Anatomy of Cerebellum - Structure & Function - Neuroanatomy - Neuroscience

about cerebellum it's some of its structure functions and clinical correlates so what is the basic function of cerebellum if someone asked you in three words tell the function of cerebellum yes if you forget everything about cerebellum you should know at least three word only three not more than that yes okay very good coordination of movement what else the two more function if someone asked you just tell three words about cerebellum the most important three words right not three-hour lecture what you will answer yes anyone balance very good posture and balance excellent now one word is left basically three most important thing that it is related with the cerebellum is related with the tone tone of muscles it is concerned with posture and balance posture and balance maintenance right and coordination of movements co-ordination of movements coordination of movements this is the minimum you should know about cerebellum it does more functions also but minimum you are supposed to know it is responsible to maintain the tone of the muscles it means the lines of cerebellum can produce hypotonia right it is responsible to maintain the posture and balance right it means some limbs of cerebellum can produce problem in the posture maintenance and even you cannot maintain your balance and of course some lines of cerebellum can produce in coordination or uncoordination uncoordinated movements right this is the minimum what you are supposed to know about cerebellum right now let's start with first of all very basic concept of cerebellum that exactly where cerebellum is if i'm going to make brain stem here mid midbrain pons medulla spinal cord you must be knowing that cerebellum is present posteriorly on the back of the brain stem right it is present on the back of the brain stem now as you know the different part of central nervous system develop from different logically differently is that right basically when there is a biological development initially there are three vesicles from yes prosoncephalon yes speak mesencephalon very good roman cephalon right cerebellum basically develops from roman cephalon it's part of the hind brain is that right in the roman cephalon it has again two component right mutant cephalon and myelin cephalon actually cerebellum developed the mutant cephalon component of the rhombone cephalon let me tell you first there are three vesicles right then this will develop into two prosencephalon goes into two secondary vesicles and methancephalon remain as single and this is what is this roman cephalon right roman cephalon divides into yes mutant cephalon and myelin cephalon now basically cerebellum develops this is bombs right bonds also develop from mutant cephalon cerebellum also develops posteriorly from the mutant cephalar is that right again from this frozen cephalon what is this component and this is diam cephalon very good this is telencephalon this is dansephalon this is mesencephalon here it is rhomboncephalon right from the roman cephalon the mutant cephalon component eventually develops into develops cerebellum right now when we talk about cerebellum cerebellum basically has three component right this is again structural age you must know that it has three components right there is this component which you can call it interior loop then there is yes posterior lobe and here is floculus area right in cerebellum there is anterior lobe then there is posterior lobe and then there is yes what is this flocculus right floccular modular area now why i have put into three areas initially because all three areas are functionally different and developmentally different and their connections are different right that is why you first know rather than knowing ten thousand thing about cerebellum primarily cerebellum has interior lobe posterior lobe and flocalo nodular area now out of this the most primitively developed area is which one yes what is the most primitive area out of that the area of the cerebellum which is even present in the fish yes very good this is the most primitive right this part of the cerebellum is most primitive right it is present in the fish now it means if it is primitive it must be doing some very primitive function like balance is that right it must be doing a very primitive function like balance so floccular nodular loop it is concerned with the yes balance is that right now because it is the most primitive we also call it primitive cerebellum or we call it archicelebello right this slope can also be called arche cerebellum is that right this is the most primitive part of cerebellum and it is also called rk cerebellum is that right this is concerned mainly with the balance right especially balance of the head and the eyes when eyes move in a very conjugate and balanced way right now after that this is the most primitive after that which area developed which is present in reptiles and birds but not in yes this is the most primitive this is archie cerebellum after that there's development of paleocerebellum and most modern should be neo cerebellum is that right which should be the paleocerebellum pardon no posterior not posterior is not failure of course now there's only one choice left what is this this cerebellum right that is what is this paleo cerebellum this is the right interior lobe and then this posterior is the most modern and we call it yes neo cerebellum now here again as i told you one function of rg cerebellum what is that balance just one function of paleo or anterior lobe just one not many tone there are many other function but the minimum you should know this is concerned with the tone in the muscles right now how many things were there tone balance balance is mainly function of floccular nodular lobe are arche cerebellum tone is mainly function of paleo cerebellum is that right and what is left now coordination of movement that is the most dominant function of neo cerebellum right so neo cerebellum has the most dominant function of which one coordination of movement is that clear now these fissures which divide make a division there are many other fissures but these are prominent this fissure is called primary fissure is that right which divides the between the interior and posterior and what is this fissure here posterolateral or dorsal lateral fissure right so this primary fissure we divide the cerebellum between interior and posterior lobes and then there is what is this dorsal lateral posterior lateral fissure we divide separates the posterior lobe from floccular is that right now there is another way here we are looking from the side let's look to the cerebellum from the back right so posterior aspect of cerebellum i'm going to draw here is that right now if we draw the posterior respect of cerebellum now we are looking from the back and what i have done this area right it has to be rolled out so that we can see all of it is that right so this is basically floccular nodular which have rolled outward so that you can see it now here when we look of course first of all there's primary fissure here so naturally when there's primary fissure here this should be which one which lobe anterior and then all this and this area is posterior and here it is floccular nodular now another way to talk about cerebellum is that from the back you divide the functional area of cerebellum vertically for example area of cerebellum which are in the very middle area there is a longitudinal depression here right because surrounding areas are more prominent right so this longitudinal depression area in which all the part of cerebellum which is present here or cerebral cortex which is present here this barrel cortex is called vermis this is called yes vermice right and lateral to the vermis all this area what is it called yes please cerebral hemispheres surrey barrel cerebral hemispheres hemi sphere so of course there is one right and other left siri balor hemisphere one thing which is very important to remember cerebellum controls the balance and posture and coordination of the movement ipsilaterally write it down why because when there are leones in the cerebellum right the neurological deficit develop if c laterally for example if i have leon in the right cerebellum hypotonia will be on the right side of the body it is opposite to cerebral hemisphere where usually if there's damage to the left cerebral hemisphere right side of the body will have neurological deficits is that right so seri brum cerebrum control the movement motor system contra laterally but cerebellum control the motor system ipc laterally am i clear right so of course if one side is damaged on the same side there will be problems with the tone problem with the coordination of the movement and problem with the balance is that right anyway the central area which is a narrow depressed area right this is called vermis and lateral to the vermice all this area is called cerebellar hemisphere now something is very important here just on the sides of what is this vermis right this yellow area which is just flanking on the side of the vermice right this area is the part of cerebral hemisphere but because this area has some special functions so it has been given special name and