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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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 5

Phosphene map and relative brightness and size of perceived phosphenes.

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Phosphene map and relative brightness and size of perceived phosphenes. ...
(A) Location of the perceived phosphenes (blue dots) and electrode numbering view from the pad side. The cross indicates the center of the subject’s visual field (the intersection of her horizontal and vertical meridians). Yellow region: Expected location of the phosphenes based on a standard retinotopic map superimposed on the anatomy of the visual cortex of the patient using the procedures described by Benson et al. (22, 23) and the selected implantation site. Calibration bar = 1 degree. (B) Changes in the location of the perceived phosphenes for the same 4 electrodes in 5 different trials. Calibration bar = 1 degree.