Neuroimaging genetics studies of specific reading disability and developmental language disorder: A review <s> | DEVELOPMENTAL LANGUAGE DISORDER <s> The aim of the present study was to investigate differences in brain activation in a family with SLI as compared to intact individuals with normally developed language during processing of language... <s> BIB001 </s> Neuroimaging genetics studies of specific reading disability and developmental language disorder: A review <s> | DEVELOPMENTAL LANGUAGE DISORDER <s> Specific language impairment (SLI) is defined as an unexpected and persistent impairment in language ability despite adequate opportunity and intelligence and in the absence of any explanatory medical conditions. This condition is highly heritable and affects between 5% and 8% of pre-school children. Over the past few years, investigations have begun to uncover genetic factors that may contribute to susceptibility to language impairment. So far, variants in four specific genes have been associated with spoken language disorders - forkhead box P2 (FOXP2) and contactin-associated protein-like 2 (CNTNAP2) on chromosome7 and calcium-transporting ATPase 2C2 (ATP2C2) and c-MAF inducing protein (CMIP) on chromosome 16. Here, we describe the different ways in which these genes were identified as candidates for language impairment. We discuss how characterization of these genes, and the pathways in which they are involved, may enhance our understanding of language disorders and improve our understanding of the biological foundations of language acquisition. <s> BIB002 </s> Neuroimaging genetics studies of specific reading disability and developmental language disorder: A review <s> | DEVELOPMENTAL LANGUAGE DISORDER <s> Atypical functional lateralization and specialization for language have been proposed to account for developmental language disorders, yet results from functional neuroimaging studies are sparse and inconsistent. This functional magnetic resonance imaging study compared children with a specific subtype of specific language impairment affecting structural language (n = 21), to a matched group of typically developing children using a panel of four language tasks neither requiring reading nor metalinguistic skills, including two auditory lexico-semantic tasks (category fluency and responsive naming) and two visual phonological tasks based on picture naming. Data processing involved normalizing the data with respect to a matched pairs paediatric template, groups and between-groups analysis, and laterality indices assessment within regions of interest using single and combined task analysis. Children with specific language impairment exhibited a significant lack of left lateralization in all core language regions (inferior frontal gyrus-opercularis, inferior frontal gyrus-triangularis, supramarginal gyrus and superior temporal gyrus), across single or combined task analysis, but no difference of lateralization for the rest of the brain. Between-group comparisons revealed a left hypoactivation of Wernicke's area at the posterior superior temporal/supramarginal junction during the responsive naming task, and a right hyperactivation encompassing the anterior insula with adjacent inferior frontal gyrus and the head of the caudate nucleus during the first phonological task. This study thus provides evidence that this subtype of specific language impairment is associated with atypical lateralization and functioning of core language areas. <s> BIB003 </s> Neuroimaging genetics studies of specific reading disability and developmental language disorder: A review <s> | DEVELOPMENTAL LANGUAGE DISORDER <s> Aim ::: The neurobiological contributions of childhood language disorder are not well understood. Yet there is increasing evidence that language disorder is associated with differences in brain structure and/or function in core language regions. A key hypothesis has been that children with language disorder do not show the same degree of leftward asymmetry of these regions as observed in typically developing children. We aimed to systematically review structural and functional magnetic resonance imaging (fMRI) studies to examine brain commonalities and differences between children with language disorder and typically developing controls; and differences in leftward asymmetry between these groups. ::: ::: Method ::: A systematic review was conducted using MeSH terms synonymous with childhood language disorder and brain MRI methods. The search identified 1443 papers, and 18 articles met the criteria and were appraised for level and quality of evidence. ::: ::: Results ::: Atypical brain structure and function was reported within traditionally recognized language regions across studies, including the inferior frontal gyrus, posterior superior temporal gyrus, and caudate nucleus. The direction of difference (e.g. increased/decreased) was variable, however, likely because of differences in language disorder groups examined and magnetic resonance data acquisition and analysis approaches. As regards asymmetry, there was some evidence of reduction of the anticipated structural and functional leftward asymmetry in frontal language regions in language disorder groups. ::: ::: Interpretation ::: Mounting evidence suggests that children with language disorder have atypical brain structure and function within neural regions integral to language. There is limited support for the hypothesis that children with language disorder show a reduction of leftward structural and/or functional asymmetry in frontal language regions. Interpretation is limited, however, by a high degree of variability in language disorder assessment and phenotype, and in magnetic resonance methodologies. A large-scale magnetic resonance study of brain structure and function is required in a well-defined language disorder population cohort, with replication, to provide confirmatory data on the neural correlates of childhood language disorder. <s> BIB004
Developmental language disorder (DLD) refers to difficulties in language acquisition that may affect comprehension and/or production of language across modalities (e.g., spoken and written; American Psychological Association, 2013). Because DLD often affects components of language that are also impaired in SRD, such as phonological awareness, similarities in the neural and genetic underpinnings of these two disorders are expected. The neurobiology of DLD has not been as well studied as that of SRD, but a small body of literature indicates decreased activation during language processing tasks (broadly construed) in individuals with DLD relative to typical controls in temporo-parietal and superior and middle temporal regions, as well as some mixed evidence for atypical functioning in the left inferior frontal gyrus BIB003 BIB001 BIB004 . A number of genes have been linked to impairments in speech and language function, including FOXP2, CNTNAP2, ATP2C2, and CMIP BIB002 . Because these genes play potentially wide-reaching roles in neurodevelopment and brain function (discussed below), imaging genetic research on these DLD-associated genes is not only helpful for linking genes to their specific neural functions in the context of expressive and receptive language but may also be helpful for understanding the potential cascading effects of these genes on reading.