HVEM OF IRIDIUM ELECTRODE STIMULATED CENTRAL NERVOUS SYS TISSUE

（由N 01-NS-5-2324、N 01-DC-5-2105、N 01-NS-5-2333和 N 01-DC-7-2103给William F.神经假体的发展 在人类中使用电子设备是一项重要的研究策略， 减少人类残疾，包括听力损失 以及视力、平衡障碍和膀胱功能受损。 我们正在开发神经修复装置， 刺激特定的大脑和脊髓区域。 我们应用 显微镜，包括LM、CTEM、IVEM和HVEM以及元素分析， 以及细胞化学和免疫细胞化学方法。 我们的研究 旨在确定安全裕度和最佳电气 刺激参数，并了解机制， 电诱导的组织损伤，以及评估 植入电极的生物相容性。 高压电子 显微镜已被证明是我们方法学的重要辅助手段， 方法，提供有价值的三维立体对图像 神经的神经元、神经胶质、突触和血管成分 暴露于电刺激的组织。 以往的研究 Tivol等人，(J. Neurosci. 方法19，1987），建立了 继续研究铱效应的框架 周围神经组织上的电极 的重要组成部分 我们在确定安全有效的电刺激方面的研究是 不仅要确定生理（激活）阈值， 以确定“治疗”窗口。 为此，我们必须超越 生理刺激强度;即，发现不仅是神经 损害阈值，也是损害的阈值 微电极本身 例如，在合作中 如前所述，使用高压微分析，我们描述了 合金P130 Ir作为慢性脉冲的合适材料，由于 在组织中发现了结晶铂和铱。 我们 正在重新评估目前的刺激技术， 多部位刺激电极。 能量色散x射线 微分析光谱和显微照片记录与IVEM从 洛辛斯基博士送来的切片 数据已发送给Lossinsky博士 提交资助申请

(Supported by N01-NS-5-2324, N01-DC-5-2105, N01-NS-5-2333 and N01-DC-7-2103 to William F. Agnew) The development of neuroprosthetic devices in humans is an important research strategy that promises to lead to the reduction of human disabilities including loss of hearing and vision, equilibrium disturbances and impaired of bladder function. We are developing neurprosthetic devices that will provide electrical stimulation to specific brain and spinal cord regions. We apply microscopy, including LM, CTEM, IVEM and HVEM and elemental analysis, as well as cytochemical and immunocytochemical methods. Our studies are intended to determine the margins of safety and optimum electrical stimulation parameters, and to understand the mechanisms of electrically-induced tissue damage, as well as to assess the biocompatibility of the implanted electrodes. High-voltage electron microscopy has proved an important adjunct to our methodological approach, providing valuable three -dimension al, stereo-pair images of neuronal, glial , synaptic and vascular components of the nervous tissue exposed to electrical stimulation. The previous studies of Tivol et al., (J. Neurosci. Methods 19, 1987), established the framework for continuing an investigation of the effects of iridium electrodes on the surrounding neural tissues. An important part of our study in determining safe and effective electrical stimulation is to determine not only physiological (activation) thresholds but also to determine the "therapeutic" window. To do this, we must exceed physiologic stimulus intensities; i.e., find not only the neural damage threshold but also the threshold for damage to the microelectrodes themselves. For example, in the collaboration mentioned previously, using high-voltage microanalysis, we described the alloy P130Ir as a suitable material for chronic pulsing, due to the finding of crystalline platinum and iridium in the tissues. We are re-evaluating present stimulation techniques which are now using multisite stimulating electrodes. Energy-dispersive X-ray microanalysis spectra and micrographs were recorded with the IVEM from sections sent by Dr. Lossinsky. The data was sent to Dr. Lossinsky for submission with a grant proposal