The Limbic System - Motivation, Emotions, Memories, and Drives

foreign [Music] guys welcome to psych explained before we get started don't forget to hit that subscribe button now in this video we're going to talk about an area of the brain called the limbic system I'll have to say out of all the videos I've created this by far the most requested one so I'm really excited to dive in this video we're going to talk about what the limit system is the parts that make up the limbic system and its major functions but let's start with a really important question why do we call this the limbic system in the first place well the word limbic stems from the Latin word limbus which means border or etch we've talked about this before but most science words have Greek or Latin roots and the reason we call it the border is because essentially it's the border between two major areas right all these structures in the middle represent the limbic system we have the bottom of the brain right this is kind of a cross-section the brain stem which is involved in primitive vital functions for survival like breathing and heartbeat right it borders this era and the top of the brain which is the cortex the neocortex which controls thinking decision making and playing right rational thoughts so this is the border of our primitive area our brainstem and our cortex which sits right on top the other thing to think about is why do we call it the system instead of the limbic part or writer's limbic structure it's because all these structures in the middle will talk about interact with each other to create some sort of Behavioral output right so for example think about this visually you have all this sensory information we'll call this sensory input coming into the brain okay what is this sights and sounds and smells right and your body's got to do something with it well it's kind of like a pinball machine all these parts of the limbic system talk to each other right so if I hear the sound this structure is going to talk to this structure and say hey based on this sound I think this should happen and then this structure talks this structure and so on and so on so you create this giant system of interconnected uh parts that talk to each other that create some sort of what creates some sort of output right which could be behavioral right some sort of action you do based on the sensor information that comes in it could be an emotional output like laughing or crying right fear anger whatever emotion is it could be a cognitive output right thought you have but that's a nice way to think about the limbic system is this border between our you know primitive brain and our our new cortex brain and that is kind of this ping-pong action of like Bing Bing Bing everything talks to each other and then you have some sort of Behavioral cognitive or emotional output all right all right so what parts actually make up the limbic system now this is really hard if you ask 10 scientists we'll make up the limbic system you'll have 10 different answers right why is that well one reason is because unlike something like the liver or the heart that you can visualize that has defined borders a lot of these structures don't really have defined borders right it might just be a bunch of neurons packed together in an area and there's like this part does something but I can't really identify so that's one reason there's not a lot of borders with a lot of these structures just kind of intertwined here and the other reason it's hard to identify is because there's just so many structures in the brain that Parts interact with and it's hard to know what deals with just emotions or memories or drives and what deals with something else so it's really hard to identify all the major structures so if I leave out structures which I know I will I don't want a bunch of hate mail right if I leave out the septal area and the mammillary bodies I don't want hate mail I know it's part of limbic system we're just going to talk about these major structures all right so let's start with one of the most dominant major structures in the limbic system we often talk about this area is the emotional Center uh we'll label it with our Roman numeral one uh and we call this the amygdala okay the amygdala so what's the amygdala do well for each of these parts we'll just label kind of the big overarching idea and we'll get in more specifics later but the amygdala is really involved in emotional response right or emotions right so feelings of anger and fear and even positive emotions like Joy you know the amygdala is probably going to play a big role all right what's another major part another major part right next to it this structure that looks like a seahorse which is what it's named after is called the hippo the HIPAA what the hippocampus right nice memory technique you would never forget a hippo on a campus why does it help you because this part deals with memory memory what memory formation right now A misconception is that the hippocampus stores memories well that's not really true well the hippocampus does is a more encodes and and brings in memories and then kind of connects them to different sensory information so it's not really a storage tank it just kind of helps encode and process information all right another pager part of the limbic system I think of this is the king of the brain uh when we're labeled as Roman numeral number three is what we call the hypo the hypo what the hypothalamus right and just kind of information why we call it the hypo well hypo means below so in other words here's the thalamus it's below the thalamus the hypo just means below that's a nice awesome to think about and hypothalamus does a lot right I said this is the king of the brain but it's major uh function is we're going to write down the word homeo homeostasis right and essentially what this means is your body's always trying to find balance what do you do if you're hungry you eat what do you do you're thirsty you drink if you're sleepy you sleep uh if you're cold you get warm your body's always trying to return to that kind of uh internal balance and what's in charge of that are hypo hypo means below are hypothalamus all right Ian Black what's another major structure number four a Roman numeral four uh is what we label this structure right here is what we call the thalamus okay the thalamus and the thalamus does