Hello everyone. This is Professor Mariah Evans. This is BSC 2085 Anatomy and Physiology 1. This is going to be an overview of Chapter 12, which is the central nervous system, which consists of the brain and the spinal cord, parts 1 and part 2. In the PowerPoints, they're listed as A and B, but in files, I list them as part 1 and part 2. All right. So again, the central nervous system is the brain and the spinal cord, as I mentioned.
When we talk about cephalization, we're talking about the fact that there is a movement of these nervous materials or nervous consistencies at the anterior end. And for us, that would be like our head. So cephalization, when you hear things like hydrocephalus, that means that there's water on the brain, for example.
And cephalus means that... small part of the head or that anterior region has been, you know, shrunken or removed or malformed, et cetera, et cetera. So cephalization is this concentration at the anterior part for us, the brain itself.
And the highest degree of cephalization is actually reached in the human brain, which equates to the fact that Homo sapiens are the smartest animals on the planet. Okay. So I do not test you on embryology, although it is extremely interesting. The only thing that I want to say about the neural tube itself is that that is where the brain and the spinal cord begin. So when you hear about a pregnant woman who is taking her prenatal vitamins and folic acid is extremely important for development, it's because if you have a folic acid deficiency, then the baby could be born with...
neural tube defects. And since the neural tube is where the brain and the spinal cord begin, then all of the ramifications of a neural tube, sorry, I'm trying to think of the words, sorry, of a neural tube birth defect could actually result in severe things like mental retardation, could result in motor function being. you know, prohibited or could also lead to spontaneous abortions, which most people call miscarriages, right? So when we talk about the neural tube, it's just an understanding that the brain and the spinal cord begin there.
And if you have a folic acid deficiency during pregnancy, then development of the neural tube will be affected. Therefore, the brain and spinal cord will be affected. Now, as far as learning about the proencephalon, mesencephalon, riencephalon, I don't teach it that way, but here in just a second, we're going to learn about various parts of the brain that you're going to be responsible for knowing.
So we do have some vesicles that are there. When we look at the vesicles, again, it's divided and I don't teach it like this, but just so you have an understanding of the forebrain, the midbrain, and the hindbrain, right? But for me, the way that I teach it is to let you know that when we talk about the cerebral hemispheres, so they tell you as far as development, that the telencephalon becomes the two cerebral hemispheres. And I'm just going to tell you specific things that I need you to know about the two cerebral hemispheres.
Not that they come from the telencephalon, but that there are a left and a right cerebral hemisphere. And that control in the cerebral hemispheres is what we say contralateral. So contralateral is like when you contradict something right across. So the right cerebral hemisphere controls the left side of the body. And the left cerebral hemisphere controls the right side of the body.
So that's what contralateral control takes up. Those two cerebral hemispheres, the left and the right cerebral hemisphere, make up the cerebrum. And the cerebrum is the largest part of the brain.
So the majority of the mass of the brain is the cerebrum. Now, it says here that the diencephalon becomes the epithalamus, the thalamus, hypothalamus, and the retina. I don't care that the diencephalon becomes these, but I...
do need you to know what the epithalamus does, what the thalamus does, what the hypothalamus does. And the retina, of course, plays a role in the eyes. And when we get to the special senses, you'll learn more about that.
But for now, it's going to be the understanding that I'm going to expect you to know the function of the epithalamus. And that's where the pineal gland is. And the pineal gland secretes melatonin.
And then the thalamus, which is the gateway to the cerebral cortex. So see these two cerebral hemispheres that make up the cerebrum? There's a cortex, which is the outer part of it.
And the way to get to the cortex of the cerebrum is through the thalamus. So it's called the gateway. And then the hypothalamus, I call the hypothalamus the boss.
And when we get a little bit further into this lecture and you see all the things that the hypothalamus is responsible for, you'll understand completely why I say it's the boss. Anyway. When we get to the pons and the cerebellum, so I don't really, again, mesencephalon becoming the midbrain, right?
So you will need to know about the pons. We're going to talk about its location and how that plays a role in connecting things from the spinal cord to the brain itself because of its location. And then the cerebellum, generally speaking, is responsible for motor control, and you'll need to know that. And then we have the medulla oblongata.
And I love to say medulla oblongata. It makes me think of the movie Waterboy with Adam Sandler. So he was Bobby Boucher, if you guys remember.
He was in class, went to college, and played foosball, according to his mama. Anyway, so the medulla oblongata has several functions, and we'll talk about each of those. And then we have these cavities, and these cavities are called ventricles. And if we were in lab and I was able to, you know, dissect the brain. and show you the ventricles, then you would see the cavities.
And so they're like little slits or openings, and you'd actually be able to see them. But for lecture purposes, just know that we do have some ventricles. There's a lateral, a third ventricle, the fourth ventricle, and the cerebral aqueduct that's there. Anyway, so again, I don't really test on development.
It's just this understanding. And these are things that you know already. The brain grows faster than the surrounding membranous skull.
So it folds on itself. So the brain is very convoluted and folded up together. And in the cerebral hemispheres, they kind of double back and envelop this diencephalon and midbrain, and it increases this folding and increases the surface area.
So remember, the cerebrum, as I mentioned before, is the largest part of the brain. The majority of the mass of the brain is the cerebrum, which makes up those two cerebral hemispheres, a left and a right. So We have the cerebral hemispheres, again, the left and the right one.
The diencephalon, we'll just leave that as it is, but that's where you would find the epithalamus, the hypothalamus, and the thalamus and the retina. And then we have the midbrain, the pons, the medulla, and then the cerebellum itself. And the cerebellum is, like I said, generally speaking, motor control.
So we'll talk about that again when we get into these things individually. this is a hologram of the brain and the reason why it's a hologram of the brain, because you can see through it. So this is that diencephalon, which again is going to be the thalamus, the epithalamus and the hypothalamus.
This is the cerebellum right here. And so this part that I'm about to outline with the arrow, all of this is the cerebrum. See how much of that, see how much of the brain is made up of the cerebrum. Now, what we're looking at is this is the anterior end, and this is like posterior. And so you're actually looking at the left side of the brain.
This is the left cerebral hemisphere. Okay. Then we have this right here is the pons.
And then if you like go down, see, it's like a little bump, right? See that? So that's the pons.
And then if you go down, you go down the medulla, and then you go into the brainstem, which is also called the spinal cord. And we're going to learn here about the tracks on the medulla oblongata. They're called pyramids.
And we'll learn about those and what they mean and why that's so important when we talk about motor control. All right. So the brain has gray matter and white matter.
And the gray matter is non-myelinated. So whenever you think of white matter, think of it as being myelinated fibers. And that's why it's white, because... Myelinated fibers is this white protein lipid mixture, and it allows for the conduction of impulses to go really fast. So if something's myelinated, it means that it's moving really fast down those axon terminals.
If it's non-myelinated, then it moves a lot slower. So gray matter is non-myelinated. The white matter is white because of that lipid protein mix.
right? And I'll show you that in pictures in just a second as well. So when we look at the brain compared to the spinal cord with the gray matter and the white matter, their patterns are a little bit different.
