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Xu X, Song X, Lin L, Pan N, Jin Y, Tan S, Cao M, Chen Y, Zhao J, Su X, Yang K, Jing J, Li X. White matter substrates underlying morphological awareness deficit in Chinese children with developmental dyslexia. Prog Neuropsychopharmacol Biol Psychiatry 2024; 134:111083. [PMID: 38992486 DOI: 10.1016/j.pnpbp.2024.111083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 06/24/2024] [Accepted: 07/08/2024] [Indexed: 07/13/2024]
Abstract
BACKGROUND Morphological awareness (MA) deficit is strongly associated with Chinese developmental dyslexia (DD). However, little is known about the white matter substrates underlying the MA deficit in Chinese children with DD. METHODS In the current study, 34 Chinese children with DD and 42 typical developmental (TD) children were recruited to complete a diffusion magnetic resonance imaging scan and cognitive tests for MA. We conducted linear regression to test the correlation between MA and DTI metrics, the structural abnormalities of the tracts related to MA, and the interaction effect of DTI metrics by group on MA. RESULTS First, MA was significant related to the right inferior occipito-frontal fascicle (IFO) and inferior longitudinal fsciculus (ILF), the bilateral thalamo-occipital (T_OCC) and the left arcuate fasciculus (AF); second, compared to TD children, Chinese children with DD had lower axial diffusivity (AD) in the right IFO and T_OCC; third, there were significant interactions between metrics (fractional anisotropy (FA) and radial diffusivity (RD)) of the right IFO and MA in groups. The FA and RD of the right IFO were significantly associated with MA in children with DD but not in TD children. CONCLUSION In conclusion, compared to TD children, Chinese children with DD had axonal degeneration not only in the ventral tract (the right IFO) but also the visuospatial tract (the right T_OCC) which were associated with their MA deficit. And Chinese MA involved not only the ventral tracts, but also the visuospatial pathway and dorsal tracts.
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Affiliation(s)
- Xiaoyu Xu
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiaojing Song
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Lizi Lin
- Guangdong Provincial Engineering Technology Research Center of Environmental Pollution and Health Risk Assessment, Department of Occupational and Environmental Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ning Pan
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yuying Jin
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Si Tan
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Muqing Cao
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yingqian Chen
- The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jingxian Zhao
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xintong Su
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Kaize Yang
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jin Jing
- Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiuhong Li
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong, China.
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Turesky TK, Escalante E, Loh M, Gaab N. Longitudinal trajectories of brain development from infancy to school age and their relationship to literacy development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.29.601366. [PMID: 39005343 PMCID: PMC11244924 DOI: 10.1101/2024.06.29.601366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Reading is one of the most complex skills that we utilize daily, and it involves the early development and interaction of various lower-level subskills, including phonological processing and oral language. These subskills recruit brain structures, which begin to develop long before the skill manifests and exhibit rapid development during infancy. However, how longitudinal trajectories of early brain development in these structures supports long-term acquisition of literacy subskills and subsequent reading is unclear. Children underwent structural and diffusion MRI scanning at multiple timepoints between infancy and second grade and were tested for literacy subskills in preschool and decoding and word reading in early elementary school. We developed and implemented a reproducible pipeline to generate longitudinal trajectories of early brain development to examine associations between these trajectories and literacy (sub)skills. Furthermore, we examined whether familial risk of reading difficulty and a child's home literacy environment, two common literacy-related covariates, influenced those trajectories. Results showed that individual differences in curve features (e.g., intercepts and slopes) for longitudinal trajectories of volumetric, surface-based, and white matter organization measures in left-hemispheric reading-related regions and tracts were linked directly to phonological processing and indirectly to second-grade decoding and word reading skills via phonological processing. Altogether, these findings suggest that the brain bases of phonological processing, previously identified as the strongest behavioral predictor of reading and decoding skills, may already begin to develop early in infancy but undergo further refinement between birth and preschool. The present study underscores the importance of considering academic skill acquisition from the very beginning of life.
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Gaab N, Duggan N. Leveraging brain science for impactful advocacy and policymaking: The synergistic partnership between developmental cognitive neuroscientists and a parent-led grassroots movement to drive dyslexia prevention policy and legislation. Dev Cogn Neurosci 2024; 66:101376. [PMID: 38608358 PMCID: PMC11019101 DOI: 10.1016/j.dcn.2024.101376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 03/01/2024] [Accepted: 04/04/2024] [Indexed: 04/14/2024] Open
Abstract
Reading proficiency is crucial for academic, vocational, and economic success and has been closely linked to health outcomes. Unfortunately, in the United States, a concerning 63% of fourth-grade children are reading below grade level, with approximately 7%-10% exhibiting a disability in word reading, developmental dyslexia. Research in developmental cognitive neuroscience indicates that individuals with dyslexia show functional and structural brain alterations in regions processing reading and reading-related information, with some of these differences emerging as early as preschool and even infancy. This suggests that some children start schooling with less optimal brain architecture for learning to read, emphasizing the need for preventative education practices. This article reviews educational policies impacting children with dyslexia and highlights a decentralized parent-led grassroots movement, Decoding Dyslexia, which centers the voices of those directly impacted by dyslexia. It utilizes civic engagement practices, advocacy and lobbying on local, federal, and social media platforms, and strong partnerships with scientists to drive systems-level change in educational practices, leading to dyslexia prevention legislation across the U.S. The ongoing partnership continues to address the profound gaps between scientific findings and policymaking to drive systems-level change for contemporary challenges in educational practices within a learning disabilities framework.
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Martins B, Baba MY, Dimateo EM, Costa LF, Camara AS, Lukasova K, Nucci MP. Investigating Dyslexia through Diffusion Tensor Imaging across Ages: A Systematic Review. Brain Sci 2024; 14:349. [PMID: 38672001 PMCID: PMC11047980 DOI: 10.3390/brainsci14040349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/17/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
Dyslexia is a neurodevelopmental disorder that presents a deficit in accuracy and/or fluency while reading or spelling that is not expected given the level of cognitive functioning. Research indicates brain structural changes mainly in the left hemisphere, comprising arcuate fasciculus (AF) and corona radiata (CR). The purpose of this systematic review is to better understand the possible methods for analyzing Diffusion Tensor Imaging (DTI) data while accounting for the characteristics of dyslexia in the last decade of the literature. Among 124 articles screened from PubMed and Scopus, 49 met inclusion criteria, focusing on dyslexia without neurological or psychiatric comorbidities. Article selection involved paired evaluation, with a third reviewer resolving discrepancies. The selected articles were analyzed using two topics: (1) a demographic and cognitive assessment of the sample and (2) DTI acquisition and analysis. Predominantly, studies centered on English-speaking children with reading difficulties, with preserved non-verbal intelligence, attention, and memory, and deficits in reading tests, rapid automatic naming, and phonological awareness. Structural differences were found mainly in the left AF in all ages and in the bilateral superior longitudinal fasciculus for readers-children and adults. A better understanding of structural brain changes of dyslexia and neuroadaptations can be a guide for future interventions.
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Affiliation(s)
- Bruce Martins
- Laboratório de Investigação Médica em Neurorradiologia—LIM44—Hospital das Clínicas da Faculdade Medicina, Universidade de São Paulo, São Paulo 05403-000, Brazil; (B.M.); (M.Y.B.); (E.M.D.)
| | - Mariana Yumi Baba
- Laboratório de Investigação Médica em Neurorradiologia—LIM44—Hospital das Clínicas da Faculdade Medicina, Universidade de São Paulo, São Paulo 05403-000, Brazil; (B.M.); (M.Y.B.); (E.M.D.)
| | - Elisa Monteiro Dimateo
- Laboratório de Investigação Médica em Neurorradiologia—LIM44—Hospital das Clínicas da Faculdade Medicina, Universidade de São Paulo, São Paulo 05403-000, Brazil; (B.M.); (M.Y.B.); (E.M.D.)
| | - Leticia Fruchi Costa
- Centro de Matemática, Computação e Cognição (CMCC), Universidade Federal do ABC, Santo André 09210-580, Brazil; (L.F.C.); (A.S.C.); (K.L.)
| | - Aila Silveira Camara
- Centro de Matemática, Computação e Cognição (CMCC), Universidade Federal do ABC, Santo André 09210-580, Brazil; (L.F.C.); (A.S.C.); (K.L.)
| | - Katerina Lukasova
- Centro de Matemática, Computação e Cognição (CMCC), Universidade Federal do ABC, Santo André 09210-580, Brazil; (L.F.C.); (A.S.C.); (K.L.)
| | - Mariana Penteado Nucci
- Laboratório de Investigação Médica em Neurorradiologia—LIM44—Hospital das Clínicas da Faculdade Medicina, Universidade de São Paulo, São Paulo 05403-000, Brazil; (B.M.); (M.Y.B.); (E.M.D.)
