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: 8239936
• 负责人: Guinevere F. Eden
• 金额: $ 19.01万
• 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 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8239936
• 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; public health relevance; 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(申请人提供)：在我们的识字社会，阅读是最重要的；不幸的是，对于患有发育性阅读障碍的遗传性疾病的人口来说，阅读并非易事，与其他认知能力和教育机会相比，这是一个意想不到的阅读困难。现代成像技术表明，典型的读者依赖于两条左侧通路：背侧回路和腹侧视觉通路，其中腹侧通路包括专门用于快速识别单个单词的视觉词形区域(VWFA)。这些通路在阅读障碍中是如何受到影响的，一直是一个密集研究的话题。目前的大多数理论都认为语音处理能力较弱是主要问题，成像研究发现阅读困难的读者和非阅读困难的读者在左侧顶叶皮质存在生理和解剖上的差异。同时，也有许多关于腹侧视觉通路活动减少的报道，腹侧视觉通路是导致语义通达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的技术方法，从而更好地表征这些腹侧和背侧支流的神经基础以及阅读障碍的差异。到目前为止，功能磁共振成像(FMRI)技术一直受到这样一个事实的限制，即选择性神经元的密度以及它们的调谐范围对测量的平均活动有贡献。然而，功能磁共振快速适应(fMRI-RA)更直接地探测神经元的选择性，并允许更好地表征神经元水平的处理及其与行为的联系。如果我们要理解当前阅读障碍研究中关于大脑不同区域活动不足和过度活动的发现，这是至关重要的，因为对这些结果的解释在某种程度上是有限的。具体地说，该项目将通过比较患有和不患有阅读障碍的成年人来检验阅读困难患者的语音和正字法表征相对于典型读者的选择性差异。本研究将首先检验这样一种假设，即阅读困难的成年人在他们的VWFA(保留的左侧VWFA或右侧VWFA补偿)中表现出对真实单词的正常选择性，而那些阅读技能较差的阅读困难者对真实单词的选择性是正常的；以及真实单词阅读能力与VWFA中的选择性相关(目标1)。其次，本研究将检验这样一种假设，即成人阅读障碍患者由于其语音编码的缺陷，在左侧顶叶皮质对语音加工的选择性低于一般读者，并且假词阅读能力与顶叶选择性相关(目标2)。这些研究将首次有可能评估阅读障碍患者大脑活动的特异性，而不是简单的激活水平。如果我们想要了解导致阅读障碍的机制，以及重要的是指导应该应用哪些干预措施，这些信息是至关重要的，因为目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受损读者的数量，并限制阅读困难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(占人口的5%-12%)阅读障碍，与其他认知能力和提供的教育机会相比出乎意料。一种新的成像方法将被用来通过比较阅读困难和非阅读困难的大学生来更好地了解参与阅读的大脑回路的特异性。这一结果将促进我们对导致阅读障碍的机制的理解，并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。

项目成果

Getting a handle on how the brain generates complexity.

了解大脑如何产生复杂性。

• DOI: 10.3109/0954898x.2012.711918
• 发表时间: 2012
• 期刊: Network (Bristol, England)
• 作者: Riesenhuber,Maximilian