1
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Lee MM, Stoodley CJ. Neural bases of reading fluency: A systematic review and meta-analysis. Neuropsychologia 2024; 202:108947. [PMID: 38964441 DOI: 10.1016/j.neuropsychologia.2024.108947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 06/26/2024] [Accepted: 06/29/2024] [Indexed: 07/06/2024]
Abstract
Reading fluency, the ability to read quickly and accurately, is a critical marker of successful reading and is notoriously difficult to improve in reading disabled populations. Despite its importance to functional literacy, fluency is a relatively under-studied aspect of reading, and the neural correlates of reading fluency are not well understood. Here, we review the literature of the neural correlates of reading fluency as well as rapid automatized naming (RAN), a task that is robustly related to reading fluency. In a qualitative review of the neuroimaging literature, we evaluated structural and functional MRI studies of reading fluency in readers from a range of skill levels. This was followed by a quantitative activation likelihood estimate (ALE) meta-analysis of fMRI studies of reading speed and RAN measures. We anticipated that reading speed, relative to untimed reading and reading-related tasks, would harness ventral reading pathways that are thought to enable the fast, visual recognition of words. The qualitative review showed that speeded reading taps the entire canonical reading network. The meta-analysis indicated a stronger role of the ventral reading pathway in rapid reading and rapid naming. Both reviews identified regions outside the canonical reading network that contribute to reading fluency, such as the bilateral insula and superior parietal lobule. We suggest that fluent reading engages both domain-specific reading pathways as well as domain-general regions that support overall task performance and discuss future avenues of research to expand our understanding of the neural bases of fluent reading.
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Affiliation(s)
- Marissa M Lee
- Department of Neuroscience, American University, USA; Center for Applied Brain and Cognitive Sciences, Tufts University, USA
| | - Catherine J Stoodley
- Department of Neuroscience, American University, USA; Developing Brain Institute, Children's National Hospital, USA; Departments of Neurology and Pediatrics, The George Washington University School of Medicine and Health Sciences, USA.
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2
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Bouhali F, Dubois J, Hoeft F, Weiner KS. Unique longitudinal contributions of sulcal interruptions to reading acquisition in children. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.30.605574. [PMID: 39131390 PMCID: PMC11312548 DOI: 10.1101/2024.07.30.605574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
A growing body of literature indicates strong associations between indentations of the cerebral cortex (i.e., sulci) and individual differences in cognitive performance. Interruptions, or gaps, of sulci (historically known as pli de passage) are particularly intriguing as previous work suggests that these interruptions have a causal effect on cognitive development. Here, we tested how the presence and morphology of sulcal interruptions in the left posterior occipitotemporal sulcus (pOTS) longitudinally impact the development of a culturally-acquired skill: reading. Forty-three children were successfully followed from age 5 in kindergarten, at the onset of literacy instruction, to ages 7 and 8 with assessments of cognitive, pre-literacy, and literacy skills, as well as MRI anatomical scans at ages 5 and 8. Crucially, we demonstrate that the presence of a left pOTS gap at 5 years is a specific and robust longitudinal predictor of better future reading skills in children, with large observed benefits on reading behavior ranging from letter knowledge to reading comprehension. The effect of left pOTS interruptions on reading acquisition accumulated through time, and was larger than the impact of benchmark cognitive and familial predictors of reading ability and disability. Finally, we show that increased local U-fiber white matter connectivity associated with such sulcal interruptions possibly underlie these behavioral benefits, by providing a computational advantage. To our knowledge, this is the first quantitative evidence supporting a potential integrative gray-white matter mechanism underlying the cognitive benefits of macro-anatomical differences in sulcal morphology related to longitudinal improvements in a culturally-acquired skill.
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Affiliation(s)
- Florence Bouhali
- Department of Psychiatry and Behavioral Sciences & Weil Institute of Neuroscience, University of California San Francisco, San Francisco, CA, USA
- Aix-Marseille University, CNRS, CRPN, Marseille, France
| | - Jessica Dubois
- University Paris Cité, NeuroDiderot, INSERM, Paris, France
- University Paris-Saclay, NeuroSpin, UNIACT, CEA, France
| | - Fumiko Hoeft
- Department of Psychological Sciences, University of Connecticut Waterbury, Waterbury, CT, USA
| | - Kevin S. Weiner
- Department of Psychology, Department of Neuroscience, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
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3
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Li M, DeMille MMC, Lovett MW, Bosson-Heenan J, Frijters JC, Gruen JR. Phonological awareness mediates the relationship between DCDC2 and reading performance with home environment. NPJ SCIENCE OF LEARNING 2024; 9:36. [PMID: 38702345 PMCID: PMC11068914 DOI: 10.1038/s41539-024-00247-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 04/11/2024] [Indexed: 05/06/2024]
Abstract
Proficient reading requires critical phonological processing skill that interacts with both genetic and environmental factors. However, the precise nature of the relationships between phonological processing and genetic and environmental factors are poorly understood. We analyzed data from the Genes, Reading and Dyslexia (GRaD) Study on 1419 children ages 8-15 years from African-American and Hispanic-American family backgrounds living in North America. The analyses showed that phonological awareness mediated the relationship between DCDC2-READ1 and reading outcomes when parental education and socioeconomic status was low. The association between READ1 and reading performance is complex, whereby mediation by phonological awareness was significantly moderated by both parental education and socioeconomic status. These results show the importance of home environment and phonological skills when determining associations between READ1 and reading outcomes. This will be an important consideration in the development of genetic screening for risk of reading disability.
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Affiliation(s)
- Miao Li
- Department of Curriculum and Instruction, College of Education, University of Houston, Houston, TX, USA.
| | - Mellissa M C DeMille
- Departments of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Maureen W Lovett
- Neurosciences and Mental Health Program, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Joan Bosson-Heenan
- Departments of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Jan C Frijters
- Department of Child and Youth Studies, Faculty of Social Sciences, Brock University, St. Catharines, ON, Canada
| | - Jeffrey R Gruen
- Departments of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT, USA.
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4
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Rinne N, Wikman P, Sahari E, Salmi J, Einarsdóttir E, Kere J, Alho K. Developmental dyslexia susceptibility genes DNAAF4, DCDC2, and NRSN1 are associated with brain function in fluently reading adolescents and young adults. Cereb Cortex 2024; 34:bhae144. [PMID: 38610086 PMCID: PMC11014888 DOI: 10.1093/cercor/bhae144] [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: 10/11/2023] [Revised: 03/16/2024] [Accepted: 03/17/2024] [Indexed: 04/14/2024] Open
Abstract
Reading skills and developmental dyslexia, characterized by difficulties in developing reading skills, have been associated with brain anomalies within the language network. Genetic factors contribute to developmental dyslexia risk, but the mechanisms by which these genes influence reading skills remain unclear. In this preregistered study (https://osf.io/7sehx), we explored if developmental dyslexia susceptibility genes DNAAF4, DCDC2, NRSN1, and KIAA0319 are associated with brain function in fluently reading adolescents and young adults. Functional MRI and task performance data were collected during tasks involving written and spoken sentence processing, and DNA sequence variants of developmental dyslexia susceptibility genes previously associated with brain structure anomalies were genotyped. The results revealed that variation in DNAAF4, DCDC2, and NRSN1 is associated with brain activity in key language regions: the left inferior frontal gyrus, middle temporal gyrus, and intraparietal sulcus. Furthermore, NRSN1 was associated with task performance, but KIAA0319 did not yield any significant associations. Our findings suggest that individuals with a genetic predisposition to developmental dyslexia may partly employ compensatory neural and behavioral mechanisms to maintain typical task performance. Our study highlights the relevance of these developmental dyslexia susceptibility genes in language-related brain function, even in individuals without developmental dyslexia, providing valuable insights into the genetic factors influencing language processing.
