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut
| | - Kevin A Pelphrey
- Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut.,School of Medicine, University of Virginia, Charlottesville, Virginia
| | - Roger J Jou
- Yale Child Study Center, Yale University School of Medicine, New Haven, Connecticut
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13
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Hrdlicka M, Sanda J, Urbanek T, Kudr M, Dudova I, Kickova S, Pospisilova L, Mohaplova M, Maulisova A, Krsek P, Kyncl M, Blatny M, Komarek V. Diffusion Tensor Imaging And Tractography In Autistic, Dysphasic, And Healthy Control Children. Neuropsychiatr Dis Treat 2019; 15:2843-2852. [PMID: 31632032 PMCID: PMC6781738 DOI: 10.2147/ndt.s219545] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/01/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Diffusion tensor imaging (DTI) is a powerful tool for investigating brain anatomical connectivity. The aim of our study was to compare brain connectivity among children with autism spectrum disorders (ASD), developmental dysphasia (DD), and healthy controls (HC) in the following tracts: the arcuate fasciculus (AF), inferior frontal occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), and uncinate fasciculus (UF). METHODS Our sample consisted of 113 children with a mean age 8.7±2.2 years (77 boys, 36 girls), divided into three subgroups: ASD (n=39), DD (n=36), and HC (n=38). The International Classification of Diseases, 10th ed. was used to make clinical diagnoses. DTI images were collected using a 1.5 T Phillips Achieva MR imaging system. RESULTS Detailed analyses of fractional anisotropy (FA) revealed significant differences among the ASD, DD, and HC groups in the left AF (p=0.014) and right AF (p=0.001), the left IFOF (p<0.001) and right IFOF (p<0.001), the left ILF (p<0.001) and right ILF (p<0.001), but not in the UF. Post-hoc analyses revealed three patterns of FA differences among the groups: (1) in the right AF, right IFOF, and right ILF, FA was significantly lower in the ASD group compared to the DD and HC groups; however, there was no difference in FA between DD and HC; (2) in the left AF and left IFOF, FA was significantly lower in the ASD than in the HC group, but there were no differences between DD vs HC nor DD vs ASD; and (3) in the left ILF, no difference in FA was seen between ASD and DD, but FA in both was significantly lower than in the HC. CONCLUSION Microstructural white matter properties differed between ASD vs DD and HC subjects. The tract where FA impairment in ASD and DD subjects was the most similar was the left ILF.
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Affiliation(s)
- Michal Hrdlicka
- Department of Child Psychiatry, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Jan Sanda
- Department of Radiology, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Tomas Urbanek
- Institute of Psychology, Academy of Sciences, Brno, Czech Republic
| | - Martin Kudr
- Department of Pediatric Neurology, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Iva Dudova
- Department of Child Psychiatry, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Stepanka Kickova
- Department of Child Psychiatry, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Lenka Pospisilova
- Department of Child Psychiatry, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic.,Charles University First Faculty of Medicine, Prague, Czech Republic
| | - Marketa Mohaplova
- Department of Child Psychiatry, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Alice Maulisova
- Department of Pediatric Neurology, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Pavel Krsek
- Department of Pediatric Neurology, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Martin Kyncl
- Department of Radiology, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Marek Blatny
- Department of Child Psychiatry, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic.,Department of Psychology, Faculty of Arts, Masaryk University, Brno, Czech Republic
| | - Vladimir Komarek
- Department of Pediatric Neurology, Charles University Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
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14
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Sui YV, Donaldson J, Miles L, Babb JS, Castellanos FX, Lazar M. Diffusional kurtosis imaging of the corpus callosum in autism. Mol Autism 2018; 9:62. [PMID: 30559954 PMCID: PMC6293510 DOI: 10.1186/s13229-018-0245-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 11/20/2018] [Indexed: 12/31/2022] Open
Abstract
