The Cerebrum - Online Tutor, Practice Problems & Exam Prep

The cerebrum, divided into left and right hemispheres, is responsible for complex functions like motor coordination, emotion, language, and memory. Each hemisphere specializes in different tasks, with the left focusing on language and logic, while the right handles visual-spatial skills and emotions. Key features include gyri (ridges), sulci (shallow grooves), and fissures (deep grooves). The cerebrum consists of four lobes: frontal (voluntary movement, cognition), parietal (sensation), temporal (hearing, memory), and occipital (vision). Understanding these areas is crucial for grasping brain function and its impact on behavior.

The Cerebrum

Hey everyone. So in this video, we are going to be talking about the cerebrum. The cerebrum is the most superior portion of our brain and it consists of 2 cerebral hemispheres, our left and our right hemisphere. The cerebrum is responsible for many complex functions. Everything from motor coordination, the experience of emotion, language, memory, you name it. Now, a really interesting phenomenon that we see with our cerebrum is something called lateralization. Lateralization is the phenomenon of each hemisphere being specialized for certain tasks. So if we scooch down here to our brain, just to kind of orient you, this is looking down at a person's brain. So, like, their forehead would be about there and this is the back of their head. So what we see is for most people, we'll get to that in a second, but for most people, the left hemisphere tends to be specialized for things like language, intellect, logic, complex problem-solving skills, and cognitive skills, and stuff like that. Whereas for most people, the right hemisphere tends to be more specialized for things like visual spatial skills, emotion understanding and regulation, and artistic and musical skills. Even though we do see this specialization in our hemispheres, please do keep in mind that these hemispheres are constantly in communication. They're always coordinating things, so they're not working completely in isolation. They're always working together to do all kinds of complex tasks. Now, you may have heard of the idea of people being left-brained and right-brained and there is a little bit of truth to that. So we see a phenomenon called cerebral dominance where a person can be dominant in either their left or right hemisphere. And what we see is that the hemisphere that is dominant is the hemisphere that is used for language. So as I just mentioned, in most people language is dominant in the left hemisphere and that's true for about 90% of humans. So if your language is dominant in the left hemisphere then you are left hemisphere dominant. But for some people, about 10 percent of people, language is dominant in the right hemisphere and they would be right hemisphere dominant. Now one last phenomenon that we see with our cerebrum is something called contralateral control, which is the idea that each hemisphere controls the opposite side of the body. So the left hemisphere is responsible for the motor function, sensation, and perception. So an easy way to know which of your hemispheres is dominant is just by which hand you use to write with. If you are right-handed, you are probably left hemisphere dominant and if you are a lefty, you're probably right hemisphere dominant. So that is the cerebrum kind of in a nutshell and I'll see you in our next video to talk more about the cerebrum and some specific features that we can see on the surface of the cerebrum. So I'll see you there.

The Cerebrum Example 1

Aphasia is a condition that often prevents people from being able to talk. For most people, this means there is an issue with the left hemisphere of their brain. Sometimes, people with aphasia can communicate by singing as this primarily uses the right hemisphere of the brain. So remember, we're talking about most people, so we're going to think about averages here, and, like we talked about, for most people, language is specialized to the left hemisphere of the brain. And keep in mind that the right hemisphere for most people tends to be specialized for things like musical skills. So being able to take language and give it a melodious quality would be something controlled more by the right hemisphere of the brain. So based on that, our answer is a. So, there you have it.