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Roy E, Richie-Halford A, Kruper J, Narayan M, Bloom D, Nedelec P, Rauschecker AM, Sugrue LP, Brown TT, Jernigan TL, McCandliss BD, Rokem A, Yeatman JD. White matter and literacy: A dynamic system in flux. Dev Cogn Neurosci 2024; 65:101341. [PMID: 38219709 PMCID: PMC10825614 DOI: 10.1016/j.dcn.2024.101341] [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: 02/22/2023] [Revised: 08/24/2023] [Accepted: 01/03/2024] [Indexed: 01/16/2024] Open
Abstract
Cross-sectional studies have linked differences in white matter tissue properties to reading skills. However, past studies have reported a range of, sometimes conflicting, results. Some studies suggest that white matter properties act as individual-level traits predictive of reading skill, whereas others suggest that reading skill and white matter develop as a function of an individual's educational experience. In the present study, we tested two hypotheses: a) that diffusion properties of the white matter reflect stable brain characteristics that relate to stable individual differences in reading ability or b) that white matter is a dynamic system, linked with learning over time. To answer these questions, we examined the relationship between white matter and reading in a five-year longitudinal dataset and a series of large-scale, single-observation, cross-sectional datasets (N = 14,249 total participants). We find that gains in reading skill correspond to longitudinal changes in the white matter. However, in the cross-sectional datasets, we find no evidence for the hypothesis that individual differences in white matter predict reading skill. These findings highlight the link between dynamic processes in the white matter and learning.
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Affiliation(s)
- Ethan Roy
- Graduate School of Education, Stanford University, Stanford, CA, USA.
| | - Adam Richie-Halford
- Graduate School of Education, Stanford University, Stanford, CA, USA; Department of Psychology and eScience Institute, University of Washington, Seattle, WA, USA; Division of Developmental-Behavioral Pediatrics, Stanford University, Stanford, CA, USA
| | - John Kruper
- Department of Psychology and eScience Institute, University of Washington, Seattle, WA, USA
| | - Manjari Narayan
- Division of Developmental-Behavioral Pediatrics, Stanford University, Stanford, CA, USA
| | - David Bloom
- Department of Psychology and eScience Institute, University of Washington, Seattle, WA, USA
| | - Pierre Nedelec
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Andreas M Rauschecker
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Leo P Sugrue
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Timothy T Brown
- School of Medicine, University of California San Diego, San Diego, CA, USA
| | - Terry L Jernigan
- Center for Human Development, University of California San Diego, San Diego, CA, USA
| | | | - Ariel Rokem
- Department of Psychology and eScience Institute, University of Washington, Seattle, WA, USA
| | - Jason D Yeatman
- Graduate School of Education, Stanford University, Stanford, CA, USA; Division of Developmental-Behavioral Pediatrics, Stanford University, Stanford, CA, USA
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Adil D, Duerden EG, Eagleson R, de Ribaupierre S. Structural Alterations of the Corpus Callosum in Children With Infantile Hydrocephalus. J Child Neurol 2024; 39:66-76. [PMID: 38387869 PMCID: PMC11083734 DOI: 10.1177/08830738241231343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/17/2024] [Accepted: 01/22/2024] [Indexed: 02/24/2024]
Abstract
This study investigates structural alterations of the corpus callosum in children diagnosed with infantile hydrocephalus. We aim to assess both macrostructural (volume) and microstructural (diffusion tensor imaging metrics) facets of the corpus callosum, providing insights into the nature and extent of alterations associated with this condition. Eighteen patients with infantile hydrocephalus (mean age = 9 years) and 18 age- and sex-matched typically developing healthy children participated in the study. Structural magnetic resonance imaging and diffusion tensor imaging were used to assess corpus callosum volume and microstructure, respectively. Our findings reveal significant alterations in corpus callosum volume, particularly in the posterior area, as well as distinct microstructural disparities, notably pronounced in these same segments. These results highlight the intricate interplay between macrostructural and microstructural aspects in understanding the impact of infantile hydrocephalus. Examining these structural alterations provides an understanding into the mechanisms underlying the effects of infantile hydrocephalus on corpus callosum integrity, given its pivotal role in interhemispheric communication. This knowledge offers a more nuanced perspective on neurologic disorders and underscores the significance of investigating the corpus callosum's health in such contexts.
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Affiliation(s)
- Derya Adil
- Western Institute for Neuroscience, Western University, London, Ontario, Canada
| | - Emma G. Duerden
- Western Institute for Neuroscience, Western University, London, Ontario, Canada
- Applied Psychology, Faculty of Education, Western University, London, Ontario, Canada
| | - Roy Eagleson
- Western Institute for Neuroscience, Western University, London, Ontario, Canada
- Electrical and Computer Engineering, Faculty of Engineering, Western University, London, Ontario, Canada
| | - Sandrine de Ribaupierre
- Western Institute for Neuroscience, Western University, London, Ontario, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
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Abbott N, Love T. Bridging the Divide: Brain and Behavior in Developmental Language Disorder. Brain Sci 2023; 13:1606. [PMID: 38002565 PMCID: PMC10670267 DOI: 10.3390/brainsci13111606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/14/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023] Open
Abstract
Developmental language disorder (DLD) is a heterogenous neurodevelopmental disorder that affects a child's ability to comprehend and/or produce spoken and/or written language, yet it cannot be attributed to hearing loss or overt neurological damage. It is widely believed that some combination of genetic, biological, and environmental factors influences brain and language development in this population, but it has been difficult to bridge theoretical accounts of DLD with neuroimaging findings, due to heterogeneity in language impairment profiles across individuals and inconsistent neuroimaging findings. Therefore, the purpose of this overview is two-fold: (1) to summarize the neuroimaging literature (while drawing on findings from other language-impaired populations, where appropriate); and (2) to briefly review the theoretical accounts of language impairment patterns in DLD, with the goal of bridging the disparate findings. As will be demonstrated with this overview, the current state of the field suggests that children with DLD have atypical brain volume, laterality, and activation/connectivity patterns in key language regions that likely contribute to language difficulties. However, the precise nature of these differences and the underlying neural mechanisms contributing to them remain an open area of investigation.
