Dr. Matt Walker

So transcranial, direct current, and then stimulation.

We're trying to stimulate the brain, specifically the cortex.

And the way that we do this is that we apply electrode pads to your head and we insert a small amount of voltage into your brain.

Now, it's so small that you typically don't feel it, but it has a measurable impact on that electrical brain activity.

So very early on, scientists, and we weren't the first to do this by any means, there was a great paper, now a famous paper in my field, by a wonderful scientist, Jan Born in Germany.

And they took a group of subjects and they applied these electrode pads specifically to the front of the brain.

And I'll explain why we target the front of the brain with sleep electrical enhancement or the electroceutical, as it were.

They applied these electropads to two groups of participants, and then they let them go into sleep.

And as you'll remember, we described that in the first two or three hours of sleep is when you get most of your deep sleep.

And they were targeting those deep, slow brain waves that we spoke about, those big, slow, powerful waves that define deep sleep.

And what they did in one of those groups, the other group was the placebo group, they still had the electrodes applied, they still went to sleep.

In the stimulation group, they waited until those individuals went into deep sleep.

And I told you in the first episode that those deep sleep brainwaves were going up and down very, very slowly, maybe just once or twice a second.

So they started to stimulate the brain, inputting these stimulation pulses at a very slow rhythm.

trying to match the rhythm of the brain.

In fact, they were less than one hertz, less than one cycle per second in terms of a pulse.

It's almost as though we're trying to act like a choir to a flagging lead vocalist.

And as these brainwaves are going up and down, you're trying to sing in time with those deep sleep brainwaves.

And in doing so, you're trying to boost and amplify the size of those deep sleep brainwaves.

Now, to begin with, they just waited until they went into deep sleep and they started to stimulate at that frequency.