Important Features of the Cerebrum

So in this video, we're going to be talking about some important features of the cerebrum. Like we talked about previously, the surface of the cerebrum or the cortex is covered in all of these grooves and ridges, and that's what gives the cortex its very kind of distinctive wrinkly appearance. Now those grooves and ridges actually have names and there are 3 of these features that you need to know. So the first is a gyrus. A gyrus is an elevated ridge of tissue on the surface of the brain. If we're looking at this kind of little zoomed-in segment of the brain here, each of these bumps or ridges would be a gyrus. These are all gyri is one way to say that as well. Okay? So the gyrus is the bump or the ridge that we can see. Now, we also have a sulcus. A sulcus is a shallow groove of tissue that separates gyri. Looking at our little cartoon here, this would be our sulcus. You can see it's not going too deep. It's pretty shallow, but it's separating out these 2 gyri there. Okay? So this feature would be the sulcus. Alright? And then finally, we have fissures. Fissures are deep grooves of tissue that separate out larger regions of the brain. In our cartoon, this would be our fissure. You can see how much deeper and larger it is compared to our little sulcus there. Sulci and fissures are both grooves; they're both kind of going in. But again, fissures are much deeper and larger and they're more visually prominent. If you're just looking at a brain with the naked eye, you can very easily tell what is a fissure and what is a sulcus, and I'll show you that in just a second. Okay? Human brains are unique. They're a little bit like fingerprints in a way, but pretty much all typically developing human brains will have certain landmarks on them. So we're going to go over the 5 most prominent landmarks that we see in the human brain. Alright. So just to kind of orient you to this image really quick, over here on the left, we have a lateral view of the brain. So we're looking this way. And over here on the right, we have a superior view. So we're looking down. This is the front of the person's head and this would be the back of the person's head. Okay? Alright. So we're going to start our journey here with the central sulcus which is this purple line right here. Okay? And you can see on the superior view over here the central sulcus appears on the left and right hemisphere and it's basically this little sulcus that goes right in about the center of your brain toward the center of your skull. Okay? And that central sulcus on either side of it, we have a very important gyrus. So right in front of the central sulcus, more anterior to the central sulcus, we have the precentral gyrus. So that is this feature right here, and then right behind the central sulcus we have the postcentral gyrus. So I always remember this as the postcentral gyrus is posterior to that central sulcus. Okay? And you can see again on our superior view where each of those would be. Okay, so those are the 2 gyri and the sulcus that you should know. Okay? Next, we're going to go over the fissures. So the first one we're going to go over is the lateral fissure and that is this blue line right here that kind of separates out this lobe. My pen stopped working for a second. There we go. That kind of separates out this lobe of the brain. And I would bet even before you watch this video, throughout your entire life even, if I asked you to draw a brain, even if you have zero artistic skills, you probably would have drawn something like this. Right? So what you included there was the lateral fissure. So again, fissures are very visually prominent. And you can tell just from looking at a brain how important they are even if you don't even know what you're looking at yet. So you've been drawing lateral fissures your entire life. Look at that. So that's our lateral fissure. And then looking at our superior view, we can see our longitudinal fissure. And the longitudinal fissure is very important because this is the feature that separates the cerebrum into the left and right hemispheres. So the lateral fissure actually is what creates our left and right hemispheres. Okay? Now one way that I always remembered this when I was a student, maybe it'll help you as well, is to imagine a world map. And if we're looking at a world map to tell direction we have our vertical lines, right, representing longitude and our horizontal lines representing latitude. So I would always remember these vertical lines are longitude, longitudinal fissure, and then these horizontal lines are latitude, which is the lateral fissure. So maybe that's helpful to you as well. Hopefully, it can be. Alright. So I will see you guys in our next video to talk even more about the cerebrum. See you there.

The Cerebrum Example 2

Alright. So this example asks us which type of matter is present in the gyri and sulci on the surface of the cerebrum. So the keyword here is the surface. If we're thinking about the surface of the cerebrum, we must be thinking about the cortex. Right? That's the surface, and the cortex is made of gray matter and gray matter only. So our answer is gray matter. As a quick refresher, the cortex is that outer layer, that surface layer of our brain, and that is all gray matter. And then under the cortex, we have our white matter. So that's kind of how it's positioned. So if we're on the surface, it's gray matter. Alright. So I'll see you guys in our next video. Bye bye.

The brain is divided into two cerebral hemispheres by the ________________.

• A. Central sulcus.
• B. Lateral fissure.
• C. Longitudinal fissure.
• D. Precentral gyrus.

