all right ninja nerds in this video today we're going to talk about the cerebral cortex primarily focusing on the temporal lobe we'll also talk a little bit towards the end in more detail about another little mini lobe that's tucked deep inside of the temporal lobe called the insula all right let's go ahead and get started all right so let's first off start talking about the temporal lobe in order for us to really understand the temporal lobe and the outline of it we have to establish some boundaries of the temporal lobe right so there's a couple boundaries the first one here is this one this boundary here this one here is actually called a particular solid so it's called the lateral sulcus right or the sylvian fish here and this sulcus beautifully separates the temporal lobe this slope here where we have all the colors from the frontal lobe and from the parietal lobe so when we talk about the boundaries of the temporal lobe we have that lateral sulcus or the sylvian fissure right that lateral sulcus or the sylvian fissure what does that do well that separates again the temporal lobe from the frontal lobe and from the parietal lobe there's another one now this one isn't actually a defined sulcus there's a little notch right here a little notch you see how kind of after the octopus you get like this little notch before you go into the temporal lobe this notch is called the preoccipital notch and what happens is if you draw this notch an imaginary line kind of like from that preoccipital notch at an angle towards the tip of the lateral sulcus it beautifully separates the temporal lobe from the occipital lobe so this imaginary line starting at the preoccipital notch so again pre occipital notch this beautifully separates the temporal lobe from the occipital lobe all right beautiful that's our boundaries now we got to start talking about some of the areas located within the temporal lobe all right the first one is this orange area this orange area here is actually called the primary auditory cortex okay it's called the primary auditory cortex and you guys can already imagine that the primary auditory cortex is for what it's for conscious awareness of auditory stimuli so it's conscious awareness of sound and we'll get into more detail of that later but that's the basic uh explanation of the primary auditory cortex if you go just a little bit kind of underneath that so just a little bit inferior to the primary auditory cortex you have this next blue area this blue area is called the auditory association cortex okay it's called the auditory association cortex now remember pretty much every primary cortex has an association cortex associated with it right because the sensation or motor function of that primary cortex has to have interact with those association cortex to give meaning purpose understanding recognition so the auditory association cortex basically it gives meaning to the sounds and we'll again we'll explain more of what that means but it gives meaning or understanding of sounds all right so this next area this green structure this green shaded in area this is called wernicke's area now wernicke's area is very interesting wernicke's area is very interesting because it's involved with the comprehension so it's wernicke's area wernicke's area is involved with the comprehension and understanding of written and spoken language okay so it's involved with the comprehension of written and spoken language so trying to understand what you are hearing or what you are reading okay so that's the significance of wernicke's area all right there's another area now this one is actually going to be difficult to see we'll show you a little bit later in another view but i kind of made like a dotted line here you can't see it it's not on the outer lateral surface of the brain it's tucked deep on the medial surface of the brain but just for right now i want you to imagine that if you guys were looking through here this dotted line with the pink lines here if you look deep in there on the medial surface of the brain you have this pink structure here and that is called the primary olfactory cortex and there's also if you see here in red there's also another association cortex associated with it so again the pink and red structure there which is going to be found deep on the medial surface of the brain in the temporal lobe is called the primary olfactory cortex and again in that red area there you're also going to have its association cortex and the association cortex so again this would be your olfactory association cortex what is the job of this primary olfactory cortex well the job of the primary olfactory cortex is to help us to become consciously aware of particular smells so it's conscious awareness of smell but then what's your auto your primary your olfactory association cortex does is is it takes those smells and it analyzes the smell okay and it helps us to recognize maybe smell patterns and another important thing of this area this association cortex is it can communicate with our limbic system so not only can it analyze the smell help us to recognize what kind of smell it is but it can connect it with our emotional system to help us to see oh this was actually a smell that brings back good memories bad memories oh this is not a good thing right so again that's the significance of the primary olfactory and association cortex the last one here it's very difficult to see the best way to kind of see this one is you have to take a coronal section of the brain and if you take a coronal section of the brain you get something like this here's your let's say this is your parietal lobe and then here these little things here on the side of your temporal lobes and then you go into your midbrain deep deep in the temporal lobe so here's your temporal lobe that i'm shading here right this is important this up here is your parietal lobe deep within that