Neural Correlates of Proficiency in Early Bilinguals

描述（由申请人提供）：为什么双语者在神经损伤后会选择性地失去学习语言的能力？对双语失语症的研究和最近使用神经成像工具的研究发现，第二语言习得的年龄和熟练程度都在两种语言的神经表征中发挥作用。目前的建议旨在从两个重要的方向扩展这项开创性的工作。首先，这项工作将着眼于早期的西班牙语-英语双语者，这是一组在行为和神经影像学文献中都被大大低估的参与者。参与者的英语水平将被匹配，但将被分为两组，一组是西班牙语水平低，一组是西班牙语水平高。他们将被要求对主谓一致、数或语法性别违反的双词短语或短句进行语法判断。这些测试是对每种语言中与词形（复数标记‘s’）违反相关的神经关联进行的测试。其次，拟议的项目将研究跨语言重叠（即功能很容易从一种语言转移到另一种语言）对群体差异的影响，这是迄今为止已发表的fMRI研究中尚未系统地操纵的一个因素。我们的假设是语言能力和语言重叠会调节神经活动。神经活动的跨语言差异在低水平受试者中应该比在高水平受试者中更大。对于不重叠的功能，将观察到活性增加。对于低水平科目，这种增加的活动将更大。最后，一组只会说西班牙语的人将接受测试，以确保语法功能之间的任何差异不是由于难度的不同。不同群体和不同语言之间活动模式的差异，将有助于我们深入了解在不太熟练的语言中处理形态信息所必需的认知机制。

DESCRIPTION (provided by applicant): Why do bilinguals selectively lose access to a language after neurological insult? Research in bilingual aphasia and more recent research using neuroimaging tools has found that both age of second language acquisition (AoA) and proficiency play a role in the neural representation of two languages. The current proposal is designed to extend this seminal work in two important directions. First, the work will look at early Spanish-English bilinguals, a group of participants who have been vastly understudied in both the behavioral and neuroimaging literature. Participants will be matched on English proficiency but will be placed in two groups which have either low or high proficiency in Spanish. They will be asked to make grammaticality judgments for two-word phrases or short sentences which have subject-verb agreement, number or grammatical gender violations. These represent a test of the neural correlates associated with morphological (the plural marking 's') violations in each language. Second, the proposed project will look at the influence of cross-language overlap (i.e. functions which transfer from one language to the other easily) on the differences across groups, a factor which has not been systematically manipulated in published fMRI research to date. Our hypothesis is that language proficiency and overlap will modulate neural activity. Cross-language differences in neural activity should be larger for low proficiency subjects than for high proficiency subjects. Increased activity will be observed for functions which do not overlap. This increased activity will be larger for low proficiency subjects. Finally, a group of monolingual Spanish speakers will be tested to insure that any differences between grammatical functions are not due to a difference in difficulty. The difference in the pattern of activity across groups and languages will provide insight into the cognitive mechanisms that are necessary to process morphological information in a less proficient language.