Okay. So this is the spinal cord and the gray matter is in the core or the center part and the white matter is on the outside. Okay. So the gray matter, again, non-myelinated fibers that are there, it's usually going to be basal nuclei.
And I'll talk to you about that as far as additional gray matter. And then the white matter is myelination, like I said before. So movement down those axons is really fast because of that myelin sheath. So this is a cross section of the spinal cord.
Gray matter in the center, white matter on the outside. So if we look at a cross section of the brain, what you see is white matter on the inside or the central part. And then you see this gray matter on the cortex, this outer part.
Well, this happens to be the cerebrum. So the cerebral cortex is made up of gray matter. Then we have all of this white matter.
in the center part here, which is the myelinated fibers. But then we have additional areas of gray matter, and those are the basal nuclei. So the basal nuclei are the nucleus of each of the neurons, and the white matter is the axon on those same neurons. So the white matter is axons that are myelinated, and the gray matter is going to be the basal nucleus. So like...
the soma or the body of the neuron is going to make up these additional gray matters. And then the cortex of the cerebrum, which is this outside part, that's also gray matter. All right. So the ventricles, like I said before, are chambers and they're filled with cerebral spinal fluid.
And like I said, if we were in the lab, I would be able to show you the lateral ventricle, the third ventricle, the fourth ventricle, and the cerebral aqueduct. So I can't show you those right now, but... you know, in lab, you still have to know them. When we look at separating the hemispheres, there is a membranous septum pellucidum.
And that's something, again, you'll have to know, if you have me for lab, you'll have to know the septum pellucidum. And when we look at the third ventricle, like I said before, so there's a third ventricle, a fourth ventricle, a lateral ventricle, and then there's the cerebral aqueduct. All of these are spaces that are filled with cerebral spinal fluid. Now what they've done here is another hologram just so that you can see them. So if you look here this septum pellucidum, it is again a membrane that's between the two cerebral hemispheres.
So this is one cerebral hemisphere, this is the other cerebral hemisphere. Remember this one down here is the cerebellum, then the pons and then the medulla, et cetera. And then they show you the ventricles. So the lateral ventricle is here, and then you have a third ventricle that's here. You have the cerebral aqueduct that's here.
And the fourth ventricle, which leads, if we had cut this on like a sagittal view, which would be down the longitudinal fissure, then you would see the fourth ventricle and it's leading down into the cerebellum. Okay. So the cerebral hemispheres, like I said before, the largest part of the brain, and they account for 83% of the mass of the entire brain.
So that's huge. There are ridges that are called gyri. Gyrus is plural, gyri. excuse me, gyrus is singular, gyrus is plural, sulcus, singular, sulci, plural. So they have these ridges and they have these grooves.
A deep groove is called a fissure. So I just said that if we were looking at a mid-sagittal view, we would have cut down the longitudinal fissure. The longitudinal fissure separates the two cerebral hemispheres. Transverse means across, and you guys know this again from your terminology. So transverse means across.
There's another fissure that runs across and separates the cerebrum from the cerebellum. Okay, so this is the longitudinal fissure, this one right here, so this deep groove separating the two cerebral hemispheres, okay? Then this is the transverse fissure, and it separates the cerebrum from the cerebellum, okay? So, transfissure.
transverse fissure. Okay. Now, when we look at the hemisphere, the cerebral hemispheres, there are individual lobes that are there. And these lobes should sound familiar to you because they're going to correspond with the bones that cover them. So the bones of the skull.
So there's a frontal bone. So there's a frontal lobe. There's parietal bone, parietal lobes, temporal bone, temporal lobes, occipital bone, occipital lobe.
The only one that doesn't correspond with bones of the skull. is the insula and that's because that's an internal lobe. So frontal, parietal, temporal, occipital lobes, and then the insula is internal. And then all it says is what I just said there, the lobes are named for the skull bones that are, you know, over top of them. And then so temporal, parietal, frontal, and then of course, occipital, and then the insular is inside.
And then you can click on this when you guys get a chance in the video. and watch that. So animated picture with colors, which is kind of nice to help you see the lobes and then mention some of the very important gyri.
So this pre-central gyrus and a post-central gyrus and then central. So central being like middle and then post being behind the middle and pre. Central being before the middle, right? Frontal lobe, occipital lobe back here in the back, the cerebellum again, of course.
And again, we're looking at the right cerebral hemisphere. I'm sorry, this is the left cerebral hemisphere because this is the head anterior and this is the posterior. And so this is the left cerebral hemisphere right here. And again, this is the cerebral cortex and then it's gray matter and then the white matter that's here. Okay.
So this is the insula. So that's that internal lobe right there, insula. This right here is the temporal lobe that they've pulled down. All right. So it's kind of cool because of terminology that the sulci are going to be named for the two things that it divides.
So the central sulcus, like I said, it's kind of in the center, precentral is before it, postcentral is behind it. And then when you look at parietal-acepital sulcus, it's exactly what it sounds like. It's going to be a sulcus.
That's between the parietal lobes and the occipital lobes. Lateral sulcus is on the side. That's where the temporal lobe is.
And then we have these main regions right here, the cerebral cortex, which I pointed out that gray matter that's around the outside. It is white matter on the inside, so myelinated fibers. And then there is the additional gray matter that is within the white matter. And that's that basal nuclei. And that basal nuclei, again, just is the soma of...
the neurons. Okay. And then just another animated picture. So that cerebral cortex is the executive suite of the brain.
It is the site of the conscious mind. So the way that you think of it is this way, conscious mind, it's what you are aware of, right? You know that it's happening. So awareness, sensory perception, voluntary motor initiation. If it's voluntary, that means you are doing it on purpose, right?
communication, memory storage, and understanding. That's huge. So the sight of the conscious mind.
What I usually tell people is when we're in the classroom, I use a person as an example. I ask them if I have permission to touch them. They usually tell me yes.
If they don't, I find someone else. But I tell them to close their eyes. And when I tell them to close their eyes, I say, I'm going to do something to you with your eyes closed, and I want you to tell me what I did.
And be very specific. So I will go and like it. I pinch them on their right arm and the person will be like, you pinched me. And I'll be like, I pinched you where?
And they're like, you pinched me on my arm. And I'll be like, what arm? And they're like, you pinched me on my right arm.
And then I'll say, is it lower arm or upper arm? And I say, you pinched me on my right lower arm. And the reality of that is, as silly as it sounds, is that the person's eyes were closed. So they didn't see me do it. But because of the cerebral cortex, they were aware of what I did.
They had the sensation, right, which was that. pinched they perceived it which means they know exactly where it happened and then they could have had a voluntary motor initiation which could have been for them to like move their arm all the way which is something that we do reflexive when we think something is going to cause us harm or injury and then of course the ability to communicate that and memory storage the person had to have been pinched before in their life or if they would they wouldn't have known that I pinched them again so you have to remember what it is that happened in order for you to, you know, know that it happened. So learn it first and then remember it.
All right. Anyway, so the cerebral cortex is that gray matter around the cerebrum, right? And that part itself, just that gray matter around the cerebrum, that's 40% of the mass of the brain. So 83% of the mass of the brain is the cerebrum itself.
