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

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.

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