Abstract
Blindness affects 40 million people worldwide, and a neuroprosthesis may restore functional vision in the future. We developed a 1024-channel, chronically implantable prosthesis for the monkey visual cortex, using electrical stimulation to elicit percepts of dots of light (‘phosphenes’) across hundreds of electrodes. Phosphene locations matched the receptive fields of stimulated neurons, and V4 activity predicted phosphene detection during stimulation in V1. Next, we stimulated multiple electrodes simultaneously to generate percepts composed of multiple phosphenes. The monkeys could immediately recognize simple phosphene shapes, directions of motion, and letters. We developed techniques such as semi-automatic phosphene mapping and current thresholding, to expedite calibration of a prosthesis. Finally, we tested and validated several of our stimulation and calibration methods in blind human volunteers, demonstrating the potential of electrical stimulation to restore life-enhancing vision in the blind.
Funding: NWO (STW Grant Number P15-42 'NESTOR'; ALW Grant Number 823-02-010 and Cross-over Grant Number 17619 'INTENSE'). European Union (ERC Grant Numbers 339490 'Cortic_al_gorithms' and 101052963 'NUMEROUS,' H2020 Research and Innovation programme Grant Number 899287 'NeuraViper'). The Human Brain Project (Grant Number 650003). BrainLinks-BrainTools, Cluster of Excellence funded by the German Research Foundation (DFG, EXC 1086).