As part of the CORTIVIS project clinicaltrials.gov/ct2/show/NCT02, which aim is to develop a Cortical Neuroprosthesis for the Blind, we worked together with a blind volunteer who had lost her vision more than a decade ago...2/
Conversation
She underwent surgery and received a 96-channel implant on her visual cortex (). Over 6 months of neural recordings and psychophysics involving electrical stimulation, we found out she could perceive phosphenes in a reliable way! Mean current needed was 66.8 uA 3/
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We investigated the effect of different stimulation parameters in phosphene perception thresholds, including pulse width (100,170,400,800uS), stim frequency (100, 200, 300Hz), train duration (50,83,166ms), and number of simultaneous electrodes. I think the curves are beautiful 4/
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Electrode impedances measures were quite stable over time but we saw some trends. Regarding neural recordings, we found both increasing firing and inhibition after electrical stimulation during different stimulation trials. 5/
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We covered only a tiny part of the visual field, which we mapped thanks to a lot of hard work by our participant. A great example of higher visual coverage and pattern perception in monkeys can be found in this foundational work (Science) by Xing et al. tinyurl.com/ChenXScience 6/
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We even tested some simple patterned stimulation and obtained drawings of the evoked perceptions. Also, we conducted 2-AFC experiments for pattern discrimination with good results! Performance swiftly increased with time. 7/
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Lastly, we had the opportunity to perform preliminary test with our DL interface and an artificial retina, Neurolight, again for the first time in humans. Proudly using Keras () . Learn more about the DL neural interface here tinyurl.com/neuroLight 8/
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“Our results demonstrate the safety and efficacy of chronic intracortical microstimulation via a large number of electrodes in human visual cortex, showing its high potential for restoring functional vision in the blind” Paper here✨🙂tinyurl.com/jciVC 9/
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This work was only possible because of the selflessness and tenacity of our volunteer. You can learn more about our story as covered by MIT technology review (tinyurl.com/MITVCimpl) and El Pais (tinyurl.com/elPaisImplante) 10/
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Thanks again to everyone who made this meaningful step possible with their work and support☺️ we will keep working towards a visual prosthesis for the blind in the upcoming years through great projects such as and #neuraViPer 11/
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Tagging great colleagues, neuroscientists and engineers I admire, @max_hodak 12/
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@Cortivis_org share if you find it interesting^^ END/
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