Visual percepts evoked with an intracortical 96-channel microelectrode array inserted in human occipital cortex
Eduardo Fernández, … , Tyler S. Davis, Richard A. Normann
Eduardo Fernández, … , Tyler S. Davis, Richard A. Normann
Published October 19, 2021
Citation Information: J Clin Invest. 2021;131(23):e151331. https://doi.org/10.1172/JCI151331.
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Clinical Medicine Neuroscience Ophthalmology

Visual percepts evoked with an intracortical 96-channel microelectrode array inserted in human occipital cortex

Abstract

BACKGROUND A long-held goal of vision therapy is to transfer information directly to the visual cortex of blind individuals, thereby restoring a rudimentary form of sight. However, no clinically available cortical visual prosthesis yet exists.METHODS We implanted an intracortical microelectrode array consisting of 96 electrodes in the visual cortex of a 57-year-old person with complete blindness for a 6-month period. We measured thresholds and the characteristics of the visual percepts elicited by intracortical microstimulation.RESULTS Implantation and subsequent explantation of intracortical microelectrodes were carried out without complications. The mean stimulation threshold for single electrodes was 66.8 ± 36.5 μA. We consistently obtained high-quality recordings from visually deprived neurons and the stimulation parameters remained stable over time. Simultaneous stimulation via multiple electrodes was associated with a significant reduction in thresholds (P < 0.001, ANOVA) and evoked discriminable phosphene percepts, allowing the blind participant to identify some letters and recognize object boundaries.CONCLUSIONS 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.TRIAL REGISTRATION ClinicalTrials.gov identifier NCT02983370.FUNDING The Spanish Ministerio de Ciencia Innovación y Universidades, the Generalitat Valenciana (Spain), the Europan Union’s Horizon 2020 programme, the Bidons Egara Research Chair of the University Miguel Hernández (Spain), and the John Moran Eye Center of the University of Utah.

Authors

Eduardo Fernández, Arantxa Alfaro, Cristina Soto-Sánchez, Pablo Gonzalez-Lopez, Antonio M. Lozano, Sebastian Peña, Maria Dolores Grima, Alfonso Rodil, Bernardeta Gómez, Xing Chen, Pieter R. Roelfsema, John D. Rolston, Tyler S. Davis, Richard A. Normann

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Figure 7

Examples of perceptions evoked by simultaneous stimulation of multiple electrodes.

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Examples of perceptions evoked by simultaneous stimulation of multiple e...
(A) The stimulation of the 2 electrodes shown in the inset electrode map induced the perception of 2 closely spaced phosphenes. (B) Box-and-whisker plot of subjective phosphene size for electrode pairs separated from 400 to 3600 μm. Inset: Relative location of electrodes 1 and 10 in the UEA, which are separated by 400 μm (light blue color), and electrodes 1 and 89, which are separated by 3600 μm (orange color). In the box-and-whisker plot, the boundary of the box closest to zero indicates the first quartile, and the boundary of the box farthest from zero indicates the third quartile. The horizontal line is the median. The whiskers show the maximum and minimum values, with the exception of outliers (small circles) and extremes (stars). (C) Simultaneous stimulation of 4 contiguous electrodes was perceived as 3 small dots. (D) Stimulation of 12 electrodes induced the perception of a horizontal line. (E) Simultaneous stimulation of the 2 groups of 4 blue electrodes evoked the percept of a line with a horizontal orientation, whereas the simultaneous stimulation of the 2 groups of 4 red electrodes evoked the percept of a line with a vertical orientation. (F) Stimulation of these electrodes elicited the perception of a lowercase letter i. (G) Stimulation of these 2 groups of electrodes unexpectedly induced the perception of an uppercase letter L. (H) Stimulation of these electrodes elicited the perception of an uppercase letter O.