Neurobiological predictors of spoken and written language learning

描述(由申请人提供)：越来越多的证据支持将阅读障碍(RD)描述为在获得流利的阅读技能方面的大脑困难，通常与语音处理缺陷有关(Lyon等人，2003年)。在认知层面上，这些缺陷被认为阻碍了拼写(O)、语音(P)和语义(S)特征的充分结合，这些特征构成了支持有效阅读所必需的词汇表征的基础(参见。Harm&Sedenberg，1999；Perfetti&Hart，2001)。在大脑系统的水平上，神经成像研究一直表明，相对于典型的发育中(TD)阅读器，RD阅读器在组成O、P和S加工的分布式回路的左半球(LH)区域显示出结构和功能上的差异。然而，目前我们还不知道这些结构和功能异常的发现中，哪些与阅读领域的具体学习问题有因果关系，哪些不是。关键的下一步是在受控实验条件下生成并测试O、P和S学习的个体差异的预测模型。为此，我们将在新的口语和书面语学习任务中使用综合的神经生物学和行为测量来确定哪些结构和功能的大脑差异总体上预测单词学习困难，以及最强的大脑预测因子是否随着对O、P或S编码的相对要求的操纵而变化。此外，尽管普遍认为RD的主要缺陷出现在解码和语音处理技能的水平上，但临床、行为和神经影像研究结果表明，RD在将新学习的信息整合到永久记忆中存在其他问题。为了探索这一假设，我们将使用大脑/行为综合分析来考察在线学习和线下巩固新学到的O、P和S形式。为了更准确地检验巩固缺陷背后的神经机制，我们还将使用有针对性的语言和非语言学习任务，这些任务系统地调节对程序性记忆系统和陈述性记忆系统的需求。对于所有这些语言和非语言的学习和巩固措施，我们测试了特定的基于大脑的TD/RD差异模型。

DESCRIPTION (provided by applicant): A growing body of evidence supports a characterization of reading disability (RD) as a brain-based difficulty in acquiring fluent reading skills, usually associated with phonological processing deficits (Lyon et al., 2003). At a cognitive level, these deficits are thought to impede adequate binding of those orthographic (O), phonological (P), and semantic (S) features that form the basis of lexical representations necessary to support efficient reading (cf. Harm & Seidenberg, 1999; Perfetti & Hart, 2001). At the level of brain systems, neuroimaging studies have consistently shown that, relative to typically developing (TD) readers, RD readers show both structural and functional differences at those left hemisphere (LH) regions that comprise the distributed circuitry for O, P, and S processing. At present though, we do not know which of these findings of structural and functional anomalies are causally related to specific learning problems in the domain of reading and which are not. A crucial next step is to generate and test predictive models of individual differences in O, P and S learning under controlled experimental conditions. To that end, we will employ integrated neurobiological and behavioral measures during novel spoken and written word learning tasks to determine which structural and functional brain differences predict word learning difficulties in general, and whether the strongest brain predictors vary as the relative demands on O, P or S coding are manipulated. Also, despite the general consensus that the primary deficit in RD arises at the level of decoding and phonological processing skills, there are clinical, behavioral, and neuroimaging findings which suggest additional problems in consolidation of newly learned information into permanent memory in RD. To explore this hypothesis, we will employ integrated brain/behavior analyses to examine both online learning and offline consolidation of newly learned O, P and S forms. To examine neural mechanisms underlying consolidation deficits more precisely we will also use targeted linguistic and non-linguistic learning tasks that systematically modulate demands on procedural vs. declarative memory systems. For all of these language and non-linguistic measures of learning and consolidation we test specific brain-based models of TD/RD differences.