Lobes of the Cerebrum

Hey everyone. So in this video, we're going to be talking about the lobes of the cerebrum, and the cerebrum has 4 lobes. And hopefully, remembering their names won't be too tricky because they're all named after the cranial bones that they are underneath. So kind of easy there. So let's start in the front of the brain with the frontal lobe. The frontal lobe has a lot going on. The frontal lobe is responsible for voluntary movement. It contains the primary motor cortex, and it also contains the central location for all of our really complex cognitive skills. Things like deliberate planning, problem-solving, working memory, the ability to inhibit your own behaviors. All those skills are housed in the frontal lobe. This is also where it seems like consciousness is as well as your personality. So what makes you you, what makes you a unique individual is largely housed in your frontal lobe. Now moving backwards a little bit we have our parietal lobe. And one of the main functions of the parietal lobe is sensation. We have our somatosensory cortex here. And so particularly, the sensation of touch is happening here in the parietal lobe. So our perception of things like temperature, pressure, pain is all happening here. This is also where we have a lot of our spatial processing, so understanding where our body is in space and how our body is moving. Now, moving down right toward your temple, we have my personal favorite little book of the brain, the temporal lobe. The temporal lobe has a lot going on as well. This is where hearing takes place. We have our primary auditory cortex. This is where smell happens. Our olfactory cortex is here. And also, we have some internal structures that are very important for memory, particularly long-term memory. So a lot going on in our temporal lobe. And then right in the back of our cerebrum, we have the occipital lobe. And the occipital lobe only has one job really, and that is vision and visual association. So humans have a pretty sizable chunk of our brain devoted solely to vision, which really goes to show you how important that particular sense is for human beings. All right. And just to be really clear, each of these lobes is present on either hemisphere. Okay? So we have, like, a left temporal lobe and a right temporal lobe, for example. Alright. So those are the lobes of the brain. Now please do keep in mind that with the exception of the occipital lobe, which really is just very focused on vision, each of these lobes does have other functions. These are just the most important functions of each of the lobes. Alright? So I will see you guys in our next video to talk even more about the cerebrum. See you there.

The Cerebrum Example 3

Alright. So in this example, we're going to be reading through this little story and filling out which lobe of the brain is performing what function. So let's get reading. Alright. So your parietal lobe allows you to sense pain after you accidentally cut yourself. So, I see an important clue here. We are sensing pain. The sensation of pain is processed in the parietal lobe. Alright. So the parietal lobe allows you to sense pain after you accidentally cut yourself, then your frontal lobe makes the decision to put on a bandage and initiates the movement to do so. I see 2 important clues here. We are making a decision and we are initiating movement. We are initiating a voluntary movement. So both of those things happen in our frontal lobe. Alright. Once you've done that, the occipital lobe allows you to see where your cut is. Alright. So if we're seeing, it's got to be our occipital lobe. And your temporal lobe helps you remember the incident so that you can avoid cutting yourself again. Remember the temporal lobe is where some memory, especially long-term memory, is housed. So that is our temporal lobe. Alright. So your parietal lobe allows you to sense pain after you accidentally cut yourself. Then your frontal lobe allows you to make the decision to put on a bandage and initiates that voluntary movement to do that. Your occipital lobe allows you to see the cut, and then your temporal lobe helps you remember that incident so that you can avoid getting hurt again in the future. Alright. There you go, and I will see you in our next one. Bye-bye.

The occipital lobe is found at the ________ of the brain, while the parietal lobe is found at the ________.

• A. Back, front.
• B. Bottom, top.
• C. Back, top.
• D. Top, front.

Functional Areas of the Cerebral Cortex

Alright. So in this video, we're going to be talking about some of the functional areas of the cerebral cortex. So as you guys recall, the cortex is the area around the outer edge of the brain or that kind of surface layer of the brain. And the cortex is where higher functions take place. And there are 3 types of functional areas in the cortex. So we're going to go through each type of functional area. We'll talk briefly about what it does and we'll give an example of each one. So we're going to start with the motor area. So the first type of functional area is motor areas. And motor areas are responsible for voluntary movement. Okay. And keep in mind that this is only voluntary. This does not include any kind of reflex activity like blinking, breathing, nothing like that. This is just voluntary conscious movement. Alright? Now the most important, arguably, motor area is the primary motor cortex which we have highlighted here in red for you. And this is part of the frontal lobe. Remember the frontal lobe is largely responsible for voluntary movement. Alright. And we're going to talk about that more in upcoming videos, so stay tuned for that.