a lot okay we're going to label kind of two you know two major functions one of them I always like to think of this as the filter of the brain in other words think about all the information that's coming into your brain right now right sights and sounds and smells you can't pay attention to everything all at once it's sensory overload so the thalamus essentially acts as a filter it decides what information you focus on and what you can't ignore right I like to think of it like that another major function is we're going to write the relay Center okay the relay Center what do I mean by that all the information that comes in the brain right things through your eyes and your ears except for smell we'll talk about that makes a pit stop of the thalamus and the thalamus size where it should go right if information is from your eye it's going to say go to the visual cortex if information comes from my skin it's going to go to the sensory cortex so it decides kind of like a pit stop a relay Center where things should go in the end so there's uh number four oh I gotta write number four there okay all right what's another structure another structure we're labeled number five uh right up here uh is what we're labeled as the cingulates the cingulates gyrus okay now this structure plays a role in everything now we know what connects to the the hippocampus right there's kind of a little structure called the fornix that connects these together and because it connects to the hippocampus you know it deals with memory by the way I keep forgetting to write a Roman numerals here so it deals with memory uh it also deals with emotions uh it deals with pain perception uh it even does things like recognize errors like if you're reading something and you recognize a word is misspelled your single hyrus is like Bing Bing there's an air there's something wrong here we should pay attention to it so the singular gyrus involved in a lot of different things all right what's another structure this blue right here will label Roman numeral number six there we go number six uh there we go six right here uh is a really important structure okay do you ever feel good eating a big cheeseburger or you get a lot of likes on social media right you're like oh this feels really good right or my intro the Euphoria of finding your car that was lost uh this structure is what we're going to label as the nucleus oops what nucleus accumbens okay it's a really cool structure and we're going to write down the word pleasure in other words anything you do that feels good uh that gives you a high uh your nucleus accumbens is probably being activated right there's probably Action potentials you know firing at this part of your brain all right last one we have three four five six uh we'll label as number seven let me get my black marker is right here this kind of little bulb right here five six seven uh deals with smell what is this little structure right here right behind the frontal lobe this is going to be here's seven our olfactory are a factory what are a factory bulb you know what our Factory bulb does it deals with well think about olfaction it deals with smell right that might be a new one you're like the limbic system deals with smell yes in fact historically the first name for the limbic system wasn't limbic system it was the Ryan cephalon big word which means the nose brain because when you study rats and rodents a lot of this area is really interconnected with the olfactory bulb right all these projections in the limbic systems so at first they thought this area only deals with smell of course we know a lot differently today so here are some of the major structures now things we might have left out the the para hippocampal gyrus which surrounds hippocampus the mammillary bodies these two kind of uh Circle you know ball like structures right underneath the hypothalamus so there are things we left out I don't want hate mail but these are the major structures okay so now that we know the parts let's dive into some of the functions we'll start with emotions now we're going to start with a major structure that deals with motions you could look at it here and the part we're going to focus on with this one we already said it is the amygdala okay the amygdala and there's our amygdala right here that little almond shaped structure and what essentially about the amygdala is that's very tiny and I think that's really important to know that the size of the structure in the brain doesn't determine the power and influence it has over you right I think that's important to know just because somebody's tiny doesn't mean it hasn't had big influence there are very tiny nuclei in the brain that have a big influence over your life okay so let's explain how the amygdal plays a role in emotional response and of course how parts of the limbic system interact with each other so imagine you're walking in your bathrobe and you see this nice blue thing right we know it's a spider but how does it actually get to the point where like oh my God there's a spider there well information let's think about this together all right so information is going to travel to the eye it's going to convert it to action potentials in the retina let's think about our eye Anatomy that information is going to travel to where the thalamus right I told you before that relay sound sir and eventually make its way to the back of the brain an area called the visual cortex okay so there's where we're at okay now the visual cortex is going to connect to where it's going to connect to and talk to are amygdala why because this is a threat right now I know it's not a big threat but your brain's like something's off here I'm in danger something might happen so we're going to label the first parts of what the amygdala does is it helps detect okay detect a threat okay now this threat can be a visual like seeing a spider uh this uh can be auditory like hearing a police siren okay or hearing uh some sort of loud bang uh it could be olfactory right smelling smoke so your your brain is always detecting a threat in terms of all of your senses right so in this case we have our visual okay what's next well after we detect the threat a couple things have to happen um one uh and most importantly is you have to actually trigger some sort of response what does my body do with this rut so trigger a fear fear uh response okay