Investigating the role of the cerebellum in reading

摘要 发展性阅读障碍的主要理论认为潜在的阅读障碍是由 大脑皮层功能障碍。同样，努力理解阅读的神经基础 发育主要集中在大脑皮层。然而，因为主要的理论是 阅读障碍并不能完全捕获其行为表型，一直以来，人们一直在考虑 阅读发展和阅读障碍的神经基础的不同观点。海流 Proposal评估了一种这样的替代理论，即由 尼科尔森和他的同事。我们提出了这一假设的一个变种，它源于元分析 阅读文献回顾，CDH*模型。在CDH*模型中，梭形顶额叶 (背侧)通路支持对陌生印刷词的解码，与小脑连接进入 这一途径提高了顶叶和额叶节点之间的表征相似性。这 增加了给定项被成功解码的可能性，从而导致拼写 学习。涉及梭形-颞叶-额叶的腹侧连接小脑-大脑回路 路径通过在解码时提供词汇-语义约束来起到辅助作用 要求很高。我们研究了涉及功能磁的三个目标的CDH*模型 成人受试者的共振成像和行为研究，以及正字法学习的应用 从基于项目(而不是基于阶段)的角度研究阅读发展的协议。在……里面 目标1，我们研究成年人阅读印在新学的人工正字法上的单词，并测试 小脑-大脑连接性、表征相似性、解码之间的预测关系 成功和拼写学习，以及语音要求对这些关系的影响。在……里面 目的2，我们将测试是否有阅读障碍的个体和没有阅读障碍的个体在小脑- 大脑连通性可以解释群体在有效连通性、解码能力、 和拼写学习。在目标3中，我们将使用损害方法来测试因果关系 获得性小脑损伤与解码和正字法学习障碍之间的关系。通过 加深对小脑--大脑的核心学习系统之一--如何 与大脑阅读网络的接口，这项工作有可能广泛影响 阅读发展与阅读障碍。

ABSTRACT The predominant theories of developmental dyslexia view the underlying disorder as arising from dysfunction in the cerebral cortex. Similarly, efforts to understand the neural basis of reading development have focused largely upon the cerebral cortex. However, because predominant theories of dyslexia do not capture its full behavioral phenotype, there has been continued consideration of alternative perspectives on the neural substrates of reading development and dyslexia. The current proposal evaluates one such alternative theory, the “cerebellar deficit hypothesis” proposed by Nicolson and colleagues. We propose a variant of this hypothesis that arose from a meta-analytic review of the reading literature, the CDH* model. In the CDH* model, a fusiform-parietal-frontal (dorsal) pathway supports the decoding of unfamiliar printed words, with cerebellar connectivity into this pathway improving the representational similarity between the parietal and frontal nodes. This increases the likelihood that a given item will be decoded successfully, and thus induce orthographic learning. A ventrally connected cerebellar-cerebral circuit involving a fusiform-temporal-frontal pathway is proposed to play an assistive role, by providing lexical-semantic constraints when decoding demands are high. We investigate the CDH* model across three aims involving functional magnetic resonance imaging and behavioral studies in adult subjects, and the use of orthographic learning protocols to study reading development from an item-based (rather than stage-based) perspective. In Aim 1, we study adults reading words printed in a newly learned artificial orthography, and test for predicted relationships between cerebellar-cerebral connectivity, representational similarity, decoding success, and orthographic learning, and the impact of phonological demands on these relationships. In Aim 2, we will test whether individuals with and without dyslexia have differences in cerebellar- cerebral connectivity that can account for group differences in effective connectivity, decoding ability, and orthographic learning. In Aim 3, we will use the lesion method to test for a causal relationship between acquired cerebellar damage and impairments in decoding and orthographic learning. By advancing current understanding of how the cerebellum – one of the brain's core learning systems – interfaces with a cerebral reading network, the work has the potential to widely influence theories of reading development and dyslexia.