Alright Ninja Nerds, in this video today we're going to talk about the cerebral cortex and all those beautiful lobes of the brain. So... If we take a look here, we got a big old brain, right? And there's a bunch of different lobes.
Now, it may seem a little kind of like intimidating right now, but give it a second, we'll clear everything up. All right, first thing I want us to know is the different lobes of the brain. There's four main lobes.
There's a fifth mini lobe called the insula. We're not going to talk about it in this video, but I want you to know the main lobes. So if you imagine right here, this lobe right here is called your frontal lobe.
This lobe right here is called your temporal lobe. This lobe right here is called your parietal lobe and this lobe back here is called your occipital lobe. Now we got to take it a step further, right? Because all we have is just where maybe in some space where the frontal lobe is.
We have these beautiful demarcations or sulci, if you will, that separate these lobes from one another. What are these demarcations or sulci? This first one is beautifully placed right here.
You can kind of see it in a combination of red and... purple it's this one right here this this little sulci here is called your central sulcus it's called your central sulcus now your central sulcus is a beautifully place that it separates what two lobes your frontal lobe which is anterior to it and your parietal lobe which is posterior to it right there's another sulcus another sulcus is running here right This color here, so this red and green one here. This one here, I'm going to have a line coming out from it. This here is called your lateral sulcus. It's called your lateral sulcus.
Sometimes also referred to as your sylvanian fissure. Okay? Now, the beautiful position of the lateral sulcus is that it separates this lobe, the temporal lobe, from the frontal lobe and the...
parietal lobe. Okay? That covers that demarcation.
There's another demarcation here. Right here. This kind of blue and red one here.
This guy is called your parieto-occipital sulcus. Now the beauty about the parieto-occipital sulcus is that it's positioned in such a way that it separates anterior to it, the parietal lobe, from posterior to it, the occipital lobe. Okay?
Now this last one here is not a actual complete sulcus or demarcation. It's an imaginary type of line. Right here, you see how we come from this occipital lobe just above this cerebellum.
There's a little notch right here, right here. I'm going to kind of draw it here in this dark black here, right? You see that little notch, that little kind of elevation point? That elevation point right there is actually referred to as the pre-occipital notch.
And if you draw an imaginary line from this little notch or this pre-occipital notch towards your parieto-occipital sulcus, guess what that does? It separates your occipital lobe, which is posterior to it from your temporal lobe, which is anterior to it. So that is going to give us our demarcations.
Now, what I want us to do is start here with the frontal lobe. Talk about some of the names of these areas and then come over and talk about their basic function. Alright, so now what I want us to do is talk about the particular areas.
I just want you guys to know where they would be in kind of a general sense. There's no complete clear cut demarcation like we have with the central sulcus between each one of these kind of general areas in the frontal lobe. So...
This first area here, this is very important, this kind of red one here. This area here is very important. It's called your primary motor cortex. What we're just going to abbreviate it for right now is PMC.
We'll write it down later. Now, just anterior to that, because I just want you to know the general position in anatomy. Just anterior to the primary motor cortex, you have this blue one here.
This blue one here is very important as well. It is called your motor association cortex. It's made up of two particular areas called the premotor cortex and your supplementary motor cortex. Okay?
Go just a little bit anterior to that, more in the superior aspect of the frontal lobe. You have another area in this green color. This is called your frontal...
eye fields. Then just go a little bit anterior and inferior to the frontal eye fields in the frontal lobe and you got this big blue structure here. This is called your prefrontal cortex. Sometimes also referred to a textbook as the prefrontal association area.
Then come at the most inferior point of the frontal lobe usually on the left side of the bream you have another area here. called, and this is in orange, this is called your Broca's area. Okay. So this is the general anatomy in the frontal lobe of these particular areas.
Now let's come over here into this chart and talk about the general functions of the, each of these areas. All right. So we talked about each one of those areas in the frontal lobe, right? So we said the first one is called our primary motor cortex, right? We call that the PMC, right?
Now, the basic function I want you to remember for the primary motor cortex, literally, kind of a one kind of liner, is that it's involved in voluntary movement. That's all I want you guys to remember. The big thing that I want you to remember, though, as an aside to keep in your brain, is that the primary motor cortex, we're looking at a lateral side of the brain, right?
If we imagine that this is the left side of the lateral surface of the brain, the left primary motor cortex... controls movement of your right side. So when I say voluntary movement, I want you to remember that it's contralateral sides.
That's all I want you to remember for right now for the primary motor cortex. We said just anterior to that was your motor association cortex, right? Now your motor association cortex, I want you to remember that it's made up of two areas, right? We're gonna write them now as your premotor cortex and supplementary, supplementary motor cortex. But again, the combination of these two is called your motor association cortex.