And so then about half of that is the cerebral cortex, right? 40%. Now, what's really cool about the cerebral cortex is because of visual imaging that we have, we can actually see what's happening in that part of the brain when it's working, when you're doing things like figuring out things, going through emotions or whatever the case may be. So it allows us to see the specific areas of that cerebral cortex that are responsible for certain things.
So cool. All right. So there's four general considerations when we look at the cerebral cortex. There's three types of functional areas. This shouldn't surprise you.
The entire nervous system, if you guys remember from chapter 11, the entire nervous system is motor, sensory, and association. So sensory input, that means it's going up to the brain. Then we have the integration or the understanding, that's the association areas. And then we have a motor output.
That's the whole central nervous system. Sensory input, understanding, which is... Understanding association and integration can all be used interchangeably. And then there's a motor output.
So sensory areas, association areas where they understand that information, and then the motor areas where they give you a voluntary. movement, which is a response. Each hemisphere is, and I said this word already, contralateral control.
So the right cerebral hemisphere controls the left side of the body. Left cerebral hemisphere controls the right side of the body. That's what contralateral means.
Lateralization means that the left cerebral hemisphere is responsible for specific things, and the right cerebral hemisphere is responsible for specific things. That's the lateralization. And then conscious behavior involves the entire cortex. So if I go back to this slide, I said that the cerebral cortex, so conscious behavior, what you do on purpose, what you do intentionally involves the entire cerebral cortex where it's the site of the conscious mind, awareness, sensory, perception, motor, communication, memory, understanding.
So anything that you do on purpose is going to involve the entire cerebral cortex. All right. Now, when we look at the motor areas.
We have premotor, which is exactly what it sounds like. Premotor is like planning something, right? Then we have primary motor, which is basically, you know, handling all the motor stuff.
We have the brocus area, and the brocus area is going to control your ability to move your tongue and other muscles to form speech. And then we have frontal eyelid, and since this is motor, this is literally being able to move your eyes, right? I know it sounds silly, but it is what it is. So premotor is the planning part.
Primary motor is carrying out, right, the majority of the motor control. Brocus is the movement of the tongue and other muscles like the pharynx to help you form speech and then frontal eye field. Well, my promise to you is that each of these things that I just talked about are going to be dissected a little bit further on in the lecture. When you've studied well enough.
You'll be able to get to this slide on your own without my recording. And then you'll be able to tell me what I just told you. Primary motor cortex, what it does.
Premotor cortex, what it does. Brocus area, what that's responsible for. Frontal eye field. So that's kind of a big deal about the things that are bolded in this lecture.
So now again, we're still looking at the left cerebral hemisphere. And I'm going to tell you that that brocus area that we just talked about a few seconds ago. So...
If you see these little dashed lines right here, here and here, the dashed lines here. So this one is the Broca's and this one is Wernicke's. Both of these dashed outlined areas are responsible for language, but different types of language.
So the Broca's area, like I just said earlier, since it's motor, it's the movement of the muscles of the tongue and the pharynx to produce speech. And Wernicke's, we'll get to. a little bit later, but I'll go ahead and say it since I'm here. But Wernicke's is your ability to understand the written or the spoken language.
Okay. So what else do we have here? Oh, okay. So the motor areas.
So we have a premotor and primary motor in the frontal eye field. And then we had the brocus. Those were those areas there.
Now, so remember how I said that when you're looking at the medulla oblongata, we're going to talk about the pyramids that run down them. So you Here are the pyramids and they're responsible for motor, so movement. So if something is on the pyramids, then we call that like direct motor control.
And if it's off the pyramids, then it would be indirect. So pyramidal cells, pyramidal cells are movement. So motor control going down into the spinal cord.
The pyramidal tracts can also be called cortical spinal. I like that better. I like that better than just pyramids because pyramids makes me think of, you know, Egypt, right? Pyramids. The reason why I like cortical spinal is because it's more, you know, definitive.
It defines it better. Cortical like cortex. So whenever you hear cortical, it's referring to the cortex and then spinal cord.
So remember I told you the pyramids run down the medulla oblongata into the spinal cord. So I like the term cortical spinal because it goes from the cortex to the spinal cord. See, I like that.
Anyway, soma means body. So somatotopy is being able to map out on the cortex where certain parts of the body will be controlled. One of my favorite commercials is the commercials where they have the guy, it's a brain surgeon, and the guy is working on kayak. So there's a brain surgeon and he is controlling the guy who's working on the computer on kayak through the brain.
Now, the reason why I like the commercial, because it's corny, but the reality is, is that we have mapped out using what we call a motor homunculus. We have mapped out where on the cerebral cortex, motor control of your hand, your arm, your toes, your tongue, your... body parts, right? So your body parts are. So I really like that commercial, really like that commercial.
Maybe at the end of this, I'll show you that. Anyway, so all it says with the somatotopy is that all the muscles of the body can be mapped out, right? So again, that movement. So motor homunculus, singular, homunculi, plural.
So this is the motor homunculus on this side, and this is the sensory homunculus. So when you look at it, as weird as it sounds, so all of this is cortex. It's pink now.
So we know it's gray matter, but in the picture it's pink. And that's just to separate motor from sensory. But if I wanted to make you wiggle your toes, then I could touch a specific area on the cerebral cortex and make you wiggle your toes. That's why I like that commercial is because the neurosurgeon is playing with the guy's brain and making him surf on kayak. and then even made him give him a high five.
I just think it's funny and cute because I'm nerdy. All right. Anyway, wiggling your fingers, right? So your thumb and your fingers would be this specific part.
So that's what they mean by the somatotopy. We can actually see how and where motor control takes place. And if we initiate a stimulus on any of these parts of the cerebral hemisphere, then we would get a motor response. So a movement.
All right. So premotor, again, I told you this already, right? Premotor, it's the beforehand. So it's planned.
That's easy. So premotor cortex helps you plan movement. Now, it also controls learn, movement, repetitious movement, patterns, coordinates, simultaneous or sequential actions, you know, stuff you have to plan out to do that. Then we have the brocus, and I already told you that this is going to direct the muscles that are needed for speech.
So your ability to speak, you have to control muscles for that. And then the frontal eye field was eye movements. So those are, again, pretty easy. Now, since you know what parts of the motor cortex are responsible for certain outcomes, then you can understand what happens when there's damage to those, right?
So if my ability to speak is on the left cerebral hemisphere, and I have a stroke, and I have a stroke. that affects my left cerebral hemisphere, I may lose the ability to speak, right? That's called aphasia.
If my stroke happened on that left cerebral hemisphere, right? And it happened in the brocus area, I may lose my ability to speak. Some of you may know people who have had strokes and lost their ability to speak. My mother had a stroke.
She actually had a few strokes. Hers were due to the chemotherapy for her cancer. My father had a severe stroke six months before my mother's cancer diagnosis, and his stroke left him paralyzed on the right side of his body and aphasic, which means the inability to speak.
