BRAIN ORGANIZATION: CLUES FROM AMERICAN SIGN LANGUAGE

这项协作工作大约开始了一年多的时间 半个月前和到目前为止，大约有14名受试者被研究，两名 提交并提交了摘要。这些研究是基于 NIH资助的PI(Bellugi博士)实验室正在进行的研究 人类语言的生物学基础是通过 美国手语(ASL)研究。ASL显示所有 口语的复杂语言结构，但编码 空间上的信息。因此，ASL允许人们将情态分离 依赖于通道对神经的独立贡献 语言组织。空间以一种多功能的方式在 ASL编码(1)单个符号之间的句法关系 句子，(2)话语中参与者之间的话语关系 跨句子；(3)语境中的空间关系本身 来描述空间布局。空间的这些独特功能是 在符号上层层叠加，但大脑组织 反映了这些功能差异。ASL广泛依赖于 语言结构编码中的空间对比会 提示右脑受累程度更大；然而， 来自病变研究的强有力证据表明ASL已被处理 主要位于左侧大脑半球，且体积较大 独立于非语言空间认知的程度。我们最初的 重点是研究半球专业化的问题 聋人受试者的语言。我们已经积累了大量的 功能磁共振成像数据。这些研究是在多个层面上进行的，涵盖了整个 大脑，因此信息在大脑的所有区域都可用 在本地签名者基于ASL的范例期间被激活。四项任务 迄今已审查过：(A)秘密签署客体：主体 被要求想象展示在屏幕上的物体的ASL标志 每隔2秒连续屏蔽(蜜蜂、花朵、苹果、汽车等)； 将使用基于英语的手动字母表拼写的对象 而不是代表)；(B)公开签署对象 一只手：与秘密任务相同，但受试者产生了 手掌靠近腿部的标志，以尽量减少运动(这是 这并不是一项不自然的任务，这种形式的签名在 需要一定程度隐私的情况；通常指的是 到“窃窃私语”)；(C)隐蔽的手势生成：向受试者展示 每隔5秒就有一只手的形状，并被要求想出 尽可能使用包含该手形的标志；(D)复制 “胡说八道”的手形；选择手形是为了没有 在ASL中的意义被连续地显示在 反投影屏幕，受试者被要求重现它们。在……里面 这些数据的初步分析(不是来自所有对象的所有数据 已检查)，观察到广泛且一致的激活 在前面提到的范例中。最值得注意的是，在这两个秘密 语言任务，激活的区域包括i)背部区域 侧裂，包括44区(布罗卡区)，ii)部分 第9区和第8区，III)内侧壁运动区(包括 辅助运动区(SMA)、前SMA区和扣带运动区 埋在扣带沟中)iv)外侧运动区4和6 (尽管没有实际签署)v)顶叶的7、40、42和22区 皮质；vi)24区的一部分，位于扣带回的前面 脑回。与语言相关的范式主要产生激活 在左额叶，但双侧激活出现在 枕叶/颞叶/顶叶皮质。广泛的数据分析仍然存在 将在现有的大量数据上执行。类似的任务将 在以英语为母语的人身上进行比较；我们已经 收集了一些以英语为母语的人的数据，但不是所有的 范例。将根据调查结果收集新数据 初步研究。

This collaborative work was started approximately a year and a half ago and to date approximately 14 subjects were studied and two abstracts were submitted and presented. These studies are based on ongoing NIH funded research in the PI's (Dr. Bellugi) laboratory on the biological foundations of human language approached through the study of American Sign Language (ASL). ASL displays all of the complex linguistic structure of spoken languages, but encodes that information spatially. Thus, ASL allows one to dissociate modality dependent from modality independent contributions to the neural organization for language. Space is used in a multifunctional way in ASL to encode (1) syntactic relations among individual signs with a sentence, (2) discourse relations among the players in a discourse across sentences, and (3) spatial relations themselves in the context of describing spatial layouts. These distinct functions of space are layered one upon another in sign, and yet the brain organization reflects these functional distinctions. ASL's extensive reliance on spatial contrasts in the encoding of linguistic structure would suggest a greater right hemisphere involvement; however, there is strong evidence from lesion studies that ASL is processed predominantly in the left cerebral hemisphere, and is to a large extent independent of non-linguistic spatial cognition. Our initial focus is to examine the issue of hemispheric specialization for language in deaf subject. We have already accumulated a large body of fMRI data. The studies are conducted in multislice covering the whole brain, so that information is available on all areas of the brain activated during ASL based paradigms in native signers. Four tasks have so far been examined : (a) covert signing of objects: subjects were asked to imagine the ASL signs for objects displayed on the screen in succession every 2 second (bee, flower, apple, car etc.; objects that would be spelled using the English-based manual alphabet rather than represented were avoided); (b) overt signing of objects with one hand: same as the covert task but subjects produced the signs with the hand adjacent to their leg to minimize motion (this is not an unnatural task and this form of signing is employed in situations requiring some degree of privacy; it is commonly referred to as "whispering"); (c) covert sign generation: subjects were shown a hand shape every 5 seconds and were asked to think of as many ASL signs as they could that contained that handshape; (d) reproducing "nonsense" hand-shapes; hand shapes that were chosen so as to have no meaning in ASL were displayed to the subjects in succession on the backprojection screen and subjects were asked to reproduce them. In these preliminary analysis of the data (not all data from all subjects have been examined), extensive and consistent activation was observed during the aforelisted paradigms. Most notably, in both covert language tasks, areas activated included i) areas dorsal to the Sylvian fissure including area 44 (Broca's area), ii) portions of areas 9 and 8, iii) medial wall motor areas (including potions of supplementary motor area (SMA), preSMA, and the cingulate motor areas buried in the cingulate sulcus) iv) lateral motor areas 4 and 6 (despite no actual signing) v) area 7, 40, 42, and 22 of the parietal cortex; vi) a portion of area 24 located anteriorly in the cingulate gyrus. Language related paradigms produced activation predominantly in the left frontal lobe but bilateral activation was present in the occipital/temporal/parietal cortex. Extensive data analysis remains to be performed on existing large body of data. Analogous tasks will be examined in native English speakers for comparison; we have already collected some data on native English speakers but not for all paradigms. New data will be collected based on the results of the initial studies.