Spatial Restriction of Neural Activation Using Focused Multipolar Stimulation With a Retinal Prosthesis
| Autor: | Thomas C Spencer, James B Fallon, Mohit N. Shivdasani, Patrick C. Thien |
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| Rok vydání: | 2016 |
| Předmět: |
0206 medical engineering
Stimulation 02 engineering and technology Prosthesis Design Retina 03 medical and health sciences chemistry.chemical_compound Spatial Processing 0302 clinical medicine medicine Electrode array Animals Visual Cortex Retinal Multielectrode array Anatomy 020601 biomedical engineering Electric Stimulation Electrodes Implanted Visual Prosthesis Disease Models Animal Phosphene Visual cortex medicine.anatomical_structure chemistry Visual prosthesis Sensory Thresholds Cats Evoked Potentials Visual 030217 neurology & neurosurgery Biomedical engineering |
| Zdroj: | Investigative Opthalmology & Visual Science. 57:3181 |
| ISSN: | 1552-5783 |
| Popis: | PURPOSE: The resolution provided by present state-of-the-art retinal prostheses is severely limiting for recipients, partly due to the broad spread of activation in the retina in response to monopolar (MP) electrical stimulation. Focused multipolar (FMP) stimulation has been shown to restrict neural activation in the cochlea compared to MP stimulation. We extended the FMP stimulation technique to a two-dimensional electrode array and compared its efficacy to MP and hexapolar (HP) stimulation in the retina. METHODS: Normally-sighted cats (n = 6) were implanted with a suprachoroidal electrode array containing 42 electrodes. Multichannel multiunit spiking activity was recorded from the visual cortex in response to MP, HP, and FMP retinal stimulation. RESULTS: When inferring retinal spread using voltage recordings off the stimulating array, FMP stimulation showed significantly reduced voltages in regions surrounding the primary stimulating electrode. When measuring the retinal and cortical selectivity of neural responses, FMP and HP stimulation showed significantly higher selectivity compared to MP stimulation (separate 2-way ANOVAs, P < 0.05). However, the lowest cortical thresholds for each stimulating electrode were higher for FMP and HP compared to MP stimulation (1-way ANOVA, P < 0.001). No significant differences were observed between FMP and HP stimulation in any measures. CONCLUSIONS: Focused multipolar and HP stimulation using a two-dimensional array are promising techniques to reduce the spread of activation for a retinal prosthesis. Clinical application would be expected to result in smaller phosphenes; thus, reducing phosphene overlap between electrodes and increasing the resolution at the expense of higher thresholds for activation. |
| Databáze: | OpenAIRE |
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