Targeted Stimulation of Retinal Ganglion Cells in Epiretinal Prostheses: A Multiscale Computational Study
| Autor: | Mark S. Humayun, Kyle Loizos, Javad Paknahad, Gianluca Lazzi |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Retinal Ganglion Cells
genetic structures 0206 medical engineering Biomedical Engineering Action Potentials Stimulation 02 engineering and technology Stimulus (physiology) Retinal ganglion Retina Article 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Internal Medicine Humans Medicine Axon business.industry General Neuroscience Sodium channel Retinal Degeneration Rehabilitation Retinal 020601 biomedical engineering Electric Stimulation eye diseases Visual Prosthesis medicine.anatomical_structure Phosphene chemistry sense organs business Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | IEEE Trans Neural Syst Rehabil Eng |
| ISSN: | 1558-0210 1534-4320 |
| DOI: | 10.1109/tnsre.2020.3027560 |
| Popis: | Retinal prostheses aim at restoring partial sight to patients that are blind due to retinal degenerative diseases by electrically stimulating the surviving healthy retinal neurons. Ideally, the electrical stimulation of the retina is intended to induce localized, focused, percepts only; however, some epiretinal implant subjects have reported seeing elongated phosphenes in a single electrode stimulation due to the axonal activation of retinal ganglion cells (RGCs). This issue can be addressed by properly devising stimulation waveforms so that the possibility of inducing axonal activation of RGCs is minimized. While strategies to devise electrical stimulation waveforms to achieve a focal RGCs response have been reported in literature, the underlying mechanisms are not well understood. This article intends to address this gap; we developed morphologically and biophysically realistic computational models of two classified RGCs: D1-bistratified and A2-monostratified. Computational results suggest that the sodium channel band (SOCB) is less sensitive to modulations in stimulation parameters than the distal axon (DA), and DA stimulus threshold is less sensitive to physiological differences among RGCs. Therefore, over a range of RGCs distal axon diameters, short-pulse symmetric biphasic waveforms can enhance the stimulation threshold difference between the SOCB and the DA. Appropriately designed waveforms can avoid axonal activation of RGCs, implying a consequential reduction of undesired strikes in the visual field. |
| Databáze: | OpenAIRE |
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