that name is yes paravermal area para vermal area but remember paravermal areas on the side of the vermours but it is itself the part of the cerebral hemisphere right the other name for the same area is intermediate zone intermediate zone so this is that right now already you know that this area is your most primitive and concerned mainly with the balance right here body is represented topographically as a human class you know in the cerebral hemisphere there is also motor homunculus and sensory human class in the same way right in vermont's and paravermal area right the sensations sensory information which is coming from the body to the cerebellum that is connected to vermouth and paravermal area in a very orderly fashion is that right and if you really look at that arrangement right so i will make it here that arrangement will be basically yes right and here is your trunk your head and neck and there are something called legs you have of course no doubt and you have also arms now what i'm trying to show in this diagram actually this diagram is representative don't think that someone has painted this diagram there no and the cerebellum these are for example from head and neck sensations are coming over here sensory information not sensation sensory information from the limbs it is coming in paravermal area but from the trunk which is coming into verbal area so what really happens that cerebellum is collecting the sensory information from all over the body right especially about the local motor system cerebellum is all the time updated that what are the information coming from the muscles or joints or tendons or ligaments right and all that information when it is going to the cerebellum right number one it is presented in verbal and paravermal area now this diagram should remind you one thing what is that that control of the trunk and axial musculature that is in thermal area right now these this is which musculature representative of this this represents the shoulder shoulder area right it represents the trunk and it represents the hip area right so it means that from here you can infer if there is damage to this area problem will be with which motor system axial musculature axial musculature mean neck then shoulder trunk musculature and hips is that right so this is verbal so if someone asks you when i talk what is the special function of thermal area you can say verbal area is basically controlling the yeah motor motor system related with the axial musculature or with the shoulder girdle hip girdle and trunk muscles but you can see that these hands and feet they are extended into which area yes please paravermal area so it means that movement of the hands and feet especially fine movement and their coordination and right that motor control of the hands and feet is in the paraverbal area why it is so important to understand because there are sometimes the midline lines if there's midline lines you will have axial atexia right a problem with the motor control of axial musculature but if there is little laterally then it may affect the motor control related with the hands or feet is that right so vermis is concerned with which musculature axial and paravermal is concerned with hands and feet it's not difficult to remember of course this is in the center and they are on the sides hands and feet is that right now another thing there are other human class present over here also but it is different way this is hand this is fate that in this slope area right what is happening that another human class is present but of course there are two parts but the special thing which is present still verbal areas controlling the neck trunk and hip region and still para paravermal is controlling the what is this distal part of the limbs is that right so there's more than one hormone plus present over there and thermal areas are concerned with truncal and paraverma are concerned with what what are these things distal part of the limbs now we come to the lateral most area which are called lateral part of the cerebral hemispheres now onward i will call them just cerebral hemisphere the good news is that there is no human class present in this area so you don't need to remember it is that right any question up to this there is no question now another thing actually cerebellum as i told you that it can be divided into interior lobe posterior lobe and floccular nodular and this is in from posteriorly when you look and divide but if you decide longitudinally divide functional areas there's thermal area for the axial there's paraformal area and there is cerebral hemisphere this is concerned with the yes coordination of the movement outermost but it does not have any common class now another concept sometimes we use the term spinocerebellum and cerebro cerebellum have you heard of these terms there is rather i should use three words vestibular cerebellum spinosary balance and cerebro cerebellum which is also called ponto cerebellum right before i put that concept i will give you a general idea i am going to give you a very general idea how the motor system work and where in motor system cerebellum plays a role again now i'm leaving the cerebellum i'm going to tell you generally how the motor system work and what is the role of cerebellum fitting into that picture i will draw one entrop the two sections of central nervous system midbrain pons medulla spinal cord and one view i will draw from the side yes now we start with the motor system where it is connected and how it works and what is the role of cerebellum why it is so important to understand listen all of you know that there is primary motor cortex there is pre-motor cortex there is supplementary motor cortex right and you know that if those areas are damaged let's suppose all of you know when primary motor area is damaged paralysis to the opposite side of the body occurs am i clear but we can initially neurologists were very confused that what is the real real role of cerebellum in the movement right now let me tell you how a movement plan start let us suppose okay tell me some movement you plan to do then we'll see how your brain is doing it pick up a book oh my god you are all the time thinking of studies okay so let's talk of something less academic let's suppose that you are sitting in a party there are some guests in your house and you have offered the tea and you are standing by the table and you want to take a cup of tea right now we will see that basically idea of having a cup of tea and eventually your muscles and joints and our locomotor system moves and then you bring the cup of tea here right and eventually put the cup back now all this thing which apparently looks very simple how the motor system plays and all this thing first of all the idea of movement will come if you are planning that you should take a cup of tea somewhere in your mind this idea should come this idea originally generated which part of the central nervous system originally most of the thoughts are generated in multiple areas of the brain but especially for this we can assume prefrontal prefrontal lobe right so this is social situation and prefrontal lobe here is the idea and you thought that you are going to have a cup of tea that's it now once you thought it do you think you immediately jump to the cup of tea or you will make certain evaluations there are many things you have to consider is that right so just having the idea does not start the motor system right if you decide that you are going to have a cup of tea what will happen this is i'm putting it here primary motor area is that right this is somatosensory area here it is motor supplementary area this is pre-motor area approximately right now what really happens idea will go to the yes pre-motor area is that right idea will go to the pre-motor area now pre-motor area right it has to consult with basal ganglia is that right so i'm going to make a simple diagram about basal ganglia here right let's suppose this is representative of basal ganglia now one thing is that idea will come right to the pre-motor area then and supplementary motor area and from here right information will go to the connections will go to the basal ganglia i will not go into detail of basal ganglia you know it already the accordate and the sputum and the there's global splinters and two special nucleus like substantia and subthalamic nucleus right anyway information will come over here from here you will bring the motor program out what you will bring motor program out now after refinements this motor program should go back right of course through the thalamus you know that it will go back to what is this area pre-motor area what is this supplementary motor area primary motor area and even somatosensory area is that right and then you know that from these areas what will happen what is coming down suppose corticospinal fibers is that right and then corticospinal fibers are going to fire and muscles contract this is a very simple diagram it's not a complete diagram because we have not shown the role of cerebellum in it right we just said idea started from frontal cortex motor areas consulted with basal ganglia and then went back but actually it is not so simple now listen very carefully with your both