Background The corpus callosum is implicated in the pathophysiology of autism spectrum disorder (ASD). However, specific structural deficits and underlying mechanisms are yet to be well defined. Methods We employed diffusional kurtosis imaging (DKI) metrics to characterize white matter properties within five discrete segments of the corpus callosum in 17 typically developing (TD) adults and 16 age-matched participants with ASD without co-occurring intellectual disability (ID). The DKI metrics included axonal water fraction (faxon) and intra-axonal diffusivity (Daxon), which reflect axonal density and caliber, and extra-axonal radial (RDextra) and axial (ADextra) diffusivities, which reflect myelination and microstructural organization of the extracellular space. The relationships between DKI metrics and processing speed, a cognitive feature known to be impaired in ASD, were also examined. Results ASD group had significantly decreased callosal faxon and Daxon (p = .01 and p = .045), particularly in the midbody, isthmus, and splenium. Regression analysis showed that variation in DKI metrics, primarily in the mid and posterior callosal regions explained up to 70.7% of the variance in processing speed scores for TD (p = .001) but not for ASD (p > .05). Conclusion Decreased DKI metrics suggested that ASD may be associated with axonal deficits such as reduced axonal caliber and density in the corpus callosum, especially in the mid and posterior callosal areas. These data suggest that impaired interhemispheric connectivity may contribute to decreased processing speed in ASD participants. Electronic supplementary material The online version of this article (10.1186/s13229-018-0245-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yu Veronica Sui
- 1Department of Radiology, New York University School of Medicine, New York, NY USA.,4Center for Biomedical Imaging, NYU Langone Health, 660 First Ave, 4th floor, New York, NY 10016 USA
| | - Jeffrey Donaldson
- 1Department of Radiology, New York University School of Medicine, New York, NY USA
| | - Laura Miles
- 1Department of Radiology, New York University School of Medicine, New York, NY USA
| | - James S Babb
- 1Department of Radiology, New York University School of Medicine, New York, NY USA
| | - Francisco Xavier Castellanos
- 2Department of Child and Adolescent Psychiatry, Hassenfeld Children's Hospital at NYU Langone, New York, NY USA.,3Nathan Kline Institute for Psychiatric Research, Orangeburg, NY USA
| | - Mariana Lazar
- 1Department of Radiology, New York University School of Medicine, New York, NY USA.,4Center for Biomedical Imaging, NYU Langone Health, 660 First Ave, 4th floor, New York, NY 10016 USA
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15
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Hyde C, Fuelscher I, Enticott PG, Jones DK, Farquharson S, Silk TJ, Williams J, Caeyenberghs K. White matter organization in developmental coordination disorder: A pilot study exploring the added value of constrained spherical deconvolution. NEUROIMAGE-CLINICAL 2018; 21:101625. [PMID: 30552074 PMCID: PMC6411781 DOI: 10.1016/j.nicl.2018.101625] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/13/2018] [Accepted: 12/01/2018] [Indexed: 12/13/2022]
Abstract
Previous studies of white matter organization in sensorimotor tracts in developmental coordination disorder (DCD) have adopted diffusion tensor imaging (DTI), a method unable to reconcile pathways with ‘crossing fibres’. In response to limitations of the commonly adopted DTI approach, the present study employed a framework that can reconcile the ‘crossing fibre’ problem (i.e., constrained spherical deconvolution- CSD) to characterize white matter tissue organization of sensorimotor tracts in young adults with DCD. Participants were 19 healthy adults aged 18–46: 7 met diagnostic criteria for DCD (4 females) and 12 were controls (3 females). All underwent high angular diffusion MRI. After preprocessing, the left and right corticospinal tracts (CST) and superior longitudinal fasciculi (SLF) were delineated and all tracts were then generated using both CSD and DTI tractography respectively. Based on the CSD model, individuals with DCD demonstrated significantly decreased mean apparent fibre density (AFD) in the left SLF relative to controls (with large effect size, Cohen's d = 1.32) and a trend for decreased tract volume of the right SLF (with medium-large effect size, Cohen's d = 0.73). No differences in SLF microstructure were found between groups using DTI, nor were differences in CST microstructure observed across groups regardless of hemisphere or diffusion model. Our data are consistent with the view that motor impairment characteristic of DCD may be subserved by white matter abnormalities in sensorimotor tracts, specifically the left and right SLF. Our data further highlight the benefits of higher order diffusion MRI (e.g. CSD) relative to DTI for clarifying earlier inconsistencies in reports speaking to white matter organization in DCD, and its contribution to poor motor skill in DCD. All previous diffusion studies of white matter in DCD have employed a tensor model We employed a non-tensor model to characterize microstructure in adults with DCD The non-tensor model showed atypical white matter organization in the SLF in DCD The tensor model failed to detect microstructural group differences for any tract Motor impairment characteristic of DCD may be subserved by white matter abnormalities
We need to move beyond the tensor model in characterizing white matter in DCD
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Affiliation(s)
- Christian Hyde
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Victoria, Australia.
