Neural Correlates of Proficiency in Early Bilinguals

描述(由申请人提供)：为什么双语者在受到神经侮辱后会选择性地失去接触一种语言的机会？对双语失语症的研究以及最近使用神经成像工具的研究发现，第二语言习得的年龄(AOA)和熟练程度在两种语言的神经表征中都起着作用。目前的提案旨在将这项开创性的工作扩展到两个重要方向。首先，这项工作将着眼于早期的西班牙语-英语双语者，这是一组参与者，他们在行为和神经成像文献中都被极大地忽视了。参与者的英语水平将被匹配，但将被分成两组，一组的西班牙语水平较低，一组的西班牙语水平较高。他们将被要求对主谓一致、数字或语法性别违规的两个单词短语或短句进行语法判断。这代表着对每种语言中与词法(标记‘S’的复数)违规相关的神经关联的测试。其次，拟议的项目将考察跨语言重叠(即容易从一种语言转移到另一种语言的功能)对跨组差异的影响，这一因素迄今尚未在已发表的功能磁共振研究中得到系统操纵。我们的假设是，语言熟练程度和重叠会调节神经活动。低水平受试者在神经活动方面的跨语言差异应该比高熟练程度受试者大。对于不重叠的功能，将观察到活动增加。对于低熟练程度的科目，这种增加的活动量会更大。最后，将对一组只会说一种西班牙语的人进行测试，以确保语法功能之间的任何差异不是由于难度的差异。不同群体和不同语言的活动模式的差异将提供对在不太熟练的语言中处理形态信息所必需的认知机制的洞察。

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.