Now the next type of functional areas are sensory areas. Alright. And these do exactly what you're probably thinking. They help us process sensory signals and they allow us to have conscious awareness of the things that we are sensing in the world. Alright? And the example we have here for you is the primary auditory cortex which is located in the temporal lobe. All right. And the final type of functional areas is association areas and these are responsible for complex processing. So you'll sometimes see association areas called multimodal association areas as well. And these areas are, as I just alluded to, very very complicated. So in these areas they're going to be receiving input from a lot of other parts of the brain and they're going to be sending output to a lot of other parts of the brain. This is where a lot of our conscious processing and awareness of what is going on in our life is taking place.

So I'm going to give you an example to kind of give you a better idea of what these areas do. So if I was cooking one day, right, I'm cooking, maybe I'm making shrimp scampi, okay, and I accidentally start a grease fire. I'm going to get a lot of sensory input very very quickly. I'm going to see the flames. I might hear, like, the crackling of the flames. I'm going to feel the heat coming off of the fire. I might have burned my finger and now I'm feeling pain in my finger. In addition to all that, I'm probably having some kind of emotional reaction, fear, panic, being startled, something like that. Right? So what's going to happen is all of those signals are going to get sent to an association area, and that area is going to process all of that as one holistic experience and I'm going to have the conscious awareness of, oh my god. I just started a grease fire by accident. Okay? And then they're going to be sending out commands of what to do next. So once they have that kind of conscious processing like this is what's happening in your life, we have to do something about that now, it's going to send, you know, signals to my motor, areas saying, alright, put the lid on the pan, you know, smother that fire, yell to the kids, hey don't come in the kitchen, walk over to the sink and run your finger under cold water. So it received a ton of input. It integrated that all into one experience, allowed me to consciously perceive what was happening, and then sent output to multiple areas to remedy that problem. So very, very complicated processing happening in these areas. And that is just one example of something that an association area can do. And the one that we have here for you for an example is the prefrontal cortex which is arguably the most complex part of the entire human brain. This is where intellect, reasoning, complex cognitive skills, and your personality, are pretty much housed. So again, very complicated areas of the brain there.

And then this final point I wanted to just remind you guys that the sensory and motor areas of our body are chiefly concerned with the opposite side of our body. Remember, we have that contralateral control. So anytime we're talking about the primary motor cortex or anything like that, remember it's going to be controlling the voluntary movement on the opposite side of the body. Alright? I will see you guys in our next video to talk even more about those motor and sensory areas. See you there.

The Cerebrum Example 4

Alright. So this example asks us, Terrence has suffered a brain injury and now struggles to recognize familiar faces and objects. Which type of functional area is injured and how do you know? So let's look at that really carefully and kind of wiggle out some of the nuance here. So what he's struggling with is recognizing familiar faces and objects. From what we can tell here, he does not have trouble seeing them. It seems like his vision is fully intact. He's having trouble recognizing them, seeing a stimulus and putting a name to what he is seeing. So that is his issue here. So based on that, I know that we can cross out a and c because there's not a problem with his vision. His vision seems to be fine. He's getting the incoming visual stimuli which leaves us with b and d. Some kind of association area injury. So let's read through each of these and see which one fits better. Alright. So b reads an association area because he's struggling to associate visual stimuli with memories and that certainly seems to be the case. That's looking pretty promising so we'll put a little line there. And then d reads an association area because this injury has reduced his intellectual capacity. So based on what we're seeing here his intellectual capacity has not been broadly impacted. This is a very specific thing that he is struggling with, a very specific skill. So we're going to cross out d and our answer is in fact b. We know that he entered an association area because what he's struggling to do is to associate incoming visual stimuli with the memories that would allow him to name the object or name the person accurately. Alright. So I will see you guys in our next video. Bye-bye.

A spinal reflex is a rapid, involuntary response to a stimulus. Tala has an issue with motor areas of her brain. Will her spinal reflexes still function? 

• A. No, because the motor areas control all movement.
• B. No, because an issue with the motor areas is likely to prohibit the sensory areas from working.
• C. Yes, because the sensory and association areas can initiate movement when motor areas are injured.
• D. Yes, because spinal reflexes are involuntary, and the motor areas are responsible for voluntary movement.

