This is what a human brain looks like. It looks kinda like raw hamburger, but each part of the brain is responsible for different tasks. I’m Alie Astrocyte and you’re watching Neuro Transmissions. This week, we’re going to talk about the different structures of the brain, the roles they play, and how to tell if it’s cooked just right. If you had to guess, how big do you think
the human brain is? Well, my head is this big, so this big? Or maybe this big? Actually, the human brain is only about as big as your two fists held together, like this. The surface of the brain, however, is much larger. You know how pictures of the brain look all wrinkly? Well, your brain is essentially folded up so it can fit more in your skull. If you unfolded all of your cortex, just the outer layer of your brain, it would cover a space of about 2.5 ft squared! That’s as big as this! Let’s see if we can make it brain-sized again. When we look at the cortex, we usually divide it into four main lobes, named after their nearby skull bones. the occipital lobe at the very back, the parietal lobe at the top, the temporal lobe on the bottom, and the frontal lobe at the front. “It all looks like brain to me”, you might be saying. But these areas are actually divided by markers on the surface. See these deep grooves? These are called sulci. And these ridges? They’re called gyri. If we keep that in mind, we can see that, for example, the frontal lobe is separated from the parietal lobe by the central sulcus while the distinction between the parietal and temporal lobes is created by this separation, called the Sylvian fissure. These may seem like fairly arbitrary distinctions when we look at the whole brain, but each of these lobes has a distinct set of functions. At the back of the brain, we find the occipital lobe. This lobe is the smallest of the four, but it’s really important The occipital lobe is responsible for visual processing. The occipital lobe itself can be broken up
into different areas that process images of objects and patterns, motion tracking, perceiving color, and mapping space. Above and in front of the occipital lobe,
we have the parietal lobe. This is the key to processing sensory information from your body. This narrow band on top of the parietal lobe is called the “somatosensory cortex”, and is responsible for processing your sense of touch. It’s almost like a map of your body. The parietal lobe is also important for for
your real life “sixth sense” The ability to see dead people. Just kidding. Your sixth sense is something we call proprioception, which is the sense of your body in space. Below the parietal lobe, we find the temporal lobe. It’s sort of a jack-of-all-trades. This lobe contains the primary auditory cortex, important for our ability to hear and process speech and language. The temporal lobe also allows us to do some higher-level visual processing, like recognizing faces and objects. Inside the temporal lobe, we find the hippocampus, a structure that’s crucial in the formation and maintenance of new memories. We’ll talk more about all of this in later segments, but feel free to check out this video for more information on how different brain injuries can cause some wild changes to your mind and memories. At the front of the brain, we have the largest lobe of them all: the frontal lobe. The name makes sense. This lobe is one of the major things that makes the human brain unique. We have an extremely large frontal lobe compared to other species. The frontal lobe is important for a lot of
different processes. For example, right next to the parietal lobe, and separated from the somatosensory cortex by just the narrow line of the central sulcus, we find the primary motor cortex. This region has a “map” of the body that sends out signals to control the use and movement of your limbs and muscles. Sort of like a remote control for your body! The frontal lobe is also important for a lot
of “higher level” cognitive abilities. These include things like planning, motivation, attention, recognizing reward, self-control, emotional processing, decision-making, and a lot of other things! Damaging the frontal lobe can have huge effects on personality! It’s so interesting to study, but we’ll talk more about some of those things in other videos. But hang on! We’re not done yet. Even though we usually think of the brain as just being this shape, it’s important to remember that there are some extra pieces being left out of the big picture. Underneath the cortex we find the thalamus, which acts as a relay station for sensory and motor signals and regulating sleep. While the hypothalamus plays a role in regulating your hormones. Behind the cerebrum, which is what scientists call the “main” portion of the brain, we have this structure that looks like a pile of spaghetti. It’s called the cerebellum, or “little brain”, and it’s very important for movement control. While the primary motor cortex in the frontal lobe is the controller of initiating motion, this structure contributes to the coordination and timing of movement, and also plays a big role in proprioception. So if you’re uncoordinated, blame your cerebellum! High five! Oh no, you’ve gotta look at the elbow. No…you gotta… You know what, okay, let’s stick to fist bumps. There you go. Finally, the brainstem, this narrow structure underneath the cerebellum, is considered the “most ancient” brain structure. That is, this is probably the first region of the brain that evolved in our earliest ancestors. This structure has three subregions: the medulla oblongata, the pons, and the midbrain. All of the information transmitted between your body and your brain has to pass through this region. It also regulates your heart rate, breathing, sleep, and eating. So you should love your brain stem. It keeps you alive! Well now we’ve painted a broad picture of your brain and understand a little bit about what the different parts do. In upcoming videos, we’ll delve into the nitty gritty about these structures and their functions. If you’re new to these parts, please subscribe! And if you liked the video, give it a thumbs up. Next time, we’ll talk about how your brain “sees” the world. Until then, I’m Alie Astrocyte, and you’re watching Neuro Transmissions. Over and out!