So you have the prefrontal cortex here,

Prefrontal cortex is an interesting brain area.

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

The arrows indicate peak gray matter volume in prefrontal cortex.

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

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.

We had this broad patch of area called the lateral prefrontal cortex that went way down in activity,

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

like the dorsal lateral prefrontal cortex or the superior temporal gyrus, there is a profound loss of gray matter.

In very short, people who have more activity in the right side of the prefrontal cortex are more depressed, withdrawn.

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.

This is an area in the prefrontal cortex, a region where we can use cognition to try to overcome aversive emotional states.

One of the big surprises is how limited our attention is, and it comes back to how small and fragile the prefrontal cortex is.

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.

To his auditory cortex.

So in my lab, we bring adolescents and adults into the lab to have a brain scan, we give them some kind of task that involves thinking about other people, their minds, their mental states, their emotions, and one of the findings that we've found several times now, as have other labs around the world, is part of the prefrontal cortex called medial prefrontal cortex, which is shown in blue on the slide, and it's right in the middle of prefrontal cortex in the midline of your head.

We've reached the gustatory cortex.

One human cortex, one machine.

Particularly, a part called the pre frontal cortex.

On the side here, this is temporal cortex.

Look at cerebral cortex, look at brain stem,

So we've got motor cortex activation up there.

So we've got motor cortex activation up there.

So from the retina you go onto visual cortex.

You're flying through the cortex of my colleague's brain.

You don't form images with your primary visual cortex.

But if I say, See a region of the brain, taking all the oxygen and glucose from all these other regions, and your prefrontal cortex suddenly has very little resources to do much, you can see that, right?

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.

You know, this is the parietal cortex, the somatosensory cortex, this is the touch of her skin, the texture of her clothes.

We have this big cortex, we're pretty proud of ourselves.

That red piece of brain tissue is your somatosensory cortex.

There is about 20 regions of the brain that have been modeled, simulated and tested the auditory cortex, regions of the visual cortex cerebellum, where we do our skill formation slices of the cerebral cortex, where we do our rational thinking.

Each individual's cortex is folded differently, very much like a fingerprint.

Their motor cortex is partially exposed at the back of their neck.

You prune away the weaker branches so that the remaining, important branches, can grow stronger, and this process, which effectively fine tunes brain tissue according to the species specific environment, is happening in prefrontal cortex and in other brain regions during the period of human adolescence.

And primary visual cortex sees just simple geometry, just the simplest of shapes.

So they're all these points of light on the outside of your cortex.

I hope you're not implying that any day is unimportant at Cortex Semi.

When people have these simple geometrical hallucinations, the primary visual cortex is activated.

You can see that that peak happens a couple of years later in boys relative to girls, and that's probably because boys go through puberty a couple of years later than girls on average, and then during adolescence, there's a significant decline in gray matter volume in prefrontal cortex.

Now that might sound bad, but actually this is a really important developmental process, because gray matter contains cell bodies and connections between cells, the synapses, and this decline in gray matter volume during prefrontal cortex is thought to correspond to synaptic pruning, the elimination of unwanted synapses.

There is the brain stem in between the cerebral cortex and the spinal cord.

largely of the brain stem and whatever there is of cortex in those species.

If you do this it turns out, the auditory cortex will learn to see.