Shape perception via a high-channel-count neuroprosthesis in monkey visual cortex

Chen X, Wang F, Fernandez E, Roelfsema PR. Science. 2020 Dec 4;370(6521):1191-1196. DOI: 10.1126/science.abd7435. PMID: 33273097.

Abstract (as cited): “Blindness affects 40 million people across the world. A neuroprosthesis could one day restore functional vision in the blind. We implanted a 1024-channel prosthesis [Utah arrays, Blackrock] in areas V1 and V4 of the visual cortex of monkeys and used electrical stimulation to elicit percepts of dots of light (called phosphenes) on hundreds of electrodes, the locations of which matched the receptive fields of the stimulated neurons. Activity in area V4 predicted phosphene percepts that were elicited in V1. We simultaneously stimulated multiple electrodes to impose visible patterns composed of a number of phosphenes. The monkeys immediately recognized them as simple shapes, motions, or letters. These results demonstrate the potential of electrical stimulation to restore functional, life-enhancing vision in the blind.”

Context (from Blackrock Neurotech science page citing the work): previous studies used surface electrodes, requiring high currents, limiting simultaneous stimulation and giving low spatial resolution (activation of several mm of cortex); Chen et al. demonstrated simultaneous multi-electrode intracortical stimulation produces shape perception and successive stimulation produces motion perception (see Perspective by Beauchamp and Yoshor).

Foundation for the Dutch NIN/Phosphoenix approach; Roelfsema received HBP Innovation Award (March 2023) for “The Brain Prosthesis for the Blind”.