People who have lost their sight are able to 鈥渟ee鈥� letters that have been traced on the surface of their brain using electrical stimulation. It is an early step towards implants that could allow more complex vision.
鈥淭he finding that we can make blind patients 鈥榮ee鈥� letters is very exciting, because we hope to build on this and do much more in the future,鈥� says Daniel Yoshor at the University of Pennsylvania. 鈥淯ltimately, we want to restore some useful visual function to blind patients and hopefully improve their lives,鈥� he says.
Yoshor and his colleagues worked with five people who had electrodes implanted in their brains on the surface of a region required for vision, called the visual cortex. Two participants had lost their sight and had received their electrode implants as part of a clinical trial to treat blindness. The other three were able to see and had received implants as part of epilepsy treatment.
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When the researchers stimulated the electrodes in sequence to trace the shapes of specific letters on the surface of the brain, all the participants reported seeing glowing spots or lines forming the same letters.
This study suggests that this type of vision may require multiple brain cells to be activated in sequence, rather than simultaneously, says Gy枚rgy Buzs谩ki at New York University.
The situation is similar to someone tracing a shape on the surface of your skin, says Buzs谩ki. It is much easier for the brain to identify the shape when it is traced compared with when many sites are simultaneously pressed at the same time, he says.
鈥淔uture designs of virtual cortical prosthetic devices will likely employ many thousands of electrodes on a much finer scale,鈥� says Michael Beauchamp at Baylor College of Medicine in Texas, who worked with Yoshor on the study.
鈥淎n early iteration would provide detection of the contours of shapes encountered. The ability to detect the form of a family member or to allow more independent navigation would be a wonderful advance for many blind patients,鈥� says Beauchamp.
Cell
