The diencephalon is the part of the forebrain worth noting because it contains the thalamus and the hypothalamus. These structures are super important, and they're actually kind of small when you look at them in the grand scheme of the brain. Here we have a zoomed-in picture, and you can see the thalamus sits above the hypothalamus, and that's where it gets its name. Hypo means, you know, like lower, so it's just below the thalamus. Now the thalamus basically acts as a relay center for the brain. I like to think of it as a telephone operator in a way. Information sent in and then it routes it to the appropriate area of the cortex. It's going to play an especially important role in visual processing, routing the different types of visual information to their appropriate areas for processing. The hypothalamus is important because it's going to serve as the link between the nervous system and the endocrine system. And it's going to do this by interacting with the pituitary gland, which is an endocrine gland that is going to have very high-level effects in the endocrine system, high-level signaling. The hypothalamus is also going to be involved in homeostasis, which is why it makes sense that it will serve as a bridge between the two major communication systems in the body, as homeostasis requires lots and lots of really good communication.
A limbic system is kind of a loose definition, that more or less encompasses a bunch of different structures, mostly in the forebrain. There are some structures in the midbrain that are referred to as limbic midbrain structures. We don't really need to worry too much about these. For the most part, the structures of the limbic system are in the forebrain, and the only ones that we need to actually know about are all located in the forebrain. These are structures that are going to be kind of deeper in the brain, so they're not at the surface, they're below the cortex, and these structures are the hippocampus and the amygdala. The hippocampus is going to be involved in learning and memory, and it's actually especially important for the formation of long-term memory and spatial memory. Long-term memories are memories that you can, you know, recall for a long time. For example, what your home when you were a child looked like, or something to that effect. Without the hippocampus, people are actually completely incapable of forming these types of long-term memories. So, there's a famous example of a person who had both of their hippocampi removed, and they were completely unable to form memories for the rest of their life. People that they met after this operation, they were never able to recognize, no matter how much time they spent with them. It's also involved in spatial memory formation, and this is sort of like your ability to construct mental maps. So, for example, when you go to a new part of a city or something and you don't know your way around, you actually have to build a mental map of the layout of the area you're in, and it's going to be the hippocampus that's responsible for that process. So, generally speaking, learning and memory, specifically long-term memory and this type of spatial memory.
The amygdala is involved in emotional processing and it's actually going to kind of sit right on the end of the hippocampus. So we have the amygdala here, and this structure is the hippocampus. So it sits right at the end of the hippocampus, and it's going to be linked in some ways to the hippocampus because emotions can create very powerful memories. There's a strong link there. I don't want to make too many wild assertions, but there's certainly a link between the emotional processing of the amygdala and long term memory formation.
Now with that, let's actually go ahead and turn the page.