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Affiliation(s)
- Nea Rinne
- Department of Psychology and Logopedics, University of Helsinki, Haartmaninkatu 3, 00014 Helsinki, Finland
| | - Patrik Wikman
- Department of Psychology and Logopedics, University of Helsinki, Haartmaninkatu 3, 00014 Helsinki, Finland
| | - Elisa Sahari
- Department of Psychology and Speech-Language Pathology, University of Turku, Assistentinkatu 7, 20500 Turku, Finland
| | - Juha Salmi
- Department of Neuroscience and Biomedical Engineering, Otakaari 3, Aalto University, (AALTO), P.O. BOX 00076, Espoo, Finland
| | - Elisabet Einarsdóttir
- Science for Life Laboratory, Department of Gene Technology, KTH-Royal Institute of Technology, SE-171 21, Solna, Sweden
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, H7 Medicin, Huddinge, Sweden
- Folkhälsan Research Center, and Stem Cells and Metabolism Research Program (STEMM), University of Helsinki, PL 63, Haartmaninkatu 8, Helsinki, Finland
| | - Kimmo Alho
- Department of Psychology and Logopedics, University of Helsinki, Haartmaninkatu 3, 00014 Helsinki, Finland
- Advanced Magnetic Imaging Centre, Aalto NeuroImaging, Aalto University, Espoo, Finland
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5
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Bonte M, Brem S. Unraveling individual differences in learning potential: A dynamic framework for the case of reading development. Dev Cogn Neurosci 2024; 66:101362. [PMID: 38447471 PMCID: PMC10925938 DOI: 10.1016/j.dcn.2024.101362] [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: 07/06/2023] [Revised: 02/02/2024] [Accepted: 03/01/2024] [Indexed: 03/08/2024] Open
Abstract
Children show an enormous capacity to learn during development, but with large individual differences in the time course and trajectory of learning and the achieved skill level. Recent progress in developmental sciences has shown the contribution of a multitude of factors including genetic variation, brain plasticity, socio-cultural context and learning experiences to individual development. These factors interact in a complex manner, producing children's idiosyncratic and heterogeneous learning paths. Despite an increasing recognition of these intricate dynamics, current research on the development of culturally acquired skills such as reading still has a typical focus on snapshots of children's performance at discrete points in time. Here we argue that this 'static' approach is often insufficient and limits advancements in the prediction and mechanistic understanding of individual differences in learning capacity. We present a dynamic framework which highlights the importance of capturing short-term trajectories during learning across multiple stages and processes as a proxy for long-term development on the example of reading. This framework will help explain relevant variability in children's learning paths and outcomes and fosters new perspectives and approaches to study how children develop and learn.
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Affiliation(s)
- Milene Bonte
- Department of Cognitive Neuroscience and Maastricht Brain Imaging Center, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Silvia Brem
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Switzerland; URPP Adaptive Brain Circuits in Development and Learning (AdaBD), University of Zurich, Zurich, Switzerland
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6
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Packheiser J, Papadatou-Pastou M, Koufaki A, Paracchini S, Stein CC, Schmitz J, Ocklenburg S. Elevated levels of mixed-hand preference in dyslexia: Meta-analyses of 68 studies. Neurosci Biobehav Rev 2023; 154:105420. [PMID: 37783301 DOI: 10.1016/j.neubiorev.2023.105420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/04/2023]
Abstract
Since almost a hundred years, psychologists have investigated the link between hand preference and dyslexia. We present a meta-analysis to determine whether there is indeed an increase in atypical hand preference in dyslexia. We included studies used in two previous meta-analyses (Bishop, 1990; Eglinton & Annett, 1994) as well as studies identified through PubMed MEDLINE, PsycInfo, Google Scholar, and Web of Science up to August 2022. K = 68 studies (n = 4660 individuals with dyslexia; n = 40845 controls) were entered into three random effects meta-analyses using the odds ratio as the effect size (non-right-handers; left-handers; mixed-handers vs. total). Evidence of elevated levels of atypical hand preference in dyslexia emerged that were especially pronounced for mixed-hand preference (OR = 1.57), although this category was underdefined. Differences in (direction or degree) of hand skill or degree of hand preference could not be assessed as no pertinent studies were located. Our findings allow for robust conclusions only for a relationship of mixed-hand preference with dyslexia.
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Affiliation(s)
- Julian Packheiser
- Social Brain Lab, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Marietta Papadatou-Pastou
- School of Education, National and Kapodistrian University of Athens, Athens, Greece; BioMedical Research Foundation of the Academy of Athens, Athens, Greece.
| | - Angeliki Koufaki
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Clara C Stein
- Division of Forensic Psychiatry, Department of Psychiatry, Psychotherapy, and Preventive Medicine, LWL-University Hospital Bochum, Bochum, Germany
| | - Judith Schmitz
- Biological Personality Psychology, Georg-August-University Goettingen, Goettingen, Germany
| | - Sebastian Ocklenburg
- Department of Psychology, Medical School Hamburg, Hamburg, Germany; ICAN Institute for Cognitive and Affective Neuroscience, Medical School Hamburg, Hamburg, Germany; Institute of Cognitive Neuroscience, Biopsychology, Department of Psychology, Ruhr-University Bochum, Bochum, Germany
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7
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Li M, DeMille M, Lovett M, Bosson-Heenan J, Frijters J, Gruen J. Phonological Awareness Mediates the Relationship between DCDC2 and Reading Performance with the Influence of Home Environment. RESEARCH SQUARE 2023:rs.3.rs-2786924. [PMID: 37214935 PMCID: PMC10197759 DOI: 10.21203/rs.3.rs-2786924/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Proficient reading requires critical phonological processing skill that interact with both genetic and environmental factors. However, the precise nature of the relationships between phonological processing and genetic and environmental factors are poorly understood. We analyzed data from the Genes, Reading and Dyslexia (GRaD) Study on 1,419 children ages 8 to 14 years from African-American and Hispanic-American family backgrounds living in North America. The analyses showed that phonological awareness mediated the relationship between DCDC2-READ1 and reading outcomes when parental education and socioeconomic status was low. The association between READ1 and reading performance is complex, whereby mediation by phonological awareness was significantly moderated by both parental education and socioeconomic status. These results show the importance of home environment and phonological skills when determining associations between READ1 and reading outcomes. This will be an important consideration in the development of genetic screening for risk of reading disability.
