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

00:00By sending electrical currents over the surface of people's brains, scientists were able to get them to see things that weren't actually there.

00:12These scientists are working to develop what are known as visual prosthetics, which in the future could be devices

00:19implanted in the brain

00:20that help to restore people's vision after they've lost their sight. In this particular study,

00:27they implanted an array of electrodes, which transfer electrical currents into tissues,

00:33onto the surface of the visual cortex,

00:36which is located at the very back of the brain. And that is a region of the brain where visual information gathered from your eyes

00:43typically gets funneled for early processing.

00:46Scientists have known that by stimulating specific points of the visual cortex,

00:51you can generate what are known as phosphenes,

00:54which are these little pinpricks of light that you can see even 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. That can also happen when you stimulate the brain itself.

01:11So even though scientists knew how to generate individual phosphenes, they'd had trouble in the past

01:18connecting the dots into one coherent picture, which would make this technology much more useful. In this experiment,

01:25they managed to connect the dots in this way and get the participants to see different letters.

01:30So 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,

01:39but it's being stimulated by that device you see on top of his baseball cap.

01:43When the device is stimulated, the idea is that this electrical current is being sent through a flurry of electrodes in the shape of

01:51a letter that the participant will then draw on the touch screen in front of them.

01:57Now, the letter has to be slightly manipulated when it's traced onto the brain because the visual

02:03information that enters our eyes is

02:05reflected and flipped upside down and then our brain makes sense of it later.

02:09So that's how these letters are drawn on the brain, and the participant, as you can see, is drawing them the correct way around.

02:16This study included both sighted individuals and blind individuals,

02:20and it is important to note that the blind individuals had lost their sight in adulthood. For now, these visual prosthetics

02:28are mostly aimed at helping to restore vision in people who have lost it at some point in their life,

02:33rather than to grant vision to people who have never been able to see.

02:37Perhaps that could be a goal of the far distant future,

02:39but for now, this is where the technology is, and it's still in its very early days.

02:45But as the author said,

02:47once this reached some sort of usable form, even having the ability to detect the form of a family member or to allow for more

02:56independent navigation would be a wonderful advance for many blind patients.

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