Cyberpunk World

Researchers at Weill Cornell Medical College have cracked a mouse’s retinal neural code and integrated this information with a prosthetic device to restore vision of blind mice. They have also deciphered the code for a monkey’s retina and since monkeys and humans have almost identical retinas, they hope to begin human trials in as short as one to two years. If proven safe and effective, the prosthetic provides hope for 25 million people who have disease-caused blindness.

With normal vision, when light falls on photoreceptors in the surface of the retina, the signals from the photoreceptors are converted into a code of electrical signals that are then sent up to the brain by ganglion cells. The brain then translates this code into images. Diseases that cause blindness include retinal tear or detachment, macular degeneration (which may occur in aging), and diabetic retinopathy. Such diseases destroy the photoreceptors and the retinal circuitry but usually do not affect the ganglion cells.

Other scientists have developed bionic eye implants and light-sensitive proteins to replace the damaged photoreceptors and stimulate the ganglion cells of the patients, but these approaches only result in rough visual fields consisting of spots and edges of light. According to lead researcher Dr. Sheila Nirenberg, “Not only is it necessary to stimulate large numbers of cells, but they also have to be stimulated with the right code — the code the retina normally uses to communicate with the brain.”

A shows normal vision. B and C shows the image the blind mice saw after the novel treatment. D shows the image they would see using conventional treatment.

(image credit: Daily Mail)

The code (a set of equations) converts light patterns into electrical impulses and this code is what Dr. Nirenberg and her co-author Dr. Chethan Pandarinath have discovered. During experiments with mice, the researchers found that with the use of the code, the novel prosthetic provides near-normal vision and allows recognition of facial features and tracking of moving images.

Dr. Nirenberg envisions the prosthetic system in the form of spectacles or a Star Trek-like visor to be worn by the user. A tiny camera embedded in the visor will pick up information in the user’s line of sight and a small processor will turn the information into code. A mini projector will then convert the code into flashes of light to activate the cells at the back of the retina and pass the encoded information to the brain.

The researchers published their study in Proceedings of the National Academy of Sciences of the United States of America.

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