[MUSIC] We're going to use a flat schematic of the brain, and I want to just make sure everyone's on board with understanding what we're looking at in this schematic which I have designed. We're going to start by looking at the cerebral cortex, and what I've done here is I simply outlined the different lobes. Now, this lobes are not that meaningful, but they're a useful categorizing tool for how to look at the brain. So here we are, just to make sure that you're oriented, this is the front, this is the back for this picture. So this here is the frontal lobe, this is the parietal lobe and this is the temporal lobe. Back here is the occipital lobe. If you pry open the temporal lobe, remember that the temporal lobe is formed by this sort of ram's horn expansion of the cerebral cortex. If you pry it off to the side and look down into the chasm that is in here between the temporal lobe and the parietal and frontal lobes, you'll see an area of cortex that typically is often called insular lobe, the insular lobe. It's inside and it's called the insular lobe. The frontal lobe has motor functions, that's where primary motor cortex is. The parietal lobe has somatosensory function. Somatosensory means touch, pain, temperature, vibration, the sense of where the body is, all of that is somatosensory. And the parietal lobe has the primary somatosensory cortex right here. Primary motor cortex is right here. In temporal lobe is primary auditory cortex. And in the occipital lobe is primary visual cortex. This is just showing you, again, a midsaggital section of the brain, and you see here's the occipital lobe, here's a little bit of parietal, this is all frontal, and then peeking in from the side is just a little touch of temporal lobe. Importantly, most of visual cortex is on this inside surface. And only a little bit of somatosensory and motor cortex is on the inside surface, none of the auditory cortex. Okay, so just think about this as if this is the brain, here's the temporal lobe, here's the frontal, parietal and occipital, that this grows back in this way, or develops in this direction. Okay, so now let's go to the schematic and what you see is everything gets laid out very smoothly. Here's the spinal cord, it has four different divisions, the sacral cord that innervates the saddle, the bladder, the colon, the sex organs, and the saddle area of the body. The lumbar cord which innervates the legs, thoracic innervates the thorax, the trunk, cervical which innervates the arms. And then we get to hind brain. We have the medulla, the pons, and then we have a tier problem, where the cerebellum is on top of there and I'm just drawing it as a dotted line. Beyond that is the midbrain. Beyond that is the diencephalon containing both the hypothalamus and the thalamus. And beyond that is the telencephalon. So remember that this can be thought of as frontal, parietal, occipital, and temporal, okay? And in the telencephalon there are three major components. One is the cerebral cortex which we've talked a lot about, this is just this outer mantle. The cerebral cortex is just this outer mantle. And another one is the amygdala which is very important for processing fear, for feeling fear, and perceiving fear in others. And the basal ganglia which is very important for selecting our actions, deciding what of the myriad things that we could do right now are we going to actually do. What are we going to do with our limited number of muscles? And the basal ganglia is very important for that, great. [MUSIC]