So just because of that physical manifestation, we knew that the brain occurred, right? The physical manifestation of being paralyzed on the right-hand side and unable to speak, we knew that the stroke occurred on his left cerebral hemisphere. Um... So again, this part here, paralysis occurs on the opposite side of the body because remember, the cerebrum is under contralateral control. Muscle strength or ability to perform discrete individual movements is not impaired, but the control over the movements is lost.
So this is the understanding of what would happen. Other premotor neurons can be reprogrammed. So a person who has had a stroke can and often does recover. They may not recover to 100%, although a lot of them can, depending on the severity of the stroke, but you can recover and the brain can learn again. It's so cool.
You know what I'm saying? And the learning is exactly the way it was when you learn things the first go around. How cool is that? So, you know, we all got here with the inability to speak and then we learned how to speak. And so if you had a stroke and you lost your ability to speak, you learn it.
in the same way that you did before. So repetition and practicing. All right. Now the sensory areas.
So we did the motor areas, right? Now we have the sensory areas and the sensory areas, the sensory areas are, um, are going to be able to sense, right? Our awareness.
So, um, When we look at our awareness, we have This primary somatosensory, there's eight total, but primary, like first, somatosensory. Hold on one second. And then we have somatosensory association. So remember that term association, which means that it's the understanding part.
Visual area, so your sense of sight, auditory, your sense of hearing, vestibular is going to be your sense of balance. Olfactory is your sense of smell. Gustory is your sense of taste. And then visceral sensory, viscera means your internal organs. Okay.
Hold on one second. Excuse me. All right.
So now let's get to those sensory areas specifically. It's everything I just told you, but just a little bit more detail on the next page. All right. So primary first, right?
Soma, body, sensory. So sensations to the body. When we look at the sensations to the body, it's about feeling things like from your skin or skeletal muscles, your joints or your tendons, right?
Then the spatial discrimination lets you know specifically what region is being stimulated. It's like the example that I told you about a student. close your eyes.
And then I have pinched students before, and I've also flicked students before, and I've like taken my finger and run it down the middle of their back. I've tapped them, right, so that they could tell me each of these different things that they were feeling, and then tell me where, so what body region it was. And that's the somatosensory homunculus. So we did the motor homunculus, right? And so somatosensory would be, of course, sensations to the body.
That literally is what it means, sensory sensations, so my body. And that is, we saw it in the same picture before, but so the motor was the pink and then the somatosensory is the blue. So I wanted you to perceive like there was something on your nose, like you felt like there's something on your nose, then I would stimulate this specific part. of the cerebral cortex and you would feel something on your nose.
So somatosensory and then motor. So remember association means understanding. So somatosensory association cortex means that you understand, right? You understand what you're being touched with.
So you would be able to understand if I touched you with something cold or something hot, you'd be able to understand if I touched you with a feather or a piece of metal, or if I touched you with sandpaper or whatever the case may be. Anyway. So now when we look at the understanding part of it, right, determine size, the texture, the relationship of the objects that are being felt. So understanding, that's association, and then somatosensory, sensations to the body. Okay.
All right, so now we have the visual, and I already said this when we first did it, is it is the sight, so your sense of vision, right, sight, and that's all it says here, is that the primary visual cortex is located on the occipital lobe, and the occipital lobe is in the back, and so, oops, sorry, and occipital lobe is on the back. So, The visual association then means understand. So I understand what it is that I am seeing.
So primary visual cortex and then visual association, understanding what you saw. And all that says is then, of course, if I understand it, it's something that I would have had to seen before. And then I remember that I saw it, so I recall that I saw it. Now the primary auditory.
Auditory was your sense of hearing, as I said before. And then auditory association means understanding what you've heard. Then vestibular, like I said, was your sense of balance. And so, you know, when you're out of balance, if you do something and you're slipping or falling or something like that, you know, so it is your awareness of your position of your head in space. And then olfactory is your sense of smell.
I've said that already. Gustory is your sense of taste. And then viscera would be your internal organs. So sensation to your internal organs. For example, it says like an upset stomach or full bladder.
Like, you know, when your bladder's full, you can feel that. Or when your stomach hurts, those are internal organs. So once you learn the parts of the brain and what they do, right, their functions, then you would understand if you had damage to them. Because you'd understand what would be impaired. So if you have damage to your primary visual cortex, and that's where your sense of sight is, then you would be blind.
Okay. But if you have damage to your visual association area, then you could see, but you wouldn't understand what you're actually seeing. Isn't that interesting?
Then if something is multimodal, it is exactly what it sounds like. So multimodal. It means many modes and association means understanding. So multimodal association means that you have the ability to understand multiple inputs.
So receive multiple inputs in sensory areas, send outputs to multiple areas, and then allow this meaning to that information so you can understand a multitude of things happening all at one time. Okay, I'm sorry. I keep getting this box that's in the way of what I'm trying to share.
So it's covering up some of what is on the screen and it keeps just popping up and then disappearing, popping up and disappearing. So I apologize. Anyway, so the multimodal, right?
So down at the bottom, it basically says that this is broadly, meaning these multimodal association areas are broadly divided into three parts. There's an anterior association area, a posterior association area, which is where the box appears to be on my screen anyway. And then there is the limbic area. So anteriors to the front, posteriors to the back, that's pretty easy. And then whenever you hear limbic, like a limb, think of emotion, emotion, emotion.
Every time you hear limbic, emotion, emotion, emotion, limbic, emotion, emotion, emotion. Okay. So now let's talk about those areas. So anterior association area is also called the prefrontal cortex. boy, this one is wild.
So this prefrontal cortex is extremely complicated, the most complicated cortical region. And that's because it deals with intellect and cognition, recall and your personality. But there's also working memory, judgment, reasoning, persistence, and planning.
And the development of this area depends on feedback from your social environment. That's complicated. I tell people not as a joke, but just as an understanding of what I mean by this depends on feedback from social environment, because you probably, like me, have different groups of friends. And there's probably very few occasions where all of your different groups of friends could be together at one time. So I have some cousins who are really good friends of mine that I'm not about to take around my church friends.
Does everybody get what I'm saying? And then I have some, you know, friends that are extremely intelligent, multiple degrees and can, you know, literally talk about rocket science. And then I have some friends who aren't as educated and probably wouldn't feel comfortable in that setting.
I have friends who, you know, use slang and, you know, Ebonics, right? And then I have friends that speak proper grammar all the time, right? So when we talk about...
this prefrontal cortex and the fact that the development of this prefrontal cortex depends on feedback from social environment, it's literally the environment that you're in. And so if you are in an environment where hate is the norm and hate is accepted and hate is learned, then when you're in that environment of hate, you think that that's the norm. And so you act that way, right? Because remember this anterior association area is your personality.
So If you're in a social environment where there's just a bunch of hate, then guess what? Hate will be in your personality. Does that make sense, you guys? And then if you're like me, you can, you know, talk sports with your sports friends. You can, you know, read scripture and talk about the Bible, you know, with your church folks.
I can speak, you know, ebonics if I need to with my other folks, you know. So I have all these different personalities that go with my groups of friends of personalities, right? You also know, while we're talking about this prefrontal cortex, and the fact that it has to do with your judgment, sometimes you can be with a group of friends and you end up doing something that is against, you guys ready?
