The Limbic System

hi everyone its mr. city and thanks for joining me today for this discussion on the limbic system of the brain that's right the olympic system has everything to do with emotion it's the emotional area of the brain now needless to say that's pretty crucial because our brain although we like to think of our brain as a thoughtful contemplative decision-making sort of cerebral cortex kind of logical contemplation a lot of what we need to do is react in the moment and emotion is as part of that in other words if we're in a fearful situation we need to get out of it and so I want to point out something you'll read out of the gate on this you'll notice that there's in this limbic system there's no particular region there's no anatomical area of the brain that is going to be called the limbic structure but rather it's a system it's the only portion of the brain that's referred to as a system because what it what it involves is a collection of various structures nuclei or regions of the brain that interact to to relate to these emotions and so hopefully this is intriguing perhaps somewhat vague but that's the point of the video and so when someone speaks aloud about the limbic system it sort of sounds as as I was saying before like a single structure but it's simply not the case it's really a collection of structures that work together collaboratively and basically it's located on sort of both sides of the thalamus and again there's more images that are going to be coming on this and it's below the the cerebrum and but the truth be told part of the cerebral cortex is part of this as well it's an end you know I should point out that it's not well understood and when I say it's not well understood it's not it's not just me it's a lot of neural scientists have been learning and been experimenting and doing all kinds of research in this area for many decades and I find it almost more interesting when less is known it kind of stimulates more curiosity if you will so I hope it does for you as well again that's the point of the videos to not to explain everything but rather to incite more questions about the topic and so in those early days of brain science it was thought that these structures were really really related to smell and IO and I will say that you know a lot of that came from research done working with rats now if you were to take a look at a rat brain the old factory area in other words the smell is huge in the brain of a rat because it gets a lot of sensory input from smell and therefore its emotions are linked to that and so we thought that that this was you know the origin the rhinencephalon a rat brain was a really important part of the lymphatic system but as it turns out the lymphatic system is more about depending on the organism like we rely a little bit on smell old factory but we have vision and other organisms rely on hearing and so all of that sensory input comes in and then we deal with it emotionally in other words if we hear something or we we hear bird songs and we're stimulated to want to respond to them or we hear something scary and so we see something and so it's it there's a lot of really cool comparative anatomy having to do with behavior in terms of evolutionary significance of the the system that we're talking about the limb the limbic system and so there's debate about the number of structures that are involved in there there's you know one could argue if you really know what you're talking about that many if not all structures of the brain are part of this emotional response and limbic system but I'm just going to break it down because there's a unanimous agreement that there's three most important structures although of course if you know me I'm going to bring up a couple more but but it's the amygdala which are two little tiny structures that reminded early anatomist of the the structure of an almond and that's where it gets its name the hippocampus which is a really cool structure and singlet gyrus and so those that particular area is actually literally part of this as cerebellum and so more to come about these structures and so functionally just to give you a fly over understanding of you know what is the limbic system doing it's basically having everything to do with emotional states it establishes these emotional states that we have in other words fear anger or happiness these kinds of things and obviously that this is it links to conscious functions of the cerebral cortex in other words decision-making about that and so when we face a particular emotion we need to decide what we want to do with it and then there's autonomic kind of responses as well and so this limbic system when it takes in emotion in fear like for example if it hears something scary then that might trigger a response and uh in hormones and that will link with an endocrine response and ultimately it will involve perhaps movement and that will involve sending nerve impulses down the brainstem motor neurons and affected action and so it's really cross communication communication is the theme here that the limbic system is sort of this emotional hub of all different kinds of structures but it's all about communicating and getting things done and then if that wasn't enough it facilitates the limbic system storage of memory in other words where new memories are formed and that's important too because you know if you think about it evolutionarily speaking learning is a important part of survival and especially things that cause emotional distress in other words it be it behooves us to remember things that put ourselves in fatal danger and so memory has got to be part of this process of emotion and so there's going to be areas as I alluded to before with this seeing singlet gyrus there's particular load of the cerebral hemisphere that are particularly important in this the hippocampus and again there's a pair of meaning to the side hippocampal gyrus that's important as well so these are part of the cerebral hemisphere I just wanted to point that out so just to you know to back it off just for a second a gyrus if you're unfamiliar with that is this convolution or fold that we have in the brain and that those folds that when you think of the the classic picture of the brain all of those folds help to increase the surface area and that you know of course or maybe not of course but that increases then the number of neurons that can be present in that area in gray matter when we talk about gray matter what we're talking about is clusters of nuclei of or soma if you will of the the neuron itself and those tend to be gray in coloration as opposed to white matter which is more of the the cords or axons that are coming out of it and so there's many Jireh that interact in the limbic system and the brain as a whole just want to point that out so these two structures are really cool they sort of arc around like this are highlighted in blue cingulate gyrus right in here and so what what are those up to so again this is a superficial coverage of what