temporal lobe you have like a little kind of gyrus here a little area a little lobe there called the insula okay so that's called the insula okay the insular cortex if you really want to be specific now the insular cortex has a couple functions two functions that we definitely have kind of some understanding of is that this insular cortex receives information about taste so it receives information about gustation the other thing that we have some cons conception of with the insular cortex is that it's also responsible for receiving visceral sensations so visceral sensations okay and the last thing that it's interesting we're trying to look into it more again it's not completely well understood but they see that vestibular information so equilibrium your dynamic and static equilibrium sense can also go to your insular cortex so this may also be where the vestibular sensations or your vestibular cortex resides so this can also be where vestibular sensations go all right that covers the basic areas and the basic boundaries of the temporal lobe let's go ahead and talk first about the primary auditory cortex all right so let's start with the primary auditory cortex what do we say was the basic function of this area conscious awareness of sound well really if we were to be more specific it helps us to identify three particular things about sound so when we talk about sound itself sound waves that are produced right we can actually our primary auditory cortex can help us to understand basically the frequency of sound right so the frequency of sound it also isn't good for it's good for interpreting uh particularly the pitch of sound so it's also important for determining the pitch of sound and last but not least it can also help with localization of sound what does that mean determining the location of where the sound is coming from the right side the left side somewhere in the middle so it's also good for localizing sound so i would say that these are the three main things when it comes to how the primary auditory cortex becomes consciously aware of sound stimulus it helps us to determine the frequency of sound pitch of sound localizing sound now how does that actually work well we've already talked about the auditory pathway in great detail and again in our neurology playlist for the vestibulocochlear nerve but from the inner ear the cochlea you have particular sensations right the based upon the sound waves activate the spiral organ of core t and then activate this vestibulocochlear nerve cranial nerve which one this is cranial nerve eight so cranial nerve eight which is your vestibular cochlear nerve will move in to your medulla and again we're not gonna focus too much here on the the details of it i only want you to know one thing that this vestibular cochlear nerve it synapses on cochlear nuclei located in your medulla then what happens is these nuclei will then cross via what structure called the trapezoid body doesn't really matter right now i only want you to get this one particular point out of this that as this crosses it eventually will come up and then synapse on some particular nuclei located here in the thalamus okay again if you guys remember from the thalamus music medial so really the nucleus here is the medial geniculate nucleus we don't really care about that but here's what i want you to two know that if you follow this let's say that we have stimulus coming from in this case the left ear and then we have stimulus via the vestibular cochlear nerve coming from the right ear if we follow the stimulus going from the left ear where is it going well it's already crossed at the medulla gone upwards synapse on the right thalamus and then from the right thalamus it's going to go to the right primary auditory cortex now here's something to remember along the way there is some crosstalk between these two pathways but for the most part the sound waves the sound stimulus via the frequency pitch and localizing localization of sound mostly goes to the contralateral primary auditory cortex so that's what i want you guys to remember so how sound waves are actually causing this primary auditory cortex to basically focus on the frequency focus on the pitch and the localizing is via this vestibulocochlear nerve and the big thing i really want you to remember because it's important clinically is that this information usually crosses and then after it crosses at the cochlear nuclei it goes to the contralateral primary auditory cortex in the temporal lobe why is that important well let's say that for some reason you develop damage to anything above your cochlear nuclear here's your cochlear nuclei you develop damage anything above that area okay so let's just say for right now we'll focus here on damage of this actual either this auditory pathway or the right primary auditory cortex that you're going to damage if you follow this back if you damage the right primary auditory cortex where is most of those sensations coming from which side of the ear the left ear so because of that a lesion of the of the primary auditory cortex in this case we're using the example a lesion of the right primary auditory cortex might cause us to develop difficulty being able to determine the location and somewhat degree of pitch and frequency of sound coming from the contralateral side so right primary auditory cortex lesion can result in contra lateral loss of sound stimulus particularly what the ability to localize the sound pitch of the sound frequency of the sound that is why this is important okay so that covers our primary auditory cortex let's move on to auditory association cortex all right auditory association cortex let's have a little bit of fun okay this is this area is actually very interesting so the audits primary auditory cortex is relatively simple right we we already kind of explained this process that if you have some type of sound right that