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Current time:0:00Total duration:10:32

Video transcript

so let's talk about the limbic system what is the limbic system well it's a set of structures in the brain and many of those structures play an important role in regulating emotion now something it gets kind of confusing when you talk about the limbic system is that experts can't actually agree on what structures make up the entire limbic system so for our purposes I'm going to address some of the most important structures and ones that everyone pretty much agrees are part of the limbic system now before I get going into the Nitty Gritty so to speak I want to give you a quick overview of what structures we're going to talk about and the way I remember these structures is suitable cartoon here this is a hippopotamus and he's wearing a hat now why is this hippopotamus wearing the stylish hat well this is my way of remembering the four most important components the limbic system when it comes to motion so we see hippopotamus here I'll write hippo and we see them wearing a hat I'll write hat now for this to be a mnemonic it has to be something useful and the reason I think of this is these are the forming structures the limbic system when it comes to emotion so hat stands for hypothalamus a for amygdala tea for thalamus and hippo short for hippocampus and these happen to be the four structures that I'd like to talk about so let's get to a little more complicated diagram and what you see here is my best attempt at drawing the limbic system an olympic system structures sit on top of the brainstem and this is the brainstem and you can imagine this as the very bottom of your brain and here's a spinal cord coming out of it and the spinal cord goes all the way down your back to about your tailbone now the limbic system are these structures up here that are drawn in bright colors now to orient you to diagram this is what you would see if you pulled off like the top part of your brain which is called the cortex and it's facing in this direction in other words while this is an ant homily correct let's say your eyes are here your nose is here and your mouth is here again this is not an tonically correct but this you can see is the front and this is the back so I can do it at an angle so you can kind of get a 3d idea so let's remove this and go back to talking about the anatomical structures so this blue thing here this is called a thalamus and you actually have two of these one here and one on the other side so your thalamus functions as like a sensory relay station meaning the things that you see here taste touch all these senses you have come through your nerves and ultimately end up in your thalamus and the thalamus directs these senses into the appropriate areas in the cortex as well as other areas of the brain and I mentioned this in terms of an emotion lecture because emotions are very contingent on the things that you see the things that you touch and here now you may have noticed there's one sense that I didn't mention and as a sense of smell and the sense of smell actually is the only sense that you have that actually bypasses the stala --mess and instead has his own private relay station that when it comes from the nose it goes to a certain area in the brain and that area that brain actually has to be very close to other areas that regulate emotion which explains why sometimes certain scents can evoke very powerful memories and bring you back to a certain moment in time but in terms of motion I mention that miss because of how the senses play an important role in your emotions now you see here there's these two purple structures this is known as an amygdala amygdala now the amygdala is sometimes called the aggression center and experiments have actually shown that if you stimulate the amygdala you can produce feelings of anger and violence as well as fear and anxiety I'm going to put stimulate and represent it as a dark green plus sign so you stimulate the amygdala invokes feelings of anger violence fear and anxiety on the other hand if you've destroyed your amygdala and I'll represent destruction as a red negative sign you destroy the amygdala it can cause a very mellowing effect I'll write mello in this melamine effect in the context of a destroyed amygdala was actually noted by a psychologist named dr. kluever and a neurosurgeon by the name of dr. Busey and I mentioned kluever and Busey because in medicine there's actually a syndrome known as kluver-bucy syndrome and that's when there's a bilateral destruction of your amygdala and bilateral means both you have bilateral destruction of the amygdalas that can result in certain symptoms that are often seen like hyper orality which means you put things in your mouth a lot also hyper sexuality as well as disinhibited behavior and disinhibited behavior is when you ignore social conventions you can act very impulsive lee you don't consider the risks of your behavior so you do dangerous reckless things so that's kluver-bucy syndrome and that's again when you destroy both sides of your amygdalas and the way I remember this is I think if you stimulate the amygdalas that can cause fear and anxiety and people who have anxiety disorders or experience an anxiety attack sometimes they're given a medication as a benzodiazepine sometimes they're called benzos and these benzodiazepine medications function pharmacologically very similar to alcohol and think of what happens when people consume too much alcohol sometimes you see these types of behaviors you see hyper orality you know you might be eating a lot you might have hypersexuality and of course you get disinhibited behavior think of the person with a lampshade on their head they're ignoring certain social conventions because of the effect of alcohol so that's how I remember the effect of stimulating versus destroying the amygdala and the screen structure here that you see curving around the thalamus is known as the hippocampus and the hippocampus plays a key role in forming new memories what it does is it helps to convert your short-term memory abbreviated as STM it helps convert that short-term memory into your long-term memory I mention that in this conversation because when you think back in your memories whether it's short-term memory or long-term memory these memories can invoke emotions as well so the hippocampus is an important structure in forming long-term memories and people had damage to this area they have difficulty forming new memories so everything that they experienced just basically fades away now what's interesting about this is if your hippocampus is destroyed while you can't form new memories you still have your old memories intact so your long-term memory function is just fine so that's the hippocampus now lastly this orange structure here this orange structure is the hypothalamus and hypo means below so hypothalamus is below the thalamus and here here's a thalamus and it's below it so that's where it gets its name from the hypothalamus is actually a very tiny structure and this diagram here really exaggerated the size of the hypothalamus hypothalamus is so small it actually makes up less than 1% of the total volume of your brain it's about the size of a kidney bean and the hypothalamus plays an incredible role in regulating so many functions in your body but for our purposes we're talking about olympic system structures in terms of emotion so when it comes to emotion the hypothalamus you can think of as regulating the autonomic nervous system abbreviated as ans in the autonomic nervous system you can think of as fight-or-flight versus rest and digest now I'm going to discuss this further in a different video but right now just think of it as regulating the autonomic nervous system it does this by controlling the endocrine system by triggering the release of hormones into your bloodstream and some of these hormones that are triggered to release or things like epinephrine norepinephrine and epinephrine is actually very commonly known as adrenaline so if you ever think of the phrase like a lot of adrenaline pumping through your veins that's actually being regulated by the hypothalamus yeah hypothalamus is also involved with regulating other basic drives like hunger thirst sleep sex but in terms of emotion I think it's most important to note that it regulates the autonomic nervous system that fight-or-flight or rest and digest response so that's the limbic system and these are the four basic structures the thalamus the amygdala the hippocampus and the hypothalamus so these are the basic structures of the limbic system