Phonetic influences on auditory feedback control

描述(申请人提供)：言语研究中的一个基本问题是产生和感知之间的相互作用。这种相互作用的性质对于理解和模拟言语发展、产出缺陷和康复策略具有深远的意义。我们的目标是刻画对他人言语的感知，特别是在音素边界，如何影响引导自己产生的言语的听觉-运动反馈过程。一方面，说话者可能以听者感知的分类方式感知他自己的讲话，从而允许快速、健壮的听觉处理。另一方面，说话人可以在高级听觉皮质对声音信号施加语音结构之前，在次范畴水平上监控他的输出。我们的目标是通过检查听觉变化条件下的语音，并探索神经信号在语音相关时对这种变化的增强反应来区分这些假说。我们的项目结合了心理物理和脑磁图实验，以研究说话者的听觉反馈突然改变所引发的神经动力学。拟议的实验旨在实现两个特定目标。首先，我们的目标是测量神经对实时语音类别变化的反应。根据以往研究的结果，我们假设跨类别或“语音”转换比相同大小的类别内或“非语音”转换引起更大的神经反应，但这种反应的动力学仍不清楚。我们的目标是使用脑磁图来检测对意外反馈扰动的时变神经反应，对比语音和非语音变化条件下的反应。其次，我们的目标是评估语音训练对听觉反馈控制的影响。在共振峰空间中学习新的元音目标具有在新的元音和习得的母语元音之间增加新的类别边界的效果。建议的实验评估了这些新学习的类别在多大程度上影响对现有元音扰动的反应。这项拟议的研究通过引入有意义的语言变化和仅仅施加在反馈中的声音变化之间的区别，增加了现有的反馈文献。我们的目标是通过确定听觉反馈控制是否受到范畴知觉的影响，从而确定它是发生在听觉皮质的高水平还是低水平，来改进言语运动控制的模型。这项研究直接适用于口吃，这是一种运动控制障碍，被认为反映了反馈过程中的异常。这些研究最终还将有助于改善沟通障碍的诊断和治疗，如帕金森氏病或痉挛性发音困难，因为反馈控制的神经成像可以用于诊断性地探测涉及感知和生产的大脑网络中的特定异常。最后，这里提出的训练研究可能对开发针对各种言语障碍的反馈相关训练策略有潜在的帮助。

DESCRIPTION (provided by applicant): A fundamental issue in speech research is the interaction between production and perception. The nature of this interaction has profound implications for understanding and modeling speech development, production deficits, and rehabilitation strategies. Our goal is to characterize how perception of others' speech, particularly at the phoneme boundary, influences the auditory-motor feedback processes that guide self- produced speech. On the one hand, a speaker may perceive his own speech in the categorical manner in which listeners perceive it, allowing for rapid, robust auditory processing. On the other hand, a speaker may monitor his output at a sub-categorical level, before high-level auditory cortex imposes phonetic structure on the acoustic signal. We aim to distinguish these hypotheses by examining speech under conditions of auditory change and probing the neural signal for an increased response to that change when it is phonetically relevant. Our project combines psychophysical and magnetoencephalography experiments to investigate the neural dynamics elicited by a sudden modification of speakers' auditory feedback. The proposed experiments were designed to achieve two specific aims. First, we aim to measure the neural responses to real-time phonetic category changes. Drawing on the results of past studies, we hypothesize that a cross-category or "phonetic" shift causes a greater neural response than a within-category or "non-phonetic" shift of the same magnitude, but the dynamics of this response are still unknown. The goal is to use MEG to examine the time- varying neural response to unexpected feedback perturbation, contrasting that response under conditions of phonetic and non-phonetic change. Secondly, we aim to assess the effects of speech training on auditory feedback control. Learning a novel vowel target in formant space has the effect of adding new category boundaries between the novel vowel and the well-learned native vowels. The proposed experiments evaluate the degree to which these newly-learned categories affect the responses to perturbation of an existing vowel. The proposed research adds to the existing feedback literature by introducing the distinction between meaningful linguistic changes and mere acoustic variations imposed in feedback. We aim to improve models of speech motor control by determining whether auditory feedback control is influenced by categorical perception, and therefore whether it occurs at a high or low level in auditory cortex. This research is directly applicable to stuttering, a motor control disorder thought to reflect abnormalities in feedback processing. These studies will also ultimately contribute to improved diagnosis and treatment of communication disorders such as Parkinsons' Disease or spasmodic dysphonia, since neuroimaging of feedback control can be used diagnostically to probe the specific abnormalities in brain networks involved in perception and production. Finally, the training studies proposed here could potentially be useful in developing feedback-related training strategies for a variety of speech disorders.