sound is going to in some way shape or form stimulate the cochlea right which will activate the vestibulocochlear nerve and from the vestibulocochlear nerve right if we were to just kind of put here cranial nerve which one eight from this it goes up you know hits the cochlear nuclei crosses over and eventually goes to the contralateral what contralateral primary auditory cortex which we drew here in orange okay so that's where the sound stimulus is going and again what is this determining it's terming the pitch the location and the frequency of the sound now from that from this primary auditory cortex it then tells the next cortex that we're focusing on here the auditory association cortex hey here's the sound stimulus here's the pitch here's the frequency here's the location or the localization of the sound now what i want you to do is go ahead and analyze that try to come up with uh basically compare that with past memories of these sounds and then tell me what is the meaning of this sound stimulus what do i mean if i were to kind of explain this in a couple ways we're going to give you an example i think that's the best way of understanding it but if you have a sound stimulus right based upon what things we talked about the the frequency of the sound the pitch of the sound and the location of the sound whenever this hits the primary auditory cortex and then tells the association cortex it might take based upon the frequency pitch location comparing it with past memories it might take that sound as a couple different things it could be a screen it could be the sound of music it could be the sound of thunder so there's a lot of things that can be interpreted based upon the frequency pitch and location of sound what's the best example of this a wife and a husband you have a wife right you've got you're coming and you're saying hey bae how are you doing today and she can say i'm fine right but you know whenever somebody says i'm fine they can say it a couple different ways right what are the different ways that they could say well they could say maybe like this i'm fine which she's like oh okay she's actually she's okay or it's like i'm fine and you're like oh is she actually fine or is she not fine and then it's like i'm fine and you're like oh she pissed right so you can determine in some way shape or form what that sound all those sounds stimulus all that thing that's coming out of her mouth which again is based upon the frequency the pitch the location all of that goes to the primary auditory cortex then to the auditory association cortex we utilize that analyze the sound help us to compare with past memories and then come up with an interpretation of that sound so again how does that work you take this thing i'm fine sound right and again based upon what things based upon the pitch based upon the frequency based upon even the amplitude based upon the location all of these things can be analyzed right so you're going to analyze all of this and the next thing that you're going to also do is you're going to compare this with past memories right so you're going to dig into past memories of these sounds previously so you're going to actually compare with past memories and what you're going to do is is after you analyze this compare with past memories then you're going to use this to come up with recognizing the purpose or meaning of that sound stimulus and again that could be interpreted in three ways right i'm fine could be i'm actually fine based upon the pitch the frequency amplitude of the way she says it or it could be she's not fine all right so that pretty much tells us how the auditory association cortex works and how it gives us the purpose meaning understanding of sound stimulus now let's move on to wernicke's area all right so wernicke's area warnicke's area is actually a really interesting area really cool area so where is it again we kind of said that we already talked about here was our primary auditory cortex and then if you guys remember what was just kind of inferior to that was our auditory association cortex now we have a couple other cortexes that we're going to point out here this one right here in purple is actually going to be the the visual cortex areas right so we're just going to assume that this is the visual primary and association cortexes now right here which we kind of drew in green like right here this was our what wernicke's area right now wernicke's area is important because it said it's involved in what it's involved with the comprehension and understanding of written and spoken language so how does that actually work how does it do that well wernicke's area receives stimulus from two areas remember we said here was our visual area right so this is where we have visual stimuli and then over here is going to be our both of these is our auditory area what happens is any kind of auditory stimulus will go to this area right and any type of visual stimulus will go to this area after these areas are stimulated from the visual auditory stimulus they analyze it they recognize it then what they do is is they send that information to wernicke's area and then wernicke's area is going to have both a understanding of visual input and understanding of auditory input and then it's going to process all that information and try to provide a complete understanding of comprehension of both the combination of visual and auditory stimulus now what it does then is it communicates to another structure located here in the frontal lobe it sends signals to this structure here in the frontal lobe via a structure called the arcuate fasciculus and this structure here located in the frontal lobe is called broca's area so this is called broca's area and what broca's area is involved in is it's involved in speech production so it's involved in speech production so let me kind of give you an example as the best way to kind of