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Practice English Speaking&Listening with: Integrative Biology 131 - Lecture 25: Spinal Cord and...

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MARIAN DIAMOND: Good morning.

It's quite loud this morning, excuse me--

sort of shocked myself too.

Let's continue with our derivatives of the neural tube.

And we were talking about the mesencephalon,

but we didn't quite complete it.

So I'd like to return to it.

And we drew a section through the mesencephalon.

We showed the aqueduct was here.

This is our central canal as it looks-- boy, this is loud.

Is that loud for you too?

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: Right, it keeps you awake.

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: It's what?

It's OK.

All right, thanks.

Aqueduct-- and then, we had the--

these could be the corpora quadrigemina-- either.

I just repeat it, repeat it, repeat it.

And sometimes, that's referred to as the tectum.

Tectum means roof.

And you'll see that in the literature too,

so I thought this morning I'd put it in.

Tectum is the same as a roof here.

Then, we had that cerebral peduncles

down on the ventral surface.

And we put in the substantia nigra,

which would be just dorsal to the peduncles.

This would be the substantia nigra.

And we said it gets its name, black substance,

from the pigment melanin--

pigment melanin.

And the fibers were rich in dopamine.

Dopamine was their transmitter.

And there's substantia nigra projects

then up to the basal ganglia.

We'll see the basal ganglia today.

We'll develop it-- basal ganglia,

which modifies motor behavior.

Does many things but just for the moment, we need this--

modifies motor-- we'll just say motor action--

so that if we get [INAUDIBLE] that

knocks out our substantia nigra.

So lose cells in substantia nigra,

what disease did we say you got?

Everybody knows that one.

It's such a clear cut one.

Parkinson's, and the tremor for Parkinson's is

a tremor at rest.

And I give you that one because there's

another part of the brain that gets destroyed

and it's a tremor when you intend to do something.

So [INAUDIBLE] when you look at your neurosurgeon,

whether he's trembling at rest, because then you know he'll

go away when he starts to do his surgery.

But the intention tremor can be sitting there quietly.

But when he picks up the scalpel, then he does that.

So you have to be careful.

So let's move on up then.

There are lots more things in our--

one other thing I do want to say though,

because I want to be consistent here.

We've been giving the cranial nerves

with each one of these areas as we move up the brain stem.

So the cranial nerves with the mesencephalon

will be three and four.

And the ventricle then was our aqueduct so--

to see how they change as we go up.

So our next area will be the diencephalon,

as we move up from the mesencepholan.

Our diencephalon-- and we might as well

give the cranial nerve associated with it,

since we just talking about it.

What cranial nerve is related to the dyancephlona.

Well, we've moved all the way up.

We've only got two more to go.

We've gone from 12 up to three, so where

are we with nyancelphlaon?

Two.

And what is the second cranial nerve?

Does anybody know?

It's the optic nerve, very important.

Yours is definitely being used right now.

And the ventricle in the dyancelphloan

then is going to be what ventricle?

We've had fourth.

We've had aqueduct.

We're moving up.

What's next-- third.

So just so you can figure these things out for yourself.

So it's not just memorizing.

You could see where you are.

So we're going to have a third ventricle.

And the structures that we'll be dealing with then will be the--

I've got to take this off, I trust you have it--

thalamus and epithalamus and hypothalamus.

But I first want to make one point, because it gives

a landmark that's used when you're

using radiology and finding out where your sections are coming

from.

So I'm going to make our old neural tube that we had.

This is our neural tube.

And the most anterior part of the neural tube

is called the lamina terminalice.

Lamina-- which just means layer--

terminalus, because we want to use this landmark when

we put it in our diencephalic structures.

So this is going to be our lamina terminalis

for a lateral view of our diencephalon.

This is our lamina terminalice--

an important structure for a landmark when you're reading

scans.

So from it, we're going to come out and form the structures

of the diencephalon.

And what we've put here will have three structures.

We'll have the epithalamus.