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Affiliation(s)
- Noelle Abbott
- School of Speech, Language, and Hearing Sciences, San Diego State University, San Diego, CA 92182, USA;
- San Diego State University/University of California San Diego Joint Doctoral Program in Language and Communicative Disorders, San Diego, CA 92182, USA
| | - Tracy Love
- School of Speech, Language, and Hearing Sciences, San Diego State University, San Diego, CA 92182, USA;
- San Diego State University/University of California San Diego Joint Doctoral Program in Language and Communicative Disorders, San Diego, CA 92182, USA
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Slaby RJ, Arrington CN, Malins J, Sevcik RA, Pugh KR, Morris R. Properties of white matter tract diffusivity in children with developmental dyslexia and comorbid attention deficit/hyperactivity disorder. J Neurodev Disord 2023; 15:25. [PMID: 37550628 PMCID: PMC10408076 DOI: 10.1186/s11689-023-09495-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/11/2023] [Indexed: 08/09/2023] Open
Abstract
BACKGROUND Developmental dyslexia (DD) and attention deficit/hyperactivity disorder (ADHD) are highly comorbid neurodevelopmental disorders. Individuals with DD or ADHD have both been shown to have deficits in white matter tracts associated with reading and attentional control networks. However, white matter diffusivity in individuals comorbid with both DD and ADHD (DD + ADHD) has not been specifically explored. METHODS Participants were 3rd and 4th graders (age range = 7 to 11 years; SD = 0.69) from three diagnostic groups ((DD (n = 40), DD + ADHD (n = 22), and typical developing (TD) (n = 20)). Behavioral measures of reading and attention alongside measures of white matter diffusivity were collected for all participants. RESULTS DD + ADHD and TD groups differed in mean fractional anisotropy (FA) for the left and right Superior Longitudinal Fasciculus (SLF)-Parietal Terminations and SLF-Temporal Terminations. Mean FA for the DD group across these SLF tracts fell between the lower DD + ADHD and higher TD averages. No differences in mean diffusivity nor significant brain-behavior relations were found. CONCLUSIONS Findings suggest that WM diffusivity in the SLF increases along a continuum across DD + ADHD, DD, and TD.
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Affiliation(s)
- Ryan J Slaby
- Department of Psychology, Georgia State University, 140 Decatur St SE, Atlanta, GA, 30303, USA
- GSU/Georgia Tech Center for Advanced Brain Imaging, 831 Marietta St NW, Atlanta, GA, 30318, USA
- Department of Psychology, University of Milano-Bicocca, Piazza Dell' Ateneo Nuovo,1, 20126, Milan, Italy
| | - C Nikki Arrington
- Department of Psychology, Georgia State University, 140 Decatur St SE, Atlanta, GA, 30303, USA.
- GSU/Georgia Tech Center for Advanced Brain Imaging, 831 Marietta St NW, Atlanta, GA, 30318, USA.
- Georgia State University, Center for Translational Research in Neuroimaging and Data Science, 55 Park Place, 18th Floor, Atlanta, GA, 30303, USA.
| | - Jeffrey Malins
- Department of Psychology, Georgia State University, 140 Decatur St SE, Atlanta, GA, 30303, USA
- GSU/Georgia Tech Center for Advanced Brain Imaging, 831 Marietta St NW, Atlanta, GA, 30318, USA
| | - Rose A Sevcik
- Department of Psychology, Georgia State University, 140 Decatur St SE, Atlanta, GA, 30303, USA
| | - Kenneth R Pugh
- Yale University, Haskins Laboratories, 300 George Street, Suite 900, New Haven, CT, 06511, USA
| | - Robin Morris
- Department of Psychology, Georgia State University, 140 Decatur St SE, Atlanta, GA, 30303, USA
- GSU/Georgia Tech Center for Advanced Brain Imaging, 831 Marietta St NW, Atlanta, GA, 30318, USA
- Georgia State University, Center for Translational Research in Neuroimaging and Data Science, 55 Park Place, 18th Floor, Atlanta, GA, 30303, USA
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Mather D. Preventing the Development of Dyslexia: A Premature Writing Hypothesis. Percept Mot Skills 2022; 129:468-487. [PMID: 35084244 PMCID: PMC9198397 DOI: 10.1177/00315125221075001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
It has been argued that dyslexia may develop in strongly left eye dominant children through learning to write using ipsilateral, right hemisphere motor pathways. New light on this theory has been cast by recent findings of atypical enhanced corpus callosum white matter in children with dyslexia, reflecting right to left hemisphere communication that is resistant to intensive remedial reading intervention. Enhanced corpus callosum white matter is consistent with uninhibited right to left hemisphere ipsilateral mirror-motor innervation, manifested as frequent mirror-letter writing errors in children with dyslexia. Delaying writing instruction until 7-8 years of age may prevent these errors and as well as the development of dyslexia. During the 7-8 year age period, visual-proprioceptive integration enables a child to mentally map whole word visual images onto kinaesthetic/proprioceptive letter engrams (memory representations). Hypothetically, this process is facilitated by anterior commissure activity involving inter-hemispheric transfer of ipsilateral mirror-to-non mirror motor movement. This postulate, involving delayed writing instruction pending further maturation, also receives indirect support from the remarkable proficiency leap among second graders reading Hebrew as Hebrew involves a leftward orthography in which ipsilateral right to left hemisphere innervation is uninhibited. Additionally, and more directly, normal reading comprehension for learning English among children with agenesis of the corpus callosum suggests that letter-sound decoding is not the sole route to proficient reading comprehension. In this paper, I make recommendations for obtaining empirical evidence of premature writing as a cause of dyslexia.
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Affiliation(s)
- David Mather
- Curriculum and Instruction8205University of Victoria
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Koirala N, Perdue MV, Su X, Grigorenko EL, Landi N. Neurite density and arborization is associated with reading skill and phonological processing in children. Neuroimage 2021; 241:118426. [PMID: 34303796 PMCID: PMC8539928 DOI: 10.1016/j.neuroimage.2021.118426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/25/2021] [Accepted: 07/21/2021] [Indexed: 12/03/2022] Open
Abstract
Background: Studies exploring neuroanatomic correlates of reading have associated white matter tissue properties with reading disability and related componential skills (e.g., phonological and single-word reading skills). Mean diffusivity (MD) and fractional anisotropy (FA) are widely used surrogate measures of tissue microstructure with high sensitivity; however, they lack specificity for individual microstructural features. Here we investigated neurite features with higher specificity in order to explore the underlying microstructural architecture. Methods: Diffusion weighted images (DWI) and a battery of behavioral and neuropsychological assessments were obtained from 412 children (6 – 16 years of age). Neurite indices influenced by orientation and density were attained from 23 major white matter tracts. Partial correlations were calculated between neurite indices and indicators of phonological processing and single-word reading skills using age, sex, and image quality metrics as covariates. In addition, mediation analysis was performed using structural equation modeling (SEM) to evaluate the indirect effect of phonological processing on reading skills. Results: We observed that orientation dispersion index (ODI) and neurite density index (NDI) were negatively correlated with single-word reading and phonological processing skills in several tracts previously shown to have structural correlates with reading efficiency. We also observed a significant and substantial effect in which phonological processing mediated the relationship between neurite indices and reading skills in most tracts. Conclusions: In sum, we established that better reading and phonological processing skills are associated with greater tract coherence (lower ODI) and lower neurite density (lower NDI). We interpret these findings as evidence that reading is associated with neural architecture and its efficiency.
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Affiliation(s)
- Nabin Koirala
- Haskins Laboratories, New Haven, Connecticut, United States.
| | - Meaghan V Perdue
- Haskins Laboratories, New Haven, Connecticut, United States; Department of Psychological Sciences, University of Connecticut, Connecticut, United States
| | - Xing Su
- Haskins Laboratories, New Haven, Connecticut, United States
| | - Elena L Grigorenko
- Haskins Laboratories, New Haven, Connecticut, United States; Department of Psychology, University of Houston, Texas, United States
| | - Nicole Landi
- Haskins Laboratories, New Haven, Connecticut, United States; Department of Psychological Sciences, University of Connecticut, Connecticut, United States
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Investigating the white matter correlates of reading performance: Evidence from Chinese children with reading difficulties. PLoS One 2021; 16:e0248434. [PMID: 33705494 PMCID: PMC7951916 DOI: 10.1371/journal.pone.0248434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 02/25/2021] [Indexed: 12/04/2022] Open
Abstract
Purpose Reading comprehension is closely associated with word recognition, particularly at the early stage of reading development. This association is reflected in children with reading difficulties (RD) who demonstrate poor reading comprehension along with delayed word recognition or reduced recognition accuracy. Although the neural mechanisms underlying reading comprehension and word recognition are well studied, few has investigated the white matter (WM) structures that the two processes potentially share. Methods To explore the issue, behavioral scores (word recognition & reading comprehension) and diffusion spectrum imaging (DSI) were acquired from Chinese-speaking children with RD and their age-matched typically developing children. WM structures were measured with generalized fractional anisotropy and normalized quantitative anisotropy to optimize fiber tracking precision. Results The children with RD performed significantly poorer than the typically developing children in both behavioral tasks. Between group differences of WM structure were found in the right superior temporal gyrus, the left medial frontal gyrus, the left medial frontal gyrus, and the left caudate body. A significant association between reading comprehension and Chinese character recognition and the DSI indices were found in the corpus callosum. The findings demonstrated the microstructural difference between children with and without reading difficulties go beyond the well-established reading network. Further, the association between the WM integrity of the corpus callosum and the behavioral scores reveals the involvement of the WM structure in both tasks. Conclusion It suggests the two reading-related skills have partially overlapped neural mechanism. Associating the corpus callosum with the reading skills leads to the reconsideration of the right hemisphere role in the typical reading process and, potentially, how it compensates for children with reading difficulties.