understand how wernicke's area receives visual auditory cues comes up with a comprehension of that and develops an information uh from that to send to the broca's area to develop a a vocal response i think this is a good example again you get another wife and you got a husband isn't this always the truth wife's talking and you don't hear anything she said okay but let's pretend at this point in time you were listening to her so she asked you were you listening to me now from this that were you listening what's that going to do that's going to be the auditory aspect so that auditory aspect is going to be hitting the ear those sound waves the way that she says it right so again depending upon the pitch the frequency the amplitude the location the pit the tone of it all of that will be taken to your ear and then from the inner ear taken to your auditory cortex where you'll interpret that what she's trying to get across this whole meaning understanding of her spoken language then you also have to visualize her facial expressions okay so her facial expressions of how she might be saying were you listening to me is going to have to hit that eyeball and then from the eye it's going to have to send that information to your visual cortex the visual cortex is going to have to take all of the social cues all her facial expressions compare it with past memories and then from there come up with a complete analysis and understanding of her facial expressions then from that the visual area and the auditory area are going to send that information to the wernicke's area so now how does the wernicke's area function in this sense well let's say she asked you were you listening and you look at her facial cues and she looks she looked mad all right because it didn't look like you were listening but some of the auditory stimulus was getting there to your ears maybe you just had some selective attention you have to read her social cues but also realize that all you heard was just and you have to do what comprehend that oh shoot i don't remember anything that she said to me i'm in big trouble what do i say well after you've comprehended that you're going to send that information via the arcuate fasciculus to the broca's area and then you're going to develop a response for that right so were you listening yeah i was i was listening to you i heard everything you said that is how the wernicke's area is involved in this process okay so again all right so let's kind of write this out and again kind of give you the whole package putting all of this together so when the wife says to the husband were you listening again how does wernicke's area work it basically takes that sound stimulus right so here's your sound stimulus and the way she says it right so again based upon the pitch based upon the tone based upon the frequency based upon the amplitude based upon the location all of these things are going to have to get sent to your what auditory cortex okay and then from there the auditory cortex will then send that what so the association cortex to basically come up with an understanding comprehension and basically meaning behind what she's saying then at the same time you're going to have the visual cues so you're also going to have to be looking at her facial expressions right so then that's going to be the visual stimulus and that visual stimulus will have to get sent and you're going to have to look at again all of her facial cues right facial expressions okay all of these things are going to have to send to the visual cortex and then from your visual cortex you're going to have to develop a complete kind of understanding meaning behind her facial expressions and facial cues and then both of these areas are going to synapse on wernicke's area and now wernicke's area is going to help us to comprehend both the kind of the language aspect whether it be non-verbal via facial cues and verbal via the sound stimulus and come up with a response by sending it to who broca's area and then broca's area will help us too do what come up with speech production via the arcuate fasciculus so that's kind of how this is all working why is all why am i spending so much time explaining explaining all this there's a condition called wernicke's aphasia where you have damage of this wernicke's area why is that important and how can they present let's talk about that all right so wernicke's aphasia right here's the big thing i want you guys to remember wernicke's aphasia there's damage of the wernicke's area usually as a result of a stroke right usually kind of like a middle cerebral artery stroke but regardless in wernicke's aphasia what happens with them well the problem with wernicke's area is that it's where basically comprehension is occurring and remember if you think about warnicky's area here if it is damaged right is broca's areas is that affected in any way shape or form no broca's area isn't really affected and broca's areas where speech production is occurring so the patient will be able to speak and they'll be able to speak rather fluently because you're not damaging the the muscles of speech production so they'll have fluent speech but here's the problem because they can't comprehend anything that they're visually or auditorily being stimulated from the speech that they have is completely nonsensical it makes no sense whatsoever it's kind of like just a word salad okay so not only is their speech fluent and nonsensical which you know again they don't make any sense when they're saying things but their comprehension is no longer intact so comprehension is not intact so let's say that a patient recovers from wernicke's aphasia they'll actually tell you that yeah when you were saying things to me and you were talking to me i couldn't understand anything that you were trying to tell me so that's kind of what it means that their comprehension is not intact now another term