Now, the premotor and supplementary motor cortex, they also are involved in voluntary movement. But more specifically, they're involved in the planning of movement. They're involved in the sequencing of movement.
They're involved in the execution of movement. So when we talk about how they're involved in movement, more specifically they're involved in the planning, the sequencing, and the execution of movement. But they do also give some axons from them that do go into the descending motor pathways that are involved in movement as well. Okay, the next area just anterior to the motor association cortex is called your frontal eye field. What is it called?
Your frontal eye field. Your frontal eye fields are also very interesting. They're involved in a kind of a specialized motor movement.
And these more specifically are involved in voluntary eye movement. Okay. If we were to kind of add on to that, it's more involved in what's called saccades, which is rapid eye movement.
So helping your eyes to move conjugately to the left, conjugately to the right, up and down. Okay. So that's your frontal eye fields.
The next one is if we move just a little bit anterior to the frontal eye fields, we have that prefrontal cortex. So it's called the prefrontal cortex. Now the prefrontal cortex has so many functions, right? It's involved in our memory. It's also involved in learning.
So kind of in the cognition process as well. It's involved in our personality, right? And even our behavior. And it is also involved in our judgment, our reasoning, or kind of we can say decision making.
So it's also involved in our decision making. And last but not least, it even has some type of input that it can send to your motor association cortex that is involved in motor planning. In the last area, that orange area that we said is usually at the bottom of the frontal lobe, usually the most inferior portion, more commonly on the dominant side of individuals. cerebral hemisphere, which is usually their left because they're most likely right-handed dominant, is your Broca's area.
Okay, so Broca's area. Now Broca's area is important because it's involved with our speech production. So it's involved in stimulating the muscles that are involved in speech production. All right, beautiful. So that covers our Broca's area.
Now let's talk about the areas of the temporal lobe and their function. All right, great. So we talked about the frontal lobe.
We went over the areas, their functions. Now let's talk about the temporal lobe, their areas, basic anatomy, and then functions. All right, remember, we had that lateral sulcus, right?
So that's separating our temporal from our frontal and parietal. Just underneath the lateral sulcus, you have this kind of like red area here, right? This red area here is very important, and it's involved in sound. This is called our primary.
auditory cortex. Okay? Just below that, okay, surrounding it, is another area in this baby blue color.
And again, it's inferior to it. This is called your auditory association cortex. Okay?
The other area is, if we follow lateral sulcus backwards, you have this purple area here. And if you look, it's in the temporal lobe mainly, but a little bit of it dips over into the parietal lobe. Okay, this area is called Wernicke's area and just like Broca's area, it's primarily only found in the dominant cerebral hemisphere.
So usually the left side of the brain for more commonly right-handed people. Now, this other area, this is a lateral surface of the brain. So you're looking at the brain, your eyes are here, you're looking at the lateral surface of the brain. Okay, there's an area in the temporal lobe, but it's deep, it's medial.
It's in the most medial aspect of the temporal lobe. I'll show you a picture a little bit later. But it is right here called the primary olfactory cortex. And there is an association cortex along with that. Okay?
So these are the areas of the temporal lobe. Now let's talk about their functions. Alright, so temporal lobe. Again, we said that we had that first area there.
Just underneath that lateral sulcus there was called our primary. Auditory cortex. Now this primary auditory cortex is very cool. It's involved with the perception of sound, right? So basically being aware that we're hearing something.
So awareness, consciously, conscious awareness of sound. But here's the cool thing. Whenever sound waves basically are carried from, you know, in the air and then into our ear and then sent to our brain, their actual sound waves.
Our primary auditory cortex really only responds to a couple aspects of sound. The pitch of sound, right? It also responds not just to the pitch of sound, but also to the frequency of sound.
And it even can determine the location of sound. So it can even localize sound. So when we're referring to sound, the primary auditory cortex is involved with conscious awareness of the pitch of sound, frequency of sound, and location of sound.
Now. The other area, which we said is just below it, is called the auditory association cortex. It's called the auditory association cortex. Now, the auditory association cortex analyzes the sound, right?
So one of the functions here is that it analyzes the sound, right? So it analyzes the pitch, the frequency, the location, the amplitude, the tone of it. And then after it analyzes it, it helps us to recognize the sound, what that sound is. Is it someone's voice?
Is it a voice that we've actually heard before? Is it even a voice at all? Is it maybe the sound of thunder, lightning, right? All of those aspects it's involved in.
Okay, so it analyzes the sound and it helps us to recognize the sound. And store it in our memory so if we're experiencing that sound again, we'll remember it. The other area which we said is kind of dipping into the temporal lobe and a little bit into the parietal lobe is called the Wernicke's area. Now the Wernicke's area is a very cool area that's involved with what's called comprehension and understanding of written and spoken language.