Primary Motor Cortex & Primary Somatosensory Cortex

So, in this video, we're going to go over some important motor and sensory areas of the brain. So, we're going to start with the primary motor cortex. If you look at the brain we have down here, you can see on the left and right hemispheres we have these red and blue areas highlighted, and they are separated by the central sulcus that we learned about. And if we look anterior to that central sulcus, more forward, we have our precentral gyrus, and that is where our primary motor cortex is. The primary motor cortex is responsible for voluntary movement. This is any movement that you have conscious processing or kind of deliberate processing around. So, me deciding to write just then was my primary motor cortex at work. Now we also have, right posterior to that central sulcus, our primary somatosensory cortex located in the postcentral gyrus. The primary somatosensory cortex is going to be receiving input from sensory receptors in our skin, muscles, and joints. So a lot of information about touch, things like pressure, temperature, pain, as well as proprioceptive input. So where our body is in space and how our body is moving through space all gets processed here in that primary somatosensory cortex.

Now, you will often see, both of these cortices represented using a homunculus. A homunculus is these kind of funny-looking pictures where we have these body parts that are very, like, kind of out of whack and look sort of weird. The reason that they look weird is that in these images the size of the body parts is proportional to the number of neural connections that that body part has in either of these cortices. So, what I mean by that, if you look over here at the primary motor cortex in red on the left of the screen, what we're looking at here is if a body part has a larger area on the motor homunculus, that means we have more motor control over that area. So you can see on our motor homunculus the entire face is quite large, the lips are disproportionately large, the tongue and the hand are all extremely large, and these are all areas of the body where we humans have excellent fine motor control. Think of all of the facial expressions that you can make in an instant. At the drop of a hat, if someone named an emotion, you could change your face to depict that emotion. Our tongues have excellent fine motor control to help us articulate words. Obviously, hands have fantastic fine motor control.

And then areas on the homunculus like the neck, the wrist, and the ankle are all kind of tiny. This is because while we can certainly move these areas, and we have voluntary control over them, we don't possess as refined motor control. That is our motor homunculus. If we look over here in blue at our sensory homunculus, you can see here a larger area on that sensory homunculus means we're going to have more sensation in that area. Again, we have a very large face. The lips are again disproportionately large. The tongue is quite large. The hand. And then areas like, you know, the ankle, the calf, the thigh are all very tiny on this one. When I say sensation, of course, we have sensation on our back and our thigh and our calf, but I'm thinking like, you know, imagine a fruit fly landed on you. If a fruit fly landed on your face or your hand or your lips, you would not only know it, but you would probably know exactly where that thing was. Whereas if a fruit fly landed on, like, the back of your thigh, if you felt it, which is kind of an if, you probably couldn't localize it quite as precisely.

So, that's what I mean by sensation here. And you can see that this homunculus also has an area for visceral organs because we can feel things like pain in our visceral organs, for example, our stomach. Our motor homunculus does not have any of those organs because we don't have voluntary motor control over them. Alright. So that is our primary motor cortex and our primary somatosensory cortex, and I will see you guys in our next video. See you there.

The Cerebrum Example 5

Okay. So this example reads, the area of the primary somatosensory cortex concerned with the foot is larger than the area of the primary motor cortex concerned with the foot. What does this mean functionally? So just to help us remember that, this is saying that we have a larger area on the sensory homunculus and a smaller area on the motor homunculus for our feet. Alright, so let's run through these options and see what we've got.

Alright, so a) is saying that the foot is not particularly sensitive and we do not have precise motor control over it but we're seeing here that it does seem to be sensitive so a is out. Option b reads that the foot is very sensitive, that's looking good, and we have very precise motor control. Nope, we have less motor control, right? Option c is that we have more motor connections with the foot than sensory connections. This depicts the opposite of that, so c is out. Then we have d saying that we have more sensory connections with the foot than we have motor connections and that is exactly what that means. In other words, the sensation that we have in our foot is more precise and fine-tuned than the amount of motor control that we have over our feet. So that is what that is saying. Alright. I will see you guys in the next one. Bye bye.

Which of the following body parts would you expect to have the greatest size difference between its area on the motor homunculus and its area on the sensory homunculus?

• A. Hand.
• B. Tongue.
• C. Stomach.
• D. Shoulder.

