Neural and cognitive changes in aging and bilingualism: Implications for language production and executive function

该奖项是作为NSF社会、行为和经济学博士后研究奖学金(SPRF)计划的一部分提供的。SPRF计划的目标是为学术界、工业界或私营部门和政府的科学职业生涯培养有前途的、早期职业博士水平的科学家。SPRF奖项包括在知名科学家的赞助下进行两年的培训，并鼓励博士后研究员进行独立研究。国家科学基金会致力于促进科学界所有阶层的科学家参与其研究方案和活动，包括那些来自代表性不足的群体的科学家；博士后阶段被认为是实现这一目标的专业发展的一个重要水平。每个博士后研究员都必须解决推动各自学科领域向前发展的重要科学问题。随着人们寿命的延长，他们的寿命更容易受到与年龄相关的认知变化的影响。老年人将单词查找困难列为他们最大的记忆问题，这使得他们的沟通越来越困难。关于年龄相关词提取问题的来源的研究主要集中在词义和词形之间映射的变化上。这项计划中的研究探索了认知能力，如执行功能，以及大脑中支持语言和认知功能的路径如何有助于老年人的语言产生。利用双语者独特的语言需求，这个跨学科的项目结合了语言学、心理学和认知神经科学的理论和方法，研究了终身双语对语言产生、执行功能和支持它们的神经结构的长期影响。这项研究不仅有助于我们理解语言产出中与年龄相关的变化，而且有助于我们理解支持执行功能和语言的神经结构。作为一个拥有大量西班牙裔和双语人口的社区，加利福尼亚州的河滨是学习年轻和年长的双语成年人，以及培训和指导来自科学界代表性较低群体的本科生的理想环境。这项研究的目的是调查反映终身语言经验的因素及其对双语和单语老年人认知和语言功能的影响。一个具体的目标是调查双语对大脑中白质通路的影响，特别是那些涉及语言和高级认知过程的通路。过去的研究表明，终生使用两种语言带来的独特认知需求会增强老年人的执行控制能力，并保护他们免受认知障碍和痴呆症症状的影响。关于这些执行控制增强对语言产生的长期影响，我们知之甚少。在这项拟议的研究中，我们调查了终身双语能力如何影响老年人的单词提取过程，并询问在认知控制方面观察到的潜在优势是否也有助于帮助双语老年人弥补语言老化的影响。使用行为和结构神经成像方法，我们探索了终生使用两种语言的老年人和只使用一种语言的老年人的词汇提取和执行控制的神经基础。该项目整合了关于双语的研究，该研究考虑了双语使用对口语和认知的影响，以及对认知、语言和衰老过程中神经变化的研究。

This award was provided as part of NSF's Social, Behavioral and Economic Sciences Postdoctoral Research Fellowships (SPRF) program. The goal of the SPRF program is to prepare promising, early career doctoral-level scientists for scientific careers in academia, industry or private sector, and government. SPRF awards involve two years of training under the sponsorship of established scientists and encourage Postdoctoral Fellows to perform independent research. NSF seeks to promote the participation of scientists from all segments of the scientific community, including those from underrepresented groups, in its research programs and activities; the postdoctoral period is considered to be an important level of professional development in attaining this goal. Each Postdoctoral Fellow must address important scientific questions that advance their respective disciplinary fields. As people live longer, their lives are more impacted by age-related cognitive changes. Older adults cite word-finding difficulties as their number one memory complaint, making communication increasingly difficult for them. Research on the source of age-related word retrieval problems has focused on changes in the mapping between word meaning and word form. The planned research explores how cognitive abilities, such as executive function, and the pathways in the brain supporting language and cognitive functions contribute to language production in older age. Taking advantage of the unique language demands placed on bilinguals, this interdisciplinary project combines theories and methods from linguistics, psychology, and cognitive neuroscience to examine the long-term effects of lifelong bilingualism on language production, executive functions, and the neural structures supporting them. The proposed research will advance our understanding not only of age-related changes in language production, but also of the the neural structures supporting executive function and language. As a community with a large Hispanic and bilingual population, Riverside, California is an ideal setting for studying younger and older bilingual adults and for training and mentoring undergraduate students who come from groups that are underrepresented in science. The goals of the proposed research are to investigate factors reflecting lifelong language experiences and their effects on cognitive and language functioning in older bilingual and monolingual adults. A specific goal is to investigate the effects of bilingualism on white matter pathways in the brain, particularly those involved in language and higher-order cognitive processes. Past research has demonstrated that the unique cognitive demands imposed by the lifelong use of two languages results in enhancements in executive control and protections against the symptoms of cognitive impairment and dementia in the elderly. Little is known about the long-term effects of these executive control enhancements on language production. In the proposed research, we investigate how lifelong bilingualism affects word retrieval processes in older adults and ask if the potential advantages observed for cognitive control also serve to help older bilingual adults compensate for language declines in aging. Using behavioral and structural neuroimaging methods, we explore the neural substrates of lexical retrieval and executive control in older adults who have used two languages throughout their lives and those who have used a single language. The project integrates research on bilingualism that considers the consequences of dual language use for spoken language and for cognition, together with research on cognition, language, and neural change in aging.