these structures are doing but if you've ever been so excited that your arms are flailing in the air in your or you're so angry that you're flinching your your fists in clenching them this portion of the brain is responsible for this is oh it plays back that plays a role in expressing emotion through gesture okay and so this is complicated though I just wanted to point out that you know in terms of this the the cerebral cortex on the very top right in here there's a separation here which is known as the central gyrus and anything to the front of this and this is in the back this is the front of the brain so this is anterior so at the very posterior part of the frontal lobe is this motor cortex which is responsible for decision-making for motion and then at the very interior part of the parietal lobe is this somatosensory area and so this is where we perceive and decide on skeletal motion this is where we sense or perceive sensory information and so this is also there's connections here as well and so this is responsible for in terms of the this motor area and sensory area are part of recognizing what part of the brain is being stimuli stimulated and decisions need to be made accordingly and so this is related to receiving emotional input okay and so below the thalamus okay when might be able to have thought about that hypo meaning below something so below the thalamus is the hypothalamus down the hypothalamus small it's about the size of a kidney bean but powerful it is involved in this because when there's a situation where the body is in danger for example though the hypothalamus works Auto Tomica lee in the audit on mcnair system it's able to produce hormones that cause pituitary gland to secrete hormones that will cause other organs in the body to secrete for example if there's a stressful situation the high both Alamos might get the pituitary gland to start releasing hormones that will stimulate the production of adrenaline or the the production of cortisol so cortisol releasing hormone for example does that because then it causes the pituitary gland to secrete adrenocorticotropic hormone in other words causing the adrenal gland to produce cortisol which is then going to increase energy production and so this is famously known as fight-or-flight likewise in terms of controlling autonomically in other words not consciously sort of a suppressive kind of situation other words are calming it to rest and digest so that's it's able to inhibit and incite endocrine glands which then produce hormones which cause response to emotion so that's part of it too so this hippocampus as you can see here highlighted in in blue is involved in memory processing and as I alluded to this before I find this to be particularly interesting because again emotion whether it be seeing something or remembering something having that caused an emotional response is useful and so it makes logical sense at the hippocampus this region right here and there's two of them are involved in memory is is very logical and so the word hippocampus just for a moment is kind of an interesting thing if you look up a Greek mythology you'll find that hippo cam which hippo kind of from Greek meaning horse but also part of it being like the tail end sort of like a centaur a little bit or chimera a combination of a hybrid organism is part of it like it's sort of an eel or a fish horse and a fish but actually it reminded early an animus of the fact that it looked a little bit like a seahorse maybe perhaps but it's found in the in the medial temporal lobe and it consists mostly of gray matter the hippocampus which means that there's a lot of nuclei in this area and again the fact that it's a bulge just to just to point this out the fact that it's that it's identifiable like this is suggestive of the fact that there's a lot of soma in in this particular area and that's why it makes this cluster like this and it's the memory forming center and so it helps a little bit more detail in this it helps to convert your short-term memory into long-term memory all right that's interesting too so and then I was saying before that memories are related to emotions as well and so people that have damage to the hippocampus have trouble forming new memories I'm not to be pretty interesting okay so that when so in other words a negative we're able to determine what the hippocampus does when they're when it's not functioning properly but yet you know the things that they experience then just simply fade away but what's interesting about this is that their long-term memory is still intact which is suggestive that that long-term memory is not where is not stored in the hippocampus and so this area righted here as you can see here I know that this is it's difficult to see again you know it's one thing in a pitcher like this to put blue arrows here and you're like look at this it's the the dentate gyrus which is thought to contribute to the formation of new memories it's this sort of area within the hippocampus in particular that is where new memories are formed but it'd be another thing to be able to identify it in an actual brain it's pretty difficult and so memories as they were saying before are not stored in the hippocampus but rather cognitive and sensory experiences are organized and unified in terms of long-term memory and that that is throughout the cerebral cortex and so when you experience it something like Qing something very hot for the very first time like okay you know you'll remember that right the hippocampus learns from the sensory input that that's not that's not good to be touching buyer so and then it plays the memory back repeatedly if that were to occur again or it sort of like conditions it a little bit into the cerebral cortex so therefore long-term memory as established this concept is called memory consolidation and so boy if this is not understating this I mean this is how learning is is taking place and so this video isn't about that but I hope you're appreciating the magnitude of what we're kicking around right here in terms of how the hippocampus will pick up short-term experiences sensory and otherwise and then consolidate them into long-term memory for future so it's kind of cool in terms of how the body uses its brain in order to respond in the future and so learning can be think of thought of as a behavioral modification to previous experience okay so think of the hippocampus is a way of teaching the cerebral cortex okay that's kind of a funny way to think of it but memory consolidation continues in in the form of long term memory and again which is held in a variety of areas in this video isn't about that but different memories are housed in different locations within the cerebral cortex it's pretty interesting there and so a more about the various components or structures within the limbic system the fornix is a particular tract of white matter that connects the hippocampus shown here with the hypothalamus and the fornix the the term itself is kind of an interesting term you know each