MECHANISMS OF INTRACOCHLEAR ELECTRICAL STIMULATION

耳蜗内电刺激的机制

• 批准号: 3094735
• 负责人: WILLIAM REICHTSMEIER
• 金额: $ 86.44万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-12-05 至 1993-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3094735
• 关键词: cochlea; computational neuroscience; electrostimulus

The objective of this program project is to identify and study mechanisms that govern current flow, neural responses and perceptual performance under conditions of intracochlear electrical stimulation. The overall strategy of the research program is reflected in the organization of the five projects, all of which are strongly interrelated. Project I deals with the design, fabrication, and characterization of intracochlear electrodes. An experimental 11-contact array for use Projects III-V will be developed, novel electrode that may provide improved spatial localization of intracochlear current will be designed and characterized, and advanced electrode materials that may carry more electrical charge will be evaluated. Project II deals with the characterization of electrical fields generated by intracochlear electrodes. Finite-element field models of cat and human cochleas will be constructed, and field patterns for clinically- applied and experimental electrodes will be studied. These models will be validated by empirical measurements of current fields in cat cochleas. Project III seeks to identify and study mechanisms governing single-neuron responses to electrical stimuli. Biophysical models of neural response will be developed and evaluated in quantitative studies of single-cell discharge patterns in the auditory nerve and anteroventral cochlear nucleus. Topics to be studied include the effects of changing the spatial geometry of the stimulating current field, correlating neural responses with temporal features of stimulating waveforms, and examining stochastic aspects of neural responses. Project IV deals with the ensemble response of multiple neural elements to electrical stimulation. Models combining the results of field models and single-cell responses will be developed, and their predictions will be evaluated in acute physiological studies that determine neural population responses to electrical signals. Project V investigates psychophysical performance of implanted animals on tasks thought to be encoded at peripheral levels of the auditory system, then conducts physiological studies to record unit activity using the same stimulus paradigms that had been studied behaviorally. Models that attempt to predict perceptual performance from neural responses will be developed and evaluated. All animal studies in Projects III-V will be conducted under conditions of both good and poor spiral ganglion survival. A separate Morphology Core allows all projects to relate findings to details of cochlear anatomy in deafened ears. Likely outcomes of the proposed research include (1) an improved knowledge of patterns of intracochlear current flow and the mechanisms by which electrical current excites auditory neurons, (2) insight into the physiological basis of auditory perceptual performance with cochlear implants, (3) identification of ways to control the spatial extend and temporal fine structure of neural responses, (4) the formulation of biophysically sound approaches to improving speech processors in individual implant patients, and (5) the development of optimized electrode designs for clinical use.

该计划项目的目标是确定和研究机制 控制电流、神经反应和知觉表现 耳蜗内电刺激的条件。 总体策略 研究计划的内容体现在五个研究项目的组织中 项目，所有这些项目都密切相关。 项目 I 涉及 耳蜗内电极的设计、制造和表征。 一个 将开发用于项目 III-V 的实验性 11 触点阵列， 新型电极可以提供改进的空间定位 耳蜗内电流将被设计和表征，并先进 可以携带更多电荷的电极材料 评价。 项目 II 涉及电场的表征 由耳蜗内电极产生。 猫的有限元场模型 将构建人类耳蜗，并为临床提供现场模式 将研究应用电极和实验电极。 这些模型将 通过对猫耳蜗电流场的经验测量进行验证。 项目 III 旨在识别和研究单神经元的控制机制 对电刺激的反应。 神经反应的生物物理模型 将在单细胞定量研究中进行开发和评估 听神经和前腹耳蜗的放电模式 核。 要研究的主题包括改变空间的影响 刺激电流场的几何形状，关联神经反应 具有刺激波形的时间特征，并检查随机 神经反应的各个方面。 项目 IV 处理整体响应 多个神经元件的电刺激。 模型组合 将开发现场模型和单细胞反应的结果， 他们的预测将在急性生理研究中得到评估 确定神经群体对电信号的反应。 项目五 研究植入动物执行任务时的心理物理表现 被认为是在听觉系统的外围水平编码的，那么 进行生理研究以使用相同的方法记录单位活动 行为学研究的刺激范式。 尝试的模型 将开发根据神经反应预测感知表现的方法 并进行了评价。 项目 III-V 中的所有动物研究都将进行 在螺旋神经节存活良好和较差的条件下。 一个 单独的形态核心允许所有项目将发现与细节联系起来 聋耳中的耳蜗解剖结构。 拟议的可能结果 研究包括（1）提高对耳蜗内模式的了解 电流流动和电流激发的机制 听觉神经元，（2）洞察听觉的生理基础 人工耳蜗的感知性能，（3）识别方式 控制神经的空间扩展和时间精细结构 反应，（4）制定生物物理学上合理的方法 改善个体植入患者的语言处理器，以及 (5) 开发用于临床的优化电极设计。