Related Experiment Video
Updated: Mar 7, 2026
12:56
Methodology for Biomimetic Chemical Neuromodulation of Rat Retinas with the Neurotransmitter Glutamate In Vitro
Published on: December 19, 2017
8.2K
High-amplitude electrical stimulation can reduce elicited neuronal activity in visual prosthesis
Alejandro Barriga-Rivera1, Tianruo Guo1, Chih-Yu Yang1
1Graduate School of Biomedical Engineering, UNSW, Sydney, 2052, Australia.
Scientific Reports
|February 18, 2017
Summary
Retinal electrostimulation for vision restoration faces challenges due to a narrow therapeutic window. High stimulating currents can inhibit retinal ganglion cells, limiting visual prosthesis performance and explaining observed phosphene shapes.
Area of Science:
- Biomedical Engineering
- Neuroscience
- Ophthalmology
Background:
- Retinal electrostimulation offers a promising approach for vision restoration therapies.
- A critical challenge is the narrow stimulating current range, balancing neuron excitation and inhibition, which impacts visual prosthesis function.
- Simultaneous activation of adjacent electrodes in visual prostheses can lead to electric field summation, potentially reaching inhibitory thresholds.
Purpose of the Study:
- To investigate the implications of high stimulating conditions in visual prostheses.
- To assess the impact of inhibitory stimulating conditions on retinal neuron activity and cortical responses.
- To elucidate the mechanisms underlying limitations in simultaneous stimulation for retinal prostheses.
Main Methods:
- In vivo electrostimulation using a suprachoroidal prosthesis in a feline model.
- In vitro electrostimulation of murine retinal preparations.
- In silico computational modeling of retinal ganglion cell population responses.
Main Results:
- High stimulating currents resulted in diminished cortical activity in feline subjects.
- Stimulus-response relationships exhibited non-monotonic profiles with increasing stimulating current.
- Both in vitro and in silico models demonstrated inhibition of nearby neuronal groups and recruitment of distant groups at specific amplitudes.
Conclusions:
- The inhibitory threshold of retinal ganglion cells limits simultaneous stimulation in retinal prostheses.
- These findings may explain halo-like phosphene perceptions reported in clinical trials.
- Understanding these limitations is crucial for optimizing visual prosthesis design and performance.