ears look if we have decided that we want to take a cup of tea it means if cup of tea is here let's suppose here on the table if cup of tea is here we know mentally what should be the final position of my hand to pick the cup of tea is that right but actually the real movement which we have to start it depends on the initial position of the body also for example if your right hand was by your side then movement have to be like this but if right hand was on shoulder of someone the movement have to be different or if you are scratching your head and then you want to take cup of tea movement has to be different now it means when you thought that you are going to take cup of tea idea generated that what is the intended final position of locomotor system is that right but to bring the locomotive system exactly at the final position to the cup first of all central nervous system should know where what is the initial position of my right hand is it by the side or it is on someone's shoulder or is it scratching head is that right the question is that how our central nervous system knows that what is the initial position in the body because from initial position you have to move and bring the final position is that right so how our central nervous system knows this information for example with your closed eyes you know in the with my closed eyes i know that where is my this finger and if i want to bring the other finger there exactly with closed eyes i can almost do that it means that my central nervous system was knowing where was the index finger of right hand and it could bring the other hand index finger almost there is that right now again i will repeat this other example let's suppose can you come here please you can stand here close your eyes i'm going to touch your hand i'm putting your one finger here now you are not going to see it but the wonderfully her mind knows where in the air this finger is right now i ask you touch with the other finger this yes i will right it means her body knew where was the original finger her body knew where was the initial position of other finger and when i said that bring the finger of left hand and touch the finger of the right hand central nervous system first had the idea she heard me then she calculated what is the position of the left finger and what is the position of the right hand other hands finger and then she compared central nervous system what is the difference in their position and according to that it calculated what motor plan should be generated you are understanding now rapidly uh okay okay now rapidly very rapidly bring the other finger and touch this finger rapidly okay now what you see what did when she rapidly brought first she brought it to wrong position then central our system calculated what was the final position and what was the position intended within center of a system some correction came and she corrected it right leave it it's okay you can open your eyes it's okay now one more test just keep it so here what we learned that our central nervous system has the information all the time which part of the body in the air or in the space how it is oriented is that right now another thing i'm going to tell tell her close your eyes and touch with your uh this finger touch your own nose okay it means her central nervous system was knowing what is the position of the nose and where is the finger and it could bring over there now keep your eyes closed and touch my nose you understand it what the what okay have a seat when i put the last question that was a classical example that central nervous system does not know what is the initial position of muscles and joints and ligaments and tendon how the central nervous system can generate a movement when i said touch my nose if she does not know her central nervous system does not know my nose where it is can she bring the movement so this is a very important concept that this is a very raw picture just idea and go over there discuss with this no because for designing the movement first of all center of the system should know where is the different parts of the body this information is all the time present in cerebellum cerebellum is a master information collector it collects the information right from the muscles and joints and ligaments and tendons and this information all the time is going to the cerebellum and you can say cerebellum has at every moment the motor picture of the body and beauty of this is this is unconscious thank god otherwise we'll have to put a lot of thought process there we don't know but cerebellum knows right that all the time it is collecting the information about our locomotor system is that right if cerebellum has all the information coming from the locomotor system is that right so it means cerebellum knows what is the initial position cerebellum knows what is the initial position as i told you that let's suppose that if i have to touch my nose then cerebellum should know right now where is my index finger of right hand and cerebellum should have an idea what is the balance in my head and then say cerebellum should guide the motor movement in such a way that i should reach that final position is that right so because cerebellum is all the time updated about the sense of position and degree of contraction in the muscles and degree of bend and angulation in the joints and rate of movement of the muscles so cerebellum has to guide the system is that right that is why basic movements occur in such a way that whenever movements are planned not only it should be discussed with basal ganglia it should be consulted with cerebellum right so what really happens a very simple thing that whenever central nervous system decides for a movement right we can call it this is intention of movement the intended movement so what happens that intended movement right whatever idea and thoughts are generated whatever movement you want to this intended movement information should come to the cerebellum so cerebellum is the master place where all body's initial position is also there but what is going on in the locomotor system cerebellum knows and what our higher nervous system want locomotor system to do cerebellum also knows that is that right now we are putting cerebellum into perspective what cerebellum is going to do number one cerebellum should know at every moment what is the information coming from locomotor system number two whenever you are going to do a movement cerebellum should be consulted during that movement or even before that movement right so it means whatever intended movement plan is there this information go to the cerebellum is that right now listen let's suppose my hand was here is that right cup of tea is here is that right at this place thought generated that i have to bring this cup of tea here central nervous system consulted with the basal ganglia plus it consulted with the cerebellum so basically higher cerebral cortex motor pre-motor supplementary motors metal sensory area all of them should send one copy of the motor plan for the intended movement and cerebellum will have what is the origin initial movement now what happens cerebellum will study both of these and find the difference in them right then it should give the information back it should give the information let's suppose back to central our system right that okay initial position of the arm is here final should be that to bring this arm up to that position this plan should be finally released so now after that plan will start going down are you understanding so what really happens before the movement start whenever you think of a movement before the actual movement starts basal ganglia fire and cerebellum fires is that right before the movement start movement cannot start properly and in a coordinated fashion without consolidation with cerebellum if the cerebellum is damaged you cannot really do proper movements now up to now what i said that whenever we planned the movement intended movement program or copy was sent right to the cerebellum this is what higher centers want the movement siri balance says okay i have already current report how is the locomotor system so when cerebellum has both reports it will analyze and then it will send a copy back right that this should be the movement and it's not so simple once motor program come down right here from here when this motor program is coming from corticospinal pathway or rubric spinal pathway multiple path has come cerebellum has again another connection from here getting another information you know what is this cerebellum again knows that once all central processing has been done once all the central processing has been done and final motor order went through upper motor neuron cerebellum want to know right program went a wrong program event it's a double check system you are understanding anyone who is confused upto now you are not confused is that right how intelligent is cerebellum so what it is doing that once the motor program are initiated when upper motor neurons are ending on the lower motor neurons and doing final orders one copy of this finalized plan will again go to the cerebellum so that cerebellum knows okay that is the movement which was desired this is the original position