Constraints and Strategies in Speech Production

描述(由申请者提供)：这项拟议的研究解决了有关言语运动的计划和执行方式的假设。这些假设是由神经控制语音运动的计算模型和基于生物力学的声道模型相结合而指导的。为了验证这些假设，我们对说话者和听话者进行了实验，测量了发音运动、言语声学、知觉和大脑激活。我们操纵语音条件(例如，清晰语音与快速语音)、音素上下文和语音类别，并引入瞬时和持续的扰动。我们还进行了模拟实验，使声道模型适应单个说话人的形态。这个声道模型的运动由我们的神经控制模型在我们实验中使用的相同发声和条件下控制，并将得到的运动和声学与建模的说话人的运动和声学进行比较，以便测试该模型。这项研究解决了三个相互关联的问题：1。发音运动的音素和音节目标的性质。这里我们研究了说话条件和说话人差异对元音听觉目标的影响；说话人的辨别能力对他们产生的音素对比的影响；听觉和发音干扰对音素对比的影响以及它们与声音类别和说话人敏锐度的相互作用。2.反馈和前馈机制在言语运动控制中的作用。通过引入不可预测和持续的扰动来研究这些控制子系统的性能。我们测试了基于模型的假设，这些假设是关于大脑激活的变化以及由每种干预引起的声学和发音轨迹的变化。3.音素与大单位拼接中的运动轨迹规划。在这项研究中，我们研究了单词连接中的动作规划。我们测量手势重叠中的发音运动及其声学和知觉的相关性，以检验这样的重叠为听者留下可感知的声学线索的假设。我们相信这些研究将提供有关言语产生的神经控制机制的重要信息。

DESCRIPTION (provided by applicant): The proposed research addresses hypotheses concerning the way speech movements are planned and executed. The hypotheses are guided by a computational model of the neural control of speech movements combined with a biomechanically based vocal-tract model. To test these hypotheses, we conduct experiments with speakers and listeners in which we measure articulatory movements, speech acoustics, perception, and brain activation. We manipulate speech condition (e.g., clear vs. fast speech), phonemic context, and speech sound class, and we introduce transient and sustained perturbations. We also perform simulation experiments in which we adapt the vocal-tract model to the morphologies of individual speakers. Movements of this vocal-tract model are commanded by our neural control model for the same utterances and conditions used in our experiments, and the resulting movements and acoustics are compared to those of the modeled speaker, in order to test the model. The research addresses 3 inter-related issues: 1. The nature of phonemic and syllabic goals for articulatory movements. Here we study the effects of speaking conditions and speaker differences on auditory goals for vowels; the effects of speakers' discriminative capacities on the phoneme contrasts they produce; and the effects of auditory and articulatory perturbations on phonemic contrast and their interaction with sound class and speaker acuity. 2. The role of feedback and feedforward mechanisms in the control of speech movements. The performance of these control sub-systems is probed by introducing unpredictable and sustained perturbations. We test model-based hypotheses about changes in brain activation and acoustic and articulatory trajectories elicited by each of these interventions. 3. Movement trajectory planning in the concatenation of phonemes and larger units. In this study we investigate the planning of movements in the concatenation of words. We measure articulatory movements in gestural overlap and their acoustic and perceptual correlates in order to test the hypothesis that such overlap leaves perceptible acoustic cues for listeners. We believe these studies will provide important information regarding the neural control mechanisms underlying speech production.