The new implant will help restore the blind’s ability to read by transmitting letter images directly to the brain
Scientists developed a brain implant consisting of a network of electrodes that were implanted over the primary visual cortex of blind people: the technology allowed them to distinguish the “shape” of letters and even pieces of text. This is what they say in an article published in Cell magazine.
Most adults who have lost their eyesight are blind due to infection, eye or optic nerve damage, while the brain remains intact. Specialists have long wanted to develop technology that would literally restore vision – bypassing the eyes and transmitting visual information directly to the brain.
Scientists at Baylor College of Medicine in Houston (USA) have developed a brain implant, which through stimulation with electrodes allows the blind to distinguish the “shape” of the letters, thus virtually restoring their ability to read.
Specialists used an approach in which implanted electrodes are stimulated in a dynamic sequence, essentially “tracking” images on the surface of the visual cortex, which blind people were able to “see”.
“When we used electrostimulation to dynamically track the letters directly in the patient’s brain, they could sort of see the supposed shape of the letters and correctly identify different letters. They described the vision of the luminous spots or lines forming the letters and therefore the writing of the text,” said senior author Daniel Yoshor.
Previous attempts to stimulate the visual cortex – the part of the cortex of the large hemispheres of the brain responsible for the processing of visual information – were less successful.
“Instead of trying to create shapes from multiple light points, we traced the contours,” scientists noted.
The study involved four sighted people and two blind people who were implanted with electrodes over the visual cortex. The sequential stimulation of several electrodes led to the perception of shapes that the participants could correctly identify as specific letters.
According to scientists, their approach demonstrated that blind people can restore the ability to recognize visual images using technology that injects visual information directly into the brain. Before this technology can be introduced into clinical practice, there are certain limitations that need to be overcome.
“The primary visual cortex, where the electrodes were implanted, contains half a billion neurons. In this study, we have stimulated only a small fraction of these neurons with a handful of electrodes. An important next step is to work with neuroengineers to develop matrices with thousands of electrodes to enable us to perform more precise stimulation. Being able to recognize the silhouette of a family member or afford more independent movement would be a great achievement for many blind patients,” the scientists said.