Executive Control in the Bilingual Brain

描述（由申请人提供）：双语者具有强大的语言控制能力。他们似乎能够在交谈中毫不费力地在语言之间切换，但很少用非故意的语言说出话来。双语研究中越来越多的共识是执行控制是语言控制的基础，这一假设导致了双语优势的发现，在非语言任务涉及执行控制。此外，功能磁共振成像研究报告了在任务和语言转换过程中活跃的类似大脑区域。尽管这一证据令人信服，但任务和语言控制之间的细微差异可能会被忽视。我们提出了一个强有力的方法来测试的假设，双语依赖于一般的执行控制，以实现语言控制，通过比较语言切换和任务切换直接在同一组的个人。本研究的目的一是探讨任务转换和语言转换的年龄效应。老年人在执行功能和语言控制方面表现出明显的年龄相关变化。如果任务转换和语言转换是类似的过程，那么这两项任务中的每一项的表现都将是相关的，因此保留了执行功能能力的老年人将保留语言控制能力。目标2的拟议研究增加了一个神经影像组件，调查语言转换和任务转换在同一组的个人。这种比较允许对每个任务中涉及的区域进行良好控制的调查。双语者的任务转换和语言转换之间类似的激活模式表明语言控制和执行控制的机制相似。另外，在双语者的语言转换和任务转换的分离模式表明，执行控制不完全解释语言控制的其他机制。在这两个实验中，一组匹配的单语对照将提供进一步的杠杆作用，以确定独特的双语处理机制。拟议的研究将阐述双语语言控制，执行控制及其在语言处理中的作用，老龄化语言系统的模型，并将为申请人提供在双语和老龄化领域取得成功所需的技能。

DESCRIPTION (provided by applicant): Bilinguals have powerful language control. They seem able to effortlessly switch between languages during conversation, but seldom produce words in an unintended language. A growing consensus in research on bilingualism is that executive control is the basis for language control, a hypothesis which led to the discovery of bilingual advantages in non-linguistic tasks involving executive control. Additionally, fMRI studies report similar brain regions active during task and language switching. Although this evidence is compelling, subtle differences between task and language control may be overlooked. We propose a powerful way to test the hypothesis that bilinguals rely on general executive control to achieve language control, by comparing language switching and task switching directly in the same group of individuals. Aim 1 of the proposed study will investigate age effects associated with task and language switching. Older adults appear to exhibit marked age-related shifts in executive function and language control. If task-switching and language-switching are analogous processes, performance on each of the two tasks will be related such that older adults who have preserved executive functioning abilities will have preserved language control abilities. Aim 2 of the proposed study adds a neuroimaging component that investigates language switching and task switching in the same group of individuals. Such a comparison allows for a well-controlled investigation of the regions involved in each task. Similar patterns of activation between task switching and language switching in bilinguals will suggest similar mechanisms underlying language control and executive control. Alternatively, dissociable patterns in language switching and task switching in bilinguals suggest additional mechanisms underlying language control not fully explained by executive control. In both experiments a group of matched monolingual controls will provide further leverage for identifying processing mechanisms unique to bilinguals. The proposed study will elaborate models of bilingual language control, executive control and its role in language processing, the aging language system, and will provide the applicant with skills necessary for leading a successful career in the field of bilingualism and aging.