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Affiliation(s)
- Miao Li
- University of Houston/Harvard University
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8
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Lachmann T, Bergström K. The multiple-level framework of developmental dyslexia: the long trace from a neurodevelopmental deficit to an impaired cultural technique. JOURNAL OF CULTURAL COGNITIVE SCIENCE 2023. [DOI: 10.1007/s41809-023-00118-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
AbstractDevelopmental dyslexia is a neurodevelopmental disorder characterized by an unexpected impairment in literacy acquisition leading to specific poor academic achievement and possible secondary symptoms. The multi-level framework of developmental dyslexia considers five levels of a causal pathway on which a given genotype is expressed and hierarchically transmitted from one level to the next under the increasing influence of individual learning-relevant traits and environmental factors moderated by cultural conditions. These levels are the neurobiological, the information processing and the skill level (prerequisites and acquisition of literacy skills), the academic achievement level and the level of secondary effects. Various risk factors are present at each level within the assumed causal pathway and can increase the likelihood of exhibiting developmental dyslexia. Transition from one level to the next is neither unidirectional nor inevitable. This fact has direct implications for prevention and intervention which can mitigate transitions from one level to the next. In this paper, various evidence-based theories and findings regarding deficits at different levels are placed in the proposed framework. In addition, the moderating effect of cultural impact at and between information processing and skill levels are further elaborated based on a review of findings regarding influences of different writing systems and orthographies. These differences impose culture-specific demands for literacy-specific cognitive procedures, influencing both literacy acquisition and the manifestation of developmental dyslexia.
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9
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Stein J. Theories about Developmental Dyslexia. Brain Sci 2023; 13:208. [PMID: 36831750 PMCID: PMC9954267 DOI: 10.3390/brainsci13020208] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Despite proving its usefulness for over a century, the concept of developmental dyslexia (DD) is currently in severe disarray because of the recent introduction of the phonological theory of its causation. Since mastering the phonological principle is essential for all reading, failure to do so cannot be used to distinguish DD from the many other causes of such failure. To overcome this problem, many new psychological, signal detection, and neurological theories have been introduced recently. All these new theories converge on the idea that DD is fundamentally caused by impaired signalling of the timing of the visual and auditory cues that are essential for reading. These are provided by large 'magnocellular' neurones which respond rapidly to sensory transients. The evidence for this conclusion is overwhelming. Especially convincing are intervention studies that have shown that improving magnocellular function improves dyslexic children's reading, together with cohort studies that have demonstrated that the magnocellular timing deficit is present in infants who later become dyslexic, long before they begin learning to read. The converse of the magnocellular deficit in dyslexics may be that they gain parvocellular abundance. This may often impart the exceptional 'holistic' talents that have been ascribed to them and that society needs to nurture.
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Affiliation(s)
- John Stein
- Department of Physiology, Anatomy & Genetics, Oxford University, Oxford OX1 3PT, UK
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10
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Beyer M, Liebig J, Sylvester T, Braun M, Heekeren HR, Froehlich E, Jacobs AM, Ziegler JC. Structural gray matter features and behavioral preliterate skills predict future literacy - A machine learning approach. Front Neurosci 2022; 16:920150. [PMID: 36248649 PMCID: PMC9558903 DOI: 10.3389/fnins.2022.920150] [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] [Received: 04/14/2022] [Accepted: 08/18/2022] [Indexed: 11/13/2022] Open
Abstract
When children learn to read, their neural system undergoes major changes to become responsive to print. There seem to be nuanced interindividual differences in the neurostructural anatomy of regions that later become integral parts of the reading network. These differences might affect literacy acquisition and, in some cases, might result in developmental disorders like dyslexia. Consequently, the main objective of this longitudinal study was to investigate those interindividual differences in gray matter morphology that might facilitate or hamper future reading acquisition. We used a machine learning approach to examine to what extent gray matter macrostructural features and cognitive-linguistic skills measured before formal literacy teaching could predict literacy 2 years later. Forty-two native German-speaking children underwent T1-weighted magnetic resonance imaging and psychometric testing at the end of kindergarten. They were tested again 2 years later to assess their literacy skills. A leave-one-out cross-validated machine-learning regression approach was applied to identify the best predictors of future literacy based on cognitive-linguistic preliterate behavioral skills and cortical measures in a priori selected areas of the future reading network. With surprisingly high accuracy, future literacy was predicted, predominantly based on gray matter volume in the left occipito-temporal cortex and local gyrification in the left insular, inferior frontal, and supramarginal gyri. Furthermore, phonological awareness significantly predicted future literacy. In sum, the results indicate that the brain morphology of the large-scale reading network at a preliterate age can predict how well children learn to read.
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Affiliation(s)
- Moana Beyer
- Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany
| | - Johanna Liebig
- Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany
- Center for Cognitive Neuroscience Berlin, Freie Universität Berlin, Berlin, Germany
| | - Teresa Sylvester
- Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany
- Center for Cognitive Neuroscience Berlin, Freie Universität Berlin, Berlin, Germany
| | - Mario Braun
- Centre for Cognitive Neuroscience, Universität Salzburg, Salzburg, Austria
| | - Hauke R. Heekeren
- Center for Cognitive Neuroscience Berlin, Freie Universität Berlin, Berlin, Germany
- Department of Biological Psychology and Cognitive Neuroscience, Freie Universität Berlin, Berlin, Germany
| | - Eva Froehlich
- Department of Decision Neuroscience and Nutrition, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
| | - Arthur M. Jacobs
- Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany
- Center for Cognitive Neuroscience Berlin, Freie Universität Berlin, Berlin, Germany
| | - Johannes C. Ziegler
- Laboratoire de Psychologie Cognitive, Aix-Marseille Université and Centre National de la Recherche Scientifique, Marseille, France
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11
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Giampiccolo D, Duffau H. Controversy over the temporal cortical terminations of the left arcuate fasciculus: a reappraisal. Brain 2022; 145:1242-1256. [PMID: 35142842 DOI: 10.1093/brain/awac057] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 12/19/2021] [Accepted: 01/20/2022] [Indexed: 11/12/2022] Open
Abstract
The arcuate fasciculus has been considered a major dorsal fronto-temporal white matter pathway linking frontal language production regions with auditory perception in the superior temporal gyrus, the so-called Wernicke's area. In line with this tradition, both historical and contemporary models of language function have assigned primacy to superior temporal projections of the arcuate fasciculus. However, classical anatomical descriptions and emerging behavioural data are at odds with this assumption. On one hand, fronto-temporal projections to Wernicke's area may not be unique to the arcuate fasciculus. On the other hand, dorsal stream language deficits have been reported also for damage to middle, inferior and basal temporal gyri which may be linked to arcuate disconnection. These findings point to a reappraisal of arcuate projections in the temporal lobe. Here, we review anatomical and functional evidence regarding the temporal cortical terminations of the left arcuate fasciculus by incorporating dissection and tractography findings with stimulation data using cortico-cortical evoked potentials and direct electrical stimulation mapping in awake patients. Firstly, we discuss the fibers of the arcuate fasciculus projecting to the superior temporal gyrus and the functional rostro-caudal gradient in this region where both phonological encoding and auditory-motor transformation may be performed. Caudal regions within the temporoparietal junction may be involved in articulation and associated with temporoparietal projections of the third branch of the superior longitudinal fasciculus, while more rostral regions may support encoding of acoustic phonetic features, supported by arcuate fibres. We then move to examine clinical data showing that multimodal phonological encoding is facilitated by projections of the arcuate fasciculus to superior, but also middle, inferior and basal temporal regions. Hence, we discuss how projections of the arcuate fasciculus may contribute to acoustic (middle-posterior superior and middle temporal gyri), visual (posterior inferior temporal/fusiform gyri comprising the visual word form area) and lexical (anterior-middle inferior temporal/fusiform gyri in the basal temporal language area) information in the temporal lobe to be processed, encoded and translated into a dorsal phonological route to the frontal lobe. Finally, we point out surgical implications for this model in terms of the prediction and avoidance of neurological deficit.
