Restore a rudimentary form of vision in the blind

The restoration of vision in blind people through a brain implant is on the verge of becoming a reality. Recent findings at the Dutch Institute of Neuroscience (NIN) show that newly developed high-resolution implants in the visual cortex allow for the recognition of artificially induced shapes and perceptions. The results were published in Science on December 3.

The idea of ​​stimulating the brain via an implant to generate artificial visual perceptions is not new and dates back to the 1970s. However, existing systems are capable of generating only a small number of artificial “pixels” at a time. At NIN, researchers from a team led by Pieter Roelfsema are now using new manufacturing and implantation technologies, cutting-edge materials engineering, microchip fabrication and microelectronics, to develop more stable and durable devices than previous implants. The first results are very promising.

Electrical stimulation

When electrical stimulation is delivered to the brain via an implanted electrode, it generates the perception of a point of light in a particular position in the visual space, known as a ‘phosphene. ‘The team developed high-resolution implants made up of 1024 electrodes and implanted them in the visual cortex of two sighted monkeys. Their goal was to create interpretable images by providing electrical stimulation simultaneously via multiple electrodes, to generate a perception composed of multiple phosphenes. “The number of electrodes we have implanted in the visual cortex and the number of artificial pixels we can generate to produce high-resolution artificial images is unprecedented,” says Roelfsema.

Recognize points, lines and letters

The monkeys first had to perform a simple behavioral task in which they performed eye movements to signal the position of a phosphene that was aroused during electrical stimulation via a single electrode. They were also tested on more complex activities such as a motion direction activity, in which micro-stimulation was delivered on a sequence of electrodes, and a letter discrimination activity, in which micro-stimulation was delivered. on 8-15 electrodes at once, creating a perception in the form of a letter. The monkeys successfully recognized shapes and perceptions, including lines, moving points, and letters, using their computer vision.

“Our implant interfaces directly with the brain, bypassing earlier stages of visual processing via the eye or optic nerve. Therefore, in the future, this technology could be used to restore low vision in blind people who have suffered injury or degeneration of the retina, eye or optic nerve, but whose visual cortex remains intact, “explains Xing Chen, a postdoctoral researcher on Roelfsema’s team.

This research lays the groundwork for a neuroprotetic device that could allow deeply blind people to regain functional vision and recognize objects, navigate unfamiliar environments and interact more easily in social contexts, significantly improving their independence and quality of life.

Provided by the Dutch Institute of Neuroscience