Epi means a upon, so it means upon the thalamus.

So the epithalamus is just going to be some structures up on top

here.

But in addition, the pineal gland back here.

So our epithalamus will be this, and this

will be our pineal gland.

It's the only structure of the epithalamus

that I'm going to give you.

It is what?

It's a neuroendocrine gland--

neuroendocrine.

It plays a role in establishing and maintaining

your biological rhythm--

your biological, or biological clock

if you like-- biological clock.

Don't you find it strange that after you've

gotten up at 6 o'clock in the morning for several months

and had your alarm, sometimes your alarm doesn't go off,

but you get up anyhow?

Your pineal is playing a role.

So beneath the epithalamus, we have the thalamus.

What is the thalamus?

The thalamus is a mass of nuclei.

We defined nuclei before.

Whoops, there it goes.

What happened?

Thalamus-- mass of nuclei.

And somebody said they're about 25, plus or minus.

We're not going to give you those, just

let you know that they exist.

All sensory impulses that are going to your cerebral cortex

first go through the thalamus before they go to the cortex,

with one exception.

So all sensory input goes through thalamus

before going to cerebral cortex.

But there's one sensation that does not.

What is that?

STUDENT: Olfaction.

MARIAN DIAMOND: Olfaction, right--

that's a course in itself.

Why doesn't olfaction?

So for example-- just making it easy--

we're going to bring light to the retina, to the thalamus,

to the visual cortex.

And one could do this with all, but you'll

find out that the auditory pathway is much more complex.

So it's not just from the main receptor

to the thalamus to the cortex.

So I picked light instead.

So that gives you a general idea of the thalamus.

What does it look like?

They're considered to be egg-shaped.

You have the two thalami, the right and the left.

And the third ventricle then will be between them,

with the hypothalamus below.

And then go on down to your pituitary here.

So these would be thalamus, thalamus.

And the third ventricle will be between them here.

And this will be hypothalamus in this slide, in this section.

And here's to pitiatary.

Just to give you, this would be a coronal view.

In some, there's a connection between the two thalami.

Does anybody know what it's called?

The massa intermedia, massa intermedia.

It's missing in 30% of males.

And we've tested that once in class when we had 20 brains.

We knew what sex they were.

Exactly 30% were missing it.

Males as you know, if we could go into sex differences

in the brain-- whole subject--

are more lateralized.

That means, many times, they have

one side that's much stronger.

The right side stronger than the left.

And perhaps those people who have this

don't have that differentiation.

But when it's missing, they have it strongly.

I don't know.

Now, the structure beneath the thalamus is the hypothalamus.

And this, many of us, when we were starting in the field,

thought was the most exciting structure in the brain.

How much does it weigh, your hypothalamus?

Hypothalamus weighs only four grams.

How much does a large grape weigh?

Four grams gives you the size of it.

I know.

It depends on the size of the grape, but still.

What are the functions of this important structure?

Why did it attract so many of us, when I did my PhD on it?

Well, number one, it's a control center

for your autonomic nervous system,

control center for the A and S, which we've introduced.

It regulates your body temperature,

regulates body temperature.

How many have an average body temperature of 98.6?

How many don't?

How many know what your average temperature is?

But how in the world?

You put all these different kinds of fuels in there,

and this machine can maintain a body temperature, because you

have a hypothalamus.

You destroy this nucleus in the hypothalamus.

The hypothalamus, again, is a mass

of nuclei, just like the thalamus

but only different functions.

If we destroy the nucleus for temperature,

temperature will climb to 106 and death.

Then, we have anterior pituitary releasing hormones.

This is our pituitary down here.

So hypothalamus can send down releasing

hormones, anterior pituitary-releasing hormones.

It regulates thirst.

You finish class, you run out and get a drink of water.

It regulates your appetite, tells you when you want to eat.

It affects emotions.

Just think, a computation that has

to go on to a little structure that's that big.

We're still going.

It affects mating behavior.