Important Areas of the Cerebral Cortex

Alright. So in this video, we're just going to cover a couple more important areas of the cerebral cortex that you may need to know. So the first one that we're going to go over is the prefrontal cortex, which we have highlighted here for you in green. And as I alluded to in a previous video, the prefrontal cortex is the most complex part of the cerebrum. So this is the most anterior part of our brain, and it's also the slowest to mature. So the prefrontal cortex doesn't fully mature until we are well into our twenties, mid-twenties, even late twenties. And this is the area where all of our most complex cognitive skills are housed. So planning, decision making, rational thought, working memory, inhibitory control, you name it. All of those incredibly complex cognitive skills are all there in the prefrontal cortex.

Now, the next area we have is Broca's area. So Broca's area is a big language area, and it's very important for speech production. And Broca's area is located in the frontal lobe. So we have this highlighted here for you in orange. You can see it's kind of wedged between the prefrontal cortex and the primary motor cortex that we have here in red. And that makes sense, right, because this is associated with speech production, as I said. So literally how we move our jaw, how we move our tongue to correctly articulate words and produce speech. And so this is technically a motor area, so being right next to that motor cortex makes sense.

Now the final area that we have here is Wernicke's area. Now Wernicke's area is also a language area, but this area is more focused on speech comprehension. And you can see we have it highlighted here in yellow for you, and it is in the temporal lobe, which makes sense because that is where the auditory cortex is. Right? So as we're hearing, this is incoming stimuli. Wernicke's area is helping us comprehend and make sense of the language that we're hearing.

So it's important to know that Broca's area is for speech production and Wernicke's area is for speech comprehension. So some memory tools that may help you with that: some people like to think of the 'b' in Broca's area as standing for 'building.' So Broca's area builds speech. We build speech with our mouth. Whereas the 'w' in Wernicke's area stands for 'what.' Like what did you just say? I'm going to use my Wernicke's area to help comprehend what you just said. If you are a Spanish speaker, a really fun easy memory tool is to just look at the word Broca and take out the 'r' and you're left with 'boca.' Right? 'Boca' meaning mouth. And what do we do with our mouth? Produce speech. And then with Wernicke's area, if you look at the end here, the 'ke,' that's pronounced like 'kay.' Like, what did you just say to me? I'm going to use my Wernicke's area to figure out what you just said. So definitely take the time to remember those two. It's a really common exam question is differentiating what Broca's area does and what Wernicke's area does.

Alright. So I will see you guys in our next video. Bye-bye.

The Cerebrum Example 6

Alright. So for this example, we have kind of a little short story here. And then for each of these blanks, we're going to be filling it out with some combination of Broca's, Wernicke's area, and the prefrontal cortex in the temporal lobe. The first blank area allows you to understand what the person is saying. So I see an important word there. If we are understanding speech, that's probably Wernicke's area, so we'll put Wernicke's area there for now. Then you use your prefrontal cortex to make the decision to check your watch. Well, if we are making a conscious decision, it must be the prefrontal cortex. And then finally, Broca's area controls your mouth and tongue as you answer the question. So Broca's area is important for speech production, right, controlling the actual motor coordination of our jaw and tongue. So our answer is Broca's area. You've got Wernicke's area for that first blank, the prefrontal cortex for that second blank, and Broca's area for the third blank. I'll see you guys in our next one.

The prefrontal cortex & Wernicke's area can both be classified as association areas, while Broca's area is classified as a motor area.

• A. True.
• B. False.

Cerebral White Matter

So in this video, we're going to be talking about cerebral white matter. We've been spending a lot of time in the gray matter. So let's kinda go subcortical and see what that white matter is up to. Cerebral white matter is responsible for communication between cerebral areas as well as some lower CNS centers, including the spinal cord. White matter gets classified into 3 groups basically depending on the direction in which it flows. The direction that those fibers or tracts are moving, and you'll see that in just one second.

We're going to go through each of those groups. We'll kinda see what they look like and talk about what they do. Association fibers, which we have here in green for you, are restricted to just one hemisphere. They're either in the left or right hemispheres, and these connect cortical gyri. Now, you can see here we have our association fibers in green and you can see how they just kind of loop between the gyri of one hemisphere and connect them and allow them to associate with each other to talk, right, and to communicate.

