University of Southern California, Biomedical Engineering, 1042 Downey Way, DRB 140, Los Angeles, CA 90089-1111, USA.
J Neural Eng. 2011 Aug;8(4):045003. doi: 10.1088/1741-2560/8/4/045003. Epub 2011 Jul 20.
Retinal prostheses aim to provide visual perception through electrical stimulation of the retina. Hence they have to operate between threshold charge density and maximum safe charge density. To date most studies in the retina have concentrated on understanding the threshold, while stimulation safety has predominantly been studied in structures other than the retina. Toward this end, the present study focuses on determining the effect of continuous electrical stimulation of the retina both on retinal morphology and on the electrically evoked responses in the superior colliculus in a rodent model. The results demonstrate that the retina is able to tolerate 1 h long stimulation with only minor changes evident in retinal histology when examined three to 14 days later, even at charge densities (0.68 mC cm(-2)) above the safe limit of platinum delivered at high stimulus frequency (300 Hz). However, this continuous electrical stimulation causes an elevation in the threshold of the electrically evoked response in the superior colliculus, indicating some form of adaptation to continuous stimulation.
视网膜假体旨在通过对视网膜进行电刺激来提供视觉感知。因此，它们必须在阈值电荷密度和最大安全电荷密度之间运行。迄今为止，大多数关于视网膜的研究都集中在理解阈值上，而刺激安全性主要在视网膜以外的结构中进行研究。为此，本研究旨在确定连续电刺激视网膜对视网膜形态和在啮齿动物模型中的上丘电诱发反应的影响。结果表明，即使在高于高刺激频率（300Hz）下铂传递的安全限制（0.68mCcm(-2))的电荷密度下，视网膜在 1 小时的刺激后也仅能耐受轻微的形态学变化，且可在 3 至 14 天后观察到。然而，这种连续的电刺激会导致上丘电诱发反应的阈值升高，表明对连续刺激存在某种形式的适应。