and this information is coming that movement have been initiated is that right so it knows that movement is going proper movement plan which has come here it is proper or not then what happens let's suppose movement start when movement start i'm going to take up now what happens my hand is moving muscles start contracting of course muscle spindles will fire which are sensory system from the muscles which tell the central nervous system about the degree of contractions in muscles rate of contraction in the muscles force of contraction in the muscles so muscle spindles fire the firing through the muscle spindle will change as i am moving my arm gauging tender organs will also fire even some pressure receptors will also fire receptors in the ligaments and tendons and joint capsule will also fire so all of them are bringing information from the muscle from the joint ligament tendon from multiple and this information is rapidly coming to central of a system you know where it is going one of the copy of this information is going to cerebellum what cerebellum is going to do you know what it is doing it is getting information that actual movement is progressing in what way is it progressing properly or not so cerebellum is such a master that first of all it knows what is the intended movement it note what is the initial position in the body right then it sends a plan and once after higher processing plan come down it again receives a copy of that plan and when movements start when movement is progressing during that time cerebellum is constantly updated that movement which is started is it going properly or not now cerebellum is such a wonderful neurological system that not only it knows what movement is going on can you believe that it can predict it can calculate from the muscle spindle information gauging tendon organ information from the information from the other sensory system whatever data is coming you know not only knows what is the actual movement going on it can predict that if movement kept on going in this way what will be the what will happen in the future again let me tell you cerebellum thinks in advance once the movement has started right it is updated what movement is going on is that right but actually it can itself anticipate that if muscles with this force and joint with this angulation keep on progressing in this way what will be the final position and if they calculate final position will be wrong they will again correct the system you are understanding me now again let me give you an example can you come here please uh same tester will do you can face them close your eyes please i'm going to touch your finger your finger is here right now you bring other finger and touch here but very rapidly you see what happened first she did a mistake and then cerebellum corrected it again do it bring both sides fingers together and touch them no no put both sides down with closed eyes just one minute not now what i'm going to tell when i will tell her that bring the fingers in front of your body and touch each other just when she heard it thought and idea generated there she has not started the movement but actually motor cortex pre-motor cortex supplementary motor cortex so then three areas all of them made a program that this is the intended movement they will send the copy to cerebellum and right now movement has not been started but her cerebellum knows what is the position of her fingers right now in the space right then cerebellum will compare and contrast both and send the final copy where to the higher centers right and higher central will bring the low upper motor neurons to lower motor neurons and she will start the movement right when she will start the movement when movement will be going on cerebellum is constantly updated what's going on and as soon as if she makes a mistake right when she's moving rapidly cerebellum start thinking okay she fingers are moving so rapidly they will overshoot it will start putting a break and automatically she will start reduce the movement and eventually she will correct it right close your eyes and very rapidly just when i say yes then what you have to do you have to bring both fingers in front of you and touch the tips of the finger yes now oh my god our cerebellum is wonderful again do it yeah this time cerebellum had to correct it so you understand it now please have a seat now this whole concept what time why i made it i spent a lot of time on this thing because most of the tests which are done in assessment of cerebral function they're based on it right that we ask the patient to do a motor movement and we see it is coordinated or in coordinated right for example if cerebellum is defective then what happens you can still do the movement very slowly and maybe when you are bringing the hand it will overshoot then then you consciously look and bring it back you want to then it will overshoot another side like it will multiple time overshoot and then it will eventually come to the central point if cerebellum is not working right it will keep on doing that for some time what is this without cerebellum you cannot perform the movement properly you cannot start the movement rapidly and bring at a specific point and you cannot stop it over there is that right so it it acts as a starter as well as terminator of the movement but only it can do this when it has the image of what should be the final position and what is going on is that right so now any question up to this basic concept if you are clear about this then i will start going into tracks and connections and functions this basic concept of the movements are clear what is the role of study balance up to the end i will give you another test can you come here please he will make me look very short i'm not happy oh my god okay excuse me you pull your hand towards your face very strongly pull your hand strongly my friend you're strong now look this is the beauty of cerebellum what happened now listen carefully forget about this lecture understand the real thing when i asked him that pull this arm or his hand towards his face what happened he started contracting these muscles and these muscles when he heard me his central nervous system made the initial image that hand should be moved in that direction then of course you know that cerebellum was consulted and survived said okay this is the initial position then he's tried to pull hand but i was resisting in opposite direction so cerebellum calculated that whatever movement has been generated it is not producing enough movement is that right so cerebellum ordered and just he started pulling his hand more strongly is that right now when he started pulling his hand more strongly i suddenly removed my hand so his hand moved very rapidly before it could hit his own face cerebellum suddenly calculated in future yes cerebellum calculated in future calculated the speed with which ligament muscles and joints information is coming hand is moving so fast that final position is going to hit the face and cerebellum knows where is the face so it immediately applies the break you did not apply the break yourself again you do it now don't be afraid cerebellum is working you see but if his cerebellum is not working he will slap himself you understand it is that clear how the cerebellum work so cerebellum calculates the things thank you i hope you get some idea about what is the real duty of the cerebellum right now we start with the connections and other things of course here cerebellum should be on the side first of all i will discuss into detail uh what do you think you want to do the connections of cerebellum first or you want to do the internal circuit of cerebellum first it's your choice just repeatedly tell me internal circuits first i think that has bothered you more okay let me draw the cerebellum here look if we talk about cerebellum right basic basic arrangement of cerebellum is here is the cerebral what is this thing cortex right it means this area is collection of the cell bodies is that right now here are deep cerebral nuclei these are deep serial nuclei will go into detail later right so basically and in between that this is the white matter is that right so basic semi barrel structure is that there's gray matter outside cerebral gray matter which is called cerebral cortex and inside is lot of white matter right which is axons of incoming and outgoing fibers and local fibers and within the white batter there are pieces of gray matter embedded which are called deep celly barrel nuclei when we talk about gray matter in the cerebellum so we can say the two type of gray matter in the cerebellum surface gray matter which is curry cerebral cortex and deep gray matter which are deep cerebral nuclei is that right now the fibers as i told you there are many fibers which are bringing the information to cerebellum many types of fibers which are bringing information to the cerebellum there are some fibers which are coming from the brain stem right some fibers coming from higher level some fibers coming from spinal cord right so the multiple sources of fibers which are coming to cerebellum right these all fibers once they enter into cerebellum right all these fibers which are entering into cerebellum all these