Patterned electrical stimulation of the retina for the design of prostheses

 描述(申请人提供)：视网膜前假体的目的是通过使用电极阵列唤起视网膜中的神经活动来模拟自然视觉。原型设备使用大的、间隔粗糙的电极，不分青红皂白地同时刺激许多细胞，产生大量的磷烯，限制盲人患者的视觉功能。为了提高未来假体装置的质量，我们需要有选择地激活单个细胞的能力 以及一组细胞，以准确地再现正常视觉期间发生的活动。我们实验室最近的研究表明，我们可以有选择地使用特定细胞密度的安全电流水平来刺激单个细胞。然而，目前尚不清楚选择性激活是否可能 适用于RGC密度较高的情况。在这个提案中，我们将检验这样一个假设，即我们可以通过使用图案化刺激来改善密集RGC区域的选择性激活。我们将利用多电极刺激和记录技术在分离的大鼠和猴子视网膜上进行拟议的实验。目标1将探索神经元胞体和轴突的不同生物物理特性是否允许选择性激活胞体胞体，同时将不必要的轴突激活降至最低。目标2将使用经验测量和计算方法相结合的方法来经验地确定选择性激活靶细胞的最佳模式。AIM 3将结合成像来指导我们使用AIMS 1和2中开发的图案化刺激来理解影响选择性激活的细胞特征。这项研究的结果将有助于更好地理解图案化电刺激是否可以提高细胞激活的选择性。提高对电刺激技术的理解可能会指导未来、先进的视网膜假体和其他脑机接口的发展。

 DESCRIPTION (provided by applicant): The purpose of epiretinal prostheses is to mimic natural vision by evoking neural activity in the retina using electrode arrays. Prototype devices use large, coarsely spaced electrodes that indiscriminately stimulate many cells simultaneously, producing large phosphenes and limited visual function in blind patients. In order to improve the quality of a future prosthetic device, we need the ability to selectively activate individual cells and groups of cells to accurately recreate the activity that occurs during normal vision. Recent studies from our lab show that we can stimulate individual cells selectively using safe current levels for specific cell densities. However, it is unknown whether selective activation is possible for cases where the density of RGCs is higher. In this proposal, we will test the hypothesis that we can improve selective activation in dense RGC regions by using patterned stimulation. We will exploit multi-electrode stimulating and recording techniques to perform the proposed experiments in isolated rat and monkey retinas. Aim 1 will explore whether the distinct biophysical properties of neuronal somas and axons will allow selective activation of somas while minimizing unwanted axon activation. Aim 2 will use empirical measurements combined with computational methods to empirically determine the best pattern for selectively activating a target cell. Aim 3 will incorporate imaging to guide our understanding of the cellular features tha influence selective activation using the patterned stimuli developed in Aims 1 and 2. The results of this study will lead to a better understanding of whether patterned electrical stimulation can improve the selectivity of cell activation. Improved understanding of electrical stimulation techniques may guide the development of future, advanced retinal prostheses and other brain-machine interfaces.