| | - Ian Fuelscher
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Victoria, Australia
| | - Peter G Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Victoria, Australia
| | - Derek K Jones
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, UK; Mary MacKillop Institute for Health Research, Faculty of Health Sciences, Australian Catholic University, Melbourne, Australia
| | - Shawna Farquharson
- Melbourne Brain Centre Imaging Unit, Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia; Imaging Division, Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Melbourne, Australia
| | - Tim J Silk
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Victoria, Australia; Developmental Imaging, Clinical Sciences, Murdoch Children's Research Institute, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Jacqueline Williams
- Institute for Health and Sport, College of Sport and Exercise Science, Victoria University, Melbourne, Australia
| | - Karen Caeyenberghs
- Mary MacKillop Institute for Health Research, Faculty of Health Sciences, Australian Catholic University, Melbourne, Australia
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16
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Drozd HP, Karathanasis SF, Molosh AI, Lukkes JL, Clapp DW, Shekhar A. From bedside to bench and back: Translating ASD models. PROGRESS IN BRAIN RESEARCH 2018; 241:113-158. [PMID: 30447753 DOI: 10.1016/bs.pbr.2018.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autism spectrum disorders (ASD) represent a heterogeneous group of disorders defined by deficits in social interaction/communication and restricted interests, behaviors, or activities. Models of ASD, developed based on clinical data and observations, are used in basic science, the "bench," to better understand the pathophysiology of ASD and provide therapeutic options for patients in the clinic, the "bedside." Translational medicine creates a bridge between the bench and bedside that allows for clinical and basic science discoveries to challenge one another to improve the opportunities to bring novel therapies to patients. From the clinical side, biomarker work is expanding our understanding of possible mechanisms of ASD through measures of behavior, genetics, imaging modalities, and serum markers. These biomarkers could help to subclassify patients with ASD in order to better target treatments to a more homogeneous groups of patients most likely to respond to a candidate therapy. In turn, basic science has been responding to developments in clinical evaluation by improving bench models to mechanistically and phenotypically recapitulate the ASD phenotypes observed in clinic. While genetic models are identifying novel therapeutics targets at the bench, the clinical efforts are making progress by defining better outcome measures that are most representative of meaningful patient responses. In this review, we discuss some of these challenges in translational research in ASD and strategies for the bench and bedside to bridge the gap to achieve better benefits to patients.
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Affiliation(s)
- Hayley P Drozd
- Program in Medical Neurobiology, Stark Neurosciences Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Sotirios F Karathanasis
- Program in Medical Neurobiology, Stark Neurosciences Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Andrei I Molosh
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Jodi L Lukkes
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - D Wade Clapp
- Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Anantha Shekhar
- Program in Medical Neurobiology, Stark Neurosciences Institute, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States; Indiana Clinical and Translation Sciences Institute, Indiana University School of Medicine, Indianapolis, IN, United States.
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17
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Wang X, Kery R, Xiong Q. Synaptopathology in autism spectrum disorders: Complex effects of synaptic genes on neural circuits. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:398-415. [PMID: 28986278 DOI: 10.1016/j.pnpbp.2017.09.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 09/05/2017] [Accepted: 09/26/2017] [Indexed: 01/03/2023]
Affiliation(s)
- Xinxing Wang
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA
| | - Rachel Kery
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA; Medical Scientist Training Program (MSTP), Stony Brook University, Stony Brook, NY 11794, USA
| | - Qiaojie Xiong
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY 11794, USA.
