Development of auditory brainstem implant

本计画的目的在建立一套适合于神经系统受损之听觉修复体的设计方法。本课题主要研究听觉系统，取得了以下主要成果：（1）建立了脑干植入系统的动物模型，包括用于听觉皮层记录的表面微电极和用于耳蜗核脑干刺激的棘波微电极阵列：（2）在听觉皮层功能组织研究的基础上，验证了脑干刺激对音高和强度感觉的影响;（3）“多重门控刺激”的发展，它可以选择性地激活位于电极之间的神经，表面微电极阵列在皮层上测量高分辨率的听觉皮层信号。该阵列采用聚酰亚胺基板，以符合弯曲和脉动的皮质表面。该阵列在2平方毫米的区域内有70个记录点。刺突微电极阵列文件16 tungs ...更多信息 10个网格状的微电极，间距400-□m，我们首先研究纯音诱发的听觉皮层反应和基于这些反应的听觉皮层组织。这些响应表示取决于刺激的频率和强度的特征时空模式。然后，棘波微电极阵列刺激脑干耳蜗核，诱发反应与声诱发反应有很好的一致性。此外，我们的研究结果强烈建议音高和强度的感觉是可能的，当一个适当的位置在脑干刺激在一个适当的电流intensity.We证明了门控刺激的可行性，通过模拟与神经方程和在体实验大鼠脊髓刺激。该技术广泛地用“阴极源电极”产生动作电位，同时用“阳极栅电极”阻断不必要的传播，导致电极之间的选择性传播。少

This project purposes to establish design methodology for auditory prostheses for patients having some neural impairment. We especially focused on auditory systems and accomplished following major achievements : (1) Development of an animal model for a brainstem implant system, which includes the surface microelectrode for anditory cortical recording and a spike microelectrode array for cochlear nuclear brainstem stimulation ; (2) Validation of brainstem stimulation for pitch and intensity sensation, based on investigation of auditory cortical functional organization ; and (3) Development of "the multiple gating stimulation," which can selectively activate nerves placing in between electrodes.The surface microelectrode array epi-cortically measures high-resolution auditory cortical signals. The array employs a polyimide substrate so as to conform curved and pulsating cortical surface. The array has 70 recording points in a 2-mm-square area. The spike microelectrode array files 16 tungs … More ten microelectrodes in a grid form with 400-□m spacing.We first investigate pure-tone-evoked auditoly cortical responses and auditory cortical organizations based on the responses. The responses represent characteristic spatio-temporal patterns depending on frequency and intensity of the stimuli. The spike microelectrode array, then, stimulates the brainstem cochlear nucleus, and the evoked responses have good agreement with acoustically evoked responses. Moreover, our results strongly suggest pitch and intensity sensation is possible when an adequate position at a brainstem is stimulated at an adequate current intensity.We demonstrate the feasibility of the gating stimulation via simulations with nerve equations and in vivo experiments of rat spinal cord stimulation. The technique broadly generates action potentials with "the cathodic source electrodes," and simultaneously blocks unnecessary propagation with "the anodic gate electrodes," resulting in selective propagation in between electrodes. Less