Auditory nerve responses to electric pulse trains

听觉神经对电脉冲序列的反应

• 批准号: 7112401
• 负责人: CHARLES A MILLER
• 金额: $ 44.89万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-15 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7112401
• 关键词: acoustic nerve; action potentials; auditory stimulus; behavioral /social science research tag; cats; cochlear implants; electrophysiology; electrostimulus; mathematical model; medical implant science; neural degeneration; neural information processing; neurophysiology; sensory signal detection; sound perception; speech recognition

A trend in cochlear implants is the use of faster per-channel pulse carrier rates, promoted on the basis of increased information capacity. However, it is not clear that higher rates achieve this goal in most or ill individuals. Clinical studies present mixed results and research promoting high (e.g., 5000 pps) rales raises important questions. For example, while beneficial, desynchronizing, effects have been reported in many auditory nerve fibers, comparable numbers become adapted to the point of being unresponsive. Furthermore, physiologic dala have only been obtained from intact fibers, not from degenerated neurons typical of chronically deaf ears. Finally, while much is known about neural adaptation to acoustic stimuli, relatively little is known about electrical adaptation, even though the latter typically produces much larger functional changes. We hypothesize that at least part of the variability in performance with higher-rate carriers is due to across-user differences in the auditory nerve's response to high-rate stimuli. This research plan seeks to fill these gaps in our knowledge of how the auditory nerve encodes information presented as modulated pulse trains. Three Aims are proposed. Aim 1 will assess signal encoding in fibers excited by modulated carriers at rates relevant to modern and proposed speech processors. Data will be collected from intact and degenerated nerves for greater applicability to clinical cases. Fiber tracing techniques will help link physiology with anatomical status. Aim 2 will use that data to help develop a computational model of the nerve that accounts for many fiber properties (e.g., integration, refractoriness, and adaptation). This model wsll be used to predict the electrically evoked compound action potential (EC'AP) so that we can tesi: the capacity of ECAP measures to assess fiber functionality, a clinically relevant issue. Finally, Aim 3 will explore the feasibility of applying specific transforms to modulated trains to compensate for adaptation and refractory effects that limit information carried by modulated pulse trains. We expect the results of this work will guide future designs of cochlear-implant speech processors so that modulated stimuli can be better tailored to the encoding capacity of the user's auditory nerve.

人工耳蜗的一个趋势是使用更快的每通道脉冲载波速率，这是在信息容量增加的基础上推广的。然而，尚不清楚在大多数或患病个体中更高的比率是否能实现这一目标。临床研究呈现出好坏参半的结果，促进高（例如 5000 pps）啰音的研究提出了重要问题。例如，虽然许多听觉神经纤维都报告了有益的去同步效应，但相当数量的神经纤维已经适应了无反应的程度。此外，生理达拉只能从完整的纤维中获得，而不是从慢性耳聋典型的退化神经元中获得。最后，虽然人们对神经对声刺激的适应了解很多，但相对来说 尽管电适应通常会产生更大的功能变化，但人们对电适应知之甚少。我们假设，较高速率载波的性能差异至少部分是由于用户间听觉神经对高速率刺激的反应差异造成的。 该研究计划旨在填补我们关于听觉神经如何编码以调制脉冲串形式呈现的信息的知识空白。提出了三个目标。目标 1 将以与现代和提议的语音处理器相关的速率评估由调制载波激励的光纤中的信号编码。将从完整和退化的神经中收集数据，以便更好地适用于临床病例。纤维追踪技术将有助于将生理学与解剖学状态联系起来。目标 2 将使用这些数据来帮助开发神经计算模型，该模型考虑了许多纤维特性（例如集成、不应性和适应性）。该模型将用于预测电诱发复合动作电位 (EC'AP)，以便我们可以测试：ECAP 测量评估纤维功能的能力，这是一个临床相关问题。 最后，目标 3 将探索将特定变换应用于调制序列的可行性，以补偿限制调制脉冲序列携带的信息的适应和难熔效应。我们预计这项工作的结果将指导未来人工耳蜗语音处理器的设计，以便调制刺激可以更好地适应用户听觉神经的编码能力。