for wernicke's aphasia is because they're having a problem with processing information this is called receptive aphasia this is called receptive aphasia so that's why i wanted us to make sure that we understand wernicke's area and then respectively wernicke's aphasia all right the next area that we have to talk about is that primary olfactory cortex and then the association cortex again you couldn't see it from the lateral view but you can see it here from this medial view now when you look here you have again frontal lobe here and then again here's going to be parietal lobe and then back here is occipital lobe and then right here is temporal lobe right so i said tucked into the temporal lobe you have this primary olfactory cortex where would it be we'll be right here towards the medial aspect of the temporal lobe called the unkis so right here is going to be the primary olfactory cortex and then just kind of right kind of underneath it here is going to be the association cortex for the olfactory system now this is actually a very interesting structure now we talked about how the primary olfactory cortex is involved with conscious awareness of smells now if we take for example how this actually does this we're going to have a big old pile of dookie here that pile of dookie is obviously going to give off some particular odorants and what happens is those odorants do what well they activate particular olfactory receptors and then once they activate those olfactory receptors that stimulates what olfactory nerves which are present within your nasal cavity those olfactory nerves move where they move up through the cribiform plate and the ethmoid bone and then to a structure here sitting on the bottom of the frontal lobe here called the what is this structure here called your olfactory bulb so what happens is from this smell okay the doodoo particles this is actually going to do what it's going to eventually activate right the olfactory receptors come up for the olfactory nerves and then eventually synapse and stimulate this olfactory bulb once you activate the neurons present within the olfactory bulb this is going to move down through the olfactory tract right and then the olfactory track will then move into what's called striae we're not going to go into crazy detail here but again you have olfactory bulb olfactory tracked and then you have these things called striae this is actually called your medial olfactory striae and this is your lateral olfactory dry again i don't want us to really focus on this i want us to really get this whole point here is that from you have this the smell stimulus activates the olfactory bulb then travels down the olfactory tract and then from here it can go via these little radiations into two areas in the brain okay one of these areas is going to be something that we're not really going to focus on here a little bit of smell stimulus can go to an area in your frontal lobe we're just going to mention here so that you guys know it it's going to be here in the frontal lobe this area here is called the orbital frontal cortex okay and we're going to leave it at that i want us to primarily focus on the primary olfactory cortex so smell stimulus will come via the olfactory bubble factory track lateral factory striae to a particular area in the temporal lobe called the primary olfactory cortex so what is this area here primary olfactory cortex now what does the primary olfactory cortex do what basically helps us to develop a conscious awareness of that smell so it gives us basically awareness of the smell then what we're going to do is based upon the awareness of the different types of smells so if we follow the stimulus you hit that olfactory bulb go down the olfactory tract follow that medial olfactory striae through the primary olfactory cortex and then now we're going to go into that olfactory association cortex so if we follow that smell signal right so we're made aware of the smell then what we're going to do is is we're going to take that sense that awareness of smell and send it to the olfactory association cortex so this is going to be the association cortex now here's what's cool about this association cortex it can take the smell and do something with it one of the things it can do with the smell is it can actually store that smell sense into memory right into memory so that if we're ever exposed to that again we know what that smell is you know dookie in this case the other thing it can do is it can take that smell and analyze it right take all the different types of odorants all the different odorant materials that are coming from it after it analyzes it and compares it with a past memory of that smell it helps us to recognize what that smell is right so we can obviously tell the difference between certain types of smells then once we've recognized this smell it helps us to again do what identify what that smell is that's important because if you can't identify some type of smell sense there may be some degree of what's called a nausea which is lack of smell so that's an important thing here's the other really interesting aspect of the association cortex the other thing it can do is is the oh the olfactory association cortex can send that smell stimulus all that smell information to your limbic system there's a couple different structures involved in your limbic system but one that really gets a lot of this stimulus is your amygdala right and your amygdala is involved with the emotional aspect right of things so anger aggression anxiety different things like that and so what this smell will do is if it goes through the limbic system you're going to tie emotions now to the smell stimulus so if i'm walking outside i got two french bulldogs i'm walking outside and i step in a poop right and then i go inside and i track it all over my house and i smell something i'm like what the what the is that and