Department of Biomedical Engineering, Duke University, Durham, NC, USA.
J Neural Eng. 2013 Jun;10(3):036002. doi: 10.1088/1741-2560/10/3/036002. Epub 2013 Apr 3.
Epiretinal stimulation, which uses an array of electrodes implanted on the inner retinal surface to relay a representation of the visual scene to the neuronal elements of the retina, has seen considerable success. The objective of the present study was to quantify the effects of multi-electrode stimulation on the patterns of neural excitation in a computational model of epiretinal stimulation.
A computational model of retinal ganglion cells was modified to represent the morphology of human retinal ganglion cells and validated against published experimental data. The ganglion cell model was then combined with a model of an axon of the nerve fiber layer to produce a population model of the inner retina. The response of the population of model neurons to epiretinal stimulation with a multi-electrode array was quantified across a range of electrode geometries using a novel means to quantify the model response-the minimum radius circle bounding the activated model neurons as a proxy for the evoked phosphene.
Multi-electrode stimulation created unique phosphenes, uch that the number of potential phosphenes can far exceed the number of electrode contacts.
The ability to exploit the spatial and temporal interactions of stimulation may be critical to improvements in the performance of epiretinal prostheses.
视网膜内刺激使用安置在内视网膜表面的电极阵列，将视觉场景的表示传递到视网膜的神经元元件，已经取得了相当大的成功。本研究的目的是定量多电极刺激对视网膜内刺激计算模型中神经兴奋模式的影响。
修改了视网膜神经节细胞的计算模型，以代表人类视网膜神经节细胞的形态，并针对已发表的实验数据进行了验证。然后，将该神经节细胞模型与神经纤维层的轴突模型相结合，生成内视网膜的群体模型。使用一种新的方法来量化模型响应-最小包围激活模型神经元的圆形半径作为诱发光点的代理，来量化多电极阵列对视网膜内刺激的模型神经元的反应，该方法在一系列电极几何形状下量化了模型响应。
多电极刺激产生了独特的光点，以至于潜在光点的数量可以远远超过电极接触的数量。
利用刺激的空间和时间相互作用的能力可能对视网膜假体性能的提高至关重要。