It's actually different in homosexual males

than heterosexual males in the one area

dealing with mating behavior.

So seven affects mating behavior.

And it affects your sleep mechanism.

Where are we-- nine, memory.

And it produces your posterior pituitary hormones.

Produces-- just, we'll put it produces--

ADHD, which is antidiuretic hormone

to be stored in the posterior pituitary.

That was my thesis, to see if it was active in the hypothalamus,

as well as in the pituitary.

And it was.

But look at that.

Isn't that amazing?

You know how you tell somebody where your hypothalamus is--

that's exactly it.

He knows exactly-- up your nose, above your ear,

where the two points meet--

because most people have never heard of a hypothalamus.

But look at what it does for you--

phenomenal.

So let's then go on to our telencephalon.

Can I take this off?

So we're way up at the top--

telencephalon.

The telencephalon than is going to account

for 85% of your brain.

It's the big [INAUDIBLE] and will

consist of the basal ganglia and the cerebral hemispheres.

These are the massive hemispheres.

So we've worked our way all the way up.

When we're drawing embryologically,

here would be our lamina terminalis

from our neural tube.

But then, we pouch out like this to start

to form our cerebral hemispheres and basal ganglia.

This was our lamina terminalis.

So that landmark is used a great deal

in talking about forebrain relationships.

So let's look at the embryo, at the reason why

it's called a basal ganglia.

Let's look at our hemispheres.

And this will be in the embryo.

And have the [INAUDIBLE] till we get to the base.

And then, we'll come in.

So here, in the base of the hemispheres,

we will have these masses of cells

that are the precursors of your adult basal ganglia--

basal ganglia.

And these, of course, are your cerebral hemispheres.

And so what will we name or number the ventricles

in the cerebral hemispheres way back

at this level-- one and two.

As we get to the adult, we call them the lateral ventricles.

One and two will become lateral ventricles.

And those are going to be reading MRIs and PET scans,

you'll have to know your ventricles backwards

and forwards, because they're affected.

If you've got a tumor, they get smaller.

If you get older, they get larger,

as the cortex decreases.

So ventricles in your medical profession

are very important to know.

But what do they look like now in the adult brain?

Let's take a section through an adult brain.

So we'll take our hemispheres again.

And we know we have the thalamus in here, the thalamus.

And we have a hypothalamus beneath it in here,

coming on down just to get our orientation.

What's the ventricle between the thalami?

Third-- very important.

Third ventricle.

Hypothalamus has the same third ventricle, because they're

both right together.

So it just lets you know what we have in our midline area

at this level.

But now, we're going to put in the basal ganglia.

They take on a very different shape in the adult.

And we're going to put in some lateral ventricle here.

So this will be a lateral ventricle at this level.

And we'll put in some more basal ganglia here,

inferior to the lateral wall, or the lateral ventricle.

Got the same duplicated on the opposite side.

We need one more structure.

It will be in here.

So we're ready to label these now basic parts

of the basal ganglia--

so parts of basal ganglia.

Let's take number one.

One is the caudate nucleus, chordate nucleus.

We'll show pictures of these.

Number two, we're going to take the lateral aspect

of this part, and this is called the putamen--

putamen.

And the medial part here has divisions,

but we're just going to show it as a whole

for introductory purposes.

It's called the globus pallidus.

These will be second nature to you

after you start studying brains.

What does that mean?

Pale globe-- so you'll be able to pick it out

because it stains much lighter than the putamen

or the caudate, for example.

And our fourth one here--

I should have had a little bigger thalamus--

so it's called the subthalamic nucleus, sub thalamic nucleus.

So one, two, three, four equal our basal ganglia--

very large, very important part of your forebrain,

modifying motor behavior.

You get different symptoms from every one of these.

If you knock out your subthalamic nucleus,

I've only seen one example in my life of subthalamic.

And he goes like this.

He was an engineer.

He could talk to you, he was fine.

But he had no control over these flailing limbs.