So it's involved in, we're just going to say here, language comprehension. But again, remember that language can be both spoken. So, auditory we hear it that language english language what i'm speaking to you guys right now and you're hearing through the computer and the written language me just writing down language comprehension you guys were able to read that all right the last area is called that primary olfactory cortex now again i want you to remember that this is not just the primary olfactory cortex but it also just around that primary olfactory cortex it'll also have an association cortex every primary cortex should have an association cortex to analyze and recognize whatever that thing that it's involved in. In this case, smell. So to give you guys a little bit more perspective on kind of where, because again, primary olfactory cortex is not on the lateral surface, and it's not the most inferior.
I just wanted to fit it in there. But if we take, again, a slice of the brain and we look at the medial surface, you'd kind of see it like this. So. Here's the medial surface.
And the best way I like to identify that is you have your corpus callosum here, right? So here would be your corpus callosum. And again, here would be your frontal lobe. You'd still have a part of that central sulcus coming down here, parietal, occipital sulcus, right? But right here is that lateral sulcus.
And the actual primary olfactory cortex sits just kind of underneath that, right? And particularly on the medial aspect of the temporal lobe. So that is where the olfactory cortex is actually located. Now, the primary olfactory cortex and it's an association cortex is responsible for what?
Awareness of smell. And again, that would be the primaries function. So awareness of smell.
But again, if you dug in a little bit deeper, the association cortex would be responsible for what? Analyzing the smell and recognizing the smell. So is this a smell of a, you know, someone cracking a rat or passing gas or cutting the cheese or farting, right? you'd be able to tell that because your association cortex is comparing that smell with past memories of smell. All right, beautiful.
That covers the temporal lobe. All right, so now let's talk about the parietal lobe. And again, we have that central sulcus beautifully separating parietal from frontal, as a reminder, and the lateral separating the parietal from the temporal, and then the parietal occipital separating the parietal from the occipital lobe. Beautiful.
Again, just posterior to that central sulcus, you have another gyrus. This is actually called your postcentral gyrus. But what I want you to remember is that the functional area on that postcentral gyrus is called your primary somatosensory cortex.
Okay, just posterior to the primary somatosensory cortex, what do you think it's going to be? You guys have already noticed that whenever there's a primary, there has to be an association cortex. So this is actually going to be called the somatosensory association cortex. Beautiful. Then just posterior to that is a very weird area.
that I felt like we're going to talk about and really more particularly discuss it within the parietal lobe. This is actually called the posterior association area. It's a multimodal association area and I'll explain what that means in a little bit. But these are the areas that we're going to focus on okay within the parietal lobe. Now let's talk about their function.
All right so when we talked about the parietal lobe again just posterior to that central sulcus we had what's that first kind of area we call it the primary somatosensory cortex, right? And again, I just want you guys to have kind of like a one-liner of what it does. The primary somatosensory cortex is involved in awareness of somatic sensations. Now to expand on that, what does that mean?
That means fine touch, discriminative touch. It means proprioceptive sensations, which is where your body, your arm, your body parts are in a three-dimensional space and even vibration sense and pressure. All of that stuff comes to this area.
of the cerebral cortex and so you're aware of those sensations. Now just posterior to that is an even cooler function. And again, what we say was just posterior to the somatosensory cortex, the primary one, it was the somatosensory association cortex. And I think you guys should at this point start to be seeing a trend here that anywhere there's a primary cortex, it's just kind of a highway system that funnels into their association cortex.
And this somatosensory association cortex will then do what? Well, it'll analyze the somatic sensations. And not only that, but it'll also do what?
It'll help with the recognition of those somatic sensations. So to give you guys a very simple example here is that if I close my eyes, so I'm not depending upon visual stimulus, right? and someone puts a marker in my hand, I can feel that the marker's in my hand, so that's the sensory pathways. I can also tell that it's in my right hand because of my proprioceptive sensations. And if I'm pretty good, I can also tell that this is a marker without actually knowing that I'm the one who put it in my hand.
So that is what this somatosensory association cortex does, is pattern recognition. Okay? The one just posterior to it is the really interesting and weird area. It's called the posterior...
association area. Now this area is actually kind of what we already kind of just explained what it is. I'm going to write it down. It's called a multi modal association area. And I'm going to very briefly explain what the heck that means.
All right, anytime you guys have noticed a trend here, you have a sensation. Let's take for example. The somatosensory cortex, the somatic sensations go to this area. Then they go to an association cortex to be analyzed and recognized. Well guess what?