Your better judgment. You know, friends talk you into doing stuff. So it depends, you know, groups of friends.
So this is a very complicated area of the brain. But guess what? It's also controlled by emotions. So let me get this straight.
My personality, my judgment, the things that I do or the things that I'm known to do could be affected by my emotion, which means if I am emotionally charged, I could do something that's out of my character or out of my personality. It's the reason why we tell people that when you're angry to count to 10 before you say something, right, or not to punish your children while you're angry because you could do or say something that you didn't really mean. So that's the whole idea about it being, you know, under the influence of emotion. Because emotions, that limbic, limbic, limbic, limbic, limbic, yeah, that emotion, that's something else. And I'm sure you don't have to confess this to me, but I'm sure some of you may have done or said, I know I have, things that you regretted because you said or did them while you were angry.
So this prefrontal cortex. is your judgment, your personality, and you lose reasoning too. So you will do something, but you didn't, you know, reason out what you've done. You didn't think about the consequences to what you've done. This is the reason why we have people who can plead temporary insanity.
So like a man, you know, walks in and realizes that, you know, his wife is being, you know, raped by a home invader. And he acts off the emotion and beats that invader to death. You know, while he's doing that, he's not thinking to himself that if I kill this guy, I'm going to spend the rest of my life in jail away from my wife and kids.
You know, that's not what he's thinking about because he's in an emotional rage. And so he's just acting on the emotion. And that's why people have done some really horrific things while they were emotionally charged. And they have a plea of that temporary insanity. Like you lost your mind.
You weren't thinking about what you were actually doing, but you did some awful things. So the posterior association area is in the temporal, parietal, and occipital lobes. This helps you recognize people's faces and recognize patterns. And this is also where the Wernicke's area of language is. So remember on that left cerebral hemisphere on the anterior part, we saw the Broca's area, which was motor control that allows you to speak.
and speaking as part of language. Now we have the Wernicke's area, which was that other dashed part on the posterior part of the left cerebral hemisphere. And that was the written and spoken language. So being able to understand the written and spoken language.
Now, when I explain to people like what damage to this area would be like, it would be the understanding if you've watched any of the Peanuts, Charlie Brown, right? cartoons, and the parents and the teachers don't have a real language. You hear the wah, wah, wah, wah, wah. It's that kind of thing. Isn't that interesting?
And then limbic. Remember I told you whenever you hear limbic, think of emotion, emotion, emotion, emotion, emotion, emotion, emotion, emotion, emotion. So we have the cingulate gyrus that's there, the parahippocampus is there, and the hippocampus itself.
And it says provides emotional impact that makes a scene important to us. And it helps us establish memories. Now that memory part is huge.
And the reason why the memory part is huge is because emotions help you remember things. So if you came to class and you had an instructor who was very slow speaking and very monotone, You'd slip into a coma and you wouldn't remember anything in his class. But if you have someone who is teaching and they're excited about the material and there is, you know, some type of, you know, establishment of an atmosphere where you're upbeat, awake, aroused, et cetera, et cetera, you're more likely to remember it.
If I were to ask you to think of your earliest childhood memory, most of my students when I do this in a face-to-face class, most of my students, you know, tell me that they were probably, you know, three or four years old. And then I tell them, don't tell me what the memory is. I said, I just want you to think of it and then tell me your age. And what I tell them is that I guarantee you, you were either extremely happy or you were extremely sad or you were traumatized. There is some strong emotion.
associated with that memory, which is why you remember it, okay? Now, again, once you go through and you learn about these three broad association areas, so the anterior area was the prefrontal cortex, then we have the posterior area, association area, and then we have the limbic, right? Those are the three parts.
So once you learn, right, what the functions are of those association areas, then you understand if damage... tumors or lesions to that area, what the outcome would be. It's just like me explaining to you that when my father had a stroke, his inability to speak and his right side being paralyzed, let me know for sure that it was the left cerebral hemisphere where the damage was and that it was his brocus area that was damaged, not his Wernicke's, right? So anyway, if a person has a lesion on the anterior association area, which is that prefrontal cortex where your personality and your judgment is. It says that they can have personality disorders and loss of judgment, loss of attentiveness, and they can lose their inhibitions.
Inhibitions are the things that stop you from doing stuff that maybe you shouldn't do. Like you thought it through and you're like, nah, maybe I shouldn't. Anyway, a person who's affected is oblivious to social restraints. And perhaps they become careless about taking care of themselves and they take risks. So.
I watch Grey's Anatomy. Amelia Shepard, which is Derek Shepard's sister, had a tumor on her prefrontal cortex, so at the anterior association area. During the time of her tumor, she was performing surgeries that no other neurosurgeon in the world would have thought about doing. So she was taking risks. She also married Owen, and they just blame it on the tumor.
So if you haven't watched Grey's Anatomy, you should watch it. That show's amazing. But Amelia had a tumor, prefrontal cortex. And of course, it interfered with her judgment and she took some huge risks. And then of course, married Owen.
All right. So different problems arise if the damage is on the posterior association area. So this involves the awareness of yourself in space.
You may refuse to like wash or dress one side of your body because you just don't think it's yours. It doesn't feel like it belongs to you. Isn't that interesting? All right. So remember we talked about how the cerebral cortex has lateralization, and that means the left cerebral hemisphere has certain responsibilities and functions, and the right cerebral hemisphere has certain responsibilities and functions.
That's what lateralization means, okay? So those two hemispheres are not identical. Having talked about the left cerebral hemisphere and explaining to you that the Wernicke's and the Broca's area are both on the left cerebral hemisphere should let you know that the two hemispheres are not identical. Now, 90% of humans are dominated by the left side of the cerebrum, which means they're right-handed.
10% of the population is dominated on the right side, which means they're left-handed. There's a joke that I learned when I was in school is that left-handed people were in their right mind. Get it?
Left-handed people. And FYI, Satan was left-handed. Sinister, just where that came from. Okay, anyway, so...
The lateralization, the left cerebral hemisphere controls language, math, and logic. Right cerebral hemisphere, spatial skills, intuition, emotion, artistic ability, and musical skills. So the right, you know, braindead people are really artsy-like type of people. Now, here's the thing.
Even though there's lateralization, meaning the left side has its own type of job, the right side has its own type of job, communication between the two hemispheres is almost instantaneous. So they... communicate with each other to carry out functions, right?
And that is part one. All right. Now, oh my gosh, it looks like I did part two first and then part one. I apologize.
All right. So now the good news is, is that the stuff that I'm talking about is going to make more sense. All right. So we have the white matter of the brain, which we already know is myelinated fibers. And when we look at the association areas, remember I told you association is that understanding part, right?
So we have some white matter that runs in different directions. We have association fibers, we have commissure fibers, and then we have projection fibers. And the projection fibers project like from lower brain to higher brain, like a projection. The commissure fibers run across the two cerebral hemispheres, so laterally, like across. And then the association fibers are...
white matter on the same side of the cerebral hemisphere and I'll show it to you in pictures. This is what I just said, like no lie, association, commissioner, and projection. Anyway, so I like this picture better with the three of them. So association, we're on the same cerebral hemisphere, and these are the white matters.