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Affiliation(s)
- Davide Giampiccolo
- Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University Hospital, Verona, Italy.,Institute of Neuroscience, Cleveland Clinic London, Grosvenor Place, London, UK.,Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, UK.,Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Hugues Duffau
- Department of Neurosurgery, Gui de Chauliac Hospital, Montpellier University Medical Center, Montpellier, France.,Team "Neuroplasticity, Stem Cells and Low-grade Gliomas," INSERM U1191, Institute of Genomics of Montpellier, University of Montpellier, Montpellier, France
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12
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Thomas T, Khalaf S, Grigorenko EL. A systematic review and meta-analysis of imaging genetics studies of specific reading disorder. Cogn Neuropsychol 2021; 38:179-204. [PMID: 34529546 DOI: 10.1080/02643294.2021.1969900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The imaging genetics of specific reading disabilities (SRD) is an emerging field that aims to characterize the disabilities' neurobiological causes, including atypical brain structure and function and distinct genetic architecture. The present review aimed to summarize current imaging genetics studies of SRD, characterize the effect sizes of reported results by calculating Cohen's d, complete a Fisher's Combined Probability Test for genes featured in multiple studies, and determine areas for future research. Results demonstrate associations between SRD risk genes and reading network brain phenotypes. The Fisher's test revealed promising results for the genes DCDC2, KIAA0319, FOXP2, SLC2A3, and ROBO1. Future research should focus on exploratory approaches to identify previously undiscovered genes. Using comprehensive neuroimaging (e.g., functional and effective connectivity) and genetic (e.g., sequencing and epigenetic) techniques, and using larger samples, diverse stages of development, and longitudinal investigations, would help researchers understand the neurobiological correlates of SRD to improve early identification.
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Affiliation(s)
- Tina Thomas
- Department of Psychology, University of Houston, Houston, TX, USA.,Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA
| | - Shiva Khalaf
- Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA
| | - Elena L Grigorenko
- Department of Psychology, University of Houston, Houston, TX, USA.,Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA.,Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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13
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Borghesani V, Wang C, Watson C, Bouhali F, Caverzasi E, Battistella G, Bogley R, Yabut NA, Deleon J, Miller ZA, Hoeft F, Mandelli ML, Gorno-Tempini ML. Functional and morphological correlates of developmental dyslexia: A multimodal investigation of the ventral occipitotemporal cortex. J Neuroimaging 2021; 31:962-972. [PMID: 34115429 PMCID: PMC10832296 DOI: 10.1111/jon.12892] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/03/2021] [Accepted: 05/21/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE The ventral occipitotemporal cortex (vOT) is a region crucial for reading acquisition through selective tuning to printed words. Developmental dyslexia is a disorder of reading with underlying neurobiological bases often associated with atypical neural responses to printed words. Previous studies have discovered anomalous structural development and function of the vOT in individuals with dyslexia. However, it remains unclear if or how structural abnormalities relate to functional alterations. METHODS In this study, we acquired structural, functional (words and faces processing), and diffusion MRI data from 26 children with dyslexia (average age = 10.4 ± 2.0 years) and 14 age-matched typically developing readers (average age = 10.4 ± 1.6 years). Morphological indices of local gyrification, neurite density (i.e., dendritic arborization structure), and orientation dispersion (i.e., dendritic arborization orientation) were analyzed within the vOT region that showed preferential activation in typically developing readers for words (as compared to face stimuli). RESULTS The two cohorts diverged significantly in both functional and structural measures. Compared to typically developing controls, children with dyslexia did not show selectivity for words in the left vOT (contrast: words > false fonts). This lack of tuning to printed words was associated with greater neurite dispersion heterogeneity in the dyslexia cohort, but similar neurite density. These group differences were not present in the homologous contralateral area, the right vOT. CONCLUSIONS Our findings provide new insight into the neurobiology of the lack of vOT word tuning in dyslexia by linking behavior, alterations in functional activation, and neurite organization.
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Affiliation(s)
- Valentina Borghesani
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
| | - Cheng Wang
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Christa Watson
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Florence Bouhali
- Department of Psychiatry and Behavioral Science, University of California, San Francisco, San Francisco, California, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
| | - Eduardo Caverzasi
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Giovanni Battistella
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Rian Bogley
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Nicole A Yabut
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Jessica Deleon
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Zachary A Miller
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Fumiko Hoeft
- Department of Psychiatry and Behavioral Science, University of California, San Francisco, San Francisco, California, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
- Department of Psychological Sciences, University of Connecticut, Mansfield, Connecticut, USA
- Brain Imaging Research Center, University of Connecticut, Mansfield, Connecticut, USA
| | - Maria Luisa Mandelli
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
| | - Maria Luisa Gorno-Tempini
- Department of Neurology, University of California, San Francisco, San Francisco, California, USA
- Dyslexia Center, University of California, San Francisco, San Francisco, California, USA
- Department of Psychiatry and Behavioral Science, University of California, San Francisco, San Francisco, California, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA
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14
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The Polygenic Nature and Complex Genetic Architecture of Specific Learning Disorder. Brain Sci 2021; 11:brainsci11050631. [PMID: 34068951 PMCID: PMC8156942 DOI: 10.3390/brainsci11050631] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/16/2022] Open
Abstract
Specific Learning Disorder (SLD) is a multifactorial, neurodevelopmental disorder which may involve persistent difficulties in reading (dyslexia), written expression and/or mathematics. Dyslexia is characterized by difficulties with speed and accuracy of word reading, deficient decoding abilities, and poor spelling. Several studies from different, but complementary, scientific disciplines have investigated possible causal/risk factors for SLD. Biological, neurological, hereditary, cognitive, linguistic-phonological, developmental and environmental factors have been incriminated. Despite worldwide agreement that SLD is highly heritable, its exact biological basis remains elusive. We herein present: (a) an update of studies that have shaped our current knowledge on the disorder’s genetic architecture; (b) a discussion on whether this genetic architecture is ‘unique’ to SLD or, alternatively, whether there is an underlying common genetic background with other neurodevelopmental disorders; and, (c) a brief discussion on whether we are at a position of generating meaningful correlations between genetic findings and anatomical data from neuroimaging studies or specific molecular/cellular pathways. We conclude with open research questions that could drive future research directions.
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15
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Zhang S, Fan H, Zhang Y. The 100 Top-Cited Studies on Dyslexia Research: A Bibliometric Analysis. Front Psychiatry 2021; 12:714627. [PMID: 34366943 PMCID: PMC8339432 DOI: 10.3389/fpsyt.2021.714627] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/28/2021] [Indexed: 02/05/2023] Open
Abstract
Background: Citation analysis is a type of quantitative and bibliometric analytic method designed to rank papers based on their citation counts. Over the last few decades, the research on dyslexia has made some progress which helps us to assess this disease, but a citation analysis on dyslexia that reflects these advances is lacking. Methods: A retrospective bibliometric analysis was performed using the Web of Science Core Collection database. The 100 top-cited studies on dyslexia were retrieved after reviewing abstracts or full-texts to May 20th, 2021. Data from the 100 top-cited studies were subsequently extracted and analyzed. Results: The 100 top-cited studies on dyslexia were cited between 245 to 1,456 times, with a median citation count of 345. These studies were published in 50 different journals, with the "Proceedings of the National Academy of Sciences of the United States of America" having published the most (n = 10). The studies were published between 1973 and 2012 and the most prolific year in terms of number of publications was 2000. Eleven countries contributed to the 100 top-cited studies, and nearly 75% articles were either from the USA (n = 53) or United Kingdom (n = 21). Eighteen researchers published at least two different studies of the 100 top-cited list as the first author. Furthermore, 71 studies were published as an original research article, 28 studies were review articles, and one study was published as an editorial material. Finally, "Psychology" was the most frequent study category. Conclusions: This analysis provides a better understanding on dyslexia and may help doctors, researchers, and stakeholders to achieve a more comprehensive understanding of classic studies, new discoveries, and trends regarding this research field, thus promoting ideas for future investigation.
