Monkey See

Researchers at the Netherlands Institute for Neuroscience (NIN) have successfully delivered high-resolution implants in areas V1 and V4 of the visual cortex of monkeys, allowing the subjects to recognize artificially induced shapes. The neuroprosthetic implants consist of 1,024 electrodes. When electrical stimulation is delivered to the brain via an implanted electrode, it generates the percept of a dot of light – also known as a phosphene – at a particular location in visual space.

To test whether the monkeys could successfully recognize percepts using their artificial vision, they were asked to perform simple behavioral tasks. First, their eye movements were monitored to see if they could report the location of a phosphene elicited during the stimulation of an individual electrode. Second, they were tested on more complex direction-of-motion and letter-discrimination tasks, in which microstimulation was delivered to up to 15 electrodes simultaneously to create a percept in the form of a letter or motion. The first results were promising; the monkey immediately recognized the percepts. The research offers hope that patients who have suffered injury or degeneration of the retina, eye, or optic nerve, but whose visual cortex remains intact, may one day be given functional vision via artificial sight.