Writing On the Brain with Electricity

Live Science

The scientists stimulated the brain using electrodes implanted on its surface. Blind and sighted participants could "see" letters traced on their brains.

Transcript

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]

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