CRCNS: Modeling the role of auditory feedback in speech motor control

当我们说话时，听众听到我们并理解我们，我们说得正确。但我们也能听到自己的声音，这种听觉反馈会影响我们正在进行的语言：延迟会导致语言不流畅；干扰它的音高或共振峰会引起补偿。然而，即使我们听不到自己的声音，我们也可以清晰地说话。由于这个原因，大多数语言运动控制模型假设，在说话过程中，听觉处理只在听觉反馈可用时进行。在这项资助中，我们建议研究一个与此主要不同的说话计算模型。我们的模型提出，无论听觉反馈是否有效，听觉系统总是在控制说话方面发挥主要作用。在语音产生的状态反馈控制（SFC）模型中，我们对听觉系统的作用做了两个假设。首先，听觉系统持续保持对当前声音输出的估计。这种估计不仅来自于现有的听觉反馈，还来自于多种其他信息来源，包括运动感知、其他感觉方式、语音和词汇语境。其次，这种对当前语音输出的估计在较低水平上用于监测和纠正正在进行的语音运动输出，在较高水平上用于调节话语序列的产生。通过将我们的模型的计算模拟与功能成像实验进行比较，我们将测试我们的计算模型的关键预测，因为它们适用于广泛的语音产生-从单个话语的产生到话语序列的产生。这项资助的具体目的是(1)证明听觉系统持续保持对当前声音输出的估计，以及(2)确定听觉反馈处理如何控制话语序列的产生。这项工作不仅解决了关于语言产生的重要基础科学问题，而且具有广泛的临床影响，因为听觉反馈处理的异常与许多语言障碍有关。

When we speak, listeners hear us and understand us we speak correctly. But we also hear ourselves, and this auditory feedback affects our ongoing speech: delaying it causes dysfluency; perturbing its pitch or formants induces compensation. Yet we can also speak intelligibly even when we can't hear ourselves. For this reason, most models of speech motor control suppose that during speaking auditory processing is only engaged when auditory feedback is available. In this grant, we propose to investigate a computational model of speaking that represents a major departure from this. Our model proposes that the auditory system always plays a major role in controlling speaking, regardless of whether auditory feedback is available. In our state-feedback control (SFC) model of speech production, we posit two things about the role of the auditory system. First, the auditory system continuously maintains an estimate of current vocal output. This estimate is derived not only from available auditory feedback, but also from multiple other sources of information, including motor efference, other sensory modalities, and phonological and lexical context. Second, this estimate of current vocal output is used both at a low level to monitor and correct ongoing speech motor output and at a higher level to regulate the production of utterance sequences. By comparing computational simulations of our model with functional imaging experiments, we will test key predictions from our computational model as they apply to a wide range of speech production - from production of single utterances to utterance sequences. The specific aims of this grant are (1) to demonstrate that auditory system continuously maintains an estimate of current vocal output, and (2) to determine how auditory feedback processing controls the production of utterance sequences. The proposed work not only addresses fundamentally important basic science questions about speech production, but also has broad clinical impact since abnormalities in auditory feedback processing are implicated in many speech impairments.