Neural Systems Underlying Sign Language Production

描述（由申请人提供）：对于使用手语作为主要和首选交流手段的先天性聋人，语言产生的神经关联知之甚少。这个项目的主要目标是(a)识别手语特有的语言结构（即，通过符号空间的标志性使用来表达位置和运动的分类器结构）产生的神经系统，(b)识别支持手语交流与手势交流（即哑戏）的神经系统，(c)识别支持无声语言中语音处理的神经系统。(d)识别与耳聋或终生手语相关的神经解剖学宏观变异。为了研究耳聋和/或使用手语是否会影响手语产生背后的神经系统，[15O] H20 PET实验将在聋人和听力正常的美国手语手语者中进行。MR和PET成像将与爱荷华大学的Thomas Grabowski博士及其同事合作完成。这些实验将检验几个具体的预测。我们预测，空间分类器结构的产生涉及顶叶皮层，顶叶皮层服务于从视觉到以身体为中心的手动表征的空间运动转换。我们预测，手语和哑剧都涉及额顶叶区域，但这些区域并不相同，而且手语还涉及颞叶结构。我们做出了一个令人惊讶的预测，手语的语音编码与口语涉及相同的神经系统（具体来说，是布洛卡区和左颞上皮层）。最后，我们预测，出生时的听觉剥夺会影响脑岛的大小和形态，但不会影响布洛卡区，而终生的手语会影响初级运动皮层中胼胝体前部和把手区域的大小。这些解剖预测将使用聋人、听力正常的母语手语使用者和听力正常的非手语使用者的MRI数据进行研究。除了有助于更好地理解手语（以及一般语言）的神经基础外，这些发现将有助于提高对患有交流障碍的聋人患者的诊断和制定康复策略。

DESCRIPTION (provided by applicant): Very little is known about the neural correlates of language production in congenitally deaf individuals who use sign language as their primary and preferred means of communication. The major goals of this project are (a) to identify the neural systems underlying the production of linguistic structures that are unique to sign language (i.e., classifier constructions that express location and motion via the iconic use of signing space), (b) to identify the neural systems that support sign communication versus gestural communication (i.e., pantomime), (c) to identify the neural systems that support phonological processing in a soundless language, and (d) to identify macroscopic variations in neuroanatomy associated with deafness or with lifelong signing. To investigate whether deafness and/or use of a signed language affect the neural systems underlying sign language production, a series of [15O] H20 PET experiments will be conducted with deaf and hearing native ASL signers. MR and PET imaging will be accomplished in collaboration with Dr Thomas Grabowski and colleagues at the University of Iowa. The experiments will test several specific predictions. We predict that the production of spatial classifier constructions engages parietal cortices that sub serve a spatial-motoric transformation from a visual to a body-centered manual representation. We predict that signing and pantomime will both engage fronto-parietal regions, but these regions will be non-identical and signing will additionally engage temporal lobe structures. We make the surprising prediction that the phonological encoding of sign language engages the same neural systems as spoken language (specifically, Broca's area and left superior temporal cortex). Finally, we predict that auditory deprivation from birth affects the size and morphology of the insula, but not Broca's area, and that life-long signing affects the size of the anterior sector of the corpus callosum and of the hand knob region within primary motor cortex. These anatomical predictions will be investigated using MRI data from deaf and hearing native signers and from hearing nonsigners. In addition to contributing to a better understanding of the neural basis of sign language (and therefore of language in general), the findings will be help improve diagnosis and develop rehabilitation strategies for deaf patients with communicative disorders.