Orthographic and phonological selectivity in dyslexia: an fMRI study

阅读障碍的拼写和语音选择性：一项功能磁共振成像研究

• 批准号: 8111565
• 负责人: Guinevere F. Eden
• 金额: $ 22.84万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-07 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8111565
• 关键词: Address; Adult; Affect; Area; Behavior; Behavioral; Brain; Brain imaging; Brain region; Code; Cognitive; Cognitive deficits; Developmental reading disorder; Dorsal; Dyslexia; Financial compensation; Functional Magnetic Resonance Imaging; Future; Goals; Hyperactive behavior; Imaging Techniques; Imaging problem; Imaging technology; Impairment; Individual; Inferior frontal gyrus; Intervention; Investigation; Lead; Learning; Left; Link; Measures; Mediating; Methods; Neurons; Orthography; Parietal; Parietal Lobe; Pathway interactions; Performance; Physiological; Population; Process; Reader; Reading; Reading Disabilities; Reading Disorder; Relative (related person); Reporting; Research; Semantics; Signal Transduction; Societies; Specificity; Stimulus; Stream; System; Techniques; Testing; Time; Visual; Visual Pathways; base; density; design; experience; imaging modality; insight; interest; literate; novel; paired stimuli; phonology; relating to nervous system; remediation; response; skills; theories; time use; university student

DESCRIPTION (provided by applicant): Reading is paramount in our literate society; unfortunately it does not come easily to 5-12% of the population who suffer the heritable condition of developmental dyslexia, a reading difficulty unexpected in relation to other cognitive abilities and the provision of educational opportunities. Modern imaging technology has demonstrated that typical readers rely on two left-lateralized pathways: A dorsal circuit mediating phonological processing and a ventral, visual pathway, including the "visual word form area", VWFA, specialized for the fast recognition of single words. How these pathways are affected in dyslexia, has been a topic of intense research. Most current theories posit a weakness in phonological processing as the primary problem and imaging studies have revealed physiological and anatomical differences in left parietal cortex when comparing dyslexic and non- dyslexic readers. At the same time, there are many reports of decreased activity in the ventral visual pathway, which represents another important part of the reading system leading to semantic access. The application's long-term objective is to employ a novel technical approach that will lead to better characterization of the neural bases of both these ventral and dorsal streams and differences in dyslexia. To date, functional magnetic resonance imaging (fMRI) technology has been limited by the fact that the density of selective neurons as well as the broadness of their tuning contributes to the average activity measured. FMRI rapid adaptation (fMRI- RA), however, probes neuronal selectivity more directly and allows a better characterization of neuron-level processing and its link to behavior. This is critical if we are to understand findings about hypo- and hyper- activity reported in various regions of the brain in current studies of dyslexia, as the interpretation of these results has been somewhat limited. Specifically, the project will examine selectivity differences in phonological and orthographic representations in dyslexic relative to typical readers by comparing adults with and without dyslexia. The study will first test the hypothesis that adults with dyslexia who have normal real word reading skills (albeit poor pseudoword reading) show normal selectivity for real words in their VWFA (preserved left VWFA or right VWFA compensation), while those dyslexics with poor real word reading skills do not; and that real word reading ability correlates with selectivity in the VWFA (Aim 1). Secondly, the study will test the hypothesis that adults with dyslexia, due to their weaknesses in phonological coding, show less selectivity for phonological processing in left parietal cortex than typical readers, and that pseudoword reading ability correlates with parietal selectivity (Aim 2). These studies will make it possible, for the first time, to gauge specificity of brain activity in dyslexia rather than simply activation levels. This information is critical if we are to understand the mechanisms that lead to disorders of reading and importantly, guide which interventions should be applied, as current treatments are likely to impact different brain systems. Advancing this field could reduce the number of impaired readers and limit the detrimental educational and vocational consequences of dyslexia. PUBLIC HEALTH RELEVANCE: Developmental dyslexia is a common (5-12% of the population) reading disability, unexpected in relation to other cognitive abilities and the provision of educational opportunities. A new imaging method will be used to better understand the specificity of the brain circuits involved in reading by comparing dyslexic and non- dyslexic college students. The results will advance our understanding of the mechanisms that lead to disorders of reading and potentially guide future interventions, eventually reducing the number of impaired readers and limiting the detrimental educational and vocational consequences of dyslexia.

描述（由申请人提供）：阅读在我们的文化社会中至关重要；不幸的是，对于患有遗传性发展性阅读障碍（与其他认知能力和教育机会的提供相关）的遗传性阅读障碍的 5-12% 的人口来说，这并不容易。现代成像技术已经证明，典型的阅读者依赖于两条左偏通路：介导语音处理的背侧回路和腹侧视觉通路，包括“视觉词形区域”，VWFA，专门用于快速识别单个单词。这些通路如何在阅读障碍中受到影响，一直是深入研究的话题。目前的大多数理论都认为语音处理的弱点是主要问题，而影像学研究揭示了在比较诵读困难和非诵读困难的读者时左顶叶皮层的生理和解剖学差异。与此同时，有许多关于腹侧视觉通路活动减少的报道，腹侧视觉通路代表了导致语义访问的阅读系统的另一个重要部分。该应用程序的长期目标是采用一种新颖的技术方法，更好地表征这些腹侧和背侧流的神经基础以及阅读障碍的差异。迄今为止，功能性磁共振成像 (fMRI) 技术受到以下事实的限制：选择性神经元的密度及其调谐的广度会影响测量的平均活动。然而，FMRI 快速适应（fMRI-RA）可以更直接地探测神经元选择性，并可以更好地表征神经元级处理及其与行为的联系。如果我们要了解当前阅读障碍研究中大脑各个区域报告的活动不足和活动过度的发现，这一点至关重要，因为对这些结果的解释有些有限。具体来说，该项目将通过比较患有和不患有阅读障碍的成年人，检查阅读困难者相对于典型读者在语音和拼写表征方面的选择性差异。该研究将首先检验以下假设：具有正常真实单词阅读能力（尽管伪单词阅读能力较差）的阅读障碍成年人在其 VWFA（保留左 VWFA 或右 VWFA 补偿）中对真实单词表现出正常的选择性，而那些具有较差真实单词阅读能力的阅读障碍患者则不然；真实单词阅读能力与 VWFA 的选择性相关（目标 1）。其次，该研究将检验以下假设：患有阅读障碍的成年人由于语音编码方面的弱点，在左顶叶皮层的语音处理方面表现出比典型读者更少的选择性，并且伪词阅读能力与顶叶选择性相关（目标 2）。这些研究将首次使测量阅读障碍患者大脑活动的特异性而不是简单地激活水平成为可能。如果我们要了解导致阅读障碍的机制，并且更重要的是指导应采取哪些干预措施，这些信息至关重要，因为当前的治疗方法可能会影响不同的大脑系统。推进这一领域的发展可以减少阅读障碍的数量，并限制阅读障碍对教育和职业造成的不利后果。 公共卫生相关性：发育性阅读障碍是一种常见的阅读障碍（占人口的 5-12%），与其他认知能力和教育机会的提供相比，这是意想不到的。通过比较阅读困难和非阅读困难的大学生，将使用一种新的成像方法来更好地了解阅读所涉及的大脑回路的特异性。研究结果将增进我们对导致阅读障碍的机制的理解，并有可能指导未来的干预措施，最终减少阅读障碍的数量，并限制阅读障碍对教育和职业的不利影响。