The headset he is talking about looks very much like a normal set of headphones. Big ear muffs cover your ears with a band that goes over the top of your head… It’s covered in foamy pointed nubs that make contact with your scalp to deliver an electrical current to your cranium.
…[Wingeir:] But what’s happening under the hood is if you take a little bit of electrical current and you put it on your scalp, enough of that makes its way through your scalp and through your skull that it makes your neurons more likely to fire together. And that’s the whole mechanism of learning. What neuroscientists say is ‘neurons that fire together wire together.’
…[Armstrong:] Think of it this way: if you lift something heavy, it is not just your bicep (for example) that is being recruited by your brain, it is also all the stabilizer muscles that support that primary muscle. This means that part of getting better at a movement is not just making the muscle stronger but also developing the coordination of all the muscles learning to fire together (and wire together). [Wingeir]: Exactly. So if you speed that up a little bit, then you accelerate the benefits from any kind of movement training.