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Dubner SE, Rose J, Bruckert L, Feldman HM, Travis KE. Neonatal white matter tract microstructure and 2-year language outcomes after preterm birth. NEUROIMAGE-CLINICAL 2020; 28:102446. [PMID: 33035964 PMCID: PMC7554644 DOI: 10.1016/j.nicl.2020.102446] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 09/18/2020] [Accepted: 09/20/2020] [Indexed: 01/04/2023]
Abstract
Preterm infant white matter tracts uniquely predict later toddler language. Neonatal medical history moderates posterior corpus callosum–language relations. Different associations by tract may relate to brain maturation and medical history.
Aim To determine whether variability in diffusion MRI (dMRI) white matter tract metrics, obtained in a cohort of preterm infants prior to neonatal hospital discharge, would be associated with language outcomes at age 2 years, after consideration of age at scan and number of major neonatal complications. Method 30 children, gestational age 28.9 (2.4) weeks, underwent dMRI at mean post menstrual age 36.4 (1.4) weeks and language assessment with the Bayley Scales of Infant Development–III at mean age 22.2 (1.7) months chronological age. Mean fractional anisotropy (FA) and mean diffusivity (MD) were calculated for 5 white matter tracts. Hierarchical linear regression assessed associations between tract FA, moderating variables, and language outcomes. Results FA of the left inferior longitudinal fasciculus accounted for 17% (p = 0.03) of the variance in composite language and FA of the posterior corpus callosum accounted for 19% (p = 0.02) of the variance in composite language, beyond that accounted for by post-menstrual age at scan and neonatal medical complications. The number of neonatal medical complications moderated the relationship between language and posterior corpus callosum FA but did not moderate the association in the other tract. Conclusion Language at age 2 is associated with white matter metrics in early infancy in preterm children. The different pattern of associations by fiber group may relate to the stage of brain maturation and/or the nature and timing of medical complications related to preterm birth. Future studies should replicate these findings with a larger sample size to assure reliability of the findings.
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Affiliation(s)
- Sarah E Dubner
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA.
| | - Jessica Rose
- Division of Pediatric Orthopaedics, Stanford University School of Medicine, Stanford, CA, USA
| | - Lisa Bruckert
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Heidi M Feldman
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Katherine E Travis
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
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13
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Meng Y, Hu X, Zhang X, Bachevalier J. Diffusion tensor imaging reveals microstructural alterations in corpus callosum and associated transcallosal fiber tracts in adult macaques with neonatal hippocampal lesions. Hippocampus 2019; 28:838-845. [PMID: 29978933 DOI: 10.1002/hipo.23006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 05/30/2018] [Accepted: 06/22/2018] [Indexed: 01/17/2023]
Abstract
To investigate the effects of neonatal hippocampal lesions on the microstructural integrity of the corpus callosum (CC) in adulthood, macaque monkeys (n = 5) with neonatal bilateral neurotoxic hippocampal lesion (Neo-Hibo) and sham-operated controls (Neo-C, n = 5) were scanned using magnetic resonance diffusion tensor imaging (DTI) technique at 8-10 years old. CC was segmented into seven regionsgrouped into anterior CC (rostrum, genu, rostral body and anterior midbody) and posterior CC (posterior midbody, isthmus and splenium) for data analysis. Associated transcallosal fiber tracts were delineated using probabilistic tractography and evaluated with tract-based spatial statistics (TBSS). Neo-Hibo lesions resulted in significant increased diffusivity indices (mean, axial and radial diffusivity) in CC posterior segments. Also, significant decreased fractional anisotropy (FA) and increased diffusivity indices were seen in the associated transcallosal fiber tracts proximal to motor, posterior parietal and retrosplenial cortices. In Neo-Hibo animals, increased mean diffusivity (MD) in posterior midbody negatively correlated with reduction of CC surface areaand the magnitude of their memory impairments was significantly correlated with FA in transcallosal fiber tracts across splenium. Although no microstructural changes were observed in CC anterior segments, changes in FA values and diffusivity indices were observed in the white matter fibers of the ventromedial prefrontal cortex. Thus, Neo-H lesions resulted in enduring degradation in transcallosal fibers proximal to parietal and retrosplenial cortices, and hemispheric connections through posterior CC. The findings may provide complementary information for understanding the neural substrate of behavioral and cognitive deficits observed in patients with early insult to the hippocampus.
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Affiliation(s)
- Yuguang Meng
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia
| | - Xiaoping Hu
- Department of Bioengineering, University of California at Riverside, Riverside, California
| | - Xiaodong Zhang
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia.,Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia
| | - Jocelyne Bachevalier
- Yerkes National Primate Research Center and Department of Psychology, Emory University, Atlanta, Georgia
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14
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Huber E, Henriques RN, Owen JP, Rokem A, Yeatman JD. Applying microstructural models to understand the role of white matter in cognitive development. Dev Cogn Neurosci 2019; 36:100624. [PMID: 30927705 PMCID: PMC6969248 DOI: 10.1016/j.dcn.2019.100624] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 12/18/2018] [Accepted: 01/29/2019] [Indexed: 11/25/2022] Open
Abstract
Diffusion MRI (dMRI) holds great promise for illuminating the biological changes that underpin cognitive development. The diffusion of water molecules probes the cellular structure of brain tissue, and biophysical modeling of the diffusion signal can be used to make inferences about specific tissue properties that vary over development or predict cognitive performance. However, applying these models to study development requires that the parameters can be reliably estimated given the constraints of data collection with children. Here we collect repeated scans using a typical multi-shell diffusion MRI protocol in a group of children (ages 7-12) and use two popular modeling techniques to examine individual differences in white matter structure. We first assess scan-rescan reliability of model parameters and show that axon water faction can be reliably estimated from a relatively fast acquisition, without applying spatial smoothing or de-noising. We then investigate developmental changes in the white matter, and individual differences that correlate with reading skill. Specifically, we test the hypothesis that previously reported correlations between reading skill and diffusion anisotropy in the corpus callosum reflect increased axon water fraction in poor readers. Both models support this interpretation, highlighting the utility of these approaches for testing specific hypotheses about cognitive development.
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Affiliation(s)
- Elizabeth Huber
- Institute for Learning & Brain Sciences and Department of Speech and Hearing Sciences, University of Washington, Seattle, WA, 98195, United States.
| | - Rafael Neto Henriques
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Julia P Owen
- Department of Radiology, University of Washington, Seattle, WA, 98195, United States
| | - Ariel Rokem
- eScience Institute, University of Washington, Seattle, WA, 98195, United States
| | - Jason D Yeatman
- Institute for Learning & Brain Sciences and Department of Speech and Hearing Sciences, University of Washington, Seattle, WA, 98195, United States
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15
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Žarić G, Timmers I, Gerretsen P, Fraga González G, Tijms J, van der Molen MW, Blomert L, Bonte M. Atypical White Matter Connectivity in Dyslexic Readers of a Fairly Transparent Orthography. Front Psychol 2018; 9:1147. [PMID: 30042708 PMCID: PMC6049043 DOI: 10.3389/fpsyg.2018.01147] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 06/14/2018] [Indexed: 01/18/2023] Open
Abstract
Atypical structural properties of the brain's white matter bundles have been associated with failing reading acquisition in developmental dyslexia. Because these white matter properties may show dynamic changes with age and orthographic depth, we examined fractional anisotropy (FA) along 16 white matter tracts in 8- to 11-year-old dyslexic (DR) and typically reading (TR) children learning to read in a fairly transparent orthography (Dutch). Our results showed higher FA values in the bilateral anterior thalamic radiations of DRs and FA values of the left thalamic radiation scaled with behavioral reading-related scores. Furthermore, DRs tended to have atypical FA values in the bilateral arcuate fasciculi. Children's age additionally predicted FA values along the tracts. Together, our findings suggest differential contributions of cortical and thalamo-cortical pathways to the developing reading network in dyslexic and typical readers, possibly indicating prolonged letter-by-letter reading or increased attentional and/or working memory demands in dyslexic children during reading.
