Artikel
Phosphene interactions among electrode groups in IntraCortical Visual Prosthesis (ICVP)
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Autoren
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Astrid Jiang
- Neuroscience Department, Johns Hopkins University
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M.P. Barry
- Pritzker Institute, Illinois Institute of Technology
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G. Dagnelie
- Ophthalmology, Johns Hopkins University
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P.R. Troyk
- Pritzker Institute, Illinois Institute of Technology
| Veröffentlicht: | 9. Mai 2025 |
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Gliederung
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Objective: With the ICVP device, consisting of 25 wireless floating microelectrode arrays (WFMAs) implanted on the visual cortex, we aim to identify interactions among neighboring phosphenes and analyze factors and patterns of such interactions.
Methods: Thirty-four pairs of microelectrode groups were stimulated separately and simultaneously under implantee control for 409 trials. The implantee reported relative positions of the two percepts and descriptions of interactions – simultaneous stimulation producing a different percept from the simple combination of the two phosphenes. The interactions were categorized, and we tested the effect of phosphene distance and electrode distance on the presence of interaction with a binomial generalized linear model (GLM).
Results: Phosphenes can interact by merging (occurred at least once in 64.7% of the pairs tested), overlapping (23.5%), mutual enhancement (26.5%), and triggering (20.6%) – stimulation on one group eliciting a phosphene associated with the other group. Within-WFMA (distance≈1,000 µm) interactions have a significantly higher (71.8%) probability than inter-WFMA interactions (17.6%; p<0.0002, two-sample permutation test). GLM results were not significant but suggested that distance between phosphenes could be a stronger predictor (z=–1.3, p=0.1) for the presence of interactions than cortical distance between electrodes (z=0.091, p=0.5). The two factors had relatively high mutual information (NMI=0.62).
Discussion: Phosphenes are more likely to interact when their stimulation electrodes are on the same array. The types of interaction differ depending on electrode group distance: close-by groups, when they interact, are more likely to merge rather than overlap, enhance, or trigger. Information on these interactions allows us to identify electrode patterns that change percepts when stimulated together, which can then be avoided or utilized in subsequent functional tests.
Acknowledgement: This work was supported by NIH grant UH3 NS095557