so how does it do that well the amygdala is going to talk to a couple structures it's going to talk to you most importantly uh your hypo what is it think about it here means below hypothalamus okay why is that important we'll have errors kind of going back and forth is because your hypothalamus it's what's going to trigger your body to be on alert okay and a couple things are going to happen one you're going to have your below Circle here your sympathetic your sympathetic nervous system uh activate and this is what creates the fight or flight response what's going to happen uh your you know breathing will intensify so your breathing will go up uh your heart rate will go up okay your pupils will dilate you know PD pupils will dilate right your body's getting to that fight or flight mode just in case there's danger another thing that's going to happen is your hypothalamus is going to communicate with these two structures here okay these two little kind of bulb like sharps are hanging called the pituitary gland okay do a deer gland and I'll put PG here PG for pituitary gland we're going to communicate with this as well uh which is going to send hormones throughout the body to start this activation of of stress hormones and this is important though your hypothalamus controls your endocrine system endocrine system okay so instead of activating like heartbeat and and uh your dilena pupils uh what we're having here is things like cortisol being released okay talk in your adrenal glands right cortisol increases this is your stress hormone right from your adrenal glands uh to create that kind of stress response norepinephrine and adrenaline in your body is going to fight or flight so we have communication with the amygdala the hypothalamus the pituitary gland we're also connecting to the uh the hippocampus right so we kind of remember this in the future like oh my god there was a spider here I'm going to remember that in the future and what's also cool is I put the structure here this is your prefrontal prefrontal what prefrontal cortex okay why is this structure important here this is where rational thought takes place and what's important to know is just because there's a threats you do have kind of a backup which is your brain saying should I be really afraid of this right um you know question mark should I be afraid well your amygdala is probably more powerful than your prefrontal cortex and rational thoughts so even though it might not be a real threat your middle is going to take over right so that's kind of our first major function we have emotional strong emotional response all right so this kind of gets us to our second major function memory and learning if the amygdala is the center of emotions for the limbic system what would be the center of memory and learning well in this case we're going to talk about a structure Roman numeral number two called the hippo never get a hip aware on a college campus right memory formation so just like the spider example let's think about a real life example everybody here has probably been in some sort of car accident or almost a car accident it'd be pretty frightening rights you know there's detecting a threat and triggering if your response is happening as well right so a car is coming towards you right let's think about our pathway we go from our you know optic nerve of our eye we're gonna make a synapse in the thalamus and we'll end in our visual cortex right we'll synapse in our visual cortex and if it's sounds that would be our auditory cortex in our temporal lobe right so think about our different parts right um so our hippocampus at this moment after we kind of see the car coming towards us and hit us is going to start to form a memory of this event so our first function of the hippocampus and memory learning is memory formation memory what memory formation and this isn't all types of memory we're really talking about our explicit memories memories of facts and dates right maybe spatial memory where you were when this event was happening right so maybe our our hippocampus is going to communicate through the fornix of our singlet gyrus right create some sort of connection there so we're not storing the member there we're just starting to encode The Sounds the sights the smells of this major event and our second major function is going to be a set of memory formation memory consolidation consolidation so what's the different consolidation make sure I spelled that correctly what we're saying is we're going from short-term memory and we want to make sure this memory lasts forever right so I want to make sure that I can remember it in the future so you know it's going to interact with the hippocampus as well so we want to make sure that the neural connections are really strong right so we have kind of two neurons and the more they communicate the more you relive this event we're going to have more neurotransmitters being released we're going to have more kind of receptor sites open up on the next neuron and the strengthening of neural connections do you remember what that's called it's called long-term potentiation okay so we're starting to our limbic system is going to help us kind of not just encode but create this kind of strengthening of this memory so we don't forget it as well right and I also have the hypothalamus here too right because you know it's going to trigger that fear response the last major function deals with memory and learning knowing that IV amygdala there is is a memory emotions emotional memories I want to be my emotional memories is you know we're going to start really feeling this memory right so when you relive in the future your heart might beat right your amygdala is going to be activated your hippocampus your amygdala talk to each other uh the old factory bulb uh might be activated the smell of gasoline so the the uh olfactory bulb is going to connect to the amygdala as well so you've got all these structures together that are going to kind of relive this event is somewhat of an emotional way so that's kind of our second major function all right what's our third major function motivation and reward now if we have the amygdala for emotions hippocampus for memory learning what's the structure we should think about for memory or sorry for motivation and uh reward we're going to start with a structure called the ventral Venture what ventral