fibers are given a special name what is that name except one group of fibers which are coming from olive right these are fibers which are coming from inferior olive now listen carefully all the fibers which enter into cerebellum external fiber right external mean coming through the different uh areas of central of a system there are fibers which are entering into cerebellum these fibers can be simply classified into two inferior or library fibers and all other fibers that simple because two of them are very different their liver cerebral fibers and all other fibers now there is a special name given to these fibers which are coming from olive inferior olive and there is a special name to given to all other fibers why because structurally and functionally they are very different what is the name given to these olivo cerebral fiber yes you have not attended any lecture on cerebellum or what have you attended any lecture so what is this fiber all these fibers which are coming from the inferior are left to cerebellum all of those fibers are called climbing fibers from the olive tree they are climbing all the way up to the outer layer of cortex what are these fibers climbing fiber have you heard of climbing fibers what are climbing fibers from the olive tree you know spartans spartan they were very good warriors right you can imagine from the olive tree spartans are going to yes climb up to the where up to the outer layer of what is this cerebellar cortex now in this sentence that from olive tree spartans are climbing up to the outer part of cerebral cortex the three things number one there are climbing fibers number two they are coming from from inferior olive and third thing spartans they are producing aspartate is that right so what are climbing fibers climbing fibers are the fiber coming to the cerebellum from inferior olive is that right and they are going to climb up to up to what up to outermost layer of cerebral cortex so these are climbing fiber thank god some doctor did not put their name on their on his own name that it is mr wilson fiber no they are just climbing fibers climbing from the olive tree like spartans up to the that and the spartate is released and they are stimulatory there's a single rule all fibers all fibers which enter into cerebellum are excitatory all fibers which enter into cerebrum are excitatory all fibers which enter into cerebellum are classified into two inferior library fibers and all other fibers inferior library fibers are climbing fibers and release aspartate and all other fibers all other fibers whatever their name right all other fibers they are called which fibers yes very good there are so many mouse coming here you look at it there's so many mouse so all these fibers other than the inferior alev they are not climbing they are mossy fibers musty fibers i don't know mossy or mozi my english is not so good but anyway you can say mouse like fibers right so there are lot of mouses entering there right these are mossy fibers it means listen carefully from spinal cord if i say that interior spinal cerebral fibers are going to the cerebellum or inferior spinosary barrel fibers are going to cerebellum or pontos cereberal fibers are going to cerebellum or reticular cell barrel fiber or vestibular cerebral fiber whatever the repair fiber or tectos cerebral fiber all of them are mossy so now you understand what are the climbing pipe first of all all the fibers which enter into cerebellum are either climbing or mossy which are climbing olive tree right and all other are mossy is that clear any question after this there's no question okay he wants a little break okay so we are going to talk about how the cerebellum work with its internal structure we should know it cerebellum should have input internal processing and then output that's so simple right so it means when we are studying cerebellum input system we already discussed input system are inferior library fiber coming and all other fiber come in so input system will basically have two types of fiber inferior library fibers are inferior library fibers are climbing fiber then all other fibers which are input system are mossy fiber right then we will see now what is the internal processing and then we'll see what is the output of cerebellum so let's see it let us suppose i remove this piece of cerebellum now if i remove this piece of cerebellum and draw internal structure here it means here i will draw what is this cerebral cortex then i will draw here a part of what is this deep nucleus is the right plus i will draw mosey fiber coming and climbing fiber coming is that right so let's draw it and see what really happens here when we talk about this is a cerebral cerebral cortex right so let's suppose this is cerebral cortex right this is outer part and this is inner part right it means that deep nucleus is supposed here this is the deep nucleus which was supposed to be here is that right am i clear now we have already discussed there are two types of fiber coming one one is what is this this was yes which fiber is this coming climbing fibers right they are coming from the library system inferior library system other fibers which are coming what are these mossy fiber you are very clear what is the origin of those fibers from where they are coming okay now once this fibers come on the way let us suppose this is one neuron this is one neuron of that deep celly barrel sorry bellar what nucleus right this neuron right why it is smiling because all these fibers before they go to the cortex they have to say hello to here all these fibers what are these climbing or mossy right before they go to the cerebral sorry barrel cortex right they have to say hello to the what is this neurons in deeper deep cerebral nuclei deep nuclear i will call them right after this they will go up now i told you all the fibers which are entering into cerebellum are excitatory all the fibers which enter into cerebellum are excitatory and these excitatory fibers it means they will stimulate this what is this deep nucleus and this fiber will also stimulate this nucleus because both of them are releasing excitatory neuro transmitter is that right now what is the neurotransmitter here yes aspartate and what is the neurotransmitter here glutamate right so there is part 8 and glutamate right mossy fibers are glutaminergic mouse like sticky glue glutaminergic and library fibers the spartans going up it's part 8 right they say hello here is that right and they are going to stimulate what deep nuclei but at the same time they will move to the cortex and when they are moving towards the cortex now it's a real game here what's going on yes my personal garden is there my personal garden is there in the cortex what does it mean that here it is molecular layer outermost then there is precondition layer and then there is granular layer there are three layers so cerebellum cortex is three cell thick layer three cell some cells are present in molecular layer some are present in per conjecture layer and some are in the granular so let's divide it into three areas right now actually the most important fibers neurons which are present over here a flask shaped neuron they are present in parking area right middle layer right and these neurons have their dendrite going in the what is this outer area the multiple dendrites over here okay rather than i'll make the dendrite in more simple way now this is for kanji cell its dendrites are going up and what is this coming down axon so axon of pertangia cell come down to where cell of the deep nuclei now this is basically inhibitory it releases what's in here gaba gamma minor butyric acid so it means deep nuclei are stimulated by climbing and what is this mossy but they are inhibited by the action of purkinje is that right now let's go back to these fibers olive color fiber or climbing fiber now climbing fibers as they are going they are climbing right on the way they said hello to what is this deep nuclei and then they go upward and they make connections with what is this dendrites of parkinson now tell me one thing that this fiber climbing fiber what was this releasing spot it and spot it will be again stimulatory here it is again stimulatory here now look at this system right attention please this is output from cerebellum the output fibers are coming from the deep nuclei right in the cerebellum input is climbing fibers and input is what is this yes mossy fibers an output from cerebellum is from which fibers from the axons of the neurons present in the deep nuclei is that right but here is the internal processing so what i said climbing fiber came stimulated the nuclei right nuclei deep nuclei get activated and give powerful on signals right meanwhile this climbing fibers climbed up to the outermost layer of cortex that is molecular layer and there they interacted with what is this dendrites off for cancer cell and the stimulated the percentage cell and parkinson's cell is stimulated the stimulated percentage cell is going to release gaba here and that will inhibit what is this that is going to inhibit deep nuclei so this is first thing to understand same fiber directly stimulating the deep nuclei right same fiber incoming information directly stimulating the deep nuclei