Neuroplasticity of Spatial Working Memory in Signed Language Processing

描述（由申请人提供）：与非签名者相比，签名者在学习手语后表现出增强的视觉空间过程，如面部辨别，心理旋转和空间维持（Bettger，Emmorey，McCullough，& Bellugi，1997; Emmorey，2002; Wilson，Bettger，Niculae，& Klima，1997）。与口语相比，符号语言的处理对视觉空间认知提出了独特的要求，因为日常符号话语中涉及的许多过程都映射到空间工作记忆（SWM）的已知属性上。因此，接触手语似乎产生独特的适应SWM功能。这种适应性效应已经被观察到扩展到非本地签名者（Keehner & Gathercole，2006），但对这种行为结果的神经基础知之甚少。 目前尚不清楚是否存在CP--一个假设的时间框架，在此框架内，年轻人的大脑最佳地学习语言（Au，Questhtly，Jun，& Oh，2002; Lennenberg，1967;纽波特，1990; Penfield & Roberts，1959）--学习手语。但是，我们知道，早期接触两种语言对神经认知发育产生积极，强大的影响，甚至可能延长CP（Jasinska & Petitto，2013; Kovelman等人，2008; Petitto & Kovelman，2003; Petitto，et.例如，2012年）。此外，在CP期间接触两种语言的儿童表现出工作记忆优势，特别是在非语言任务中增强了执行控制（例如stroop和simon）（Bialystok，1999）。双语优势在美国手语（ASL）-英语双语者中没有发现（Emmorey，Pyers，& Bialystok，2008），但这可能是因为研究中的非语言任务（定向侧翼）没有挖掘对手语处理至关重要的认知功能，如SWM。 在这里，我们问，是否手语习得的时间产生的神经资源促进SWM的变化。具体而言，我们将调查是否有一个关键时期的SWM维持增强在其他研究中发现的，以及是否有一个关键时期的SWM执行抑制。通过研究像ASL这样的基于空间句法的语言，获得了一个独特的窗口，这在口语中是不可能的，进入了人脑的结构和功能可塑性。此外，这项研究将为关于大脑可塑性和人类一生中学习的本质的科学辩论提供进步。此外，如果我们发现在关键期之后学习手语是可能的，那么就有可能逆转成年学习者的CP。

DESCRIPTION (provided by applicant): Signers, when compared to nonsigners, have demonstrated enhanced visuo-spatial processes such as facial discrimination, mental rotation, and spatial maintenance following the learning of a signed language (Bettger, Emmorey, McCullough, & Bellugi, 1997; Emmorey, 2002; Wilson, Bettger, Niculae, & Klima, 1997). The processing of signed, as compared to spoken, language makes unique demands on visuo-spatial cognition because many of the processes involved in everyday sign discourse map onto the known properties of spatial working memory (SWM). As a consequence, exposure to sign language appears to produce unique adaptations to SWM functioning. This adaptive effect has been observed to extend to nonnative signers (Keehner & Gathercole, 2006) but little remains known about the neural foundations of such behavioral outcomes. It is not clear if there is a CP--a hypothesized time frame within which young human brains optimally learn language (Au, Knightly, Jun, & Oh, 2002; Lennenberg, 1967; Newport, 1990; Penfield & Roberts, 1959)-- for learning a signed language. But, we know that early exposure to two languages produces positive, robust impact on neurocognitive development, even possibly prolonging the CP (Jasinska & Petitto, 2013; Kovelman, et al., 2008; Petitto & Kovelman, 2003; Petitto, et. al., 2012). Furthermore, children exposed to two languages during the CP have shown working memory advantage, specifically enhanced executive control in nonverbal tasks (e.g. stroop and simon) (Bialystok, 1999). The bilingual advantage was not found in American Sign Language (ASL)-English bilinguals (Emmorey, Pyers, & Bialystok, 2008), but it might be because the administered nonverbal tasks (directional flanker) in the study didn't tap cognitive functions that are essential for sign language processing such as SWM. Here we ask, whether the timing of sign language acquisition yield changes in the neural resources facilitating SWM. Specifically, we will investigate whether there is a critical period fo the SWM maintenance enhancement found in other studies; and whether there is a critical period for SWM executive inhibition. By studying a spatial syntax based language like ASL, a unique window, that would not be possible with spoken language, is gained into the structural and functional plasticity of the human brain. Furthermore, this study will provide advancement to scientific debate about the nature of brain plasticity and learning across the human lifespan. Furthermore, if we discover that learning a signed language is possible after the critical period, then it may be possible to reverse the CP in adult learners.