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18
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Kirkovski M, Suo C, Enticott PG, Yücel M, Fitzgerald PB. Short communication: Sex-linked differences in gamma-aminobutyric acid (GABA) are related to social functioning in autism spectrum disorder. Psychiatry Res Neuroimaging 2018; 274:19-22. [PMID: 29500101 DOI: 10.1016/j.pscychresns.2018.02.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 01/22/2018] [Accepted: 02/09/2018] [Indexed: 01/08/2023]
Abstract
Magnetic resonance spectroscopy (MRS) was utilized to investigate sex differences in gamma-aminobutyric acid (GABA) between adults with autism spectrum disorder (ASD) and neurotypical (NT) controls. GABA at the right superior temporal sulcus (STS) is reported for 12 ASD and 14 NT participants. The results show no group differences in GABA. There was, however, a significant positive association between GABA at the STS and autism-related social impairments in females with ASD. These findings provide preliminary support for sex differences in GABAergic distribution and processes that contribute to social functioning in ASD.
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Affiliation(s)
- Melissa Kirkovski
- Deakin Child Study Centre, School of Psychology, Deakin University, Geelong, Australia; Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Clayton, Australia.
| | - Chao Suo
- Brain & Mental Health Laboratory, Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Victoria, Australia
| | - Peter Gregory Enticott
- Deakin Child Study Centre, School of Psychology, Deakin University, Geelong, Australia; Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Clayton, Australia
| | - Murat Yücel
- Brain & Mental Health Laboratory, Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Victoria, Australia
| | - Paul Bernard Fitzgerald
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Clayton, Australia
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19
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Abstract
PURPOSE OF REVIEW Neurodevelopmental disorders disproportionately affect males. The mechanisms underlying male vulnerability or female protection are not known and remain understudied. Determining the processes involved is crucial to understanding the etiology and advancing treatment of neurodevelopmental disorders. Here, we review current findings and theories that contribute to male preponderance of neurodevelopmental disorders, with a focus on autism. RECENT FINDINGS Recent work on the biological basis of the male preponderance of autism and other neurodevelopmental disorders includes discussion of a higher genetic burden in females and sex-specific gene mutations or epigenetic changes that differentially confer risk to males or protection to females. Other mechanisms discussed are sex chromosome and sex hormone involvement. Specifically, fetal testosterone is involved in many aspects of development and may interact with neurotransmitter, neuropeptide, or immune pathways to contribute to male vulnerability. Finally, the possibilities of female underdiagnosis and a multi-hit hypothesis are discussed. This review highlights current theories of male bias in developmental disorders. Topics include environmental, genetic, and epigenetic mechanisms; theories of sex chromosomes, hormones, neuroendocrine, and immune function; underdiagnosis of females; and a multi-hit hypothesis.
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Affiliation(s)
- Sarah L. Ferri
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Pappajohn Biomedical Discovery Building, 169 Newton Road, Iowa City, IA 52242 USA
| | - Ted Abel
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Pappajohn Biomedical Discovery Building, 169 Newton Road, Iowa City, IA 52242 USA
| | - Edward S. Brodkin
- Center for Neurobiology and Behavior, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Translational Research Laboratory, 125 South 31 Street, Room 2202, Philadelphia, PA 19104-3403 USA
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20
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Picci G, Gotts SJ, Scherf KS. A theoretical rut: revisiting and critically evaluating the generalized under/over-connectivity hypothesis of autism. Dev Sci 2018; 19:524-49. [PMID: 27412228 DOI: 10.1111/desc.12467] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 05/28/2016] [Indexed: 11/29/2022]
Abstract
In 2004, two papers proposed that pervasive functional under-connectivity (Just et al., ) or a trade-off between excessive local connectivity at the cost of distal under-connectivity (Belmonte et al., ) characterizes atypical brain organization in autism. Here, we take stock of the most recent and rigorous functional and structural connectivity findings with a careful eye toward evaluating the extent to which they support these original hypotheses. Indeed, the empirical data do not support them. From rsfMRI studies in adolescents and adults, there is an emerging consensus regarding long-range functional connections indicating cortico-cortical under-connectivity, specifically involving the temporal lobes, combined with subcortical-cortical over-connectivity. In contrast, there is little to no consensus regarding local functional connectivity or findings from task-based functional connectivity studies. The structural connectivity data suggest that white matter tracts are pervasively weak, particularly in the temporal lobe. Together, these findings are revealing how deeply complex the story is regarding atypical neural network organization in autism. In other words, distance and strength of connectivity as individual factors or as interacting factors do not consistently explain the patterns of atypical neural connectivity in autism. Therefore, we make several methodological recommendations and highlight developmental considerations that will help researchers in the field cultivate new hypotheses about the nature and mechanisms of potentially aberrant functional and structural connectivity in autism.
