Age of acquisition effects on sign language development and brain processing

项目摘要 习得年龄对手语发展和大脑加工的影响 第一语言习得年龄，L1 AoA，对语言能力和大脑语言有终身影响 处理.先天性耳聋的婴儿通常在不同的年龄段第一次体验语言，因为他们无法 感知口头语言，直到老年才接触手语。我们自然地使用这个 L1 AoA发生变化，以模拟语言的关键期。在一系列的研究中， 关键期的语言和神经相关性。我们检验了这个假设， 大脑语言系统是语言经验之间相互作用的结果 和后天大脑发育的关系。我们用两种发展范式来检验这一假设， 回顾性和纵向。回顾性研究测试了ASL获得完成的聋人成年人。 这些研究调查了1-8岁之间的L1 AoA效应是否与水平呈线性关系 句法复杂性的获得，神经语言处理的场所和分布，以及特征 背部和腹部白色物质束。纵向研究测试了听力正常的青少年， 获得可能是持续的，并且其L1 AoA开始于婴儿期或儿童早期或晚期。的 每年对青少年进行连续三年的测试，实验与成人相同。 study.语言实验旨在测试美国手语句子的理解和产生 结构是句法复杂性的函数。实验范例是从图片到图片 匹配、诱发模仿、句法启动和自发产出。神经语言学实验 使用功能磁共振成像来研究句子和词汇加工。脑结构研究采用弥散张量成像技术 背侧和腹侧白色束发育。如果大脑语言系统需要语言经验 在出生后的早期大脑发育过程中， 与大脑中神经语言处理的分布和位置以及与大脑中的神经元相对应。 大脑语言网络中白色物质束发育的稳健性。

Project Summary Age of acquisition effects on sign language development and brain processing Age of first-language age of acquisition, L1 AoA, has lifelong effects on language abilities and brain language processing. Infants born deaf often first experience language at a variety of ages due to an inability to perceive spoken language and not being exposed to sign language until older ages. We use this naturally occurring variation in L1 AoA to model the critical period for language. In a series of studies, ask what the language and neural correlates of the critical period might be. We test the hypothesis the organization of the brain language system is an emergent property arising from interactive effects between language experience and acquisition and post-natal brain growth. We test the hypothesis with two developmental paradigms, retrospective and longitudinal. The retrospective studies test deaf adults whose ASL acquisition is complete. These studies investigate whether L1 AoA effects between the ages of 1-8 are linear with respect to the level of syntactic complexity acquired, the locus and distribution of neurolinguistic processing, and characteristics of the dorsal and ventral white matter tracts. The longitudinal studies test deaf adolescents whose ASL acquisition may be ongoing and whose L1 AoA began in infancy, or in early or late childhood. The adolescents are tested annually for three consecutive years with same experiments as used in the adult study. The language experiments are designed to test the comprehension and production of ASL sentence structure as a function of syntactic complexity. The experimental paradigms are sentence-to-picture matching, elicited imitation, syntactic priming, and spontaneous production. The neurolinguistic experiments use fMRI to investigate sentence and lexical processing. The brain structure studies use DTI to investigate dorsal and ventral white matter tract development. If the brain language system requires linguistic experience during early post-natal brain growth to become fully functional, then levels of syntactic development should correspond with the distribution and location of neurolinguistic processing in the brain as well as with the robustness of white matter tract development in the brain language network.