 Now we need a highway. We know the anatomy inside the tongue that's going to receive the taste information, and we've delivered that taste information from the taste bud to the sensory neuron. And now we need a highway. How are we going to get to the brain? In fact, where are we going to go in the brain? And what path are we going to follow to get there? And why? And you know what? I want you to push pause. This little guy is peeking around the corner right now, and he's like, please let me out, I've got the answer, but you first go and think about it. See if you can figure it out, see if you can hypothesize, where would you expect the fibers to go, and through what highways would you expect them to travel? And I know you can do it, because look, this is the picture that shows you, okay, cool, we actually do have a path that we're traveling. And look, oh, are you excited? Because I love this stuff. I love it when we put together pieces. I think this might be my favorite unit in anatomy, because all the pieces build and then you're like, oh, what, what, who is this? Who is that, what is that path that looks like it is bringing information from the anterior two thirds of your tongue? And remember this cranial nerve number seven, which was responsible for carrying sensory information of taste from the anterior two thirds of your tongue? Yeah, I know you remember that. Who is responsible from the posterior two thirds from my little tongue here? Who's bringing this information? It's another neuron that is synapsing with my taste buds, who's this guy? Remember that was cranial nerve nine, hypoglossal. Glossopharyngeal, it didn't sound right. Glossopharyngeal is cranial nerve nine and is receiving taste sensation from the posterior one third of your tongue. That's all review. You guys are like, boom, I could have figured that one out. So now we've got the information coming in. Okay, you can figure it out. Where would you expect it to go next? Well, first of all, and this is true for the rest of the entire lecture, there are details that we are leaving out. We are not, I'm not going to hold you accountable to every single little nucleus inside the brain, every single little stop, every single possible pathway. We're getting comfortable with the idea that, you know what, we need a road. We need a road to get somewhere. And we're going to make our roads structures that we've already done, structures in the brain, nerves that we've already looked at. Let's make use of them now and let's see how they actually play in a pathway. Yes, there are some other stops along the way. There are some stops we do first. But there's like five billion more stops that our book doesn't even go into. And so we're just going to take it one step out because we want to see the big picture. We want to get overwhelmed by the crazy details, right? We always want to avoid overwhelming you in anatomy. Okay, where are you going to expect to go next? Craneal nerves are going to ultimately go where? Wouldn't you expect a stop at the thalamus? Who is the only sense that doesn't stop at the thalamus? The only one was smell. Everybody else stops at the thalamus. Everyone else synapses at the thalamus. And so you can just imagine that, yeah, we're going to take a cranial nerve to the thalamus. Yes, there's another pathway in there, but we're just going to... I want you to know cranial nerve and ultimately to thalamus. At the thalamus, what's the thalamus going to do? Is this worthy of consciousness? And if it is, where's it going to go? This is something, we're talking about our chocolate here. Let's send the message on because you know what? Let's be aware when we're eating delicious chocolate that somebody bought you because you're awesome. Where are you going to go next? Remember? The insula. The insula is the lobe of the cerebrum that's responsible for processing conscious sensations of taste. If you actually are tasting something, then it's the insula that is doing the processing. Now, once you've tasted it, our sensory pathways are going to get the information there. From your insula, think about all the possible reactions that you could have when you eat your piece of chocolate. You could be like, hmm, that's so yummy. You could be like my kids who, if it's brown chocolate, they're like, mm-mm. And the darker brown it gets, the more they're like, this stuff's awful. And so you could actually have all your facial muscles go, the facial nerve is sending motor information, making you go bleh, and maybe you even gag. Maybe you feel it spit it out. But if you're me, maybe you do a little happy dance, like, life is good. We're eating that chocolate, mm-mm-mm. And look at all those other muscles that just got all excited and did their thing. And who's sending the message there? Whoa, isn't the nervous system fantastic? And isn't it kind of cool to put the pieces together here? All right, let's talk about smell next.