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Affiliation(s)
- Gojko Žarić
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center (M-BIC), Maastricht, Netherlands
| | - Inge Timmers
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | | | - Gorka Fraga González
- Department of Developmental Psychology, University of Amsterdam, Amsterdam, Netherlands
| | - Jurgen Tijms
- IWAL Instituut Voor Leerproblemen, Amsterdam, Netherlands
| | | | - Leo Blomert
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center (M-BIC), Maastricht, Netherlands
| | - Milene Bonte
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Maastricht Brain Imaging Center (M-BIC), Maastricht, Netherlands
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16
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Nikki Arrington C, Kulesz PA, Juranek J, Cirino PT, Fletcher JM. White matter microstructure integrity in relation to reading proficiency☆. BRAIN AND LANGUAGE 2017; 174:103-111. [PMID: 28818624 PMCID: PMC5617339 DOI: 10.1016/j.bandl.2017.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 07/12/2017] [Accepted: 08/07/2017] [Indexed: 06/07/2023]
Abstract
Components of reading proficiency such asaccuracy, fluency, and comprehension require the successful coordination of numerous, yet distinct, cortical regions. Underlying white matter tracts allow for communication among these regions. This study utilized unique residualized tract - based spatial statistics methodology to identify the relations of white matter microstructure integrity to three components of reading proficiency in 49 school - aged children with typically developing phonological decoding skills and 27 readers with poor decoders. Results indicated that measures of white matter integrity were differentially associated with components of reading proficiency. In both typical and poor decoders, reading comprehension correlated with measures of integrity of the right uncinate fasciculus; reading comprehension was also related to the left inferior longitudinal fasciculus in poor decoders. Also in poor decoders, word reading fluency was related to the right uncinate and left inferior fronto - occipital fasciculi. Word reading was unrelated to white matter integrity in either group. These findings expand our knowledge of the association between white matter integrity and different elements of reading proficiency.
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Affiliation(s)
- C Nikki Arrington
- Texas Institute for Measurement, Evaluation and Statistics (TIMES), and Department of Psychology, University of Houston, 4849 Calhoun Rd., Houston, TX 77204, USA.
| | - Paulina A Kulesz
- Texas Institute for Measurement, Evaluation and Statistics (TIMES), and Department of Psychology, University of Houston, 4849 Calhoun Rd., Houston, TX 77204, USA
| | - Jenifer Juranek
- Department of Pediatrics, Division of Developmental Pediatrics, The University of Texas Medical School at Houston, 6655 Travis St. Suite 1000, Houston, TX 77030, USA
| | - Paul T Cirino
- Texas Institute for Measurement, Evaluation and Statistics (TIMES), and Department of Psychology, University of Houston, 4849 Calhoun Rd., Houston, TX 77204, USA
| | - Jack M Fletcher
- Texas Institute for Measurement, Evaluation and Statistics (TIMES), and Department of Psychology, University of Houston, 4849 Calhoun Rd., Houston, TX 77204, USA
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17
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Darki F, Massinen S, Salmela E, Matsson H, Peyrard-Janvid M, Klingberg T, Kere J. Human ROBO1 regulates white matter structure in corpus callosum. Brain Struct Funct 2017; 222:707-716. [PMID: 27240594 PMCID: PMC5334444 DOI: 10.1007/s00429-016-1240-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 05/20/2016] [Indexed: 12/17/2022]
Abstract
The axon guidance receptor, Robo1, controls the pathfinding of callosal axons in mice. To determine whether the orthologous ROBO1 gene is involved in callosal development also in humans, we studied polymorphisms in the ROBO1 gene and variation in the white matter structure in the corpus callosum using both structural magnetic resonance imaging and diffusion tensor magnetic resonance imaging. We found that five polymorphisms in the regulatory region of ROBO1 were associated with white matter density in the posterior part of the corpus callosum pathways. One of the polymorphisms, rs7631357, was also significantly associated with the probability of connections to the parietal cortical regions. Our results demonstrate that human ROBO1 may be involved in the regulation of the structure and connectivity of posterior part of corpus callosum.
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Affiliation(s)
- Fahimeh Darki
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Satu Massinen
- Research Programs Unit, Haartman Institute, University of Helsinki, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Elina Salmela
- Research Programs Unit, Haartman Institute, University of Helsinki, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Hans Matsson
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 7, 14183, Huddinge, Sweden
| | - Myriam Peyrard-Janvid
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 7, 14183, Huddinge, Sweden
| | - Torkel Klingberg
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Juha Kere
- Research Programs Unit, Haartman Institute, University of Helsinki, Helsinki, Finland.
- Folkhälsan Institute of Genetics, Helsinki, Finland.
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 7, 14183, Huddinge, Sweden.
- Science for Life Laboratory, Karolinska Institutet, Solna, Sweden.
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18
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Microstructural White Matter Alterations in the Corpus Callosum of Girls With Conduct Disorder. J Am Acad Child Adolesc Psychiatry 2017; 56:258-265.e1. [PMID: 28219492 DOI: 10.1016/j.jaac.2016.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/14/2016] [Accepted: 12/20/2016] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Diffusion tensor imaging (DTI) studies in adolescent conduct disorder (CD) have demonstrated white matter alterations of tracts connecting functionally distinct fronto-limbic regions, but only in boys or mixed-gender samples. So far, no study has investigated white matter integrity in girls with CD on a whole-brain level. Therefore, our aim was to investigate white matter alterations in adolescent girls with CD. METHOD We collected high-resolution DTI data from 24 girls with CD and 20 typically developing control girls using a 3T magnetic resonance imaging system. Fractional anisotropy (FA) and mean diffusivity (MD) were analyzed for whole-brain as well as a priori-defined regions of interest, while controlling for age and intelligence, using a voxel-based analysis and an age-appropriate customized template. RESULTS Whole-brain findings revealed white matter alterations (i.e., increased FA) in girls with CD bilaterally within the body of the corpus callosum, expanding toward the right cingulum and left corona radiata. The FA and MD results in a priori-defined regions of interest were more widespread and included changes in the cingulum, corona radiata, fornix, and uncinate fasciculus. These results were not driven by age, intelligence, or attention-deficit/hyperactivity disorder comorbidity. CONCLUSION This report provides the first evidence of white matter alterations in female adolescents with CD as indicated through white matter reductions in callosal tracts. This finding enhances current knowledge about the neuropathological basis of female CD. An increased understanding of gender-specific neuronal characteristics in CD may influence diagnosis, early detection, and successful intervention strategies.