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Affiliation(s)
- Shijie Zhang
- Department of Respiratory and Critical Care Medicine, West China Hospital/West China School of Medicine, Sichuan University, Chengdu, China
| | - Hong Fan
- Department of Respiratory and Critical Care Medicine, West China Hospital/West China School of Medicine, Sichuan University, Chengdu, China
| | - Yonggang Zhang
- Department of Periodical Press and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Chinese Evidence-Based Medicine Center, West China Hospital, Sichuan University, Chengdu, China
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16
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Grant JG, Siegel LS, D'Angiulli A. From Schools to Scans: A Neuroeducational Approach to Comorbid Math and Reading Disabilities. Front Public Health 2020; 8:469. [PMID: 33194932 PMCID: PMC7642246 DOI: 10.3389/fpubh.2020.00469] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 07/24/2020] [Indexed: 11/13/2022] Open
Abstract
We bridge two analogous concepts of comorbidity, dyslexia-dyscalculia and reading-mathematical disabilities, in neuroscience and education, respectively. We assessed the cognitive profiles of 360 individuals (mean age 25.79 ± 13.65) with disability in reading alone (RD group), mathematics alone (MD group) and both (comorbidity: MDRD group), with tests widely used in both psychoeducational and neuropsychological batteries. As expected, the MDRD group exhibited reading deficits like those shown by the RD group. The former group also exhibited deficits in quantitative reasoning like those shown by the MD group. However, other deficits related to verbal working memory and semantic memory were exclusive to the MDRD group. These findings were independent of gender, age, or socioeconomic and demographic factors. Through a systematic exhaustive review of clinical neuroimaging literature, we mapped the resulting cognitive profiles to correspondingly plausible neuroanatomical substrates of dyslexia and dyscalculia. In our resulting "probing" model, the complex set of domain-specific and domain-general impairments shown in the comorbidity of reading and mathematical disabilities are hypothesized as being related to atypical development of the left angular gyrus. The present neuroeducational approach bridges a long-standing transdisciplinary divide and contributes a step further toward improved early prediction, teaching and interventions for children and adults with combined reading and math disabilities.
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Affiliation(s)
- Jeremy G Grant
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - Linda S Siegel
- Department of Educational and Counselling Psychology, and Special Education, The University of British Columbia, Vancouver, BC, Canada
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17
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Cui X, Xia Z, McBride C, Li P, Pan J, Shu H. Shared Neural Substrates Underlying Reading and Visual Matching: A Longitudinal Investigation. Front Hum Neurosci 2020; 14:567541. [PMID: 33192396 PMCID: PMC7642616 DOI: 10.3389/fnhum.2020.567541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 09/22/2020] [Indexed: 11/13/2022] Open
Abstract
The role of visual skills in reading acquisition has long been debated and whether there is shared neurobiological basis between visual skills and reading is not clear. This study investigated the relationship between Visual Matching and reading and their shared neuroanatomical basis. Two hundred and ninety-three typically developing Mandarin-speaking children were followed in a longitudinal study from ages 4 to 11 years old. A subsample of 79 children was further followed up at 14 years old when the MRI data were collected. Results showed that the development of Visual Matching from ages 6 to 8 predicted reading accuracy at age 11. In addition, both the development of Visual Matching and reading accuracy were associated with cortical surface area of a cluster located in fusiform gyrus. These findings suggested that the mapping from visual codes to phonological codes is important in learning to read and that left fusiform gyrus provided neural basis for such mapping. Implications of these findings in light of a new approach toward the neurocognitive mechanisms underlying reading development are discussed.
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Affiliation(s)
- Xin Cui
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Zhichao Xia
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.,School of Systems Science, Beijing Normal University, Beijing, China
| | - Catherine McBride
- Department of Psychology, Brain Mind Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Ping Li
- Department of Chinese and Bilingual Studies, Faculty of Humanities, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jinger Pan
- Department of Psychology, The Education University of Hong Kong, Hong Kong, China
| | - Hua Shu
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
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18
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Laasonen M, Lahti-Nuuttila P, Leppämäki S, Tani P, Wikgren J, Harno H, Oksanen-Hennah H, Pothos E, Cleeremans A, Dye MWG, Cousineau D, Hokkanen L. Project DyAdd: Non-linguistic Theories of Dyslexia Predict Intelligence. Front Hum Neurosci 2020; 14:316. [PMID: 32922276 PMCID: PMC7456923 DOI: 10.3389/fnhum.2020.00316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/16/2020] [Indexed: 11/13/2022] Open
Abstract
Two themes have puzzled the research on developmental and learning disorders for decades. First, some of the risk and protective factors behind developmental challenges are suggested to be shared and some are suggested to be specific for a given condition. Second, language-based learning difficulties like dyslexia are suggested to result from or correlate with non-linguistic aspects of information processing as well. In the current study, we investigated how adults with developmental dyslexia or ADHD as well as healthy controls cluster across various dimensions designed to tap the prominent non-linguistic theories of dyslexia. Participants were 18–55-year-old adults with dyslexia (n = 36), ADHD (n = 22), and controls (n = 35). Non-linguistic theories investigated with experimental designs included temporal processing impairment, abnormal cerebellar functioning, procedural learning difficulties, as well as visual processing and attention deficits. Latent profile analysis (LPA) was used to investigate the emerging groups and patterns of results across these experimental designs. LPA suggested three groups: (1) a large group with average performance in the experimental designs, (2) participants predominantly from the clinical groups but with enhanced conditioning learning, and (3) participants predominantly from the dyslexia group with temporal processing as well as visual processing and attention deficits. Despite the presence of these distinct patterns, participants did not cluster very well based on their original status, nor did the LPA groups differ in their dyslexia or ADHD-related neuropsychological profiles. Remarkably, the LPA groups did differ in their intelligence. These results highlight the continuous and overlapping nature of the observed difficulties and support the multiple deficit model of developmental disorders, which suggests shared risk factors for developmental challenges. It also appears that some of the risk factors suggested by the prominent non-linguistic theories of dyslexia relate to the general level of functioning in tests of intelligence.
