Dynamic bidirectional sensorimotor interactions in stuttering

项目摘要/摘要 人们普遍认为，了解口吃背后的基本神经机制是 知情诊疗。这一重要知识所需的基石是理论上的 口吃的框架，它解释了各种主要和相关的语音特征，即 与经验验证的感觉运动控制和神经功能模型一致。这项研究 这里提出的方案采用了一种综合的神经生物学方法来开发机械模型 通过一系列理论驱动的、假设驱动的、 最先进的实验。在整个拟议的实验中，一个共同的主题是，神经 运动的控制依赖于动态调整的传出和传入之间的双向相互作用 系统。其直接目的是阐明这些感觉-运动相互作用及其在口吃中的作用。 根据经验和计算工作表明，中枢神经系统能够控制FAST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身上完全缺乏。因此，预测调节机制被证明是 是一个特别强大的模型，用于阐明语言运动障碍的潜在机制 口吃。这项研究计划中的个人实验旨在确定 口吃的个体在言语前听觉调制方面有充分证据的缺陷已经出现在 儿童时期接近口吃发作，无论这种缺陷是运动到听觉相互作用的特有还是 影响躯体感觉领域的加工，并揭示该现象的各个方面 言语感觉运动控制中的功能关联。拟议中的研究将儿童和成人进行比较 通常讲得很流利的口吃者有可能提供对发展的机械性见解 以及语音感觉运动系统在这种常见的语音流畅性障碍中的局限性。具体来说， 关键的新见解将会涉及到反馈监控中的感觉运动交互作用 长期以来，人们一直认为这些机制在脑血管疾病的生理基础上起着重要作用 口吃。此外，这些发现将为非侵入性治疗等新的治疗方法提供建议 大脑刺激的神经通路涉及运动前的运动到感觉的信号。因此，这项工作的 与公众健康直接相关的是它对理解 口吃和--通过产生这种新的见解--促进改进方法的开发 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.