Transcript

I'm Marcus Rakel. I'm at Washington University in St Louis. I'm a neurologist by training, but most of my work has been done in the laboratories of the Mallinckrodt Institute of Radiology. No, emphatically not. No, this is, you know, you still hear this, you know. Or I'm only using part of my brain, or I activated my brain, or I turned it on, and all of which implies that it goes into some sort of dormant state, that if I were to look in, it would just be a true black box. And nothing could be further from the truth.

I mean, the first thing to know is that among the organs of the body, it's continuously the most expensive. Now, the muscles can have bursts of energy use when you're running or walking, but they can go to zero. The brain kind of oscillates between somewhere between 95% and 100% most of the time, and we've known this for a long time. It goes back to studies that were done right after the Second World War, where whole brain metabolism was measured the amount of oxygen consumed, which tells us how much energy is used. And it became patently obvious that it was using a lot. It's only 2% of the body's weight, and it's 20% of the cost of running the body that's in an adult, in a child of age 10, it is twice the cost.