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Affiliation(s)
- Marja Laasonen
- Department of Psychology and Logopedics, University of Helsinki, Helsinki, Finland.,Department of Otorhinolaryngology and Phoniatrics - Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Pekka Lahti-Nuuttila
- Department of Psychology and Logopedics, University of Helsinki, Helsinki, Finland.,Department of Otorhinolaryngology and Phoniatrics - Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Sami Leppämäki
- Department of Psychiatry, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Pekka Tani
- Department of Psychiatry, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Jan Wikgren
- Department of Psychology, Centre for Interdisciplinary Brain Research, University of Jyväskylä, Jyväskylä, Finland
| | - Hanna Harno
- Clinical Neurosciences, Department of Neurology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Henna Oksanen-Hennah
- Pediatric Neuropsychiatric Unit, Department of Child Psychiatry, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Emmanuel Pothos
- Department of Psychology, City University of London, London, United Kingdom
| | - Axel Cleeremans
- Center for Research in Cognition & Neurosciences, Université libre de Bruxelles, Brussels, Belgium
| | - Matthew W G Dye
- National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester, NY, United States
| | - Denis Cousineau
- School of Psychology, University of Ottawa, Ottawa, ON, Canada
| | - Laura Hokkanen
- Department of Psychology and Logopedics, University of Helsinki, Helsinki, Finland
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19
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Tecoulesco L, Skoe E, Naigles LR. Phonetic discrimination mediates the relationship between auditory brainstem response stability and syntactic performance. BRAIN AND LANGUAGE 2020; 208:104810. [PMID: 32683226 DOI: 10.1016/j.bandl.2020.104810] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 02/03/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Syntactic, lexical, and phonological/phonetic knowledge are vital aspects of macro level language ability. Prior research has predominantly focused on environmental or cortical sources of individual differences in these areas; however, a growing literature suggests an auditory brainstem contribution to language performance in both typically developing (TD) populations and children with autism spectrum disorder (ASD). This study investigates whether one aspect of auditory brainstem responses (ABRs), neural response stability, which is a metric reflecting trial-by-trial consistency in the neural encoding of sound, can predict syntactic, lexical, and phonetic performance in TD and ASD school-aged children. Pooling across children with ASD and TD, results showed that higher neural stability in response to the syllable /da/ was associated with better phonetic discrimination, and with better syntactic performance on a standardized measure. Furthermore, phonetic discrimination was a successful mediator of the relationship between neural stability and syntactic performance. This study supports the growing body of literature that stable subcortical neural encoding of sound is important for successful language performance.
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Affiliation(s)
- Lisa Tecoulesco
- University of Connecticut Psychological Sciences, United States.
| | - Erika Skoe
- University of Connecticut, Speech Language and Hearing Sciences, United States
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20
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Higuchi H, Iwaki S, Uno A. Altered visual character and object recognition in Japanese-speaking adolescents with developmental dyslexia. Neurosci Lett 2020; 723:134841. [PMID: 32081567 DOI: 10.1016/j.neulet.2020.134841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/05/2020] [Accepted: 02/16/2020] [Indexed: 10/25/2022]
Abstract
Many studies have confirmed a brain dysfunction in people with developmental dyslexia (DD) in certain brain regions, including the left superior temporal gyrus and the left fusiform gyrus. However, the neurobiological substrates in Japanese-speaking people with dyslexia are not fully understood, mostly due to the uniqueness of the orthographic systems. Since a substantial part of the written Japanese includes the logographic Kanji as well as the phonographic Kana systems, the reading disability might be caused not only by a dysfunction in the phonological system, but also by a dysfunction in the visual recognition system. Previous studies reported altered hierarchical visual word form processing in the left occipitotemporal cortex; however, it remains unclear whether the altered hierarchical visual processing is language stimuli-specific. Therefore, we aimed to investigate whether (a) Japanese-speaking individuals with DD exhibit atypical hierarchical visual processing, and if so, (b) whether the altered hierarchical visual processing is language stimuli-specific or not. The present study investigated the brain activation pattern for the hierarchical component of the Kanji characters and object stimuli in typically developing (TD) adolescents and adolescents with DD using functional magnetic resonance imaging. For the Kanji characters, adolescents with DD showed a greater activation in the left occipital gyrus and right occipital fusiform gyrus, and this hyperactivity was also found for pseudo and artificial Kanji characters. These results imply reliance on an early visual system in Kanji reading in Japanese-speaking adolescents with DD. Additionally, we also investigated the brain activity for object stimuli, and adolescents with DD showed a greater activation in the bilateral occipital gyri compared with the TD adolescents. These results imply an altered hierarchical visual processing characterized by overactivation in the early visual areas, which is a not restricted to language stimulus only.
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Affiliation(s)
- Hiroki Higuchi
- Automotive Human Factors Research Center, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan.
| | - Sunao Iwaki
- Automotive Human Factors Research Center, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan
| | - Akira Uno
- Faculty of Human Sciences, University of Tsukuba, Laboratory of Advanced Research D, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
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21
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Ma S, Zhang X, Hatfield H, Wei WH. Pinyin Is an Effective Proxy for Early Screening for Mandarin-Speaking Children at Risk of Reading Disorders. Front Psychol 2020; 11:327. [PMID: 32174873 PMCID: PMC7055296 DOI: 10.3389/fpsyg.2020.00327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/11/2020] [Indexed: 12/29/2022] Open
Abstract
Reading disorders (RD) are common and complex neuropsychological conditions associated with decoding printed words and/or reading comprehension. Early identification of children at risk of RD is critical to allow timely interventions before mental suffering and reading impairment take place. Chinese is a unique medium for studying RD because of extra efforts required in reading acquisition of characters based on meaning rather than phonology. Pinyin, an alphabetic coding system mapping Mandarin sounds to characters, is important to develop oral language skills and a promising candidate for early screening for RD. In this pilot study, we used a cohort of 100 students (50 each in Grades 1 and 2) to derive novel profiles of applying Pinyin to identify early schoolers at risk of RD. Each student had comprehensive reading related measures in two consecutive years, including Pinyin reading and reading comprehension tested in the first and second year, respectively. We showed that Pinyin reading was mainly determined by phonological awareness, was well developed in Grade 1 and the top predictor of reading comprehension (explaining ∼30% of variance, p < 1.0e-05). Further, students who performed poorly in Pinyin reading [e.g. 1 standard deviation (SD) below the average, counting 14% in Grade 1 and 10% in Grade 2], tended to perform poorly in future reading comprehension tests, including all four individuals in Grade 1 (two out of three in Grade 2) who scored 1.5 SDs below the average. Pinyin is therefore an effective proxy for early screening for Mandarin-speaking children at risk of RD.
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Affiliation(s)
- Shaowei Ma
- School of Foreign Languages, Langfang Teachers University, Langfang, China
- Department of English and Linguistics, University of Otago, Dunedin, New Zealand
- School of Teacher Education, College of Education, University of Canterbury, Christchurch, New Zealand
| | - Xiumei Zhang
- School of Foreign Languages, Langfang Teachers University, Langfang, China
| | - Hunter Hatfield
- Department of English and Linguistics, University of Otago, Dunedin, New Zealand
| | - Wen-Hua Wei
- Department of Women’s and Children’s Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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22
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Pleisch G, Karipidis II, Brem A, Röthlisberger M, Roth A, Brandeis D, Walitza S, Brem S. Simultaneous EEG and fMRI reveals stronger sensitivity to orthographic strings in the left occipito-temporal cortex of typical versus poor beginning readers. Dev Cogn Neurosci 2019; 40:100717. [PMID: 31704655 PMCID: PMC6974919 DOI: 10.1016/j.dcn.2019.100717] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 08/23/2019] [Accepted: 10/01/2019] [Indexed: 01/18/2023] Open
Abstract
The level of reading skills in children and adults is reflected in the strength of preferential neural activation to print. Such preferential activation appears in the N1 event-related potential (ERP) over the occipitotemporal scalp after around 150–250 ms and the corresponding blood oxygen level dependent (BOLD) signal in the ventral occipitotemporal (vOT) cortex. Here, orthography-sensitive (print vs. false font) processing was examined using simultaneous EEG-fMRI in 38 first grade children with poor and typical reading skills, and at varying familial risk for developmental dyslexia. Coarse orthographic sensitivity was observed as an increased activation to print in the N1 ERP and in the BOLD signal of individually varying vOT regions in 57% of beginning readers. Finer differentiation in processing orthographic strings (words vs. nonwords) further occurred in specific vOT clusters. Neither method alone showed robust differences in orthography-sensitive processing between typical and poor reading children. Importantly, using single-trial N1 ERP-informed fMRI analysis, we found differential modulation of the orthography-sensitive BOLD response in the left vOT for typical readers only. This result, thus, confirms subtle functional alterations in a brain structure known to be critical for fluent reading at the very beginning of reading instruction.