tegmental area ventral tegmental area or will abbreviate as the v t a okay and essentially it's a structure deep within the midbrain that's packed with neurons now not just any type of neurons but neurons uh that we're going to call dopaminergic there's our big word of the day dopa menergic okay and what this means is all these neurons that are packed Together release an excess supply of dopamine what neurotransmitter we're talking about dopamine okay and this chemical message this neurotransmitter controls everything from pleasure and reward even motor function right affects Parkinson's disease and I think the biggest misconception about dopamine is that like dopamine is only released when you do something good like eating french fries or uh you know getting a like on social media but really it's about that motivation is that urge that compels you and urges you to do something right so when you're sitting on your couch and you're like you that urge to pick up your phone that's really what dopamine is right it's the kind of the goal directed Behavior towards something okay so just like our other examples of spiders and and a car accidents let's think about our social media right you're on social media you're getting all these likes and it feels good so what's going to happen your VTA or venturement era has axons that are going to project to other parts specifically it's going to synapse with a part called let's write this in together your nucleus nucleus accumbens okay in your nucleus accumbens um deals with pleasure okay so when you do something pleasurable whether it is you know eating something sugary uh you know winning money you know gambling uh you know could be sex we'll talk about in a moment or in this case you know getting some likes on social media your VTA is going to set up all these dopaminergic uh Action potentials to the to the nucleus accumbens and it just feels good and why is that important because you're going to do it again and again and again and that's of course you know how things feel good and we'll synapse with the you know the hippocampus as well because we want to remember to do it again right and we want strong emotion so it's going to synapse with the amygdala right so your VTA is going to synapse with all these different structures and the other idea knowing I have a heart here is sex motivation right kind of that taboo topic right that that dry people have right is all controlled by your limbic system as well um the idea is let's think about the king of the brain or queen of the brain the hypothalamus okay you know when sex feels good they're it's gonna your brain's like let's do it again and again and again uh and it's going to release things like you know oxytocin uh that love hormone that bonding hormone testosterone so this area is involved in not just food and money and likes but that that drive uh for sexual motivation right that would be our hypothalamus okay so there's motivation reward what is our last functional limit system homeostasis all right do you remember what structure deals with homeostasis if you're thinking it must be the hypothalamus again oh this structure comes up a lot you are correct okay hypothalamus and essentially what we're saying here is our bodies always trying to reach um a right homeostasis you know stasis which essentially is this kind of internal balance right if you are hungry eats if you're thirsty drink if you sleep you gotta sleep and our hypothalamus controls all of this all right so let's think about an example you got pizza in front of your eating uh you don't eat too much you don't eat too little so how's that going to work well of course we have our hypothalamus right I'll put H here for this structure right here and your hypothalamus we'll kind of draw it together you could kind of divide it to two parts uh the top part we're going to call the lateral hypothalamus okay and this is actually what's going to make us hungry right so when this sends out messages right down our brainstem to our body uh this is going to say eat right eat right my blood sugar glucose is low let's keep eating but after a while what happens you feel full and this is thanks to a part of your hypothalamus called the ventromedial okay medial means towards the middle right so ventromedial and this is going to make us full okay so you kind of have this Balancing Act for homeostasis of you know you eat but not eat too much another way to think about is I have all these structures here that also play a role uh in make sure that our we have we have homeostasis so for example you have all these fat cells uh these are going to release leptin right this is going to make you full so that's going to talk to the hypothalamus you have your pancreas do you know what your pancreas releases if you're thinking insulin you're doing a good job that's going to help turn you know glucose into fuel it's going to help glucose enter our cells for fuel we also have our stomach what is our stomach release well if you're hungry it's going to release something called ghrelin okay and this is going to make you hungry so you've kind of had this feedback loop of like you know I'm hungry I'm hungry I'm full and your hypothalamus is then going to send signals back down your body to communicate as well so this is a nice way to think of homeostasis now I do have another you know asterisk there because we have this part called the amygdala why is that important we don't just eat one or hungry folks I mean there's emotional eating right there's emotional part of of homeostasis which is uh maybe we just eat because we're bored maybe we're eating because we're lonely and our prefrontal cortex right is like we're not hungry I don't think it's a good decision to eat remember you're you're amygdala very strong is like I think we should eat right so there's definitely kind of like memory an emotional part to everything that we do and the limbic system does all right guys thanks for watching I really hope you liked the video and guess what if you're feeling really good right now it's probably your limbic system that's letting you feel that way don't forget the like video subscribe I'll see you next time

Channel: Psych Explained

Views: 46,799

Keywords: limbic system, amygdala, hippocampus, homeostasis, memories, hypothalamus

Id: xodDIAehIfU

Length: 24min 41sec (1481 seconds)

Published: Mon May 22 2023