Dynamic bidirectional sensorimotor interactions in stuttering

项目概要/摘要 了解口吃背后的基本神经机制被广泛认为是治疗口吃的基础。 知情的诊断和治疗。这一重要知识所需的基石是一个理论 口吃的框架，占各种主要和相关的语音特征，这是 与实验验证的感觉运动控制和神经功能模型一致。研究 这里提出的程序需要一个全面的神经生物学方法来开发一个机械模型 通过一系列综合的理论动机，假设驱动， 最先进的实验一个共同的主题，在整个拟议的实验是事实，神经 运动的控制依赖于传出和传入之间动态调整的双向相互作用 系统.直接的目的是阐明这些感觉运动的相互作用和他们的作用，口吃的讲话。 基于经验和计算工作表明，中枢神经系统能够控制快速自愿 通过不断预测未来的感觉状态，我们的实验室最近在多项研究中发现， 典型的说话者在语音运动开始之前调节听觉处理机制，但是 这种机制在口吃的成年人中完全缺乏。因此，预测性调节机制证明， 是一个特别强大的模型，用于阐明潜在的语言运动障碍的机制， 口吃本研究计划中的单个实验旨在确定 口吃者在言语前听觉调制方面的缺陷已经存在， 儿童期接近口吃发作，无论这种缺陷是特定的运动到听觉的相互作用， 影响躯体感觉领域的处理，并揭示该现象的各个方面， 言语感觉运动控制中的功能相关性。拟议中的儿童和成人比较研究 与通常流利的演讲者交谈时口吃的人有可能对发展提供机械的见解， 和语言感觉运动系统的局限性在这种常见的语言流畅性障碍。具体地说， 在反馈监测中，感觉运动相互作用的参与将获得至关重要的新见解 长期以来，人们一直假设这些机制在生理学基础上发挥着重要作用， 口吃此外，这些发现将为新的治疗方法提供建议，如非侵入性 运动前运动-感觉信号传导中涉及的神经通路的脑刺激。因此，这项工作的 与公共卫生的直接相关性在于它有助于理解潜在的神经机制 口吃和-通过产生这种新的见解-促进发展的改进方法， 诊断和治疗。

PROJECT SUMMARY/ABSTRACT Understanding the basic neural mechanisms underlying stuttering is widely acknowledged as fundamental to informed diagnosis and treatment. The required cornerstone for this important knowledge is a theoretical framework of stuttering that accounts for various primary and associated speech characteristics, and that is consistent with empirically-verified models of sensorimotor control and neural functioning. The research program proposed here takes a comprehensive neurobiological approach to developing a mechanistic model of stuttered speech dysfluencies through an integrated series of theoretically-motivated, hypothesis-driven, state-of-the art experiments. A common theme throughout the proposed experiments is the fact that the neural control of movement depends on dynamically adjusted bidirectional interactions between efferent and afferent systems. The direct aim is to elucidate these sensorimotor interactions and their role in stuttered speech. Based on empirical and computational work suggesting that the CNS is able to control fast voluntary movements by continually predicting future sensory states, our lab recently found in multiple studies that typical speakers modulate auditory processing mechanisms prior to the initiation of speech movements, but that this mechanism is entirely lacking in adults who stutter. Thus, predictive modulatory mechanisms prove to be a particularly powerful model for elucidating the mechanisms underlying speech motor breakdowns in stuttering. The individual experiments within this program of research are designed to determine whether stuttering individuals’ well-documented deficit in pre-speech auditory modulation is already present in childhood close to stuttering onset, whether this deficit is specific to motor-to-auditory interactions or also affects processing in the somatosensory domain, and to uncover various aspects of the phenomenon’s functional relevance in speech sensorimotor control. The proposed studies comparing both children and adults who stutter with typically fluent speakers have the potential to offer mechanistic insights into the development and limitations of the speech sensorimotor system in this common disorder of speech fluency. Specifically, crucial new insights will be gained into the involvement of sensorimotor interactions in feedback monitoring mechanisms that have long been hypothesized to play a fundamental role in the physiological basis of stuttering. Moreover, these findings will offer suggestions for novel treatment approaches such as non-invasive brain stimulation of neural pathways involved in pre-movement motor-to-sensory signaling. Thus, this work's direct relevance to public health lies in its contributions to understanding the neural mechanisms underlying stuttering and – by generating such new insights – facilitating the development of improved approaches to diagnosis and treatment.