but going to the cortex and indirectly through the what is this parking fiber inhibit the nuclei so it means here it makes it on and then indirectly through the cortex it makes it off on off mechanism is that right okay then we come to this muzzy fiber system it's a little more complicated when mosey fiber come over here right there's a cell here we call what layer the cell this area my personal garden granule layer because the granular cell here right so the granular cell here let's suppose this is granular cell here right and granular cell has many dendrites here right and this mossy fibers it is mossy fiber is not going to climb up to the outer layer of contact so of course this is not climbing fiber you understand that if climbing are going to climb all the way mostly fiber will end up at granular cells and at the granular cells what they will be doing yes they will have multiple dendrites and they will have multiple stimulation to the cells granular cells they will stimulate the granular cell i'm going to make the granular cell different color so these are the granular cell dendrites and they are stimulated by which granular cells are stimulated by the mussy fibers is that right any problem up to this then these granular cells their axon will go upward up to the outer layer and there they will bifurcate into two and then they will run parallel to the folia or the foldings right in the white matter of the cortex cortex is mainly gray but it does have some white matter mixed with it the white matter is coming from these fibers now listen again granular cells are stimulated by which fibers muscle fibers and then their axons go outward to the cortex and the single axons suddenly bifurcate into two and then it runs very long distance and on the way it connects with millions of percentage health not thousands millions of percentages right so what happens but consistent layer as many many per conjure cell right and these are their dendrites and these parallel cells sorry these parallel fibers which are the exons of granule they are getting multiple connections here now one thing which is very important to note now climbing cells are not promiscuous they are very faithful clinton cell climb only to the dendrites of one what one perkins yourself they come from one region inferior olive and there are millions of climbing cell but each climbing cell inner weight one percent yourself it's a one-on-one connection very faithful right am i clear but these moshi cell you know mouse not having much values so what happened they connect with multiple what is this granular cell so it means one mossy fiber will get connected with multiple what are these cells granular cells so it means signal will remain one and one or it will become diffuse muscle cell signal will become diffuse and then from here so what we really see that one mossy cell can stimulate many granular cells and granular cells make axon bifurcation as parallel fiber and one parallel fiber may be connected with many one parallel fiber may be connected with many for kanji and one per k may be connected with many parallel so it means this information is very promiscuous information very diffuse information is that right but claiming information is very very one-on-one base is that right am i clear right and i told you mossy was stimulatory fibers so they were living here what gluta mate is that right they were living glutamate and these are also glutaminergic fibers so they also release glutamate is that right now this type of simple circuit it's a very simple i will put little complication after few minutes and these are of course coming to the deep nuclear cells right and of course these are inhibitory fibers to the deep nuclear cells which are going to be what output fibers now listen the point which you have to understand again up to now what i have taught you and incoming fibers are the input to the cerebellum is what is this climbing and mossy climbing is from olive and inferior olive and mossy are all other input fibers right this is one thing and output fibers are all axons of what is this most of the output fibers are exons are cells of the deep nuclei is that right input output clear now internal arrangement climbing fibers come and mostly fiber come both of them stimulate what deep nuclei then they ascend outward climbing fibers climb all the way to the outer layer there they stimulate the targeted fiber dendrite on one on one basis clear but mostly fibers they terminate into which layer granular layer there they connect with multiple connections with multiple granular cells and every granular cell gives axons which rush towards the outer layer of contacts there if they bifurcated right angle to each other and then what they do they run parallel so these are called parallel fibers and one mossy fiber may stimulate many granules and cells and one parallel fiber from one granular cell may interact with many many per cancer cell so we can say that percentages cells are stimulated directly by the climbing cells and purkinje cells are stimulated indirectly and diffusely by the mossy granular system mossy granular parallel fiber system is that right any problem here there is no now another question which is there i have already told this is releasing glutamate here these are also releasing glutamate here now one thing which is clear that both incoming fibers mossy climb climbing and bossy both of them directly or indirectly will stimulate nj which will eventually inhibit is that right any question up to this no this is the basic circuit if there's no confusion then i will go into further detail anyone who is not clear about it now in this system there should be some inhibitory fibers local inhibitory fiber so that no area over fires right now let me tell you these inhibitory fibers there should be which color okay i will put this yellow color here or some blue color here okay actually in the same granular cell layer there are cells which are called golgi cells golgi cells now golgi cells are golgi cells can be stimulated by what is this can be stimulated by parallel fibers golgi cells can be stimulated by parallel fibers but when golgi cells are stimulated they release gamma minor butyric acid on granular cells so what does it mean that in parallel fibers are going up they produce auto inhibition of granular cell again listen mossy cells stimulate the what is the cell granular granulosure fire on the way when granular cell is going to stimulate the purkinje on the way it also stimulate what is the cell golgi cell and golgi cell releases gamma minor butyric acid on granular cell it means this is an autoinhibitory system is that right this is auto break applied on the granular cell what does it mean look here granular cell will fire but it will not excessively fire as soon as granular cell fire action potential go to stimulate for kanji but at the same time granular cells stimulate the golgi cells and golgi cell inhibit the granular sun is that clear any question here if it is inhibitory it is gamma minor butyric acid there is a very simple thing all the inhibitory neurons in cerebellum are gathering that's it all the inhibitory neurons in cerebellum are gamma myobutyric acid releasing neurons so this is gabaergic right then ok i should make them rather black so that you know they are doing negative function granular cell inhibiting it and they are stimulated by them plus another thing this cell can be stimulated by what is this what is this mass so mostly cell can directly stimulate the granular cell and they inhibit the sorry mossy cell can directly stimulate the golgi cell which may inhibit the granular or granular cell once they're activated they inhibit the they stimulate the golgi cell which inhibit it are you clear at the end yes right now there are two more special control cells what is this percentages are now let me tell you this is the middle layer these are three per k now we see this one central park engines activated but why they are weeping let me tell you actually the inhibitory cells there also now attention please there are some inhibitory cells here right some of them are like a star some of them are like a star and other are like baskets right so there are star of stellate cell and basket cells these are also internal cell for inhibition now what happens look here let's suppose i'm going to draw this specific fiber this specific fiber is this specific parallel fiber is stimulating this specific purkinje stimulating this central perkinj but it at the same time it will stimulate nearby a stellate cell and what is this basket cell and basket install it will inhibit the surrounding purkinje now i know it's getting difficult but let me explain for example you have three people standing and you want to enhance the presentation of one person what you will do to the other to depress them is that true if there are three people in computation you want one should really win one should become very prominent excellent performance and negative attitude is inhibit the other two is that right now exactly this happens when this granular cell filed it wanted to stimulate this specific percentage system it directly through the parallel fiber is stimulated this percentage cell right and when