For most adults who lose their vision, blindness results from damage to the eyes or optic nerve while the brain remains intact. For decades, researchers have proposed developing a device that could restore sight by bypassing damaged eyes and delivering visual information from a camera directly to the brain. In a paper published in Cell on May 14, 2020, a team of investigators at Baylor College of Medicine in Houston, Texas, report that they are one step closer to this goal. The open-access Cell article is titled "Dynamic Stimulation of Visual Cortex Produces Form Vision in Sighted and Blind Humans." The authors describe an approach in which implanted electrodes are stimulated in a dynamic sequence, essentially "tracing" shapes on the surface of the visual cortex that participants were able to "see." "When we used electrical stimulation to dynamically trace letters directly on patients' brains, they were able to 'see' the intended letter shapes and could correctly identify different letters," said senior author Daniel Yoshor (at right in photo), MD, Chairman of Neurosurgery at Baylor College of Medicine (https://www.bcm.edu/news/appointments-faculty-staff/dr-daniel-yoshor-named-chair-of-neurosurgery). "They described seeing glowing spots or lines forming the letters, like skywriting." Previous attempts to stimulate the visual cortex have been less successful. Earlier methods treated each electrode like a pixel in a visual display, stimulating many of them at the same time. Participants could detect spots of light, but found it hard to discern visual objects or forms. "Rather than trying to build shapes from multiple spots of light, we traced outlines," says first author Michael Beauchamp, PhD (https://www.bcm.edu/research/labs/michael-beauchamp).
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