The reason is, they're treating other people like a computer, and the brain is too.

And as they follow them over 5 years comparing them to age match controls, you can see that, particularly in areas

And you see activity in some regions we've seen today, medial prefrontal cortex, dorsomedial, however, up here, ventromedial prefrontal cortex, anterior cingulate, an area that's involved in lots of types of conflict resolution, like if you're playing Simon Says, and also the right and left temporoparietal junction.

So you have the prefrontal cortex here,

In red is an area that's active in the prefrontal cortex, the frontal lobe of the brain, and in blue is this area that was deactivated.

It's also, by the way, a characteristic of certain kinds of brain damage.

It peaks in early adolescence.

So this is a model of the human brain, and this is prefrontal cortex, right at the front.

It goes to the nucleus accumbens, all the way up to the prefrontal cortex, orbital frontal cortex, where decisions are made, high level.

So we had this focal area called the medial prefrontal cortex that went way up in activity.

It's keeping me standing. It's involved in coordinated movement.

And one of the main reasons our brain got so big is because it got a new part, called the frontal lobe.

The bell curve shows 150 controls, and what is being looked at is the difference between the right and the left frontal lobe.

(Laughter)

And if you closed your eyes you'd be able to mentally navigate it.

Well it turns out there is a way to measure happiness in the brain.

One of the brain regions that changes most dramatically during adolescence is called prefrontal cortex.

It's been shown to promote pre frontal cortex development where a lot of cognition is happening.

The pattern is that those people, every one of them I looked at, who was a murderer, and was a serial killer, had damage to their orbital cortex, which is right above the eyes, the orbits, and also the interior part of the temporal lobe.

So that's the part of the brain that is activated when you give a word to something.

It's called the hippocampus.

And you do that by measuring the relative activation of the left prefrontal cortex in the fMRl, versus the right prefrontal cortex.

This is the work of Dr. Bruce Miller.

The frontal lobe, the neocortex, the human part that doesn't come back.

And in the Charles Bonnet syndrome, you don't go to those higher levels.

We're only going to talk about three of them.

The bullet entered The frontal bone Just above the left orbit, Traveled in an upward trajectory

But in addition, if you compare the skull with a comparably aged chimpanzee and little George Bush here, you see that you have vertical forehead.

The olecranon, the medial epicondyle, the lateral epicondyle, the radial head, the location of the posterior interosseous nerve, and the biceps tendon in the antecubital fossa.

It's important if you try to model this.

On the medial side palpate the medial collateral ligament, the medial joint line, the pes anserine bursa.

And this region, the regions within the limbic system, have been found to be hypersensitive to the rewarding feeling of risk taking in adolescents compared with adults, and at the very same time, the prefrontal cortex, which you can see in blue in the slide here, which stops us taking excessive risks, is still very much in development in adolescents.

And instead of getting normal perception, you're getting an anarchic, convulsive stimulation, or release, of all of these visual cells in the inferotemporal cortex.

And what pattern do you see here?

And, of course, there's the entire cytoplasm in the rest of the cell.

These are contrast maps that are showing subtractions between what changes when you're improvising vs. when you're doing something memorized.

We made a wheel to figure that out,

Because our egocentric perception from the Buddha's point of view, misperception is that all we are is what is inside our skin.

The reptilian part of our brain, which sits in the center of our brain, when it's threatened, it shuts down everything else, it shuts down the prefrontal cortex, the parts which learn, it shuts all of that down.

If you look at the first slide there, that's the temporal lobes, frontal lobes, parietal lobes, OK the lobes that constitute the brain.

That's the good news.

To hear it, you'll need a frontal lobe and things with names like colliculus and temporal gyrus, but you won't have them anymore because they'll just be soup.

What does a pre frontal cortex do for you that should justify the entire architectural overhaul of the human skull in the blink of evolutionary time?

So MRI studies looking at the development of this region have shown that it really undergoes dramatic development during the period of adolescence.

So if you look at gray matter volume, for example, gray matter volume across age from age four to 22 years increases during childhood, which is what you can see on this graph.