Although it is a proof of concept, the possibility of restoring vision in blind people through a brain implant is about to become a reality. A work of the Dutch Institute of Neuroscience, which is published today in Science, presents a new generation of high-resolution implants in the visual cortex that make it possible to recognize shapes and contours.
The idea of stimulating the brain through an implant to generate artificial visual perceptions is not new and dates back to the 1970s. However, existing systems can only generate a small number of artificial ‘pixels’ at a time.
But the team led by Pieter Roelfsema has employed new implant implantation and production technologies, cutting-edge materials engineering, microchip manufacturing and microelectronics to develop devices that are more stable and durable than previous implants. And the first results are very promising.
Through an electrode implanted in the brain, electrical stimulation is activated that generates the perception of a point of light in a particular location in visual space, known as a ‘phospheno.’
The team developed high-resolution implants that have 1,024 electrodes and implanted them in the visual cortex of two blind monkeys.
The goal was to create interpretable images by electrical stimulation through multiple electrodes and, at the same time, to generate a perception that is made up of multiple phosphenes. “The number of implanted electrodes that we have in the visual cortex, and the number of artificial pixels to generate that we can produce artificially high-resolution images, is unprecedented,” says Roelfsema.
Recognize points, lines and letters
The animals had to perform simple tasks such as moving their eyes to locate the location of a ‘phosphene’ that was generated during electrical stimulation through a single electrode. They were also tested on more complex tasks, such as a motion direction task, in which micro-stimulation was delivered on a sequence of electrodes, and a letter discrimination task, in which micro-stimulation was delivered on 8-15 electrodes simultaneously. , creating a perception in the form of a letter.
The monkeys successfully recognized shapes and perceptions, including lines, moving dots, and letters, using their computer vision.
«Our implant accesses directly with the brain, without going through the previous stages of visual processing through the eye or the optic nerve. Therefore, in the future, this technology could be used to restore vision in people who are blind due to lesions or degeneration of the retina in the eye or optic nerve, but whose visual cortex remains intact “, explains Xing Chen , a postdoctoral researcher in Roelfsema’s team.
This research lays the foundations for a neuroprosthetic device that could allow blind people to regain functional vision capable of recognizing objects, moving through an unknown place and interacting in social settings more easily, significantly improving their independence and quality of life.