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Affiliation(s)
- Georgette Pleisch
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Switzerland
| | - Iliana I Karipidis
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Switzerland; Center for Interdisciplinary Brain Sciences Research, Stanford University School of Medicine, Stanford, CA, USA
| | - Alexandra Brem
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland
| | - Martina Röthlisberger
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland
| | - Alexander Roth
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland
| | - Daniel Brandeis
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Switzerland; Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany; Center for Integrative Human Physiology Zurich, University of Zurich, Switzerland
| | - Susanne Walitza
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Switzerland; Center for Integrative Human Physiology Zurich, University of Zurich, Switzerland
| | - Silvia Brem
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Switzerland; MR-Center of the University Hospital of Psychiatry and the Department of Child and Adolescent Psychiatry and Psychotherapy, University of Zurich, Switzerland.
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23
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Landi N, Perdue M. Neuroimaging genetics studies of specific reading disability and developmental language disorder: A review. LANGUAGE AND LINGUISTICS COMPASS 2019; 13:e12349. [PMID: 31844423 PMCID: PMC6913889 DOI: 10.1111/lnc3.12349] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Developmental disorders of spoken and written language are heterogeneous in nature with impairments observed across various linguistic, cognitive, and sensorimotor domains. These disorders are also associated with characteristic patterns of atypical neural structure and function that are observable early in development, often before formal schooling begins. Established patterns of heritability point toward genetic contributions, and molecular genetics approaches have identified genes that play a role in these disorders. Still, identified genes account for only a limited portion of phenotypic variance in complex developmental disorders, described as the problem of "missing heritability." The characterization of intermediate phenotypes at the neural level may fill gaps in our understanding of heritability patterns in complex disorders, and the emerging field of neuroimaging genetics offers a promising approach to accomplish this goal. The neuroimaging genetics approach is gaining prevalence in language- and reading-related research as it is well-suited to incorporate behavior, genetics, and neurobiology into coherent etiological models of complex developmental disorders. Here, we review research applying the neuroimaging genetics approach to the study of specific reading disability (SRD) and developmental language disorder (DLD), much of which links genes with known neurodevelopmental function to functional and structural abnormalities in the brain.
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Affiliation(s)
- Nicole Landi
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut, United States; Haskins Laboratories, United States
| | - Meaghan Perdue
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut, United States; Haskins Laboratories, United States
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24
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The interplay of socio-economic status represented by paternal educational level, white matter structure and reading. PLoS One 2019; 14:e0215560. [PMID: 31048844 PMCID: PMC6497374 DOI: 10.1371/journal.pone.0215560] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 04/05/2019] [Indexed: 11/19/2022] Open
Abstract
A child’s school achievement is influenced by environmental factors. The environmental factors, when represented by socio-economic status (SES) of the family, have been demonstrated to be related to the reading skills of a child. The neural correlates of the relation between SES and reading have been less thoroughly investigated. The present study expands current research by exploring the relation between SES, quantified by paternal educational level, reading of the offspring and the structure of white matter pathways in the left hemisphere as derived from DTI-based tractography analyses. Therefore, three dorsal white matter pathways, i.e. the long, anterior and posterior segments of the arcuate fasciculus (AF), and three ventral white matter pathways, i.e. the inferior fronto-occipital fasciculus (IFOF), the inferior longitudinal fasciculus (ILF) and the uncinate fasciculus (UF), were manually dissected in the left hemisphere of 34 adolescents with a wide range of reading skills. The results demonstrated a relation between word reading, SES quantified by paternal educational level, and fractional anisotropy (FA) within the left dorsal AF segment and the left ventral UF. Thus, the present study proposes a relationship between paternal educational level and a specific white matter pathway that is important for reading, aiming to guide future research that can determine processes underlying this relationship.
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25
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Skeide MA, Evans TM, Mei EZ, Abrams DA, Menon V. Neural signatures of co-occurring reading and mathematical difficulties. Dev Sci 2018; 21:e12680. [PMID: 29920856 PMCID: PMC6347422 DOI: 10.1111/desc.12680] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/23/2018] [Indexed: 01/13/2023]
Abstract
Impaired abilities in multiple domains is common in children with learning difficulties. Co-occurrence of low reading and mathematical abilities (LRLM) appears in almost every second child with learning difficulties. However, little is known regarding the neural bases of this combination. Leveraging a unique and tightly controlled sample including children with LRLM, isolated low reading ability (LR), and isolated low mathematical ability (LM), we uncover a distinct neural signature in children with co-occurring low reading and mathematical abilities differentiable from LR and LM. Specifically, we show that LRLM is neuroanatomically distinct from both LR and LM based on reduced cortical folding of the right parahippocampal gyrus, a medial temporal lobe region implicated in visual associative learning. LRLM children were further distinguished from LR and LM by patterns of intrinsic functional connectivity between parahippocampal gyrus and brain circuitry underlying reading and numerical quantity processing. Our results critically inform cognitive and neural models of LRLM by implicating aberrations in both domain-specific and domain-general brain regions involved in reading and mathematics. More generally, our results provide the first evidence for distinct multimodal neural signatures associated with LRLM, and suggest that this population displays an independent phenotype of learning difficulty that cannot be explained simply as a combination of isolated low reading and mathematical abilities.
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Affiliation(s)
- Michael A. Skeide
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California 94305, USA
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Tanya M. Evans
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California 94305, USA
| | - Edward Z. Mei
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California 94305, USA
| | - Daniel A. Abrams
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California 94305, USA
| | - Vinod Menon
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California 94305, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305, USA
- Stanford Neuroscience Institute, Stanford, California 94305, USA
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26
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van Oers CAMM, Goldberg N, Fiorin G, van den Heuvel MP, Kappelle LJ, Wijnen FNK. No evidence for cerebellar abnormality in adults with developmental dyslexia. Exp Brain Res 2018; 236:2991-3001. [PMID: 30116863 PMCID: PMC6223834 DOI: 10.1007/s00221-018-5351-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 08/02/2018] [Indexed: 01/18/2023]
Abstract
Developmental dyslexia is commonly believed to result from a deficiency in the recognition and processing of speech sounds. According to the cerebellar deficit hypothesis, this phonological deficit is caused by deficient cerebellar function. In the current study, 26 adults with developmental dyslexia and 25 non-dyslexic participants underwent testing of reading-related skills, cerebellar functions, and MRI scanning of the brain. Anatomical assessment of the cerebellum was conducted with voxel-based morphometry. Behavioural evidence, that was indicative of impaired cerebellar function, was found to co-occur with reading impairments in the dyslexic subjects, but a causal relation between the two was not observed. No differences in local grey matter volume, nor in structure-function relationships within the cerebellum were found between the two groups. Possibly, the observed behavioural pattern is due to aberrant white matter connectivity. In conclusion, no support for the cerebellar deficit hypothesis or the presence of anatomical differences of the cerebellum in adults with developmental dyslexia was found.
