Here, the red is the positive terminal, and I'm going to put that over your left forehead,

and the black is the negative terminal, and I'm going to put that over your right forehead.

And the electricity is going to run between them through my head, from the positive to the negative.

This is me in the laboratory of Marone Bixen. He's a professor of biomedical engineering at the City College of New York,

and he's attaching electrodes to my forehead. Professor Bixen's about to run a couple millimets of electrical

current through my skull. Your head is the circuit because you think about it, right, that the

electricity will arrive at one sponge. And after that, it's just your head. So it has nowhere to go. It has to

cross into your head, flow through your head, and then you have a worried look on your face.

That did ramp up my anxiety when I thought about it that way. Here's one. Here's a wire. Here's

another wire. Let's just going to go through those wires. And the thing that it's going to go

through is me. My brain. Do you want to feel it on your arm first?

Sure. Professor Bixen first became intrigued by brain stimulation when he was a student and he was

studying epilepsy, and he found out that a seizure is like an electrical storm in the brain. That idea

fascinated him. Nowadays, Professor Bixen designs medical devices, and some of those devices

are battery-powered caps that you can wear on your head. The caps give off about as much

electrical current as a 9-volt battery. In some cases, it could look like a swimming cap

with little knobs in it, and those knobs press onto the scalp. Each one of those knobs has a

wire coming out of it that connects

to a little computer. And by controlling how much current is sent to each knob, you can direct

the electrical energy to different parts of the brain. He's hoping that using this kind of cap might do

things like help people recover faster from a stroke. So really our mission is to reduce human suffering with technology.

And we work with all kinds of technology, including brain stimulation devices.

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