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Overview of the functions of the cerebral cortex

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- [Voiceover] What I've drawn for you here is the human brain. And this is what you would see if you were looking at someone and they were standing in profile, or if they were standing sideways in front of you. So this would be the front of their head, so their eyes, and their nose and mouth would be located down here. This would be the back of their head. And this would be the top. And then down here would be the bottom. And we refer to this area, this big one right here, which is the first thing that you would see if you were just looking at the outer portion of the brain, we call this the cerebral cortex. And you might notice something about the cerebral cortex right away, which is that it looks kind of wrinkly. And it actually is. Rather than having a smooth surface, it actually has a ton of bumps and folds. And this is actually extremely useful, because it allows the cerebral cortex to have a greater surface area. It allows it to have room for more neurons. It gives it an increased cellular mass. We usually split the cerebral cortex up in to four different hemispheres. The first is the frontal lobe, which I'm shading in blue right here. The next area is the parietal lobe, which is back here, towards the top and the back end. We also have the occipital lobe, which I'm going to color in pink. And then finally we have the temporal lobe, which I'll draw in violet right here. The frontal lobe is comprised of two main regions. Those include the motor strip or the motor cortex, as well as the prefrontal cortex. The motor cortex or the motor strip is responsible for our body movements. In fact, if you could peel back someone's skull and electrically stimulate different areas of the motor cortex, you could make someone's hand twitch or their leg move just by stimulating that area on their brain. The frontal lobe also contains the prefrontal cortex, and this is the part of the brain that's responsible for what we refer to as executive functions. Things like thinking and problem solving all take place in the prefrontal cortex. Not only that, but it also helps to supervise and direct all of the other areas of our brain. Another part of the frontal lobe that's worth mentioning is referred to as Broca's area. And this is a part of the brain that's associated with speech production. Let's move on to this yellowish-orange portion here, which we said was the parietal lobe. And this part of the cerebral cortex is also important for a number of different tasks. One important part of the parietal lobe is the somatosensory cortex. And this is the part of your brain that's associated with feeling. And by that I don't mean emotional feeling. What I actually mean is that this part of the brain receives information from all over your body about touch, and pressure, and temperature, and pain. So the motor cortex would help us reach forward and grab a cup of coffee, but the somatosensory cortex is what would allow us to feel the pressure of that coffee cup or tell us how hot it is. And you might be thinking to yourself that these two things seem like they're intimately related, and they are. In fact, even though we say that they're in different lobes of the brain, they're actually right next to each other. So this side of the brain, to this side of the crevice, within the frontal lobe is the motor cortex. And right next to it, in the parietal portion towards the back, is the somatosensory cortex. And together they can be thought about as the sensorimotor cortex. Our parietal lobe is also responsible for spatial processing, or spatial manipulation. And by that I mean that it helps to orient yourself in three-dimensional space. But this part of the brain doesn't only help us understand where we are in space, but it helps us to understand the space around us more generally. For example, if I wanted to reach out and grab a cup of coffee that's in front of me, I could use my prefrontal cortex to plan the movement and my motor cortex to complete that movement, but I also need my parietal cortex to tell me where that coffee cup is in front of me. And without that, I wouldn't actually be able to reach out and pick it up. Other things like knowing how to navigate around your house or your town, that's also what we mean when we talk about spatial manipulation or spatial processing. Our occipital lobe, which is in the back of our brain, is responsible for things related to vision. We may see with our eyes that are in the front of our head, but after collecting that information from the world around us, that information actually gets transported all the way to the back of our brain for processing. So let's put vision right here. Another term that you might hear in association with the occipital lobe is the term striate cortex. And this simple refers to the fact that if you looked at the occipital lobe under the microscope, if you looked at those cells, that they would appear striped or striated. The last lobe of the brain is the temporal cortex, and that's in violet. And this is the part of the brain that's responsible for auditory processing. As was the case with vision in our occipital lobe, information comes in through our ears, but it is processed in our brain, in our temporal cortex. Another important area in the temporal cortex is what's referred to as Wernicke's area. And when we talked about the frontal cortex, we talked about Broca's area, which we said was responsible for speech production. Well, Wernicke's area is responsible for language reception and language comprehension. Before I end this video, I just wanna take a moment to point out that the different lobes of the brain do a lot more than just the things that I've listed here. However, in general, these are the things that you should think about whenever you think about the different lobes of the brain.