Just amazing-- so you better be thankful that you're

subthalamic nuclei are in order, because I don't see anybody

going through such gyrations.

But it was amazing and fatiguing too.

So just to let you know the importance

of these when they work.

You just take them for granted.

So what else would we want to say about our basal ganglia

before we move up?

Let's be sure we're catching it.

Yes, we want to mention another important structure here.

Let's put in the internal capsule, internal capsule.

So we're going to see a pathway, fibers that are surrounding

the basal ganglia.

These x's make up the internal capsule.

And you say well, is there an external?

Yes, but not as much is known about it,

but I'll put it in out here.

This will be external capsule.

But the internal is extremely important

because we've put these basal ganglia

right in the middle of our hemispheres

where we have all this information coming

from the thalamus, coming from the spinal cord,

into the cortex.

And it's got to go around these big nuclei.

So they call the inner one the internal capsule.

So it consists of ascending and descending fibers

to and from cerebral cortex.

So if I break a blood vessel right in here,

we know exactly what fibers will be knocked out coming

from my motor behavior.

These are very well-defined within the internal capsule.

All right, that gives us one component of our telencephalon.

And our next one then are these large cerebral hemispheres,

which make you you and me me, give us our uniqueness

to our brains.

So cerebral hemispheres-- so we're

going to divide these into the archicortex, which

means the old cortex, and the neocortex.

Let's take the archicortex first.

It will only have three layers in its components.

And what are they?

They're found in what's known as the hippocampal complex,

hippocampal complex.

What does that consist of?

It consists of the hippocampus and the dentate gyrus,

dentate gyrus.

We've used this term before when we

said that there were neurogenesis

or new nerve cells can be formed in the adult,

in the dentate gyrus, because it had granule cells

with small, short axons.

So where is this hippocampal complex?

Let's put it in and then say a word about its function.

So let's take a medial view of the hemispheres.

Just to put in some landmarks, when we cut through the two

hemispheres, we'll have a big mass of fibers

that we've cut through, that are connecting the two hemispheres.

Who can tell me what they're called--

the corpus callosum.

So this is the corpus callosum.

For those who haven't studied neural before,

we'll look at them a different way,

and we'll see that we've got these fibers that

are connecting back and forth to the hemispheres,

coming around and going here.

So it's crossing like this.

But what we've done, we've cut in the middle.

So we've got them crossing and looking at them

from a medial view.

So that's the corpus callosum those are fibers

connecting both hemispheres.

All right, those for a landmark, whenever you see those,

you know it's a medial view.

To pick up the hippocampal complex,

we're going to go into this lobe.

What is this lobe--

temporal, good for you.

Temporal lobe just beneath your temporal bone.

You can figure these out.

This would be which lobe up here--

frontal, sure.

So we want to go deep into the lobe,

because it's not going to be on the surface.

So deep within this lobe, we'll find

this structure that looks like a sea horse

to the early anatomists.

And this is the hippocampal complex in here.

When you study neural, you'll follow all of its pathways,

but we're just identifying it here.

This is hippocampal complex.

And I'd have to peel at a part so you

could see the dentate gyrus.

Why is it called dentate?

What does dentate mean?

Teeth, you look at it, and it's just got all these little rows

like this.

And that's the dentate gyrus.

So it's easy to identify when you have a brain

and can peel back the hippocampus.

What does a hippocampus do for you?

Hopefully, it's working in your brains at this moment.

What's it doing?

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: What kind of memory?

There are all sorts.

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: Pardon.

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: Short-term memory, right, thank you.

So this complex deals with short-term memory processing--

terribly important.

And what's another function for the hippocampus--

visual spatial acuity, visual spatial acuity.

So when is it important?

Let's say you're going on a trip for three weeks.

You park your car in the parking lot down in the Oakland

Airport, and you've got to remember where you parked it.

So as you leave it, you turn around,

reinforce your visual spatial acuity,

so you know exactly where it is.

So when you're coming from the other direction,

you'll recognize where it is.

