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Harris GJ, Chabris CF, Clark J, Urban T, Aharon I, Steele S et al. Brain activation during semantic processing in autism spectrum disorders via functional magnetic resonance imaging. Brain Cogn 61: 54-68

Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, USA.
Brain and Cognition (Impact Factor: 2.48). 07/2006; 61(1):54-68. DOI: 10.1016/j.bandc.2005.12.015
Source: PubMed

ABSTRACT

Language and communication deficits are core features of autism spectrum disorders (ASD), even in high-functioning adults with ASD. This study investigated brain activation patterns using functional magnetic resonance imaging in right-handed adult males with ASD and a control group, matched on age, handedness, and verbal IQ. Semantic processing in the controls produced robust activation in Broca's area (left inferior frontal gyrus) and in superior medial frontal gyrus and right cerebellum. The ASD group had substantially reduced Broca's activation, but increased left temporal (Wernicke's) activation. Furthermore, the ASD group showed diminished activation differences between concrete and abstract words, consistent with behavioral studies. The current study suggests Broca's area is a region of abnormal neurodevelopment in ASD, which may be linked with semantic and related language deficits frequently observed in ASD.

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    • "tudies ( ASD : N 5 156 ; TD : N 5 157 ) , while the Nonequivalent Task Performance group consisted of contrasts from 6 studies ( ASD : N 5 89 ; TD : N 5 89 ) . ii . Social / Pragmatic Language Processing . Studies reporting contrasts of social / pragmatic language processing were included in this analysis . Three studies [ Gaffrey et al . , 2007 ; Harris et al . , 2006 ; Shen et al . , 2012 ]"
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    ABSTRACT: Language impairments, a hallmark feature of autism spectrum disorders (ASD), have been related to neuroanatomical and functional abnormalities. Abnormal lateralization of the functional language network, increased reliance on visual processing areas, and increased posterior brain activation have all been reported in ASD and proposed as explanatory models of language difficulties. Nevertheless, inconsistent findings across studies have prevented a comprehensive characterization of the functional language network in ASD. The aim of this study was to quantify common and consistent patterns of brain activation during language processing in ASD and typically developing control (TD) participants using a meta-analytic approach. Activation likelihood estimation (ALE) meta-analysis was used to examine 22 previously published functional Magnetic Resonance Imaging (fMRI)/positron emission tomography studies of language processing (ASD: N = 328; TD: N = 324). Tasks included in this study addressed semantic processing, sentence comprehension, processing figurative language, and speech production. Within-group analysis showed largely overlapping patterns of language-related activation in ASD and TD groups. However, the ASD participants, relative to TD participants, showed: (1) more right hemisphere activity in core language areas (i.e., superior temporal gyrus and inferior frontal gyrus), particularly in tasks where they had poorer performance accuracy; (2) bilateral MTG hypo-activation across many different paradigms; and (3) increased activation of the left lingual gyrus in tasks where they had intact performance. These findings show that the hypotheses reviewed here address the neural and cognitive aspects of language difficulties in ASD across all tasks only in a limited way. Instead, our findings suggest the nuances of language and brain in ASD in terms of its context-dependency. Autism Res 2016. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.
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    • "además insertamos estas palabras en oraciones que describen las acciones de un sujeto en un contexto social. esfuerzos preliminares por encontrar diferencias en el desempeño y la activación de áreas cerebrales para este tipo de palabras (concretas, epistémicas y metafísicas) no habían sido del todo satisfactorios (Harris et al., 2006). Una de las hipótesis bajo escrutinio proponía que si hubiese una fuente común de procesamiento para las palabras abstractas, deberíamos esperar que el desempeño en palabras epistémicas y metafísicas fuese similar, sin ninguna distinción entre ellas. "

    Full-text · Article · Dec 2015
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    • "Functional underconnectivity between frontal and posterior brain regions was first detected using a sentence comprehension task in children with high-functioning autism [Just et al., 2004]. Reduced interregional collaboration was also shown in other studies using semantic processing tasks [Harris et al., 2006; Kana et al., 2006]. In contrast to this task-dependent functional connectivity, other studies focused on spontaneous low-frequency fluctuations in BOLD signal intensity by low-pass filtering and by removing task-dependent effects from the time series data before calculating functional connectivity links. "
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