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Affiliation(s)
- Giorgia Picci
- Department of Psychology, Pennsylvania State University, USA
| | - Stephen J Gotts
- Department of Psychology, Pennsylvania State University, USA
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21
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Nickel K, Tebartz van Elst L, Perlov E, Endres D, Müller GT, Riedel A, Fangmeier T, Maier S. Altered white matter integrity in adults with autism spectrum disorder and an IQ >100: a diffusion tensor imaging study. Acta Psychiatr Scand 2017; 135:573-583. [PMID: 28407202 DOI: 10.1111/acps.12731] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/13/2017] [Indexed: 12/16/2022]
Abstract
OBJECTIVE White matter (WM) alterations have been reported in children and adults with autism spectrum disorder (ASD). In particular, impaired connectivity of limbic structures may be related to social deficits. Heterogeneous findings could be explained in terms of differences in sample characteristics and methodology. In this context, non-syndromic forms might differ substantially in WM structure from secondary ASD forms. METHOD In an attempt to recruit a homogeneous study sample, we included adults with high-functioning ASD and an IQ > 100 to decrease the influence of syndromic forms being often associated with cognitive deficits. Diffusion tensor imaging (DTI) was performed in 30 participants with ASD and 30 pairwise-matched controls. Fractional anisotropy (FA) and mean diffusivity (MD) as surrogate imaging markers for WM integrity were calculated. RESULTS We found a significant FA decrease in the ASD group in the genu and body of the corpus callosum (CC). Increased MD was detected in the subgenual anterior cingulate cortex (sACC). CONCLUSION The finding of decreased WM integrity in the genu of the CC is in line with earlier studies reporting a decreased number of interhemispheric fibers in the frontal lobe of ASD. Alterations in the sACC might be associated with 'Theory of mind' deficits.
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Affiliation(s)
- K Nickel
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center - University of Freiburg, Freiburg, Germany
| | - L Tebartz van Elst
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center - University of Freiburg, Freiburg, Germany
| | - E Perlov
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center - University of Freiburg, Freiburg, Germany.,Luzerner Psychiatrie, Hospital St. Urban, St. Urban, Switzerland
| | - D Endres
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center - University of Freiburg, Freiburg, Germany
| | - G T Müller
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center - University of Freiburg, Freiburg, Germany
| | - A Riedel
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center - University of Freiburg, Freiburg, Germany
| | - T Fangmeier
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center - University of Freiburg, Freiburg, Germany
| | - S Maier
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, Medical Center - University of Freiburg, Freiburg, Germany
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22
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Kirkovski M, Enticott PG, Hughes ME, Rossell SL, Fitzgerald PB. Atypical Neural Activity in Males But Not Females with Autism Spectrum Disorder. J Autism Dev Disord 2016; 46:954-63. [PMID: 26520145 DOI: 10.1007/s10803-015-2639-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The medial prefrontal cortex (mPFC) and the right temporo-parietal junction (rTPj) are highly involved in social understanding, a core area of impairment in autism spectrum disorder (ASD). We used fMRI to investigate sex differences in the neural correlates of social understanding in 27 high-functioning adults with ASD and 23 matched controls. There were no differences in neural activity in the mPFC or rTPj between groups during social processing. Whole brain analysis revealed decreased activity in the posterior superior temporal sulcus in males with ASD compared to control males while processing social information. This pattern was not observed in the female sub-sample. The current study indicates that sex mediates the neurobiology of ASD, particularly with respect to processing social information.
