Husain Fatima T, Patkin Debra J, Thai-Van Hung, Braun Allen R, Horwitz Barry
Brain Imaging and Modeling Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA.
Brain Res. 2009 Jun 18;1276:140-50. doi: 10.1016/j.brainres.2009.04.034. Epub 2009 May 3.
Manual gestures occur on a continuum from co-speech gesticulations to conventionalized emblems to language signs. Our goal in the present study was to understand the neural bases of the processing of gestures along such a continuum. We studied four types of gestures, varying along linguistic and semantic dimensions: linguistic and meaningful American Sign Language (ASL), non-meaningful pseudo-ASL, meaningful emblematic, and nonlinguistic, non-meaningful made-up gestures. Pre-lingually deaf, native signers of ASL participated in the fMRI study and performed two tasks while viewing videos of the gestures: a visuo-spatial (identity) discrimination task and a category discrimination task. We found that the categorization task activated left ventral middle and inferior frontal gyrus, among other regions, to a greater extent compared to the visual discrimination task, supporting the idea of semantic-level processing of the gestures. The reverse contrast resulted in enhanced activity of bilateral intraparietal sulcus, supporting the idea of featural-level processing (analogous to phonological-level processing of speech sounds) of the gestures. Regardless of the task, we found that brain activation patterns for the nonlinguistic, non-meaningful gestures were the most different compared to the ASL gestures. The activation patterns for the emblems were most similar to those of the ASL gestures and those of the pseudo-ASL were most similar to the nonlinguistic, non-meaningful gestures. The fMRI results provide partial support for the conceptualization of different gestures as belonging to a continuum and the variance in the fMRI results was best explained by differences in the processing of gestures along the semantic dimension.
手动手势存在于一个连续体中，从伴随言语的手势到约定俗成的象征手势再到语言符号。我们在本研究中的目标是了解沿着这样一个连续体对手势进行加工的神经基础。我们研究了四种类型的手势，它们在语言和语义维度上有所不同：有语言意义的美国手语（ASL）、无意义的伪ASL、有意义的象征手势以及非语言的、无意义的虚构手势。先天性失聪的ASL母语手语使用者参与了功能磁共振成像（fMRI）研究，并在观看手势视频时执行两项任务：视觉空间（识别）辨别任务和类别辨别任务。我们发现，与视觉辨别任务相比，分类任务在更大程度上激活了左腹侧额中回和额下回等区域，这支持了对手势进行语义层面加工的观点。相反的对比结果显示双侧顶内沟的活动增强，这支持了对手势进行特征层面加工（类似于对语音的音系层面加工）的观点。无论任务如何，我们发现非语言的、无意义的手势的脑激活模式与ASL手势相比差异最大。象征手势的激活模式与ASL手势的最为相似，而伪ASL手势的激活模式与非语言的、无意义的手势最为相似。fMRI结果为将不同手势概念化为属于一个连续体提供了部分支持，并且fMRI结果的差异最好通过沿语义维度对手势加工的差异来解释。