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Affiliation(s)
- Casper A M M van Oers
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
- Department of Neurology, Amphia Hospital, Breda, The Netherlands.
| | - Nadya Goldberg
- Utrecht institute of Linguistics OTS, Utrecht, The Netherlands
| | - Gaetano Fiorin
- Utrecht institute of Linguistics OTS, Utrecht, The Netherlands
| | - Martijn P van den Heuvel
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - L Jaap Kappelle
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
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27
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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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28
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Corballis MC. Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal. Front Hum Neurosci 2018; 12:140. [PMID: 29706878 PMCID: PMC5907058 DOI: 10.3389/fnhum.2018.00140] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/27/2018] [Indexed: 11/23/2022] Open
Abstract
Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d) must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia.
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29
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Vandermosten M, Cuynen L, Vanderauwera J, Wouters J, Ghesquière P. White matter pathways mediate parental effects on children's reading precursors. BRAIN AND LANGUAGE 2017; 173:10-19. [PMID: 28558269 DOI: 10.1016/j.bandl.2017.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 04/28/2017] [Accepted: 05/06/2017] [Indexed: 06/07/2023]
Abstract
Previous studies have shown that the link between parental and offspring's reading is mediated by the cognitive system of the offspring, yet information about the mediating role of the neurobiological system is missing. This family study includes cognitive and diffusion MRI (dMRI) data collected in 71 pre-readers as well as parental reading and environmental data. Using sequential path analyses, which take into account the interrelationships between the different components, we observed mediating effects of the neurobiological system. More specifically, fathers' reading skills predicted reading of the child by operating through a child's left ventral white matter pathway. For mothers no clear mediating role of the neural system was observed. Given that our study involves children who have not yet learned to read and that environmental measures were taken into account, the paternal effect on a child's white matter pathway is unlikely to be only driven by environmental factors. Future intergenerational studies focusing on the genetic, neurobiological and cognitive level of parents and offspring will provide more insight in the relative contribution of parental environment and genes.
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Affiliation(s)
- Maaike Vandermosten
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium; Research Group ExpORL, Department of Neurosciences, KU Leuven, Belgium.
| | - Lieselore Cuynen
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium
| | - Jolijn Vanderauwera
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium; Research Group ExpORL, Department of Neurosciences, KU Leuven, Belgium
| | - Jan Wouters
- Research Group ExpORL, Department of Neurosciences, KU Leuven, Belgium
| | - Pol Ghesquière
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium
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Identification of NCAN as a candidate gene for developmental dyslexia. Sci Rep 2017; 7:9294. [PMID: 28839234 PMCID: PMC5570950 DOI: 10.1038/s41598-017-10175-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 08/04/2017] [Indexed: 01/22/2023] Open
Abstract
A whole-genome linkage analysis in a Finnish pedigree of eight cases with developmental dyslexia (DD) revealed several regions shared by the affected individuals. Analysis of coding variants from two affected individuals identified rs146011974G > A (Ala1039Thr), a rare variant within the NCAN gene co-segregating with DD in the pedigree. This variant prompted us to consider this gene as a putative candidate for DD. The RNA expression pattern of the NCAN gene in human tissues was highly correlated (R > 0.8) with that of the previously suggested DD susceptibility genes KIAA0319, CTNND2, CNTNAP2 and GRIN2B. We investigated the association of common variation in NCAN to brain structures in two data sets: young adults (Brainchild study, Sweden) and infants (FinnBrain study, Finland). In young adults, we found associations between a common genetic variant in NCAN, rs1064395, and white matter volume in the left and right temporoparietal as well as the left inferior frontal brain regions. In infants, this same variant was found to be associated with cingulate and prefrontal grey matter volumes. Our results suggest NCAN as a new candidate gene for DD and indicate that NCAN variants affect brain structure.
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Neurogenetics of developmental dyslexia: from genes to behavior through brain neuroimaging and cognitive and sensorial mechanisms. Transl Psychiatry 2017; 7:e987. [PMID: 28045463 PMCID: PMC5545717 DOI: 10.1038/tp.2016.240] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/15/2016] [Indexed: 01/18/2023] Open
Abstract
Developmental dyslexia (DD) is a complex neurodevelopmental deficit characterized by impaired reading acquisition, in spite of adequate neurological and sensorial conditions, educational opportunities and normal intelligence. Despite the successful characterization of DD-susceptibility genes, we are far from understanding the molecular etiological pathways underlying the development of reading (dis)ability. By focusing mainly on clinical phenotypes, the molecular genetics approach has yielded mixed results. More optimally reduced measures of functioning, that is, intermediate phenotypes (IPs), represent a target for researching disease-associated genetic variants and for elucidating the underlying mechanisms. Imaging data provide a viable IP for complex neurobehavioral disorders and have been extensively used to investigate both morphological, structural and functional brain abnormalities in DD. Performing joint genetic and neuroimaging studies in humans is an emerging strategy to link DD-candidate genes to the brain structure and function. A limited number of studies has already pursued the imaging-genetics integration in DD. However, the results are still not sufficient to unravel the complexity of the reading circuit due to heterogeneous study design and data processing. Here, we propose an interdisciplinary, multilevel, imaging-genetic approach to disentangle the pathways from genes to behavior. As the presence of putative functional genetic variants has been provided and as genetic associations with specific cognitive/sensorial mechanisms have been reported, new hypothesis-driven imaging-genetic studies must gain momentum. This approach would lead to the optimization of diagnostic criteria and to the early identification of 'biologically at-risk' children, supporting the definition of adequate and well-timed prevention strategies and the implementation of novel, specific remediation approach.
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Predicting early signs of dyslexia at a preliterate age by combining behavioral assessment with structural MRI. Neuroimage 2016; 143:378-386. [PMID: 27608602 DOI: 10.1016/j.neuroimage.2016.09.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/23/2016] [Accepted: 09/02/2016] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Recent studies suggest that neurobiological anomalies are already detectable in pre-school children with a family history of developmental dyslexia (DD). However, there is a lack of longitudinal studies showing a direct link between those differences at a preliterate age and the subsequent literacy difficulties seen in school. It is also not clear whether the prediction of DD in pre-school children can be significantly improved when considering neurobiological predictors, compared to models based on behavioral literacy precursors only. METHODS We recruited 53 pre-reading children either with (N=25) or without a family risk of DD (N=28). Quantitative T1 MNI data and literacy precursor abilities were assessed at kindergarten age. A subsample of 35 children was tested for literacy skills either one or two years later, that is, either in first or second grade. RESULTS The group comparison of quantitative T1 measures revealed significantly higher T1 intensities in the left anterior arcuate fascicle (AF), suggesting reduced myelin concentration in preliterate children at risk of DD. A logistic regression showed that DD can be predicted significantly better (p=.024) when neuroanatomical differences between groups are used as predictors (80%) compared to a model based on behavioral predictors only (63%). The Wald statistic confirmed that the T1 intensity of the left AF is a statistically significant predictor of DD (p<.05). CONCLUSIONS Our longitudinal results provide evidence for the hypothesis that neuroanatomical anomalies in children with a family risk of DD are related to subsequent problems in acquiring literacy. Particularly, solid white matter organization in the left anterior arcuate fascicle seems to play a pivotal role.
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