The role of motor systems on the functional neural organisation of language processing: Cross-linguistic evidence from sign and speech

背景：语音处理的理论认为不同的特征是语言处理的关键决定因素。生成语法认为语法信息驱动言语知觉[1]，而言语知觉的运动理论则认为语言知觉涉及到言语产生网络。参与运动产生的大脑区域与感知有意义的动作(包括言语)之间的密切联系已经明确建立。对于言语感知，语法以及知觉和产出之间的潜在联系都是混乱的--因为言语通过一个单一的发音器(嘴)连续地传达语法信息。然而，手语(SLS)是由多个发音器--手、嘴、头--在独立的大脑皮层控制下产生的。目的：本项目将使用神经成像(功能磁共振成像，fMRI)和神经刺激(运动诱发电位，MEP，经颅磁刺激，TMS)相结合的综合神经科学方法，系统地探讨发音对英国手语(BSL)聋人母语手语(BSL)语言加工功能组织的影响。我们将对听力为英语的人进行平行研究，在语言结构中允许提出感兴趣的问题，以获得跨语言方法来研究语言感知中的运动系统。方法：fMRI将通过检测签名者在处理不同符号句法结构时的激活模式来探索感知的语言清晰器对词汇和语法加工的影响，如否定，这可以通过非手动标记(摇头)或通过共同扩展的非手动和手动标记来实现。第二项研究将侧重于听非签名者处理视听英语，以对比视听句子和非强制性面部动作。这些发现将提供有关运动系统和语法系统如何相互作用的信息。神经刺激将被用来通过记录单个脉冲反应到聋人手部和嘴部运动前皮质区域的MEP来检查相关皮质区域之间的关系，并使用TMS建立运动产生和语言感知之间的因果联系。包括非语言的嘴和手的动作将使我们能够评估这些影响的领域特异性。一项让非听障人士观看相同材料的平行实验将允许我们将发音运动(手和嘴)的大小和轨迹与语言知识(聋人参与者的手势和语音阅读，听力参与者只阅读语音)的影响分开。同时的行为测量可以提供对这些神经成像和TMS数据中个体变异性的洞察。时间表：第1年-fMRI-BSL研究和BSL水平1，第2年-fMRI-AV和MEP-BSL研究和BSL水平2，第3年-MEP-AV和TMS-BSL研究，第4年TMS-AV研究影响：这项研究将为我们理解语言处理的皮质组织以及最终为语言障碍(例如，失语)治疗干预措施的发展提供重要贡献。此外，从事该项目的工作将通过获得fMRI、MEP和TMS技术方面的专业知识来发展学生的学术生涯，并将建立(或继续)在高影响力、同行评议的期刊上发表高质量论文的强劲记录。

Background: Theories of speech processing suggest different features as the crucial determinants of language processing. Generative grammar suggests that grammatical information drives speech perception [1] whereas the motor theory of speech perception proposes that language perception involves access to the speech production network. Close links between brain areas involved in motor production and the perception of meaningful actions, including speech, have been clearly established. For speech perception, both grammar and the potential connection between perception and production are confounded - as speech conveys grammatical information serially via a single articulator (mouth). However, signed languages (SLs), are produced by multiple articulators -- hands, mouth, head, which are under independent cortical control. Objectives: This project will use an integrative neuroscience approach combining neuroimaging (functional magnetic resonance imaging, fMRI) and neurostimulation (motor evoked potentials, MEP, transcranial magnetic stimulation, TMS) to systematically explore the articulatory effects on the functional organisation of language processing in deaf native signers of British Sign Language (BSL). We will conduct parallel studies in hearing speakers of English where the questions of interest are permissible within the language structure, in order to gain a cross-linguistic approach to the motor systems in language perception. Methods: FMRI will be used to explore the effects of the perceived language articulator on lexical and grammatical processing by examining the patterns of activation in signers as they process different signed syntactic structures such as negation, which can be realised solely by non-manual markers (headshake), or by coextensive non-manual and manual markers. A second study will focus on hearing non-signers processing audio-visual (AV) English to contrast AV sentences with non-obligatory facial actions. The findings will provide information about how the motor and grammatical systems may interact. Neurostimulation will be used to examine the relationship between the relevant cortical areas by recording MEPs in response to single pulses to the hand and mouth regions of premotor cortex in deaf signers viewing language produced using different articulators and to establish the causal link between motor production and language perception using TMS. Including non-linguistic mouth and hand actions will allow us to assess the domain specificity of these effects. A parallel experiment in hearing non-signers viewing the same materials will allow us to separate the effects due to size and trajectory of articulatory movement (hand > mouth) and language knowledge (sign and speech reading in deaf participants, speech reading-only in hearing participants). Concurrent behavioural measures may offer insight into individual variability in these neuroimaging and TMS data.Schedule: Year1 -fMRI-BSL study and BSL Level 1, Year2 -fMRI-AV & MEP-BSL studies and BSL Level 2, Year3 -MEP-AV & TMS-BSL studies , Year4 TMS-AV study Impact: This research will provide a major contribution to our understanding of the cortical organisation of language processing as well ultimately informing the development of therapeutic interventions for language impairment (e.g., aphasia). In addition, working on the project will develop the student's academic career through gaining expertise in fMRI, MEP and TMS techniques, and will establish (or continue) a strong record of high quality papers published in high impact, peer-reviewed journals.