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19
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Fernandez VG, Juranek J, Romanowska-Pawliczek A, Stuebing K, Williams VJ, Fletcher JM. White matter integrity of cerebellar-cortical tracts in reading impaired children: A probabilistic tractography study. BRAIN AND LANGUAGE 2016; 161:45-56. [PMID: 26307492 PMCID: PMC4803624 DOI: 10.1016/j.bandl.2015.07.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 07/01/2015] [Accepted: 07/10/2015] [Indexed: 06/04/2023]
Abstract
Little is known about the white matter integrity of cerebellar-cortical pathways in individuals with dyslexia. Building on previous findings of decreased volume in the anterior lobe of the cerebellum, we utilized novel cerebellar segmentation procedures and probabilistic tractography to examine tracts that connect the anterior lobe of the cerebellum and cortical regions typically associated with reading: the temporoparietal (TP), occipitotemporal (OT), and inferior frontal (IF) regions. The sample included 29 reading impaired children and 27 typical readers. We found greater fractional anisotropy (FA) for the poor readers in tracts connecting the cerebellum with TP and IF regions relative to typical readers. In the OT region, FA was greater for the older poor readers, but smaller for the younger ones. This study provides evidence for discrete, regionally-bound functions of the cerebellum and suggests that projections from the anterior cerebellum appear to have a regulatory effect on cortical pathways important for reading.
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Affiliation(s)
- Vindia G Fernandez
- University of Houston, 4811 Calhoun Rd., 3rd Floor, Houston, TX 77204-6022, United States.
| | - Jenifer Juranek
- University of Texas Health Science Center, 6655 Travis, Houston, TX 77030-1312, United States.
| | | | - Karla Stuebing
- University of Houston, 4811 Calhoun Rd., 3rd Floor, Houston, TX 77204-6022, United States.
| | - Victoria J Williams
- University of Houston, 4811 Calhoun Rd., 3rd Floor, Houston, TX 77204-6022, United States.
| | - Jack M Fletcher
- University of Houston, 4811 Calhoun Rd., 3rd Floor, Houston, TX 77204-6022, United States.
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20
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Ozernov-Palchik O, Gaab N. Tackling the 'dyslexia paradox': reading brain and behavior for early markers of developmental dyslexia. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2016; 7:156-76. [PMID: 26836227 DOI: 10.1002/wcs.1383] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/15/2015] [Accepted: 12/23/2015] [Indexed: 01/18/2023]
Abstract
Developmental dyslexia is an unexplained inability to acquire accurate or fluent reading that affects approximately 5-17% of children. Dyslexia is associated with structural and functional alterations in various brain regions that support reading. Neuroimaging studies in infants and pre-reading children suggest that these alterations predate reading instruction and reading failure, supporting the hypothesis that variant function in dyslexia susceptibility genes lead to atypical neural migration and/or axonal growth during early, most likely in utero, brain development. Yet, dyslexia is typically not diagnosed until a child has failed to learn to read as expected (usually in second grade or later). There is emerging evidence that neuroimaging measures, when combined with key behavioral measures, can enhance the accuracy of identification of dyslexia risk in pre-reading children but its sensitivity, specificity, and cost-efficiency is still unclear. Early identification of dyslexia risk carries important implications for dyslexia remediation and the amelioration of the psychosocial consequences commonly associated with reading failure.
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Affiliation(s)
- Ola Ozernov-Palchik
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Boston Children's Hospital, Boston, MA, USA.,Eliot-Pearson Department of Child Study and Human Development, Tufts University, Medford, MA, USA
| | - Nadine Gaab
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Boston Children's Hospital, Boston, MA, USA.,Harvard Graduate School of Education, Cambridge, MA, USA
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21
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Garcia-Zapirain B, Garcia-Chimeno Y, Saralegui I, Fernandez-Ruanova B, Martinez R. Differences in effective connectivity between children with dyslexia, monocular vision and typically developing readers: A DTI study. Biomed Signal Process Control 2016. [DOI: 10.1016/j.bspc.2015.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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22
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Wu XP, Gao YJ, Yang JL, Xu M, Sun DH. Quantitative measurement to evaluate morphological changes of the corpus callosum in patients with subcortical ischemic vascular dementia. Acta Radiol 2015; 56:214-8. [PMID: 24445093 DOI: 10.1177/0284185114520863] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Subcortical ischemic vascular dementia (SIVD) is a subtype of dementia associated with abnormalities in the subcortical white matter regions. Recent imaging techniques can be used to detect such abnormalities in vivo. PURPOSE To examine morphological changes of the corpus callosum in patients with SIVD by using magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). MATERIAL AND METHODS MRI was performed to explore changes of cerebral white matter, especially corpus callosum. Brain matter diffusivity was examined with DTI by measuring the fractional anisotropy (FA). Results of 30 patients diagnosed with SIVD and 30 healthy subjects were analyzed and compared. RESULTS The thicknesses of the genu, the anterior third, middle, and posterior third of the body, and the splenium of the corpus callosum were smaller in SIVD patients compared to healthy controls (0.54 ± 0.08 vs. 0.68 ± 0.09 cm, P = 0.0011; 0.27 ± 0.06 vs. 0.38 ± 0.07 cm, P = 0.002; 0.28 ± 0.05 vs. 0.38 ± 0.08 cm, P = 0.009; 0.18 ± 0.04 vs. 0.26 ± 0.06 cm, P = 0.013; 0.54 ± 0.07 vs. 0.72 ± 0.09 cm, P = 0.003, respectively). The FA values of the genu and splenium of the corpus callosum in patients with SIVD were decreased compared to healthy controls (0.664 ± 0.042 vs. 0.778 ± 0.041, P < 0.001; 0.691 ± 0.038 vs. 0.786 ± 0.039, P = 0.001, respectively). CONCLUSION Patients with SIVD exhibit corpus callosum atrophy and morphological changes, and these characteristics may be useful for diagnosis.
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Affiliation(s)
- Xiao-Ping Wu
- Department of Radiology, The Xi’an Municipal Central Hospital, Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Yan-Jun Gao
- Department of Radiology, The Xi’an Municipal Central Hospital, Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Jun-Le Yang
- Department of Radiology, The Xi’an Municipal Central Hospital, Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Min Xu
- Department of Radiology, The Xi’an Municipal Central Hospital, Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Dong-Hai Sun
- Department of Radiology, The Xi’an Municipal Central Hospital, Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
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Truong DT, Rendall AR, Rosen GD, Fitch RH. Morphometric changes in subcortical structures of the central auditory pathway in mice with bilateral nodular heterotopia. Behav Brain Res 2014; 282:61-9. [PMID: 25549859 DOI: 10.1016/j.bbr.2014.12.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 12/17/2014] [Accepted: 12/21/2014] [Indexed: 02/09/2023]
Abstract
Malformations of cortical development (MCD) have been observed in human reading and language impaired populations. Injury-induced MCD in rodent models of reading disability show morphological changes in the auditory thalamic nucleus (medial geniculate nucleus; MGN) and auditory processing impairments, thus suggesting a link between MCD, MGN, and auditory processing behavior. Previous neuroanatomical examination of a BXD29 recombinant inbred strain (BXD29-Tlr4(lps-2J)/J) revealed MCD consisting of bilateral subcortical nodular heterotopia with partial callosal agenesis. Subsequent behavioral characterization showed a severe impairment in auditory processing-a deficient behavioral phenotype seen across both male and female BXD29-Tlr4(lps-2J)/J mice. In the present study we expanded upon the neuroanatomical findings in the BXD29-Tlr4(lps-2J)/J mutant mouse by investigating whether subcortical changes in cellular morphology are present in neural structures critical to central auditory processing (MGN, and the ventral and dorsal subdivisions of the cochlear nucleus; VCN and DCN, respectively). Stereological assessment of brain tissue of male and female BXD29-Tlr4(lps-2J)/J mice previously tested on an auditory processing battery revealed overall smaller neurons in the MGN of BXD29-Tlr4(lps-2J)/J mutant mice in comparison to BXD29/Ty coisogenic controls, regardless of sex. Interestingly, examination of the VCN and DCN revealed sexually dimorphic changes in neuronal size, with a distribution shift toward larger neurons in female BXD29-Tlr4(lps-2J)/J brains. These effects were not seen in males. Together, the combined data set supports and further expands the observed co-occurrence of MCD, auditory processing impairments, and changes in subcortical anatomy of the central auditory pathway. The current stereological findings also highlight sex differences in neuroanatomical presentation in the presence of a common auditory behavioral phenotype.
