 Now we're going to zoom into two specific locations on our cerebron that have unique and important functional significance. Are you ready? First, we have to identify a couple of landmarks that are important. One of the landmarks is this longitudinal fissure that is the fissure that separates my right and left hemispheres of my brain. So this longitudinal fissure is going to give us kind of an orientation when we're looking down to find these other structures. The other one that we're going to keep track of, and this is an anatomical location, is a structure called the central sulcus. Central sulcus. The central sulcus is in the coronal plane, like it separates anterior and posterior of the brain. It's perpendicular to the longitudinal fissure and it is the mark that separates the frontal lobe from the parietal lobe. Now, you have a specific bump anterior to the central sulcus, a specific anatomical structure in the frontal lobe, which is this one right here, and it's called the precentral gyrus. Does that work for you? It's a bump, it's a gyrus. It's precentral. It's in front of the central sulcus. So guess what this one is? The same thing, it's a gyrus, but it is the post-central gyrus. Now, those are anatomical structures. Those are bumps on your brain that we could find and identify. The precentral gyrus is the most posterior bump on the frontal lobe. The post-central gyrus is the most anterior bump on the parietal lobe. Does that work? So you can see how these are just anatomical structures. Now, why do we even care? Well, they have functional significance. The post-central gyrus is the location for a functional area and it is called the... Do you remember, first of all, do you remember what was the purpose of the parietal lobe? Like, what was its overall function? It's like a general sensory zone. Not for specific senses, but general senses. So in the post-central gyrus is this functional zone called the primary somatosensory, somatosensory cortex. That's the name of the functional area found in the post-central gyrus. So primary somatosensory cortex. This is where the majority of general sensory information goes. When you feel something crawling on your arm, that sensation that you feel, that information is going to travel through afferent neurons to the spinal cord at the level wherever it's going to go in and then it's going to go up to your brain and if it's deemed worthy of consciousness, like if it's a spider or something, then your brain's going to be like, dude, you better pay attention to this and it will go to the primary somatosensory cortex in the post-central gyrus of the parietal lobe of the cerebrum. What? How crazy is that? Guess what is in the pre-central gyrus? This is a primary motor cortex. Primary, primary motor cortex. And that's somatic motor information, the primary, like it's actually interesting that they're so close together. So in comes some sensory information just from general senses, the spider's crawling on my arm, my brain processes it, says, yeah, it's worthy of consciousness, sends it to the post-central gyrus, which contains the primary somatosensory cortex. So I process that and go, yeah, this is a spider. I'd like to whack it. And so then the information travels to my primary motor cortex in the pre-central gyrus of the frontal lobe of my cerebrum. And that portion of my cerebrum actually processes the information and says, okay, we're going to need to activate the deltoid, we're going to need to activate the biceps, and we're going to need to get the pectoral muscles here for the big whack, and it coordinates the action. It sends the message out to activate all those folks and they get activated and you whack the spider. Or you can be really kind and catch it in a cup and carry it outside, which is going to activate a whole nether set of muscles, again, all coordinated by the primary motor cortex. If that is like, what the hell is she talking about? It's a visual that hopefully makes everything crystal clear, right? Doesn't that clarify everything? This is one half of your primary motor cortex. This is the motor one. Look, you can compare. Motor is anterior, sensory is posterior. Now, what is this? All this is showing you where specifically, you have to have some motor action of your face. The processing or the information is going to come from this specific part of your primary motor cortex of your frontal lobe, of your cerebrum. What? Look at that. Your tongue has a whole zone that specifically, like, if you need to lick the spider off of your, that's kind of disturbing. I wish I wouldn't have gone there, but I suppose if you need to do that, it's going to be this part of your primary motor cortex that's going to send a message to your tongue to make it happen. We've got a bunch of swallowing stuff going on here. This is all motor. Look at how much motor information goes to your hands, to your thumb. We can actually have a significant amount of control of our thumb. Your torso, your legs, not so much a little bit more with your feet, but you can see that, yeah, the thumb, the face, we've got a lot of brain real estate dedicated to running those structures. What about the sensory land? What about that sensory land? Shall we go there and look? Whoa, whoa, look at this guy. What do you, oh my gosh, how cool is this? So this is where general sensory information is coming in. We care a lot about our hands. General sensory, we've dedicated a lot of real estate to making sure that our hands are sensitive, can receive general sensory information. Lips, what teeth? You guys are kidding me, tongue. We got a lot of sensory information, so go ahead and start looking things to tell about them. Not so much sensory information from your digestive tract, you know, kind of important, dude, really. Yeah, worthless. I don't know why I even spend any time. Hands are much more sensitive than other body parts. How fantastic is that? Okay, that is, those are the structures that come from the telencephalon. Now let's look at the diencephalon.