And you need your recent memory to put it into long-term

memory--

so hippocampus, just a small example.

It's very much affected with Alzheimer's.

I saw in University of Iowa, [? Dimassio ?]

said you want to see a defunct hippocampus?

And I said, yes.

And he said he just has one in from an Alzheimer patient.

So you looked under the microscope,

and the cells were all disoriented

and decreasing for recent memory.

So you need to work on your recent memory for a lifetime,

because otherwise, you lose it.

All right, so this is the archicortex.

And as we said, it's three-layered.

It's not as complex.

It's older.

But we go up to our neocortex, which

is the most highly-evolved mass on this Earth

and most recently designed.

It's the last to develop embryologically and the last

to develop phylogenetically.

So we're up to our cerebral hemispheres.

Let's look at a lateral view again.

And as we showed you previously, that it's thrown into folds.

How big did I say it would be if it weren't folded?

[INTERPOSING VOICES]

Not the cerebral cortex.

No, that would really be interesting,

because to fold that as big as a cortex,

we'd have heads as big as this center part of our auditorium.

So to have, it's as big as two and 1/2 feet square.

And we always ask, why can't you have a head that's

two and 1/2 feet square.

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: Pardon.

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: Well, I think it's something

more important than that.

Pardon, why can't you have a head two and 1/2 feet square.

Why does it have to fold as it evolves?

STUDENT: Childbirth.

MARIAN DIAMOND: Childbirth, of course.

You imagine, any woman who's given birth

and knows two and 1/2 feet square.

That's not gonna work.

So it's highly folded, and it's folded

so that you have these folds.

And the top of the fold is called a gyrus.

And the indentation between the folds--

these are gyri-- would be sulci or a sulcus.

Some people like hills and valleys.

The hills are the dry rye.

Anyway, just to remember them, because when

you have Alzheimer's, the sulci are very much pronounced

because the gyri have been losing their cells.

So they're important to know.

And when we look at the lateral aspect of our brain over here,

we have a central sulcus.

You have a lateral fissure--

lateral fissure.

So what lobe is this?

What lobe is this?

[INTERPOSING VOICES]

What lobe is this?

[INTERPOSING VOICES]

What lobe is it--

temporal.

So we've learned that the occipital deals with vision,

all sorts of modifications.

Part of the temporal-- just a little part up here--

deals with hearing.

The parietal deals with sensory--

general sensory-- pain, touch pressure.

We'll just put sensory.

Lots of other functions but just to give it a name.

And part of the frontal, what's this first part

of the frontal deal with?

Motor but it's really refined motor.

And then, we have what's called supplementary motor.

We'll just give you one other that you've already had.

What is here--

Broca's area, good for you.

What artery is supplying Broca's area?

Middle cerebral, don't forget it.

You heard the fellows at 131 using that the other day.

So this is Broca's area.

What does Broca's area do for you?

[INTERPOSING VOICES]

Motor speech.

I wouldn't be able to talk if I had

broken my middle cerebral blood vessel.

Now, the area that is uniquely human

and has advanced furthest in the brain is our prefrontal cortex.

So let's say a word about the prefrontal cortex.

So functions of prefrontal cortex--

One, planning ahead-- how many have

thought what they're going to do on Thanksgiving vacation?

So you have a prefrontal cortex.

Two-- sequencing events, knowing how

you're going to fit things together to carry out

an action, sequencing events.

Initiative-- decide what we're going to do.

And then, once you decide, is it really wise to do it--

judgement from prefrontal cortex.

Working memory-- how does working memory

differ from others?

That you hold the memory in your thoughts

while you're working with it.

I hold telencephalon.

What am I going to bring in next to say?

That's working memory-- so working memory.

Oh, lots more-- lots, lots, more.

Let me just pull up a couple just so that you

get the dynamics of them.

Oh, that's fine.

We'll do it with those.

Now, what game of cards uses all of these functions?

Bridge-- yes.

