@inproceedings{cd26a1d748794e849e2977a92d9d03d3,
title = "Computational model of electrical stimulation of a retinal ganglion cell with hexagonally arranged electrodes",
abstract = "In retinal prosthetic devices an electrode array is used for electrical stimulation of retinal neurons to induce phosphene perception. The shape and size of the evoked phosphenes are in part dependent on the spatial patterns of retinal activation. In this study, a computational model of a cat beta retinal ganglion cell (RGC) excitation following simulated electrical stimulation was investigated. Seven epiretinal disk electrodes with hexagonal configuration (Hex electrodes) were used. 100 {\~A}{\v Z}{\^A}¼s/phase anodic-first biphasic pulses were injected at the center electrode and one sixth of the total current was returned at each surround electrode. The aim was to obtain a spatial threshold map of the RGC excitation. We found that the spatial threshold pattern was highly dominated by axonal excitation. With 50 {\~A}{\v Z}{\^A}¼m Hex electrodes, relative thresholds for activation of the distal axon was almost the same as that for excitation of the axonal trigger segment (high sodium channel density region), causing an elongated activation pattern. The model presented in this study can be used to investigate the extent to which spatial RGC activation patterns are influenced by cell and stimulus parameters.",
keywords = "computer simulation, electric stimulation, electrodes, prosthesis, retina, retinal ganglion cells",
author = "Miganoosh Abramian and Lovell, {Nigel H.} and Morley, {John W.} and Suaning, {Gregg J.} and Socrates Dokos",
year = "2012",
doi = "10.1109/EMBC.2012.6346602",
language = "English",
isbn = "9781424441198",
publisher = "IEEE",
pages = "3029--3032",
booktitle = "Proceedings of the 34th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2012): 28 Aug. 2012 - 1 Sep. 2012, San Diego, California",
note = "IEEE Engineering in Medicine and Biology Society. Annual Conference ; Conference date: 30-04-2015",
}