Experimental brain implants in monkeys offer hope for vision restoration in blind people

Researchers developed implants with 1024 electrodes – conductors that carry electrical currents in and out of the brain – and implanted them in the visual cortex, the part of the brain that processes visual information, in two macaques.

By sending electrical signals to the brains of the monkeys, researchers created “phosphenes” – points of light that can be “seen” or perceived by the brain and used to create the illusion of shapes and objects.

Lead researcher Pieter Roelfsema told CNN that the team wanted to show that it was possible to induce “vision of objects” through direct electrical stimulation of the brain, and explained that the visual cortex has “a kind of visual map of space.”

“You can work with it like a matrix sign along the highway. If you stimulate or light multiple signs, you can see patterns,” he told CNN.

The monkeys performed a series of tasks and, using their artificial vision, were able to recognize shapes and “perceptions,” including lines, moving points and letters, researchers reported Friday in findings published in the journal Science.

Broader implications for vision restoration

The team believes that such technology could one day be used to simulate vision in blind people who have been able to see at some point in their lives.

Roelfsema told CNN that when people’s eyes stop functioning and they lose their vision, their cortex gets no input.

“Then what you do is bypass the defective eyes and put the images you normally see right into the visual cortex,” he said.

“When you stimulate with one electrode, you get one point of light. When you stimulate with a pattern of electrodes, you can create a pattern of these points, and from these patterns of points you can reproduce meaningful images,” he said, explaining that dots can be used to make letters of the alphabet.

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In the future, Roelfsema said, someone could wear a camera on their glasses that could translate the images into electrical stimulation patterns for the brain, and send them to the electrodes.

“The electrodes would then activate the appropriate cells, and the person might be able to see a car passing by, or a person walking into the road. It will give rise to some form of vision,” he said, adding. that he hopes the technology will be ready for testing in humans by 2023.

Holy grail of research

Researchers around the world are looking to the cortex as a way to restore vision. This year, a team from Spain’s Miguel Hern√°ndez University revealed that they could use brain implants to temporarily restore seminal vision in blind patients.

“The ability to artificially impose patterns of neural activity similar to those in the brain is a holy grail of neuroprosthetic research,” said Tom Mrsic-Flogel, director of the Sainsbury Wellcome Center for Neural Circuits and Behavior at University College London. , to CNN via email. .

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Mrsic-Flogel, who was not involved in the study, told CNN that the Amsterdam team “demonstrates that non-human primates can respond to complex stimulation patterns in the visual cortex in a way that is comparable to viewing normal shapes.

“While we will never know what another animal perceives, it is tempting to speculate that electrical stimulation resulted in visual perception,” he said.

This transformative study adds to the growing body of evidence linking neural activity and sensation.

“Studies such as these will pave the way for brain implants that enhance brain function when it is compromised, such as when we lose peripheral vision or hearing,” he added.

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