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Affiliation(s)
- Melissa Kirkovski
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, VIC, Australia. .,Cognitive Neuroscience Unit, School of Psychology, Deakin University, Melbourne Burwood Campus, Building BC, Level 5, 221 Burwood Hwy, Burwood, VIC, 3125, Australia.
| | - Peter G Enticott
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, VIC, Australia.,Cognitive Neuroscience Unit, School of Psychology, Deakin University, Melbourne Burwood Campus, Building BC, Level 5, 221 Burwood Hwy, Burwood, VIC, 3125, Australia
| | - Matthew E Hughes
- Brain and Psychological Science Research Centre, Faculty Health, Arts and Design, Swinburne University, Hawthorn, VIC, Australia
| | - Susan L Rossell
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, VIC, Australia.,Brain and Psychological Science Research Centre, Faculty Health, Arts and Design, Swinburne University, Hawthorn, VIC, Australia
| | - Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University, Melbourne, VIC, Australia
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Kirkovski M, Rogasch NC, Saeki T, Fitzgibbon BM, Enticott PG, Fitzgerald PB. Single Pulse Transcranial Magnetic Stimulation-Electroencephalogram Reveals No Electrophysiological Abnormality in Adults with High-Functioning Autism Spectrum Disorder. J Child Adolesc Psychopharmacol 2016; 26:606-16. [PMID: 27284688 DOI: 10.1089/cap.2015.0181] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Neuroimaging and electrophysiological research have revealed a range of neural abnormalities in autism spectrum disorder (ASD), but a comprehensive understanding remains elusive. We utilized a novel methodology among individuals with ASD and matched controls, combining transcranial magnetic stimulation (TMS) with concurrent electroencephalogram (EEG) recording (TMS-EEG) to explore cortical function and connectivity in three sites implicated in the neuropathophysiology of ASD (dorsolateral prefrontal cortex, primary motor cortex, and temporoparietal junction). As there is evidence for neurobiological gender differences in ASD, we also examined the influence of biological sex. METHODS TMS pulses were applied to each of the three sites (right lateralized) during 20-channel EEG recording. RESULTS We did not identify any differences in the EEG response to TMS between ASD and control groups. This finding remained when data were stratified by sex. Nevertheless, traits and characteristics associated with ASD were correlated with the neurophysiological response to TMS. CONCLUSION While TMS-EEG did not appear to clarify the neuropathophysiology of ASD, the relationships identified between the neurophysiological response to TMS and clinical characteristics warrant further investigation.
