0:00

Let's take a look at a three-year-old.

0:02

Now, a three-year-old is not going to accumulate

0:04

much brain iron until they are 12, 13, or 14.

0:07

So my purpose here is not to show you

0:09

the iron distribution or stores,

0:11

which would be important in Parkinson-related

0:14

disorders, but to focus on the corpus striatum,

0:18

the caudate,

0:19

which is this large structure right here,

0:21

kind of oval or lentiform shape,

0:23

and the putamen.

0:26

And most people don't realize

0:27

that the caudate, not only has a head,

0:30

this is the head right here.

0:31

But if you look at it sagittally,

0:33

which I'm not going to do right now,

0:35

it has a head, a body,

0:38

and kind of fades away as a tail.

0:40

So you can actually continuously follow the

0:44

caudate nucleus around, as we are right here.

0:47

This is all part of the caudate,

0:49

and the caudate will become diminished or

0:53

atrophic in certain disease states,

0:55

especially Huntington's chorea.

0:57

When that happens,

0:58

the ventricle will bulge outward.

1:01

We also have the putamen.

1:03

There's an inner and an outer section of the

1:05

putamen, which with higher resolution,

1:07

you could divide up.

1:08

But there's also an inner and outer section of the

1:12

globus pallidus, which as iron accumulates,

1:14

you can also divide up.

1:15

But you can see the outer globus is a little

1:19

bit brighter than the inner globus,

1:21

which tends to smear or blend with the genu,

1:24

right there, of the internal capsule.

1:26

So this would be the anterior limb

1:27

of the internal capsule genu,

1:29

and then posterior limb of the internal capsule,

1:32

and then retro lentiform portion of the internal

1:35

capsule seen on the T2-weighted image.

1:37

Look at the signal intensity in a normal,

1:40

healthy young infant and the size of the caudate

1:45

nucleus and the globus pallidus.

1:47

Very important when we're assessing

1:49

neurodegenerative disorders.

1:51

Then as we move out from the globus,

1:52

we run into the external capsule,

1:55

a little hard to see in this case,

1:57

the extreme capsule.

1:58

And we do see the centrosylvian cortex.

2:02

More posteriorly,

2:03

we've got the thalamus with its many divisions

2:06

to be discussed a little bit later.

2:07

And in the coronal projection,

2:09

we see the thalamus as a relatively large

2:11

structure with this bump along the

2:14

posterior aspect of the thalamus,

2:15

known as the thalamic pulvinar.

2:17

This will be an important structure

2:19

in certain metabolic disorders.

2:22

Now, as we move away from our axial and we've got our

2:27

anterior limb of internal capsule and genu as a

2:29

great marker, separating the

2:31

putamen from the caudate.

2:33

Let's move over to the coronal projection.

2:35

We were back in the region of the thalamus.

2:37

Let's move a little bit forward where

2:39

we see the anterior commissure.

2:42

If we go right below the anterior commissure

2:44

and slightly anterior to it,

2:46

you're going to run into the subthalamic nucleus,

2:49

which is responsible for cases

2:51

of ballism or hemiballism.

2:53

And ballism or hemiballism is considered a subset of chorea.

2:59

Now, in the next accompanying vignette,

3:01

we're going to talk about the inhibitory and

3:04

stimulatory and interactive function of the corpus

3:08

striatum and basal ganglia structures.

3:10

Let's do it, shall we?