The scientists stimulated the brain using electrodes implanted on its surface. Blind and sighted participants could "see" letters traced on their brains.
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00:00By sending electrical currents over the surface of people's brains, scientists were able to
00:05get them to see things that weren't actually there.
00:12These scientists are working to develop what are known as visual prosthetics, which in
00:17the future could be devices implanted in the brain that help to restore people's vision
00:23after they've lost their sight.
00:25In this particular study, they implanted an array of electrodes, which transfer electrical
00:31currents into tissues, onto the surface of the visual cortex, which is located at the
00:37very back of the brain.
00:39And that is a region of the brain where visual information gathered from your eyes typically
00:43gets funneled for early processing.
00:47Scientists have known that by stimulating specific points of the visual cortex, you can generate
00:53what are known as phosphenes, which are these little pinpricks of light that you can see
00:58even if no light is actually entering your eyes.
01:01Another way you can generate phosphenes is by rubbing your eyes really hard in a dark room.
01:06Little pinpricks of light appear.
01:08That can also happen when you stimulate the brain itself.
01:12So even though scientists knew how to generate individual phosphenes, they'd had trouble in
01:17the past connecting the dots into one coherent picture, which would make this technology much
01:22more useful.
01:24In this experiment, they managed to connect the dots in this way and get the participants
01:29to see different letters.
01:31So here in this video, we can see one of the participants in the study.
01:34He has had electrodes implanted on the surface of his brain under the skull, but it's being
01:40stimulated by that device you see on top of his baseball cap.
01:44When the device is stimulated, the idea is that this electrical current is being sent through
01:49a flurry of electrodes in the shape of a letter that the participant will then draw on the text
01:56screen in front of them.
01:57Now, the letter has to be slightly manipulated when it's traced onto the brain because the
02:02visual information that enters our eyes is reflected and flipped upside down, and then
02:08our brain makes sense of it later.
02:09So that's how these letters are drawn on the brain.
02:12And the participant, as you can see, is drawing the correct way around.
02:17This study included both sighted individuals and blind individuals, and it is important
02:21to note that the blind individuals had lost their sight in adulthood.
02:25For now, these visual prosthetics are mostly aimed at helping to restore vision in people
02:31who have lost it at some point in their life, rather than to grant vision to people who have
02:35never been able to see.
02:37Perhaps that could be a goal of the far distant future, but for now, this is where the technology
02:42is, and it's still in its very early days.
02:46But as the author said, once this reached some sort of usable form, even having the ability
02:52to detect the form of a family member or to allow for more independent navigation would
02:57be a wonderful advance for many blind patients.
03:06We should say to conclude, for now, it's possible that the few commanders were not facing one point in
03:18the border.
03:19We should be vigilant to make sure that they are Joe Benjamin is
03:22perfect to handle the last heartbeat.
03:25Thanks for listening.