i i look down at my shoe and i see a big old pile of dookie on there i'm obviously gonna know the smell based upon the familiarity of it with my dogs and then i'm also going to remember oh i tracked it all through my house i'm going to be mad so because of that smell can have this involvement right of where it can be linked with emotions and we help this association cortex can actually it's so cool because it can store our smell memory and then help us to analyze it and recognize what that smell is so that's how our primary olfactory and olfactory association cortex work all right so the insula the insula is very interesting and again we actually consider this this is important to remember it's not actually a part of the temporal lobe it's actually kind of its own little area of the cerebral cortex so technically we consider four lobes of the cerebral cortex right classically frontal parietal occipital temporal well a lot of the times we consider insula the fifth mini lobe of the cerebral cortex now where is the insula so this area right here is going to be your parietal lobe right we'll just say that we're taking a section through the parietal lobe and then over here it's the same thing parietal lobe this right area right here is going to be your temporal lobe right so deep within the temporal lobe you have this kind of separate area from it which is called your insula now your insulin is really cool because we said it's involved in receiving it has three primary functions one of it is it receives visceral sensations so visceral sensations so maybe pain temperature sensations maybe just some type of sensation from what areas visceral sensations from the heart visceral sensations from the lungs and visceral sensations from your maybe your gastrointestinal tract if any of these signals are coming up here right let's just combine all of these sensations from the lungs and then sensations from the heart here this is all visceral sensations where can they go they can go to your insula why is this important why is having visceral sensations going to this area important if any of you guys have ever had gastroenteritis right so maybe some type of food poisoning you had some definite irritation of your git or your viscera that pain information coming from your gi2 to the git from the due to the gastroenteritis will send that information to your insula and then your insulin takes that visceral sensation and helps you to remember it for the next time you decide to go and eat maybe somebody's potato salad that's been baking out in the sun all day you're like oh never mind i'm not going to eat that i remember what happened the last time i did that so again the visceral sensations going to the insula is important for helping us to realize those sensations and maybe helping us to prevent us from making those same decisions that caused that in the first place the other function of the insula is we said that it might have some type of involvement with vestibular sensations right so from your inner ear right you have your vestibule and your semicircular canals and that is involved with your equilibrium right your equilibrium sensations what type of equilibrium well your static equilibrium and your dynamic equilibrium obviously dynamic via this semicircular canals static via the vestibule but either way information from this area from your inner ear will then go where to your insula it'll also go to your insula now obviously these vestibular sensations can go to a bunch of different areas right they can go to vestibular nuclei located within your medulla and then from here they can go where they can go to your cerebellum they can go down to your actual vestibular spinal tract but one of the things that can happen is is that it can go to this insula and help you to have again a sense of awareness of your equilibrium to some degree all right the last thing that the insula is actually responsible for is taste sensations so what do i mean so obviously when you think about taste there's different types of taste right and this is how the insula helps in this process it helps us to maybe differentiate the types of taste so what are the different types of taste well you guys know that there is sweet sour salty bitter and then the newer one is ooh umami right due to protein-rich foods and glutamate but either way all of these different types of um tastes are dependent upon what foods we eat right but all of these different types of taste stimuli will activate particular types of taste buds you know your gustatory receptors present on your tongue and then from your tongue you have nerves right obviously of the different cranial nerves that'll take that information up to an area in your brain stem called the nucleus attractive solitarius so all this information will be carried up via cranial nerves from these different areas of the tongue it'll be carried up and then eventually we'll go to an area here if you guys really want to write it down it's called the nucleus of tractor solitarius but what will happen here this taste stimulus will then go to the insula so that we can be consciously aware of the different types of taste that we're actually having within our food oh is this a sweet food a salty food a sour a bitter or an umami taste so that's how the insula functions in visceral sensation awareness equilibrium and the taste all right engineers so in this video we talk about the temporal lobe and the insula of the cerebral cortex i hope all of it made sense i hope you guys enjoyed it if you guys did hit that like button comment down in the comment section and please subscribe also down in the description box we'll have links to our facebook instagram go follow us as well as we have links to our patreon you guys want to go donate there we would truly appreciate all right ninjas thank you love you and as always till next time [Music] [Music] so [Music] you