this percentage cell was stimulated it fired on what is this deep new but at the same time same same parallel fiber also stimulated nearby stellar cell and what is this basket cell and they are inhibitory gabaergic neuron these two inhibit the inhibited the surrounding neighboring percentages so what happened that central perchangeable is stimulated directly by the parallel fibers and neighboring precancerous cells are inhibited indirectly through the skeleton basket cells what does it mean that your stimulatory action will be sharpened again if you want something to be prominent what you do if there's light and if you put a very black thing around it darkness light will become more prominent and the same in central nervous system sometimes to sharpen the signal to sharpen the signals when one group of neuron is firing in central nervous system neighboring group of neurons are suppressed you are understanding there is a basic rule in cerebral cortex as well as in cerebral cortex what is the basic rule that when in the cortex some group of neurons are going to fire we automatically inhibit the surrounding group of neurons so that firing area becomes very prominent our signals become sharpened is that right same thing happen here look this was granular cell it took the fibers upward it wanted to stimulate the signal stimulate what is this central parking j right so it directly stimulated it but at the same time the neighboring purkinje were inhibited by stimulation through the stellate cell then stimulating the basket cell when stellate and basket cells were stimulated they released gaba on the surrounding what is this a and the surrounding park engine become inhibited and central remain active and of course then it will release gaba and inhibit this deep nuclear so this is the basic internal structure of and internal connections of cerebral cortex and the relationship with the deep nuclei any question up to this yes no no let look all these cells with black faces are negative minded inhibitory are there a basket they are going to multiple neighboring parking right so the point is that that when parallel fibers come if they stimulate one per kanji right they automatically stimulate the surrounding basket and starlet and those neighboring basket and stellar cells inhibit the neighboring perkinj so central perkins uh stimulus become or its signals become sharpened is there any confusion after this no it happens like this that whenever parallel fiber are going to stimulate any perk engine right they will also stimulate the neighboring vasculatin what is this stellate and these baskets and stellate will not inhibit this one they will inhibit the surrounding now let me tell you if let's suppose if parallel wanted to stimulate this one then they will end directly on this to stimulate it and they will stimulate not this style itself some other style itself which will inhibit this one right the rule is this that parallel cells parallel fibers from the granular cells directly stimulate the parkinson's rights target practice they directly stimulate the target for ninja and they inhibit the neighboring purkinje through the inhibitory cells which are skeleton basket am i clear any question here no okay so let's remove now this diagram now we have to go in further detail we have just seen what are the internal processing right basically cerebral function can be explained at three level as i told you rk cerebellum there was paleo cerebellum and there was near cerebellum other name for them is our key cerebellum okay our cheese cerebellum this is also called vegetable cerebellum or otherwise what was that paleocerebellum that is also called spinal cerebellum spino cerebellum and most modern is neo cerebellum which is also called cerebral cerebellum cerebral cerebellum again the most primitive part of cerebellum right most primitive part of cerebellum is connected with the vestibular system right cerebellum is connected with spinal cord so spinal cerebellum and neo cerebellum most modern cellular cerebellum is connected with the cerebral cerebral cortex is that right so in a simple diagram yes if these are vestibular nuclei right yes they are connected here and these two-way connections what is this called this part of cerebellum should be archethyribalam of vestibulo cerebellum some fibers grow from spinal cord to some part right and this part of cerebellum where these fibers are going what is this spino cerebellum and some fibers coming from the top right and these fibers which are connected with the top what is this which part of the cerebellum cerebral cerebellum because these fibers first come to the pons and from the pawns fiber go inside so we also call them cortico cerebral pathway cortico punto cerebral pathway is that right now this is called cerebro cerebellum or ponto cerebellar what i want i'm trying to put in your mind that cerebellum functionally can be divided into three mainly concerned with the balance vestibulo cerebellum mainly concerned with the verbal and paravermal area where trunk and limb movements are controlled spinocerebellum is that right and rest of the cerebellum where connections are from cerebral cortex right but no connection from spinal cord and no connection from the vestibular nuclei this cerebellum is called cerebro cerebellum any question here there is no okay now i will going to tale of one by one in these three areas first of all i will explain vegetable or cerebellum which is the most primitive cerebellum or archie cerebellum now let's suppose here it is vestibular nuclear complex then it has superior nucleus inferior nucleus middle ear lateral nucleus and here is the vestibular complex you know vestibular operators which is part of the inner ear which is concerned with the balance have you studied it or not in a year right in the inner ear you know there is a vestibular apparatus and around this there are semicircular yes canals multiple semicircular canals actually from this area the fibers which come right they are bringing the information about the balance especially position of the head right you will study in detail in the lectures of vestibular system but what is happening that if i draw it properly in the vestibule in the vestibule there are uterical and they are having special type of sensory epithelium here right this sensory epithelium is also called autoleth organ you will discuss in detail in some other videos right but these are concerned with the static balance and if you're moving your head at any angle then fluid will move in what is the semicircular canals there are three semicircular canal on right and three on the left and in semicircular canal when fluid will move that will stimulate another sensory epithelial system here so what really happens depending upon your head balance or angulation or movement of the head action potentials are generated in these sensory epithelium and these action potentials are brought to the brain stem as a vestibular nerve vestibular part of the vestibulo cochlear nerve now some of these fibers end up into vestibular nuclei and some of these fibers right they directly enter into cerebellum they directly enter into cerebellum now some fibers go directly into cerebellum other fibers they terminate into vestibular nuclei and from there next fibers go to the cerebellum is that right now when these fibers will enter into cerebellum of course they are entering through inferior cerebral peduncle you know there are three cerebral peduncle which are connecting the cerebellum with the brain stem superior cell barrel middle third parallel and furious very viral product so through inferior cervical right vestibular cerebral fibers are going now these fibers which are going in the floccular nodular lobe which is the most primitive cerebral part they will reach up to what is this cortex what are these fibers are they climbing or mosey they are climbing or mosey they are mosey because climbing fibers only come from olive all other are going to be mosey anyway so these moji fibers from vessel system eventually enter into floccular neutral region right there of course they go to the cortex right internal processing occur then there is a nucleus here and from this nucleus deep nucleus you know from here there are fibers which are going which fibers are going from here to their parking gear cell fibers do you remember of course there's no fun in telling that all vestibular cerebral fiber come over here on the way they stimulate deep nucleus and then they go up to the what is this cortex and internal processing and cortex is done and then fibers come from the purkinje fibers and they inhibit this deep nucleus is that right and from this deep nucleus from this deep nucleus fibers come back these are called cerebellar vestibular fiber again fibers which are entering their vestibulo cerebellum fibers which are returning their cerebellum vestibular fiber is that right and these cerebellar vestibular fiber will come out and yes stimulate the vestibular nuclear complex now vestibular nuclear complex now fires down as well as fires up when it fires down what is this pathway going on vestibular vestibular spinal tract what is this pathway going down vestibulo spinal tract is that right some