Now, in blue here, we have commissural fibers. Commissural fibers run left to right and they connect the left and right hemispheres, and the largest set of these fibers is the corpus callosum, which we have pictured here for you in blue. These are the commissural fibers of the corpus callosum. That's a very important structure as it allows our left and right hemispheres to communicate, which allows for coordinated activity between the two of them.

And then here in red, we have our projection fibers. Projection fibers are a bit similar to association fibers in a way because they operate or they connect the cortex within just one hemisphere. And these also, as you can see, these kind of run all the way down into the spinal cord. So these also connect the brain and the spinal cord, so very important to allow our brain to communicate with the rest of our body.

Projection fibers form two structures. The first one down here is the internal capsules. This is kind of like a dense, very tightly compact area of these fibers. And then right superior to that, we have the corona radiata, which you can see this area right here is the corona radiata. You can see how the fibers kind of fan out or radiate outwards. Corona radiata actually means "radiating crown," which is kind of what these fibers look like here. Just to fill this out, these are our projection fibers in red.

Alright. So we have our association fibers, which allow communication between the cortical gyri of one hemisphere. We have our commissural fibers, which allow the left and right hemispheres to communicate, and we have our projection fibers that allow the spinal cord to communicate with the brain. Right, so that is our white matter in a nutshell, and I will see you guys in our next video to finally finish up the cerebrum. So I'll see you there.

The Cerebrum Example 7

Okay. So, this example asks us which of the following is accurate regarding association fibers? Now, just to kind of refresh our memories, association fibers operate within one hemisphere and they connect the cortical gyri of that hemisphere. Okay? So let's look through these and kind of see which one is alluding to that. So I see (a), they form ascending tracts that allow the cortex to communicate with the spinal cord. So, spinal cord should not be happening here. That would be projection fibers. Right? So (a) is out. (b) says they're used mainly for long-distance communication in the CNS. That would also involve the spinal cord or at least going from hemisphere to hemisphere, which is not what these fibers are doing. So (c) is saying they connect different areas of the brain across hemispheres, for example, the left and right parietal lobe, but again these are confined to one hemisphere. So (c) is out and we're left with (d). They connect different areas of the brain within the same hemisphere, for example, the left temporal lobe to the left prefrontal cortex. And that is accurate, so our answer here is (d). I'll see you guys in our next one.

Basal Nuclei

All right. So in this video, we're going to be talking about the basal nuclei. Now, as you may recall from when we first introduced nervous tissue, nuclei are clusters of neuron cell bodies, and the basal nuclei are a group of subcortical nuclei, which just means that they're under the cortex. You can kind of picture these like little islands of gray matter inside all of that white matter. And these primarily communicate with the premotor cortex. And as you may have guessed from that, they are primarily responsible for regulating movement. Now, some of their more specific functions include starting and stopping movement. They also handle repetitive motions. So for example, the way that your legs are moving when you're walking or riding a bike. And they also inhibit antagonistic movement. A different way to say that is that they're going to be inhibiting unwanted or unnecessary movement. So quite often, if we have some kind of damage or dysfunction of the basal nuclei, we'll see unwanted movement like tremors, twitching, or jerking very commonly. Now, the basal nuclei are made of several structures. So looking here at this coronal slice of the brain, you can see here in blue is the largest structure, and that is the caudate nucleus. And then right underneath that, here in yellow, we have the putamen. Now, you'll sometimes hear people talk about a structure called the striatum. And the striatum is just the caudate nucleus and putamen together. So if you look up here in this lateral view of the brain, you can see this green structure, and that is the striatum. Right? Blue and yellow make green. And so these two structures, the caudate nucleus and putamen, get lumped together because functionally they're quite similar. So these are both input structures of the basal nuclei. So when signals are coming in, these are the structures that are receiving those signals. So a handy little phrase to help you remember that these two nuclei make up the striatum is the phrase, "Please consider the striatum." So we have that p in "please" for putamen, that c for "consider" is the caudate nucleus, and then of course, s is striatum. Now, right underneath those, in this kind of pinkish-purple color, we have our globus pallidus. Now, globus pallidus actually means pale globe. So, I always think of this as like the globus pallidus is kind of off in its own little world, and then that caudate nucleus and putamen are super tight and they're hanging out and making up that striatum. Now, one last thing I do want to mention is that you will very often see the basal nuclei called basal ganglia. So the technical anatomical term is basal nuclei, but a lot of other fields, including medical fields, research, and psychology, will call it the basal ganglia. So these are interchangeable terms. They mean the exact same thing. It's just different fields using different terms for the exact same anatomy, just so you know. Alright. And with that, we have finished our unit on the cerebrum. That was a long one, but you guys stuck with it. You did an amazing job, and I will see you all in our next video. Bye bye.