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Affiliation(s)
- Melissa Kirkovski
- 1 Cognitive Neuroscience Unit, School of Psychology, Deakin University , Geelong, Australia .,2 Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University , Clayton, Australia
| | - Nigel C Rogasch
- 2 Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University , Clayton, Australia .,3 Monash Clinical and Imaging Neuroscience, School of Psychological Sciences and Monash Biomedical Imaging, Monash University , Clayton, Australia
| | - Takashi Saeki
- 2 Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University , Clayton, Australia .,4 Department of Psychiatry, Yokohama City University School of Medicine , Yokohama, Japan
| | - Bernadette M Fitzgibbon
- 2 Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University , Clayton, Australia
| | - Peter G Enticott
- 1 Cognitive Neuroscience Unit, School of Psychology, Deakin University , Geelong, Australia .,2 Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University , Clayton, Australia
| | - Paul B Fitzgerald
- 2 Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School, Monash University , Clayton, Australia
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24
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Koolschijn PCMP, Caan MWA, Teeuw J, Olabarriaga SD, Geurts HM. Age-related differences in autism: The case of white matter microstructure. Hum Brain Mapp 2016; 38:82-96. [PMID: 27511627 DOI: 10.1002/hbm.23345] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 07/25/2016] [Accepted: 08/01/2016] [Indexed: 11/09/2022] Open
Abstract
Autism spectrum disorder (ASD) is typified as a brain connectivity disorder in which white matter abnormalities are already present early on in life. However, it is unknown if and to which extent these abnormalities are hard-wired in (older) adults with ASD and how this interacts with age-related white matter changes as observed in typical aging. The aim of this first cross-sectional study in mid- and late-aged adults with ASD was to characterize white matter microstructure and its relationship with age. We utilized diffusion tensor imaging with head motion control in 48 adults with ASD and 48 age-matched controls (30-74 years), who also completed a Flanker task. Intra-individual variability of reaction times (IIVRT) measures based on performance on the Flanker interference task were used to assess IIVRT-white matter microstructure associations. We observed primarily higher mean and radial diffusivity in white matter microstructure in ASD, particularly in long-range fibers, which persisted after taking head motion into account. Importantly, group-by-age interactions revealed higher age-related mean and radial diffusivity in ASD, in projection and association fiber tracts. Subtle dissociations were observed in IIVRT-white matter microstructure relations between groups, with the IIVRT-white matter association pattern in ASD resembling observations in cognitive aging. The observed white matter microstructure differences are lending support to the structural underconnectivity hypothesis in ASD. These reductions seem to have behavioral percussions given the atypical relationship with IIVRT. Taken together, the current results may indicate different age-related patterns of white matter microstructure in adults with ASD. Hum Brain Mapp 38:82-96, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- P Cédric M P Koolschijn
- Dutch Autism & ADHD Research Center, Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands.,Amsterdam Brain and Cognition (ABC), University of Amsterdam, Amsterdam, The Netherlands
| | - Matthan W A Caan
- Department of Radiology, Brain Imaging Center, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Jalmar Teeuw
- Department of Radiology, Brain Imaging Center, Academic Medical Center, University of Amsterdam, The Netherlands.,Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Sílvia D Olabarriaga
- Department of Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Hilde M Geurts
- Dutch Autism & ADHD Research Center, Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands.,Amsterdam Brain and Cognition (ABC), University of Amsterdam, Amsterdam, The Netherlands.,Dr Leo Kannerhuis, The Netherlands
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25
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Abstract
Abstract
ASD research is at an important crossroads. The ASD diagnosis is important for assigning a child to early behavioral intervention and explaining a child’s condition. But ASD research has not provided a diagnosis-specific medical treatment, or a consistent early predictor, or a unified life course. If the ASD diagnosis also lacks biological and construct validity, a shift away from studying ASD-defined samples would be warranted. Consequently, this paper reviews recent findings for the neurobiological validity of ASD, the construct validity of ASD diagnostic criteria, and the construct validity of ASD spectrum features. The findings reviewed indicate that the ASD diagnosis lacks biological and construct validity. The paper concludes with proposals for research going forward.
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Dunlop WA, Enticott PG, Rajan R. Speech Discrimination Difficulties in High-Functioning Autism Spectrum Disorder Are Likely Independent of Auditory Hypersensitivity. Front Hum Neurosci 2016; 10:401. [PMID: 27555814 PMCID: PMC4977299 DOI: 10.3389/fnhum.2016.00401] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 07/26/2016] [Indexed: 01/06/2023] Open
Abstract
Autism Spectrum Disorder (ASD), characterized by impaired communication skills and repetitive behaviors, can also result in differences in sensory perception. Individuals with ASD often perform normally in simple auditory tasks but poorly compared to typically developed (TD) individuals on complex auditory tasks like discriminating speech from complex background noise. A common trait of individuals with ASD is hypersensitivity to auditory stimulation. No studies to our knowledge consider whether hypersensitivity to sounds is related to differences in speech-in-noise discrimination. We provide novel evidence that individuals with high-functioning ASD show poor performance compared to TD individuals in a speech-in-noise discrimination task with an attentionally demanding background noise, but not in a purely energetic noise. Further, we demonstrate in our small sample that speech-hypersensitivity does not appear to predict performance in the speech-in-noise task. The findings support the argument that an attentional deficit, rather than a perceptual deficit, affects the ability of individuals with ASD to discriminate speech from background noise. Finally, we piloted a novel questionnaire that measures difficulty hearing in noisy environments, and sensitivity to non-verbal and verbal sounds. Psychometric analysis using 128 TD participants provided novel evidence for a difference in sensitivity to non-verbal and verbal sounds, and these findings were reinforced by participants with ASD who also completed the questionnaire. The study was limited by a small and high-functioning sample of participants with ASD. Future work could test larger sample sizes and include lower-functioning ASD participants.
