Newly designed brain implants are demonstrating the promising possibility of relieving blindness. Using brain implants to trigger the perception of vision is not an unfamiliar suggestion. For many years, the idea of directly exciting the brain and circumventing the visual pathway has been discussed, with the earliest recorded proposition found to be from the 70s. Since then, the development of such technology has not been successful enough to generate high resolution, perceptible visual imagery.
Researchers from the Netherlands have recently designed highly progressive implants that demonstrate shape and image recognition by artificial excitation of the visual cortex. As of now, the discoveries are encouraging and exhibit higher resolution of recognized images and better durability than older designs.
What is the science behind the discovery?
The perception of vision and the extent of spatial ability is a reflection of the number of ‘phosphenes’. A phosphene is a precise point within visual space at which a spot of light is seen upon electrical excitation of the brain by a single electrode.
The research team used many electrodes concurrently to excite the visual cortex causing the formation of numerous phosphenes. This allowed the generation of a perceptible simulated image. The new implant is comprised of 1024 electrodes resulting in the generation of a greater number of artificial pixels than previous implant designs. Thus, improving the quality of perceived images.
How effective could the newly designed implant be in re-establishing vision?
The researchers experimented on two monkeys, not blind, to test the efficacy of the new prototype by implanting them into their visual cortex. They evaluated the monkeys carrying out multiple tasks of varying intricacy.
The first task tested the monkeys’ ability in discerning the exact point of a phosphene which was developed by using one electrode to stimulate the visual cortex. The monkeys carried out a simple task while the researchers observed their eye movements in a direction that should correspond with the generated phosphene.
A more intricate task tested their ability to differentiate letters and involved synchronous microscopic excitation of electrodes to develop a perceived image in the shape of a letter. The researchers also stimulated a succession of electrodes to test tasks related to direction-of-motion.
They found that by using artificial vision, the monkeys were capable of recognizing and discriminating a wide variety of simulated images, such as lines and letters, and movement in the form of moving dots.
What can we hope to happen as a result of this development?
Brain implants such as this one could potentially allow the partial treatment of blindness in anyone with an unscathed visual cortex. This means that trauma or deterioration of any part of the visual pathway other than the cortex, such as the eye or retina, may not mean total blindness. Blind people may hopefully one day be able to reclaim low vision and independence.