The Cerebrum Example 8

Alright. So this example asks us which of the following statements is false. So let's run through them and see what we've got. a reads basal nuclei are found exclusively in the cerebrum and that is true. We know that the basal nuclei are not part of the diencephalon, they're not part of the brainstem, they are part of the cerebrum. So it's definitely not a. b reads that the basal nuclei are part of the cortex and that's not looking great, right, because basal nuclei are subcortical structures. They're under the cortex, not on the surface. So it's probably b, but let's just keep going through to make sure. c reads that basal nuclei coordinate with the cortex to produce smooth movement, and that is true. They are very important for motor control, particularly nice smooth motor control. And d reads that basal nuclei are also called basal ganglia and that is absolutely true. You will often see those two terms used interchangeably. So our answer is b, basal nuclei are part of the cortex. That statement is false. These are subcortical structures. Alright. So I'll see you guys in our next video. Bye bye.

Which of the following diseases would you expect might result from a dysfunction of the basal nuclei?

• A. Multiple sclerosis (MS).
• B. Guillain-Barré Syndrome.
• C. Parkinson's Disease.
• D. Alzheimer's Disease.

Here’s what students ask on this topic:

What are the main functions of the cerebrum?

The cerebrum is responsible for a wide range of complex functions. These include motor coordination, the experience and regulation of emotions, language processing, memory storage and retrieval, and various cognitive skills such as problem-solving and logical reasoning. The cerebrum is divided into two hemispheres, each specializing in different tasks. The left hemisphere typically handles language, logic, and analytical tasks, while the right hemisphere is more involved in visual-spatial skills, emotional understanding, and artistic abilities. Despite these specializations, both hemispheres constantly communicate to perform complex tasks efficiently.

What is the difference between gyri, sulci, and fissures in the brain?

Gyri, sulci, and fissures are features of the brain's surface that contribute to its wrinkled appearance. Gyri (singular: gyrus) are the elevated ridges of tissue on the brain's surface. Sulci (singular: sulcus) are the shallow grooves that separate the gyri. Fissures are deeper grooves that separate larger regions of the brain. For example, the central sulcus separates the frontal and parietal lobes, while the longitudinal fissure divides the cerebrum into left and right hemispheres. These structures increase the brain's surface area, allowing for more neurons and higher cognitive functions.

What are the four lobes of the cerebrum and their primary functions?

The cerebrum is divided into four lobes, each with distinct functions. The frontal lobe is responsible for voluntary movement, complex cognitive skills, and personality. It contains the primary motor cortex. The parietal lobe processes sensory information such as touch, temperature, and pain, and is involved in spatial processing. The temporal lobe handles auditory processing, memory, and olfaction. It contains the primary auditory cortex. The occipital lobe is primarily responsible for vision and visual association. Each lobe is present in both the left and right hemispheres, contributing to their respective functions.

What is the role of the prefrontal cortex in the brain?

The prefrontal cortex, located in the most anterior part of the frontal lobe, is the most complex part of the cerebrum. It is responsible for higher cognitive functions such as planning, decision-making, rational thought, working memory, and inhibitory control. This area is crucial for personality development and social behavior. The prefrontal cortex is also the slowest to mature, not fully developing until the mid to late twenties. Its complex functions make it essential for tasks that require conscious thought and deliberate action.

What are Broca's area and Wernicke's area, and what are their functions?

Broca's area and Wernicke's area are two critical regions involved in language processing. Broca's area, located in the frontal lobe, is responsible for speech production. It helps in the articulation of words and the physical act of speaking. Wernicke's area, located in the temporal lobe, is responsible for speech comprehension. It helps in understanding and making sense of spoken language. Damage to Broca's area can result in difficulty speaking (Broca's aphasia), while damage to Wernicke's area can lead to problems understanding language (Wernicke's aphasia).