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Affiliation(s)
- Dongnhu T Truong
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, USA
| | - Amanda R Rendall
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, USA
| | - Glenn D Rosen
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - R Holly Fitch
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, USA.
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Horowitz-Kraus T, Wang Y, Plante E, Holland SK. Involvement of the right hemisphere in reading comprehension: a DTI study. Brain Res 2014; 1582:34-44. [PMID: 24909792 DOI: 10.1016/j.brainres.2014.05.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 05/17/2014] [Accepted: 05/22/2014] [Indexed: 01/18/2023]
Abstract
The Simple View of reading emphasizes the critical role of two factors in normal reading skills: word recognition and reading comprehension. The current study aims to identify the anatomical support for aspects of reading performance that fall within these two components. Fractional anisotropy (FA) values were obtained from diffusion tensor images in twenty-one typical adolescents and young adults using the tract based spatial statistics (TBSS) method. We focused on the arcuate fasciculus (AF) and inferior longitudinal fasciculus (ILF) as fiber tracts that connect regions already implicated in the distributed cortical network for reading. Our results demonstrate dissociation between word-level and narrative-level reading skills: the FA values for both left and right ILF were correlated with measures of word reading, while only the left ILF correlated with reading comprehension scores. FA in the AF, however, correlated only with reading comprehension scores, bilaterally. Correlations with the right AF were particularly robust, emphasizing the contribution of the right hemisphere, especially the frontal lobe, to reading comprehension performance on the particular passage comprehension test used in this study. The anatomical dissociation between these reading skills is supported by the Simple View theory and may shed light on why these two skills dissociate in those with reading disorders.
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Affiliation(s)
| | - Yingying Wang
- Pediatric Neuroimaging Research Consortium, Cincinnati, OH, USA; Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - Elena Plante
- Department of Speech, Language, & Hearing Sciences, The University of Arizona, Tucson, AZ, USA
| | - Scott K Holland
- Pediatric Neuroimaging Research Consortium, Cincinnati, OH, USA; Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA; Department of Radiology, Cincinnati Children׳s Hospital, Cincinnati, OH, United States
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25
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Gullick MM, Booth JR. Individual differences in crossmodal brain activity predict arcuate fasciculus connectivity in developing readers. J Cogn Neurosci 2014; 26:1331-46. [PMID: 24456399 DOI: 10.1162/jocn_a_00581] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Crossmodal integration of auditory and visual information, such as phonemes and graphemes, is a critical skill for fluent reading. Previous work has demonstrated that white matter connectivity along the arcuate fasciculus (AF) is predicted by reading skill and that crossmodal processing particularly activates the posterior STS (pSTS). However, the relationship between this crossmodal activation and white matter integrity has not been previously reported. We investigated the interrelationship of crossmodal integration, both in terms of behavioral performance and pSTS activity, with AF tract coherence using a rhyme judgment task in a group of 47 children with a range of reading abilities. We demonstrate that both response accuracy and pSTS activity for crossmodal (auditory-visual) rhyme judgments was predictive of fractional anisotropy along the left AF. Unimodal (auditory-only or visual-only) pSTS activity was not significantly related to AF connectivity. Furthermore, activity in other reading-related ROIs did not show the same AV-only AF coherence relationship, and AV pSTS activity was not related to connectivity along other language-related tracts. This study is the first to directly show that crossmodal brain activity is specifically related to connectivity in the AF, supporting its role in phoneme-grapheme integration ability. More generally, this study helps to define an interdependent neural network for reading-related integration.
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26
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Weyandt L, Swentosky A, Gudmundsdottir BG. Neuroimaging and ADHD: fMRI, PET, DTI findings, and methodological limitations. Dev Neuropsychol 2013; 38:211-25. [PMID: 23682662 DOI: 10.1080/87565641.2013.783833] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by pervasive and developmentally inappropriate levels of inattention, impulsivity, and hyperactivity. There is no conclusive cause of ADHD although a number of etiologic theories have been advanced. Research across neuroanatomical, neurochemical, and genetic disciplines collectively support a physiological basis for ADHD and, within the past decade, the number of neuroimaging studies concerning ADHD has increased exponentially. The current selective review summarizes research findings concerning ADHD using functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and diffusion tensor imaging (DTI). Although these technologies and studies offer promise in helping to better understand the physiologic underpinnings of ADHD, they are not without methodological problems, including inadequate sensitivity and specificity for psychiatric disorders. Consequently, neuroimaging technology, in its current state of development, should not be used to inform clinical practice.
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Affiliation(s)
- Lisa Weyandt
- Psychology Department, University of Rhode Island, Kingston, Rhode Island 02881, USA.
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27
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Lee JC, Nopoulos PC, Bruce Tomblin J. Abnormal subcortical components of the corticostriatal system in young adults with DLI: a combined structural MRI and DTI study. Neuropsychologia 2013; 51:2154-61. [PMID: 23896446 DOI: 10.1016/j.neuropsychologia.2013.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 06/03/2013] [Accepted: 07/01/2013] [Indexed: 11/15/2022]
Abstract
Developmental Language Impairment (DLI) is a neurodevelopmental disorder affecting 12% to 14% of the school-age children in the United States. While substantial studies have shown a wide range of linguistic and non-linguistic difficulty in individuals with DLI, very little is known about the neuroanatomical mechanisms underlying this disorder. In the current study, we examined the subcortical components of the corticostriatal system in young adults with DLI, including the caudate nucleus, the putamen, the nucleus accumbens, the globus pallidus, and the thalamus. Additionally, the four cerebral lobes and the hippocampus were also comprised for an exploratory analysis. We used conventional magnetic resonance imaging (MRI) to measure regional brain volumes, as well as diffusion tensor imaging (DTI) to assess water diffusion anisotropy as quantified by fractional anisotropy (FA). Two groups of participants, one with DLI (n=12) and the other without (n=12), were recruited from a prior behavioral study, and all were matched on age, gender, and handedness. Volumetric analyses revealed region-specific abnormalities in individuals with DLI, showing pathological enlargement bilaterally in the putamen and the nucleus accumbens, and unilaterally in the right globus pallidus after the intracranial volumes were controlled. Regarding the DTI findings, the DLI group showed decreased FA values in the globus pallidus and the thalamus but these significant differences disappeared after controlling for the whole-brain FA value, indicating that microstructural abnormality is diffuse and affects other regions of the brain. Taken together, these results suggest region-specific corticostriatal abnormalities in DLI at the macrostructural level, but corticostriatal abnormalities at the microstructural level may be a part of a diffuse pattern of brain development. Future work is suggested to investigate the relationship between corticostriatal connectivity and individual differences in language development.
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Affiliation(s)
- Joanna C Lee
- Department of Communication Sciences and Disorders, The University of Iowa, Wendell Johnson Speech and Hearing Center, Iowa City, IA 52242, USA.
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28
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Seghete KLM, Herting MM, Nagel BJ. White matter microstructure correlates of inhibition and task-switching in adolescents. Brain Res 2013; 1527:15-28. [PMID: 23811486 DOI: 10.1016/j.brainres.2013.06.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 05/22/2013] [Accepted: 06/02/2013] [Indexed: 11/15/2022]
Abstract
Although protracted prefrontal gray matter development is associated with concomitant executive function (EF) development in adolescents, few studies have explored the relationship between white matter and EF. This study examined the relationship between white matter microstructure and two aspects of EF, inhibition and task-switching, in a sample of 84 adolescents using diffusion tensor imaging (DTI). Tract-Based Spatial Statistics (TBSS) were used to examine fractional anisotropy (FA) and mean diffusivity (MD). Adolescents completed the Color-Word Interference task from the Delis-Kaplan Executive Function System, a clinical version of the Stroop task. Inhibition and task-switching performance were group normalized and measured using both reaction time and errors. Performance and the interaction of age and performance were regressed on FA and MD white matter skeletons, controlling for age and IQ, separately for inhibition and task-switching. Follow up analyses examined the relative contributions of axial and radial diffusivities. Greater FA in the anterior corona radiata (ACR) was associated with better inhibition, independent of age. Greater FA in the SCR and precentral gyrus white matter were associated with better task-switching, regardless of age, whereas an association between FA in the ACR and task-switching was dependent on age. There were no significant associations between MD and performance. Results suggest better inhibition and task-switching are associated with greater integrity of white matter microstructure in regions supporting cross-cortical and cortical-subcortical connections stemming from the prefrontal cortex. These findings are consistent with functional studies of cognitive control and models of EF that propose separate, yet related, latent factors.