What happens is the association cortexes from your visual pathway Your auditory pathway and your sensory pathways all kind of coalesce into one area. So your visual association cortex, auditory association cortex, and somatosensory association cortex then funnel their info into the posterior association area. Now, I can determine a sense of spatial coordination of visual stimuli, auditory stimuli, and sensory stimuli. That is the function of this beautiful area. And it can communicate with a bunch of other areas in the brain.
All right, beautiful. That covers a parietal lobe. All right, so now we got our last lobe here that we got to talk about, the occipital lobe, right?
And again, what did we say was the demarcation points? We had the parietal occipital sulcus, which separates it from the parietal lobe. And that imaginary line coming from the preoccipital notch that comes and meets the parietal occipital sulcus separates the occipital from the temporal.
All right. We got two cortex in this area, or two areas particularly. One, we're going to start with this one most posteriorly. Okay? This one right here is actually referred to as, let's do it in red so we can really differentiate it.
This one is called your primary visual cortex. Now, if you go just anterior to the primary visual cortex, you have another area. And this area, again, you guys should already get the point of this. Wherever there's a primary, there is an association. So this is called your visual association cortex.
All right, that covers the areas. Now let's go ahead and talk about their function. All right, beautiful.
So occipital lobe. Now let's talk about the functions of those areas. What were the first area that we talked about? The primary visual cortex, right? And the primary visual cortex, what do we say it's responsible for?
Awareness, so conscious awareness of vision, right? So a visual stimulus, if you will. Now, when the visual stimuli comes from your eyeballs, right, and then goes to your occipital lobe and your primary visual cortex, then it has to go to what other structure? What's the highway system for the other structure that it moves into? It then goes into the association cortex.
So the next one, which was just anterior to it, is called the visual association cortex. And again, what does this do? It... analyzes the visual stimulus. Alright so how does it how does it do that?
Well it takes the visual stimulus and it looks at the color. Maybe again this is orange. I'm telling that because of my visual association cortex. It also tells me the angles right of how I wrote V how I kind of wrote I.
It tells me if something's moving alright or if it's staying still. All of that stuff that visual stimulus of all these things are coming to your primary visual then to your visual association cortex. where it analyzes the color, the movement, the angles. So it helps us to recognize our visual stimulus, right? Now that's really important if you think about the overall concept of that.
So if you think about it, I have a marker here, right? How am I able to tell that that's a marker? Well, I'm able to tell because I see kind of the shape of it.
I see kind of the angles involved in it. I see the color that it's an orange marker. I can tell that basically what I can do with it because the visual association cortex is responsible for that. So that's the beauty of this cortex.
All right, that covers our occipital lobe. All right, so I said I wasn't going to cover the insula in this video, but I feel bad. I want to make sure that you guys know kind of the basic idea of where it is. So imagine I had two hooks, right?
I'm going to take a hook and I'm going to stick it into the lateral sulcus and I'm going to yank down. I'm going to take another hook and I'm going to stick it under the lateral sulcus and I'm going to pull up. If I pull down and pull up.
there's going to be a little lobe of brain tissue sitting right here and that's called the insula Now, what I want you guys to know about the insula is just the basic functions of the insula. All right. So again, the insula is that structure that we talked about if we were to kind of pull on that lateral sulcus, right? I want you to know just the three basic functions of the insula.
One is that it is responsible for receiving taste sensations. So it's involved in gustation. So this might be where your gustation cortex is actually located.
So gustation is also known as... taste. Let's just write that down.
It's known as taste. So this is where taste is taken to. So we're aware of taste.
And then the association gustation cortex would be involved in what? Telling us what kind of taste it is. If it's sweet, if it's sour, if it's bitter, if it's salty, or if it's umami, you know, and the other function of the insula is it's involved with visceral being aware of our visceral sensations.
So sensations coming from the GI tract, the heart, the lungs, things of that nature. If you guys have ever had gastroenteritis, The pain from that, right? So just a GI bug, the pain from that GI tract will go to your insula and make you aware of that.
So you remember in the future not to eat that potato salad that's been sitting out in the sun all day. The last function of the insula is that it's believed that this may be where the vestibular cortex is actually located. And your vestibular cortex would be involved with your vestibular sensations, which is basically your sense of movement, right?
So your sense of like what's called dynamic equilibrium. which is kind of involved with rotational acceleration. And then your static equilibrium, which is kind of linear motions, right? So kind of like head nodding. That is where those sensations may go to.
So that gives you the basic function of the insula. All right, Nisner. So in this video, we talk about the basic overview of the cerebral cortex, all the lobes, the particular kind of functional areas, and what those areas do.
I hope this made sense. I hope you guys enjoyed it. If you guys did, hit that like button, comment down in the comment section. Please subscribe. Also down in the description box, we'll have links to our Facebook, Instagram.
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Appreciate you. And as always, Niners, until next time.