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了增强的视觉-空间过程，如面部辨别、心理旋转和空间维持(Bettger，Emmore y，McCullough，&Bellugi，1997；Emmore，2002；Wilson，Bettger，Nrulae，&Klima，1997)。与口语相比，手语的加工对视觉空间认知提出了独特的要求，因为日常手语话语中涉及的许多过程都映射到已知的空间工作记忆(SWM)特性上。因此，接触手语似乎会产生对SWM功能的独特适应。这种适应性效应已经被观察到延伸到非本土签名者(Keehner&Gathercole，2006)，但关于这种行为结果的神经基础仍然知之甚少。 目前尚不清楚是否存在手语学习的CP--一个假设的时间框架，在这段时间内，年轻人的大脑以最佳方式学习语言(Au，Knighly，Jun，&oh，2002；Lennenberg，1967；Newport，1990；Penfield&Roberts，1959)。但是，我们知道，早期接触两种语言会对神经认知发展产生积极而有力的影响，甚至可能延长CP(Jasinska&Petito，2013；Kovelman等人，2008；Petitto&Kovelman，2003；Petito等人)。Al.，2012)。此外，在CP过程中接触两种语言的儿童表现出了工作记忆优势，特别是在非语言任务中增强了执行控制(例如，斯特罗普和西蒙)(Bialystok，1999)。在美国手语(ASL)-英语双语者中没有发现双语优势(Emmore，Pyers，&Bialystok，2008)，但这可能是因为研究中接受的非语言任务(定向侧翼)没有利用对手语处理至关重要的认知功能，如SWM。 在这里，我们问，手语习得的时机是否会导致促进SWM的神经资源的变化。具体地说，我们将调查是否存在其他研究中发现的SWM维护增强的关键期，以及是否存在SWM执行抑制的关键期。通过研究像ASL这样的基于空间句法的语言，我们获得了一个独特的窗口，这是口语无法实现的，它获得了人类大脑结构和功能可塑性的独特窗口。此外，这项研究将为关于大脑可塑性的本质和人类一生中的学习的科学辩论提供进展。此外，如果我们发现在关键时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.