So white matter on the same side of the cerebrum. Then we have these little green dots here, and these are the commissioners. And the commissioners would join the left cerebral hemisphere to the right cerebral hemisphere. By the way, this one is the right side. The left side's been taken away.
So this would connect the right cerebral hemisphere to the left cerebral hemisphere. And then here's the projection ones, these ones that are in purple, projecting from lower areas to higher areas, okay? So those are the three types of fibers that are found in the white matter of the brain. All right, basal nuclei.
I already know this, right? Basal nuclei, that's that gray matter. So remember I told you that white matter is going to be myelinated fibers. You learned that from chapter 11, and then I reiterated it today.
And then we have the basal nuclei, which is going to be the soma of the neurons and nucleus is found in all cells, right? So we have the nuclei there. Now you don't have to know these specifically, but you do have to know that, remember, we looked at the brain and we saw the cerebral cortex, which was gray matter. Then we saw white matter. And then we saw additional gray matter scattered within that white matter.
That's the basal nuclei. And basal nuclei has a function. And its function is to kind of, you know, inhibit antagonistic movement or prevent unwanted or unnecessary movement. So that basal nuclei has a function.
So when we look here... Whenever you see nucleus, you're going to think of gray matter. So the thalamus has a lot of nuclei, and so it's gray matter that's there.
The caudate nucleus is also gray matter, hence the name nucleus. So the functions, like I said, of the basal nuclei in general is they play a role in muscle movement. But this is the big part, right? Filters out incorrect or inappropriate responses, inhibits antagonistic or unnecessary or unwanted movement. So if a person has a disorder or a disease that damages their basal nuclei, like Parkinson's disease and Huntington's disease, they're going to have a lot of unwanted movement that is a physical manifestation of the disease.
So Michael J. Fox has Parkinson's disease. The late Muhammad Ali had Parkinson's disease. And Richard Pryor had Parkinson's disease.
And there was just... uncontrollable shaking. I think Richard Pryor actually had multiple sclerosis and Parkinson's disease when everything was said and done. But anyway, Parkinson's disease and Huntington's disease are disorders of the basal nuclei. So again, this is the cerebral cortex, which we know is gray matter.
All of this center part here is white matter, and this is additional gray matter. Of course, they have it in different colors just because it's different parts, but this is the additional gray matter. And then you'll see things like... caught it, nucleus, you know, that's there.
The thalamus is there right here, which is also gray matter. And then this is a real brain. So now you can see, of course, that's gray matter, gray matter, gray matter, gray matter, gray matter, white matter. And then on the outside, this rubric cortex is gray matter.
All right. So we already know that this is diencephalon, but you don't have to know it this way. Thalamus, hypothalamus, epithelius. And we're going to talk about what each of those are responsible for, even though I mentioned it earlier, we're going to talk about it now. So now...
So the mid-tagital view is a cut down that longitudinal fissure, as I said before. So you're looking at half of the brain that's there. And so this is what we're going to be looking at now. So this whole thing right here is the thalamus. And see how we have the bold here, thalamus, and then the epithalamus and the hypothalamus.
That's all of this right here. All of this right here. Okay.
Now, the thalamus itself is quite large as far as... you know, the other parts. So the thalamus itself is kind of interesting because it says that there's nuclei, because it's gray matter, that project and receive fibers from the cerebral cortex. So remember, I said earlier that it's the gateway. Nothing goes to the cerebral cortex without having to pass through the thalamus first.
So thalamic processing is what is required before something goes to the cortex. And then remember, the cerebral cortex had those four motor functions. and then it had eight discrete sensory functions that we talked about.
So the motor, was the primary motor, the premotor, the brocus area, and then the frontal eye field. And then the sensory part was the primary somatosensory and then somatosensory association area. And then it was the gust story.
And then it was olfactory. And then it was visual, right? So all of those senses.
And then that was the vestibular, which is your um, Sense of balance, right? So anything that's going to the cerebral cortex, which is the side of the conscious mind, anything you do on purpose, has to go through the thalamus first. The thalamus, the thalamus, thalamus. Now, you do not have to identify all these things for me, but I'm going to make a point.
The thalamus is gray matter, and gray matter is made up of nuclei. Nuclei is the plural of nucleus. So all you'd have to do is, like, really to understand this is that not the names themselves, but this says medial dorsal nucleus.
lateral dorsal nucleus, lateral posterior nucleus, and then I see nuclei, and I see nucleus, and then I see more nuclei. You know what I'm saying? So that's gray matter. That's your confirmation that basal nuclei make up gray matter.
All right. So I said this already, but I'm just going to say it again. So the main thalamic function is to act as the relay center from information coming into the cortex. So anything that goes to the cortex has to go through the thalamus first.
So the thalamus is going to sort and edit and relay that information that's going up to the cerebral cortex. Impulses from the hypothalamus, and we'll talk about the hypothalamus next, or epithalamus next, whatever. We'll talk about the three of them. But that hypothalamus, remember the boss? Wait till you see all the stuff it does.
Impulses from the cerebellum. So remember, cerebellum was motor control. And the basal nuclei from the motor cortices. So remember the pyramids.
And I said if something's on the pyramid, it's going to be direct motor. direct motor. And then of course, memory and sensory integration. So overall, this thalamus, it acts to mediate sensation, motor activity, cortical arousal, right?
The cortex being aroused and you're learning in memory. So the first time you do something, it's learned and then you remember it. That's part of the cortex. Now that hypothalamus is the boss, hypo like below.
So it's located below the thalamus. This hypothalamus, when I tell you this hypothalamus is controlling some stuff, I really, really mean it. So look, it says the hypothalamus is the main visceral control and regulating center.
It is necessary for homeostasis. You learned about homeostasis in chapter one, right? Homeostasis.
Look what it says about this hypothalamus. Controls your blood pressure, your rate and your force of your heartbeat, your digestive tract motility, your pupil size. It's part of the limbic system. So helps you perceive pleasure and fear and rage and your drives, biological rhythms, like your sleep and your wake cycle, and then your sex drive, but there's more.
Regulates your body temperature. So you sweat, right, to cool off and you shiver to warm up. Regulates your hunger and your sciatica. So sciatica is being satisfied in response to your nutrient levels or hormones that are in your body. Regulates your hunger and your thirst.
or sorry, I already said hunger and thirst. So when you feel thirsty, it's the hypothalamus telling you that you're partially dehydrated and that you need to get water in your system and then helps regulate your sleep and your wake cycles. Yes, your biological clock. And you know, we just set the time back.
So, you know, some of us are still struggling with that, but there's more. This hypothalamus, I'm telling you, is the boss. It also has endocrine control and your endocrine system is the glandular system. that secretes hormones that tells your body what to do.
And the hypothalamus has control over that. Yes, indeed. So the hypothalamus controls secretions of the anterior pituitary gland. You'll learn more about that in 2086. And the production of posterior pituitary hormones. Oh yeah, the hypothalamus is the boss, Ricky Rosé.
All right, hypothalamic disturbances. Since the hypothalamus does so many things, disturbances in the hypothalamus can cause a myriad of things to happen. So...