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Affiliation(s)
- Kristen L Mackiewicz Seghete
- Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, L470, Portland, OR 97239, USA.
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29
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Szalkowski CE, Booker AB, Truong DT, Threlkeld SW, Rosen GD, Fitch RH. Knockdown of the candidate dyslexia susceptibility gene homolog dyx1c1 in rodents: effects on auditory processing, visual attention, and cortical and thalamic anatomy. Dev Neurosci 2013; 35:50-68. [PMID: 23594585 DOI: 10.1159/000348431] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 01/23/2013] [Indexed: 12/24/2022] Open
Abstract
The current study investigated the behavioral and neuroanatomical effects of embryonic knockdown of the candidate dyslexia susceptibility gene (CDSG) homolog Dyx1c1 through RNA interference (RNAi) in rats. Specifically, we examined long-term effects on visual attention abilities in male rats, in addition to assessing rapid and complex auditory processing abilities in male and, for the first time, female rats. Our results replicated prior evidence of complex acoustic processing deficits in Dyx1c1 male rats and revealed new evidence of comparable deficits in Dyx1c1 female rats. Moreover, we found new evidence that knocking down Dyx1c1 produced orthogonal impairments in visual attention in the male subgroup. Stereological analyses of male brains from prior RNAi studies revealed that, despite consistent visible evidence of disruptions of neuronal migration (i.e., heterotopia), knockdown of Dyx1c1 did not significantly alter the cortical volume, hippocampal volume, or midsagittal area of the corpus callosum (measured in a separate cohort of like-treated Dyx1c1 male rats). Dyx1c1 transfection did, however, lead to significant changes in medial geniculate nucleus (MGN) anatomy, with a significant shift to smaller MGN neurons in Dyx1c1-transfected animals. Combined results provide important information about the impact of Dyx1c1 on behavioral functions that parallel domains known to be affected in language-impaired populations as well as information about widespread changes to the brain following early disruption of this CDSG.
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Affiliation(s)
- Caitlin E Szalkowski
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, Storrs, Conn. 06269, USA.
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30
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Szalkowski CE, Fiondella CF, Truong DT, Rosen GD, LoTurco JJ, Fitch RH. The effects of Kiaa0319 knockdown on cortical and subcortical anatomy in male rats. Int J Dev Neurosci 2013; 31:116-22. [PMID: 23220223 PMCID: PMC3689304 DOI: 10.1016/j.ijdevneu.2012.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 11/20/2012] [Accepted: 11/21/2012] [Indexed: 12/13/2022] Open
Abstract
Developmental dyslexia is a disorder characterized by a specific deficit in reading despite adequate overall intelligence and educational resources. The neurological substrate underlying these significant behavioral impairments is not known. Studies of post mortem brain tissue from male and female dyslexic individuals revealed focal disruptions of neuronal migration concentrated in the left hemisphere, along with aberrant symmetry of the right and left the planum temporale, and changes in cell size distribution within the medial geniculate nucleus of the thalamus (Galaburda et al., 1985; Humphreys et al., 1990). More recent neuroimaging studies have identified several changes in the brains of dyslexic individuals, including regional changes in gray matter, changes in white matter, and changes in patterns of functional activation. In a further effort to elucidate the etiology of dyslexia, epidemiological and genetic studies have identified several candidate dyslexia susceptibility genes. Some recent work has investigated associations between some of these genetic variants and structural changes in the brain. Variants of one candidate dyslexia susceptibility gene, KIAA0319, have been linked to morphological changes in the cerebellum and functional activational changes in the superior temporal sulcus (Jamadar et al., 2011; Pinel et al., 2012). Animal models have been used to create a knockdown of Kiaa0319 (the rodent homolog of the human gene) via in utero RNA interference in order to study the gene's effects on brain development and behavior. Studies using this animal model have demonstrated that knocking down the gene leads to focal disruptions of neuronal migration in the form of ectopias and heterotopias, similar to those observed in the brains of human dyslexics. However, further changes to the structure of the brain have not been studied following this genetic disruption. The current study sought to determine the effects of embryonic Kiaa0319 knockdown on volume of the cortex and hippocampus, as well as midsagittal area of the corpus callosum in male rats. Results demonstrate that Kiaa0319 knockdown did not change the volume of the cortex or hippocampus, but did result in a significant reduction in the midsagittal area of the corpus callosum. Taken in the context of previous reports of behavioral deficits following Kiaa0319 knockdown (Szalkowski et al., 2012), and reports that reductions of corpus callosum size are related to processing deficits in humans (Paul, 2011), these results suggest that Kiaa0319 has a specific involvement in neural systems important for temporal processing.
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Affiliation(s)
- Caitlin E Szalkowski
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, Storrs, 06269, United States.
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The dyslexia candidate locus on 2p12 is associated with general cognitive ability and white matter structure. PLoS One 2012; 7:e50321. [PMID: 23209710 PMCID: PMC3509064 DOI: 10.1371/journal.pone.0050321] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 10/17/2012] [Indexed: 11/25/2022] Open
Abstract
Independent studies have shown that candidate genes for dyslexia and specific language impairment (SLI) impact upon reading/language-specific traits in the general population. To further explore the effect of disorder-associated genes on cognitive functions, we investigated whether they play a role in broader cognitive traits. We tested a panel of dyslexia and SLI genetic risk factors for association with two measures of general cognitive abilities, or IQ, (verbal and non-verbal) in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort (N>5,000). Only the MRPL19/C2ORF3 locus showed statistically significant association (minimum P = 0.00009) which was further supported by independent replications following analysis in four other cohorts. In addition, a fifth independent sample showed association between the MRPL19/C2ORF3 locus and white matter structure in the posterior part of the corpus callosum and cingulum, connecting large parts of the cortex in the parietal, occipital and temporal lobes. These findings suggest that this locus, originally identified as being associated with dyslexia, is likely to harbour genetic variants associated with general cognitive abilities by influencing white matter structure in localised neuronal regions.
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Herron TJ, Kang X, Woods DL. Automated measurement of the human corpus callosum using MRI. Front Neuroinform 2012; 6:25. [PMID: 22988433 PMCID: PMC3439830 DOI: 10.3389/fninf.2012.00025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 08/27/2012] [Indexed: 01/16/2023] Open
Abstract
The corpus callosum includes the majority of fibers that connect the two cortical hemispheres. Studies of cross-sectional callosal morphometry and area have revealed developmental, gender, and hemispheric differences in healthy populations and callosal deficits associated with neurodegenerative disease and brain injury. However, accurate quantification of the callosum using magnetic resonance imaging is complicated by intersubject variability in callosal size, shape, and location and often requires manual outlining of the callosum in order to achieve adequate performance. Here we describe an objective, fully automated protocol that utilizes voxel-based images to quantify the area and thickness both of the entire callosum and of different callosal compartments. We verify the method's accuracy, reliability, robustness, and multisite consistency and make comparisons with manual measurements using public brain-image databases. An analysis of age-related changes in the callosum showed increases in length and reductions in thickness and area with age. A comparison of older subjects with and without mild dementia revealed that reductions in anterior callosal area independently predicted poorer cognitive performance after factoring out Mini-Mental Status Examination scores and normalized whole brain volume. Open-source software implementing the algorithm is available at www.nitrc.org/projects/c8c8.
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Affiliation(s)
- Timothy J Herron
- Human Cognitive Neurophysiology Laboratory, Research Service, US Veterans Affairs, Northern California Health Care System Martinez, CA, USA
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