Writing On the Brain with Electricity
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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TechTranscript
00:00 By sending electrical currents over the surface of people's brains, scientists were able to get them to see things that weren't actually there.
00:07 These scientists are working to develop what are known as visual prosthetics, which in the future could be devices
00:18 implanted in the brain
00:20 that help to restore people's vision after they've lost their sight. In this particular study,
00:27 they implanted an array of electrodes which transfer electrical currents into tissues
00:33 onto the surface of the visual cortex, which is located at the very back of the brain.
00:38 And that is a region of the brain where visual information gathered from your eyes typically gets funneled for early processing.
00:45 Scientists have known that by stimulating specific points of the visual cortex,
00:51 you can generate what are known as phosphenes, which are these little pinpricks of light that you can see even if no light is
00:59 actually entering your eyes.
01:01 Another way you can generate phosphenes is by rubbing your eyes really hard in a dark room. Little pinpricks of light appear.
01:08 That can also happen when you stimulate the brain itself. So even though scientists knew how to generate
01:14 individual phosphenes, they'd had trouble in the past
01:18 connecting the dots into one coherent picture, which would make this technology much more useful. In this experiment,
01:25 they managed to connect the dots in this way and get the participants to see different letters.
01:30 So here in this video, we can see one of the participants in the study.
01:34 He has had electrodes implanted on the surface of his brain under the skull,
01:39 but it's being stimulated by that device you see on top of his baseball cap.
01:43 When the device is stimulated, the idea is that this electrical current is being sent through a flurry of electrodes in the shape of
01:51 a letter that the participant will then draw on the text screen in front of them.
01:57 Now, the letter has to be slightly manipulated when it's traced onto the brain because the visual
02:02 information that enters our eyes is
02:05 reflected and flipped upside down, and then our brain makes sense of it later.
02:09 So that's how these letters are drawn on the brain, and the participant, as you can see, is drawing them the correct way around.
02:16 This study included both sighted individuals and blind individuals,
02:20 and it is important to note that the blind individuals had lost their sight in adulthood. For now, these visual prosthetics are
02:27 mostly aimed at helping to restore vision in people who have lost it at some point in their life,
02:32 rather than to grant vision to people who have never been able to see.
02:37 Perhaps that could be a goal of the far distant future, but for now,
02:40 this is where the technology is, and it's still in its very early days.
02:44 But as the author said,
02:47 once this reached some sort of usable form, even having the ability to detect the form of a family member or to allow for more
02:55 independent navigation would be a wonderful advance for many blind patients.
03:00 [Music]