It says severe body wasting and then it says obesity. Well, how can it be both? Well, because the hypothalamus controls your hunger, right? If you are hungry, you eat.
If you aren't hungry, then you don't eat. So if you never feel the urge to eat because you don't feel hungry, you would waste away. But if you feel the urge to eat all the time, then you would eat all the time and you'd be obese, right? Sleep disturbances, that goes both ways. Because it is your sleep and your awake cycle that is controlled by the hypothalamus.
So sleep disturbances, you can't sleep or you can sleep, right? So you have, you know, insomnia, right, where you can't sleep at all, or you just sleep all day. Then there's dehydration, because again, the hypothalamus, remember, controls your thirst. It tells you that you're thirsty.
So if I'm... If the hypothalamus tells me that I'm thirsty, I'm going to drink. But if I don't get that signal saying that I'm thirsty, then I will become dehydrated.
And then emotional imbalances. And that's because since it plays a role in your sleep and your wake cycle, it can definitely affect your emotions. I have a one-year-old granddaughter and, you know, she gets sleepy and needs to go down for a nap, but doesn't want to go down for a nap because she's.
think she's going to miss something. And as a result of that, she is cranky. But you guys know this as well. You are my college age, you know, demographic. And you guys know that you probably sleep on average three and a half to four hours a night.
That's not very much sleep. So yes, you can be cranky, right? Have emotional imbalances because you're cranky. All right. Um, failure to thrive can be implicated.
When there's damage to the hypothalamus, the child is deprived of warmth or a nurturing environment, and that could lead to the whole idea about this failure to thrive. All right. So if you don't have a loving or nurturing relationship, failure to thrive. All right. So now let's look at the epithalamus.
The epithalamus, again, so we had thalamus and the hypothalamus and the epithalamus. And again, these are all parts of the diencephalon, but you're not going to have to know that they're parts of the diencephalon. You're just going to have to know them respectively. And the pineal gland is there and the pineal gland secretes melatonin and melatonin controls your sleep and your wake cycle. So here we are again, all of this gray matter here.
So the thalamus itself, the hypothalamus right below that. And then if you look here, like how this goes with the epithalamus, hypothalamus, it's kind of this little right there. All right.
So those are thalamus, thalamus here, hypothalamus here, and then the hypothalamus. All right. And then a real brain. So animated brains with, you know, color coding and then the real brain. This right here is the thalamus.
Isn't that cool? That's like almost a perfect circle. And then the hypothalamus is below it. That's there. And you can't really see it.
It's kind of. Oh no, there it is. I was about to say it's kind of cut off, but this right here, that's the pineal gland.
This little thing that I'm outlying with my arrow, that's the pineal gland. In the sheep brain for lab, you'll see it again. It's just this little, little, you know, gland that's there. All right. This is, again, just animated pictures.
There's not much that I go over here because in this picture right here, they're showing the cranial nerves. The cranial nerves come in 12 pairs and they are numbered with Roman numerals. And so these are the Roman numerals. So there's one which is olfactory and they don't show that one, but two is the optic and three is ocular motor.
And we're going to get into all of those. They're their own chapter. They are their own chapter for the cranial nerves.
All right. And then the brainstem, which has this midbrain, the pons and the medulla, we're going to talk about each of those and what that... means and how that matters.
In this area, again, would be those cranial nerves. It says 10 of the 12 pairs of cranial nerves. So again, I've already mentioned that there's 12 pairs of cranial nerves. And then this picture, again, just shows the nerves.
This one actually does show the olfactory. I'm sorry about the... Here, I can... I think I can actually... I guess I can't.
I was going to try to fix that. While we're on here, I'm just going to make all this smaller and get it out of the way. Not that you have to know much about this picture in general, just that it will be a little bit easier to see the actual brain if I can make it smaller and get it again out of the way. So let's make it like, I don't know, 16. Okay. So when we look at this right here, it's olfactory.
So this right here is cranial nerve number one. And then you guys, again, will know this for lab, but these are the optic nerves. They're cut off, but they cross each other.
And where they cross each other is at the optic chiasma. And then the cranial nerves are their own chapter, but you're able to see, right, the nerves coming off. So 10 of the 12 pairs of cranial nerves actually come off the midbrain.
All right. Let's see what else we need to know. The cerebral aqueduct.
So this right here is a chamber. And we talked about this already when we talked about the lateral ventricle and the fourth ventricle. So lateral ventricle, fourth ventricle, third ventricle, and the cerebral aqueduct.
So cerebral spinal fluid runs through there. We know that gray matter is nuclei, so that shouldn't surprise you. So this is periaqueductal gray matter.
nuclei that plays a role in pain suppression and your fight and flight response that's there. And then of course they mentioned more of the cranial nerves and then that animated picture showing them again. Now we do have the corpora quagmina and the corpora quagmina consists of four parts. Hence the quad that's in the name there. There's two superior caniculi and then there's two inferior colliculi and the two superior colliculi.
are part of the visual reflex. And when we get into our special senses, this will come up again. And the two inferior colliculi are part of the auditory, which is your sense of hearing. So sense of sight, sense of hearing. And the four of these make the corpora quadrumina.
And then substantia nigra is again, gray matter. So nigra, like Negro and Espanol, right? Black.
And it says here that this... is part of the area that degenerates with a person who has Parkinson's disease. Well, I've already told you, right, if somebody has damage to their basal nuclei, then they lose the ability to control unwanted or unnecessary movement, right? They can't inhibit antagonistic movement. So there's a lot of jerking and moving that goes along with that.
And then the red nucleus is not really red. It's still gray matter because it's nuclei. And that is part of the limb, which are your arms and legs.
flexion motor pathway. All right. And then they just, again, just show you more areas. So this is a cross section and then this is still gray matter.
So see the red nucleus there, substantial nigra is there. And then the colliculus. So remember I told you there's corpora quadrumula, so superiors on top, superior colliculus, and then the inferior colliculus, but there's four.
So two superior and two inferior ones. And then we have the pons and the pons is in a great location for what it does. And the pons basically relays impulses between the motor cortex, which is part of the cerebral cortex, right? So the cerebrum and the cerebellum.
Now, remember, I told you that generally speaking, the cerebellum is motor. So if I have a motor cortex, which you guys know was primary motor and premotor, right? If I have a motor cortex and its job is motor and I have cerebellum and its job is motor.
Communication between these two motor centers in different parts of the brain has to happen, right? Or else I'm not going to be able to consciously carry out what I desire to do, right? Voluntary movement.
So of course, there has to be communication in the pons is what helps with that because of its location. Then these are some of the cranial nerves. Again, I have a whole lecture on cranial nerves, but there's the trigeminal cranial nerve, abductions, and facial, which are five, six, and seven if you're not...
familiar with your Roman numerals. V is five, and this is six. So V plus one is six, and then this is five again, plus two, one and one is seven. So the facial nerve is cranial nerve number seven.
The abdescence is cranial nerve number six, and trigeminal is cranial nerve number five. And we'll get into all of those in their own special lecture. Then we have the medulla oblongata, sometimes just referred to as the medulla itself. We've already talked about the fact that there's pyramids on there that are responsible for motor control because the pyramids lead down into the brainstem.