of these are related either Greek or Latin but find that that's to be somewhat interesting so if you don't mind it's a little side bar on this the four decks it comes from like when you think of back in the the Roman gladiator times and some of them some of those events I had prostitution and prostitutes hanging out around the Coliseum and so when people said that they were going to go to the art the arches of the Colosseum the the fornix it was kind of associated with the fact that that might mean that they were going to go pick up a prostitute and so fornicate comes from from the this idea for necks and that to be kind of interesting and so right at the very tip of the hippocampus you get these two almond like structures called the amygdala and this is known as the aggression Center and again that's again simplification hopefully and this is intriguing enough to stimulate further understanding but this is your aggression Center and the brain the amygdala and but the truth is that it acts as an interface between the limbic system and this in the cerebrum in other words various sensory systems need to be called into play here and so this whole idea of the emotional response of the limbic system being separate from a sort of rational thought provoking decision-making is isn't really true there's a there's lots of connection and communication that goes from decision-making and in an aggression whether or not to to act or to not act accordingly and so just to sort of you know bring this up how do we know these things and stuff so in other words when when the Mikula is stimulated and it won't go into necessarily how that occurs but I'll just put a plus here saying that the the neurons can be stimulated in other words cause to be fired in the brain and what we see and not only in animal models but also in humans we see it creased anger violence fear and anxiety so this anxiety is stimulated by the amygdala and again you know this isn't necessarily don't think of it as being at such a bad thing the anxiety and fear is useful information in terms of getting us out of harm's way I mean it one could say that those members of the population that didn't have a lot of anxiety and fear didn't survive okay so I can be blunt about that so anxiety disorders however are are curious when we study things that aren't going well so in xiety disorders or experiencing an anxiety attack this is overboard so having too much is bad and so sometimes these patients are prescribed medication and again and not a physician but one of the more common form illogical medicines that are given are these sort of bends oi whoops I'm sorry been Zoid diet diet zappa pain diet or just been Zoids if you difficult pronouncing that so they act basically to inhibit the amygdala and so what what is happening here is that it's sort of a mellowing effect these been Zoids provide sort of a calm if you're experiencing anxiety to a hyper state and so what that does is interestingly cause these medications cause hyper orality meaning that the individual has maybe increased desire to putting things in their mouth increased hunger or hypersexuality increased desire for sexual activity and this is curious less inhibited behavior so more reckless under the influence of been Zoids which is which is kind of curious all of these sort of if you if I could make this simplified are a little bit related to been Zoids act a little bit like what alkyl might be doing to a person other words increasing sexual activity hunger and also inhibiting behavior a little bit like sort of running around with the lampshade so inhibited like your social controls or not at fully functional and so you know again superficial understanding of that and so what's happening here is that the outputs from the amygdala goes either to the hypothalamus and if that's the case the hypothalamus is going to act on a sort of autonomic basis it's good as I mentioned before it's going to produce these hormones and it's going to cause perhaps increased heart rate or it's going to produce Ultem indirectly influence the production of cortisol in adrenaline for example or it could go to the prefrontal part of the cortex as well and so that helps to think about what is happening and so as as I was saying the hypothalamus in Flute influences visceral and somatic motor systems ultimately heart rate that sort of thing breathing rate respiration hormones like your heart racing whereas the prefrontal influence is conscious response in other words you know like as a result of this emotion you might act on it in other words I'm going to do this act of violence or I'm going to tell someone you know to keep it positive will tell someone that I love them or it could be you know though though I'm feeling this I'm in actually consciously control this anger and not act on it okay and so just to wrap this up again these two little small but powerful little almond structures right here making amygdala are all controlling that that area now the thalamus is I mentioned a little bit hypothalamus the thalamus on superior to the hypothalamus and there's two lobes to it and basically it's a relay system where all kinds of nerve impulses are coming into the thalamus and that's sending and routing all of that information all the different parts of the brain so clearly if you're following this the thalamus has to be part of this limbic system it has to be because these emotions are related to in contingent on things that we're seeing so sensory information is that comes into the stalinist and then that gets shot out to different areas in the cerebral cortex things that you touch and hear we're going to have a response to and so in particular just to point this out and it's in this interior part or sub region right in here and again your neural scientists you get into all these little sub structures within parts of the brain and that is part of the this interior nuclei are part of the limbic system because it's affecting related to emotion okay and so as I was saying this interior nuclei and again anterior nuclei don't get overwhelmed it's just the soma involved in the neurons and that relays information from for example the mammillary bodies to the cingulate gyrus the mammillary bodies are also involved in memory right in here in reticular formation if you're familiar with that these are tracks of neurons that either stimulate or inhibit emotion and then these are found within the the thalamus and you know the range of emotion so rage and fear pain sexual arousal pleasure these kinds of things are are being routed and being sent to different parts of the cortex the cerebral cortex and that's happening in the in the thalamus which is writing right in this location right there okay so hopefully you enjoyed that presentation on the lymphatic system and hopefully it stirred your curiosity and thanks for watching

Channel: Ray Cinti

Views: 98,529

Rating: 4.7730689 out of 5

Keywords: limbic system

Id: mN9y2LTg8nk

Length: 26min 38sec (1598 seconds)

Published: Wed Apr 12 2017