Biological Psychology and Neuropsychology, University of Hamburg, Germany.
Biological Psychology and Neuropsychology, University of Hamburg, Germany.
Neuroimage. 2019 Oct 15;200:231-241. doi: 10.1016/j.neuroimage.2019.06.025. Epub 2019 Jun 17.
The study of deaf and hearing native users of signed languages can offer unique insights into how biological constraints and environmental input interact to shape the neural bases of language processing. Here, we use functional magnetic resonance imaging (fMRI) to address two questions: (1) Do semantic and syntactic processing in a signed language rely on anatomically and functionally distinct neural substrates as it has been shown for spoken languages? and (2) Does hearing status affect the neural correlates of these two types of linguistic processing? Deaf and hearing native signers performed a sentence judgement task on German Sign Language (Deutsche Gebärdensprache: DGS) sentences which were correct or contained either syntactic or semantic violations. We hypothesized that processing of semantic and syntactic violations in DGS relies on distinct neural substrates as it has been shown for spoken languages. Moreover, we hypothesized that effects of hearing status are observed within auditory regions, as deaf native signers have been shown to activate auditory areas to a greater extent than hearing native signers when processing a signed language. Semantic processing activated low-level visual areas and the left inferior frontal gyrus (IFG), suggesting both modality-dependent and independent processing mechanisms. Syntactic processing elicited increased activation in the right supramarginal gyrus (SMG). Moreover, psychophysiological interaction (PPI) analyses revealed a cluster in left middle occipital regions showing increased functional coupling with the right SMG during syntactic relative to semantic processing, possibly indicating spatial processing mechanisms that are specific to signed syntax. Effects of hearing status were observed in the right superior temporal cortex (STC): deaf but not hearing native signers showed greater activation for semantic violations than for syntactic violations in this region. Taken together, the present findings suggest that the neural correlates of language processing are partly determined by biological constraints, but that they may additionally be influenced by the unique processing demands of the language modality and different sensory experiences.
手语的聋人和听力正常的母语使用者的研究可以提供独特的见解，了解生物限制和环境输入如何相互作用，塑造语言处理的神经基础。在这里，我们使用功能磁共振成像 (fMRI) 来解决两个问题：（1）手语的语义和句法处理是否依赖于与口语语言一样的解剖和功能上不同的神经基质？（2）听力状况是否会影响这两种语言处理的神经相关性？聋人和听力正常的母语使用者对手德语（Deutsche Gebärdensprache：DGS）句子进行句子判断任务，这些句子是正确的，或者包含句法或语义违规。我们假设，正如在口语语言中一样，DGS 中的语义和句法违规处理依赖于不同的神经基质。此外，我们假设听力状况的影响在听觉区域内观察到，因为已经表明聋人母语使用者在处理手语时比听力正常的母语使用者更广泛地激活听觉区域。语义处理激活了低水平的视觉区域和左侧下额回（IFG），表明存在依赖于模态和独立于模态的处理机制。句法处理引起了右侧缘上回（SMG）的激活增加。此外，心理生理交互（PPI）分析显示，在左中枕叶区域中存在一个集群，在句法处理相对于语义处理时与右侧 SMG 显示出增加的功能耦合，这可能表明了特定于手语语法的空间处理机制。听力状况的影响在右侧颞上回（STC）中观察到：在该区域，聋人母语使用者的语义违规比句法违规的激活更大，而不是听力正常的母语使用者。总的来说，这些发现表明语言处理的神经相关性部分由生物限制决定，但它们也可能受到语言模态的独特处理要求和不同感官体验的影响。