And another name for the brainstem is the spinal cord. And that's all it says is that we have the medulla, it blends into the spinal cord, right? Contains the fourth ventricle, which I've mentioned before as well.
And again, the spinal cord, which you know, is, you know, responsible for your ability to move. You know, that if someone, you know, had a severe back injury, right? Damage to their spinal cord could cause them to be paralyzed from the neck down or from the back down or, you know, whatever, you know, wherever the damage is. And then there's a choroid plexus and it's filled with cerebral spinal fluid because this is where it is actually made. All right.
Now the pyramids are on the medulla and then they cross. So discussation of the pyramids is the part where they cross. This makes sense to you because the cerebral cortex is contralateral control.
That means the right cerebrum, right, cerebral hemisphere, controls the left side of the body and the left cerebral hemisphere controls the right side of the body. That's contralateral control. So in order for that movement to happen, like a person like my dad who had a stroke, on his left cerebral hemisphere and was paralyzed on his right hand side, crossover had to take place somewhere.
And it crosses over at the pyramid. So, the scussation of the pyramids is where we get control of the opposite side of the body. Then we have down here, and this is just to let you know, of course, more gray matter. The reason why you know it's gray matter is because it's olivary nuclei.
You know what I'm saying? So, anything that says nuclei on it's going to be gray matter. We have vestibular and cochlear nuclei. These are part of the... cranial nerves.
There's a vestibular cochlear nerve. Again, we'll get to that in and of itself, but whenever there's nuclei, it's going to be gray matter. And then vestibular was equilibrium. So remember when we talked about the cerebral cortex and we talked about the eight sensory areas, vestibular was there and vestibular was your sense of balance that was there. All right.
So what's the function of the medulla oblongata? Well, the medulla oblongata actually has some overlapping functions with the hypothalamus. And then it has some functions that are just for itself.
So the hypothalamus itself, as far as the overlap, the overlap with the hypothalamus and the medulla oblongata is cardiovascular. So cardio heart vascular, so cardiovascular. And then the other part is going to be respiratory. That's the overlapping with the hypothalamus because the hypothalamus, remember your rate and depth of breathing, and then your control of blood pressure, remember? it was the boss.
So I could go on and on, but those are the two centers that have overlap. So cardiovascular and respiratory, but then the medulla oblongata is responsible for vomiting, hiccuping, swallowing, coughing, and sneezing. Vomiting, hiccuping, swallowing, coughing, and sneezing.
So those are controlled by the medulla oblongata. Now we move to the cerebellum, which I've already mentioned is going to be motor, right? Motor, motor, motor.
Now my promise to you is that they're going to go in great detail. about how the cerebellum controls motor function. And then you have to remember, there was a part of the cerebral cortex that was also motor.
The pons, remember, was the relay center between the motor cortex, cerebral cortex where the motor areas are, and the cerebellum. So here it says that the cerebellum is processing input from the cortex, the brainstem and sensory receptors to provide coordinated movement. That means motor, right, of your skeletal muscle.
And it also plays a role in your balance. So the cerebellum is similar to the cerebrum. There are hemispheres.
So we have cerebral hemispheres and we have cerebellar hemispheres. They're connected by a worm-like vermis. There's folia that's there. And then there's three lobes, anterior, posterior, and then a floccular, ocular, nodular. I know, floccular, ocular, nodular, flock.
oculonodular. Sounds great. Say that three times fast. But then we have white matter in the cerebellum. So the outside is cortex, which is gray, right?
Just like the cerebral cortex. The inside is white matter, and that's called arborvitae. And that literally translates to the tree of life.
Arborvitae. Arbor, like Arbor Day, plant a tree. Vitae, life. Okay. So Purgenji fibers originate within that cortex, and they synapse within the cerebellum.
So cerebellum is motor control. You also have a cerebellar homunculus that shows the sensory map of the entire body. So remember we talked about somatotopy where I could go to the cerebral cortex and find out a specific place on the cerebral cortex that was responsible for movement of the body.
All right. So this right here is the entire cerebellum. This whole thing is the cerebellum.
It's cut in half. And so the white matter is on the inside here. And on the outside is the cerebellar.
cortex, that's gray matter. You can see it better in an animated picture. So in the animated picture, this is the cerebellar cortex, which is that darker beige color.
So that's the gray matter. And then this center part right here is the white matter. The white matter is still and always will be myelinated fibers, right? Myelinated fibers.
All right. Now, unlike the cerebrum, the cerebellum is... the abso-lateral control.
Abso-lateral control means same side control. So in the cerebellum, which has motor responsibilities, it is the right cerebellar hemisphere that moves the right side of the body and the left cerebellar hemisphere that moves the left side of the body. That means abso-lateral control, okay, in contrast to the cerebral hemisphere. All right.
What else is there? We have some peduncles that are there. Again, they're just named, I mean, you know your terminology, superior, middle, and inferior.
So superior is up high, so cerebellum to midbrain. Inferior would be a little bit lower, like medulla going into the cerebellum. And then the middle, like the pons, right, that connects the...
motor cortex to the cerebellum, that would be middle. So superior is going up higher, inferior is down lower, like going again from the medulla into the cerebellum. And then right in the middle here is that pons, location, location, location.
All right. So all of this is motor, right? So what does the cerebellum do?
It's motor control. What's the cerebellum do? Motor control.
What's the cerebellum do? It is motor control. It's great.
So if I read all this, it should have something to do with motor. Receives impulses from the cerebral cortex to initiate voluntary muscle contraction. Oh, that's motor.
Receives signals and proprioceptors throughout the body for visual and equilibrium pathway. Equilibrium? Is that motor?
Sure is. When you lose your balance, you reflexively move in the opposite direction trying to gain your balance again. Yep, it's there. Cerebellum.
cerebellar cortex calculates the best way to smoothly coordinate muscle contraction. Yep, that's motor. It sends a blueprint of coordinated movement, that's muscle movement, to the cerebromotor cortex and the brainstem, you know, because they need to communicate because the cerebral hemisphere has a motor responsibility and the cerebellum has a motor responsibility.
So the two of them have to communicate in order for you to consciously carry out Voluntary muscle movement. All right. Now, I always say that the cerebellum is motor, motor, motor, motor, motor.
And I always laugh because I personify everything. So I'm like, oh, cerebellum. What do you need to know about cerebellum?
Movement, movement, movement. What do you need to know about the cerebellum? Movement, movement, movement. And the cerebellum says to me, hey, prof, you know what?
I'm more than just muscle here, right? Because the cerebellum is muscle movement. I'm more than just muscle here. I can do some other stuff.
And this is me personifying the cerebellum. And I'm like, really, like what? I can think. So the reality is, and it's true, is that through neuroimaging, we realize that even though the cerebellum is mainly associated with motor control, that when you are thinking or you are using language or you are suffering through emotions, the cerebellum is lit up. Which indicates that the cerebellum plays a role in those things.
How cool is that? So, hey, Professor Evans, I'm not just a muscle. That's like my impressions. Don't judge me.
Okay. All right. Guess what, ladies and gentlemen?
That's it. Chapter 12, parts one and two.