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Affiliation(s)
- William A. Dunlop
- Neuroscience Program Biomedicine Discovery Institute, Department of Physiology, Monash UniversityMelbourne, VIC, Australia
| | - Peter G. Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin UniversityGeelong, VIC, Australia
- Monash Alfred Psychiatry Research Centre, Monash UniversityMelbourne, VIC, Australia
| | - Ramesh Rajan
- Neuroscience Program Biomedicine Discovery Institute, Department of Physiology, Monash UniversityMelbourne, VIC, Australia
- Ear Sciences Institute of AustraliaPerth, WA, Australia
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27
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Supekar K, Menon V. Sex differences in structural organization of motor systems and their dissociable links with repetitive/restricted behaviors in children with autism. Mol Autism 2015; 6:50. [PMID: 26347127 PMCID: PMC4559968 DOI: 10.1186/s13229-015-0042-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 08/17/2015] [Indexed: 12/03/2022] Open
Abstract
Background Autism spectrum disorder (ASD) is diagnosed much less often in females than males. Emerging behavioral accounts suggest that the clinical presentation of autism is different in females and males, yet research examining sex differences in core symptoms of autism in affected children has been limited. Additionally, to date, there have been no systematic attempts to characterize neuroanatomical differences underlying the distinct behavioral profiles observed in girls and boys with ASD. This is in part because extant ASD studies have included a small number of girls. Methods Leveraging the National Database for Autism Research (NDAR), we first analyzed symptom severity in a large sample consisting of 128 ASD girls and 614 age- and IQ-matched ASD boys. We then examined symptom severity and structural imaging data using novel multivariate pattern analysis in a well-matched group of 25 ASD girls, 25 ASD boys, 19 typically developing (TD) girls, and 19 TD boys, obtained from the Autism Brain Imaging Data Exchange (ABIDE). Results In both the NDAR and ABIDE datasets, girls, compared to boys, with ASD showed less severe repetitive/restricted behaviors (RRBs) and comparable deficits in the social and communication domains. In the ABIDE imaging dataset, gray matter (GM) patterns in the motor cortex, supplementary motor area (SMA), cerebellum, fusiform gyrus, and amygdala accurately discriminated girls and boys with ASD. This sex difference pattern was specific to ASD as the GM in these brain regions did not discriminate TD girls and boys. Moreover, GM in the motor cortex, SMA, and crus 1 subdivision of the cerebellum was correlated with RRB in girls whereas GM in the right putamen—the region that discriminated TD girls and boys—was correlated with RRB in boys. Conclusions We found robust evidence for reduced levels of RRB in girls, compared to boys, with ASD, providing the strongest evidence to date for sex differences in a core phenotypic feature of childhood ASD. Sex differences in brain morphometry are prominent in the motor system and in areas that comprise the “social brain.” Notably, RRB severity is associated with sex differences in GM morphometry in distinct motor regions. Our findings provide novel insights into the neurobiology of sex differences in childhood autism. Electronic supplementary material The online version of this article (doi:10.1186/s13229-015-0042-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kaustubh Supekar
- Department of Psychiatry & Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd., Stanford, CA 94304-5719 USA
| | - Vinod Menon
- Department of Psychiatry & Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Rd., Stanford, CA 94304-5719 USA ; Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94304 USA ; Stanford Neurosciences Institute, Stanford University School of Medicine, Stanford, CA 94304 USA
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