That's why we use Bridge, to see if we could stimulate

the prefrontal cortex, because we

found in an immune-deficient animal,

he was bilaterally deficient in his dorsal lateral frontal

cortex.

We transplanted the thymus, came back again.

We knew we had an area of the cerebral cortex that

controls the immune system.

Whoops, we've got slides.

I didn't see the lights.

Did you see the lights?

Boy, I was involved-- sorry.

Here we go.

Can we go fast because I've got lots of good slides for you.

I'm sorry.

First slide, please.

No show-- too bad.

We've got it.

What part of the brain stem are we--

hindbrain, midbrain, forebrain?

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: Midbrain, sure.

Here is your aqueduct.

Here are your colliculi.

Here is the cerebral peduncles.

And is a substantia nigra.

You see, it's a major part of that midbrain.

In the next one--

at our cerebral hemispheres thrown into folds,

what area is this?

STUDENT: Broca's.

MARIAN DIAMOND: Broca's area-- good for you.

What area is this?

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: Hearing.

What area is this?

STUDENT: Prefrontal cortex.

MARIAN DIAMOND: Prefrontal cortex.

What area is this?

STUDENT: [INAUDIBLE]

MARIAN DIAMOND: Occipital.

This area?

[INTERPOSING VOICES]

Parietal.

Great-- next one.

And now, it shows what the ventricles look like inside.

This is our fourth ventricle back here in the hindbrain.

Then, we have the aqueduct.

This thin one, you can see what happens

if a tumor gets against that.

So that's really dangerous there,

to have such a narrow tube.

But then, we come up.

This is third ventricle.

And these are the lateral ventricles

as they get stretched.

This would be in the temporal lobe.

This will be back in the occipital lobe.

And this one will be in the frontal lobe.

So you get all, but you learn to know those ventricles--

landmarks.

Next one.

And this shows our brain stem.

This was fourth ventricle.

Our cerebellum was over here.

We cut it off, but we wanted to see the thalamus now.

This was all midbrain here.

Here, we come up into the diencephalon.

The epithalamus would be on the surface in the midline here.

We don't see the pineal here on this slide.

But then, the basal ganglia would

be out here with the whole hemispheres

surrounding the whole thing.

In the next one--

and here it shows the basal ganglia.

You have to look sharp.

Here's the head of the caudate.

Here's the putamen, pale globe, thalamus, third ventricle.

And you could see--

this line that divides here-- that's

that big internal capsule with fibers

coming from the motor cortex.

Coming through there, you break a blood vessel,

you're paralyzed on the opposite side,

because they're all condensed in the internal capsule because

of these masses of nuclei that sit here.

In the next one--

and this shows the fibers as they have to be condensed.

So this would be internal capsule

from a different point of view, because then, nuclei

would be in here, coming down very narrow,

as they come down your brainstem.

In the next one--

and this shows the dentate gyrus forming.

The hippocampus, just to let you see how they're related.

In the next one--

and it shows step-by-step how it curls up,

so that you end up with a dentate gyrus

and the hippocampus right together,

in the hippocampal complex, within your temporal lobe.

In the next one--

and this shows what it really looks like.

Here's your hippocampus here.

And see the little dentates here.

So this is where your recent memory is processed and sent

on then to long-term memory.

And an article I just read doesn't put long-term memory

in the frontal lobe.

I have doubts about that, but it did not put it there.

It put in parietal, occipital, and temporal.

In the next one--

and then, this shows that you will eventually

learn the names of all these gyri and what they do.

In the next one--

and I put this one in.

What is this?

[INTERPOSING VOICES]

How many have been to Rome--

a few of you.

Where is this in Rome?

[INTERPOSING VOICES]

Sistine Chapel, the roof of the Sistine Chapel.

Here's God, and here's man.

But what's the shape of the shroud that's around God?

[INTERPOSING VOICES]

Did Michelangelo have fun up there,

at the top of that chapel?

Think about it.

All right, that's it.

The Description of Integrative Biology 131 - Lecture 25: Spinal Cord and...