AnIn VitroModel of a Retinal Prosthesis
- 16 May 2008
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Biomedical Engineering
- Vol. 55 (6), 1744-1753
- https://doi.org/10.1109/tbme.2008.919126
Abstract
Epiretinal prostheses are being developed to bypass a degenerated photoreceptor layer and excite surviving ganglion and inner retinal cells. We used custom microfabricated multielectrode arrays with 200-mum-diameter stimulating electrodes and 10-mum-diameter recording electrodes to stimulate and record neural responses in isolated tiger salamander retina. Pharmacological agents were used to isolate direct excitation of ganglion cells from excitation of other inner retinal cells. Strength-duration data suggest that, if amplitude will be used for the coding of brightness or gray level in retinal prostheses, shorter pulses (200 mus) will allow for a smaller region in the area of the electrode to be excited over a larger dynamic range compared with longer pulses (1 ms). Both electrophysiological results and electrostatic finite-element modeling show that electrode-electrode interactions can lead to increased thresholds for sites half way between simultaneously stimulated electrodes (29.4 plusmn 6.6 nC) compared with monopolar stimulation (13.3 plusmn 1.7 nC, < 0.02). Presynaptic stimulation of the same ganglion cell with both 200- and 10- m-diameter electrodes yielded threshold charge densities of 12 plusmn 6 and 7.66 plusmn 1.30 nC/cm 2 , respectively, while the required charge was 12.5 plusmn 6.2 and 19 plusmn 3.3 nC.Keywords
This publication has 55 references indexed in Scilit:
- Inner Retinal Mechanisms Engaged by Retinal Electrical StimulationInvestigative Ophthalmology & Visual Science, 2006
- Functional Organization of Ganglion Cells in the Salamander RetinaJournal of Neurophysiology, 2006
- A Method for Generating Precise Temporal Patterns of Retinal Spiking Using Prosthetic StimulationJournal of Neurophysiology, 2006
- Perceptual thresholds and electrode impedance in three retinal prosthesis subjectsIEEE Transactions on Neural Systems and Rehabilitation Engineering, 2005
- Thresholds for Activation of Rabbit Retinal Ganglion Cells with Relatively Large, Extracellular MicroelectrodesInvestigative Ophthalmology & Visual Science, 2005
- In vitroactivation of retinal cells: estimating location of stimulated cell by using a mathematical modelJournal of Neural Engineering, 2005
- Design and Testing of an Impedance-Based Sensor for Monitoring Drug DeliveryJournal of the Electrochemical Society, 2005
- The Development of Subretinal Microphotodiodes for Replacement of Degenerated PhotoreceptorsOphthalmic Research, 1997
- Cortical responses to local electrical stimulation of retinaExperimental Neurology, 1962
- Theoretical Analysis of the Current Density Distribution in Electrolytic CellsJournal of the Electrochemical Society, 1951