of these fibers also go back and interact with some reticular nuclei and what is this fiber going down reticular spinal so what is happening that in this vestibular cerebellum input is coming from vestibular system output is going to vestibular nuclei and reticular nuclei from there descending output is going to vestibular spinal and reticular spinal tract this vestibular spinal tract what is the function of vestibular spinal tract what is the function of rubber spinal tract rubra spinal you can you can choose you can tell me vestibular spinal or rubrus finally okay vegetable spinal is anti-gravity muscles stimuli when in the morning when you stand up it is vegetable spinal and when you relax and flex your body that is rubrowspiner is that right am i clear so extensor muscle tone or anti gravity tone is increased by vestibular spinal i told you this is concerned with what balance and if you have to keep balance your extensor muscle anti-gravity muscle should have a good tone is that right so what happens the vestibular spinal tract is going down is that right and actually it increases muscles of uh tone in which muscles extensor muscles is that right rubra spinal we'll discuss later they enhance the tone in flexor muscles is that right okay now downward firing is as vestibular spinal tract upward fibers are going which will stimulate third of nuclei outflow forcing of nuclei outflow and section of nuclei outflow oculomotor proclaimer and what is the subduecent can you tell me the name of this fiber yes this should go to you yes ma'am listen when i will tell you all of you have heard of it just one minute i'm saying again balanced position of head static or dynamic is in form through the vestibular nerve to the vestibular complex and to the floccular nodular lobe from there information goes to very deep nucleus this nucleus is also called festigious what is this nucleus festigious nucleus right fastidious nucleus can send fibers to the vestibular complex from there their going fibers which are what are these vestibular spinal and the up going fibers which are interact with third fourth and sixth nerve so that they move the extra ocular muscle in such a way when head movement is going on eye movement should be adjusted very natural that for example it's quite possible this is a young man he keep his eyes fixated on a young beautiful lady and keep on running to other direction and his height is moving like this it happens very commonly in your age isn't it now what happens actually when he is running or he is moving his head all information is going on to cerebellum r cerebellum vestibular cerebellum right and then information is coming back here but because there's a very intimate relationship in the movement of head and movement of the eyeball so position of the head and eyeball relationship is determined by special connections between the vestibular complex nuclei and third fourth six nuclei which are moving the eyeballs what is the name of this fiber i'm going to be depressed if none of you tell me yes what is the name of this virus all of you know it this is called medial longitudinal fasciculus have you heard of it medial longitudinal fasciculus medial longitudinal fasciculus what is this this is internal connections in the brainstem nuclei and of course this is an internal connection is that right so this is the main function of what is this what is this vestibular vestibular cerebellum or rc cerebellum concerned with the balance concerned with the extensor tone right and concerned with the movement of the eye with the movement of the head is that clear any question no now we go to the spinal cerebellum now this was your rc cerebellum or vegetable cerebellum which was flocculated you know input is from vestibular system output is going to vestibular system and reticular system and when output goes to vestibular system downward going on vestibular spinal upward going on medial longitudinal fasciculus is that right now we come to this area back again you remember that there was something like this here right and yes what was this area yes vermis and outside that what was para thermal area is that right and in the vermis we have made this you remember right and there are is that layer now we are going to study this area now in this area right vermis and paravermal area they receive the sensory information from the spinal cord so they will be the part of what which cerebellum spinal cerebella they will be the part of spinal cerebellum of course when i'm making their trunk here upper limbs are lower limbs here if i say information has to come to vermis and paravermus from the trunk and from the upper limb and lower limb of course information comes through spinal cord so lot of information from spinal cord will come into verbal area and paravermal area is that right the question is that how that information will come here and how this area will work is that right i am going to draw a diagram here is a spinal cord i have made two sections one upper section and other is of course lower section now here is your cerebellum is that right we have to bring the information from the trunk and from the limbs to the cerebellum right now how it this information goes there number one for example from the lower lamp right information this is posterior root ganglion from the lower limb and lower part of the trunk information is going from muscle spindle golgi tendon organ yes yes no this is going to cerebellum pacinian corpuscle than other now these muscle spindle gauge tendon organ and other receptors right which are present in the ligaments and kept joint capsules all they bring the information to the spinal cord right now in the spinal cord first order neuron terminate here from here second order neuron go on the lateral white column and from here it is going up going up and this is inferior cerebral peduncle right through the inferior cerebellar peduncle these fibers will come into cerebellum once they enter into cerebellum they're moving forward as what which fibers mossy fibrous right now what is this track dorsal spino seri barrel track this is dorsal spino cerebral tract right of course there are two dorsal spinosary by track there is no fun in telling but still dorsal spinal cerebel track take the proprioceptive information from the lower limb and lower part of the trunk right and they ascend this is new what is this nucleus from where the second order neurons start nucleus of clark anyway so from here dorsal spinosady barrel fibers are going up and through the inferior cerebral peduncle they go ipsilaterally is that right going to of course spinal cerebellum now out of these fibers fibers which are coming from the hip region they will go to thermal area and fibers which are coming from the foot region they will be going to paravermal area you understand it why hyperison will be coming to formal area and distal part of the limb will be coming to the paraverbal area is that right then from upper limbs because these fibers start from t1 up to l3 but upper limb you know c5 cervical output and okay upper lymph fibers they enter over here of course proprioception has to come from upper limb also cerebellum should know what are the actual movement and actual position of not only lower limb but also upper limb right this information will come over here and it will terminate at a nucleus here and then also come and right upper limb of course there are two upper limbs and here now be ready i am going to ask question what is this nucleus and what is this track i have told you from lower limb and trunk fibers come they enter if selectorally second order neurons if still laterally ascend and if see literally they go to the spinosary balance vermus and paravermal area right and these are fibers from the dorsal spinal cerebellum but because upper limb does has its proprioception entering through another track these fibers enter in with all the proper reception from upper limb for the cerebellum fibre ascent upward terminate at one nucleus and then through inferior circular production enter here what is this track called you have heard of it pardon fasciculus oh my god my friend fasciculus cunatas and gracilas they go to the nucleus kuniatas and graceless make internal arcade fiber then go up as medial laminess close to ventropostal lateral nucleus they don't send anything to cerebellum it is something going clearly to the cerebellum it is not fasciculus cunatus but it has something common actually this nucleus is called it is not q in nucleus you need us this is a parakinatous nucleus and this is called curiosity barrel pathway actually listen now carefully from lower limb it is dorsal spinal cerebral pathway from upper limb same function is done by union cerebral pathway but actually from upper limb lower limb when the trunk all information is going to the cerebellum to vermal and parathermal region there's no need to remember it is that right so look these fibers which are bringing information they will be bringing with yes here will be the trunk information coming and here from the upper limb and lower limb is that right connected here verbal and paravermal areas now there is another pathway which is called ventral spinosary barrel pathway have you heard of it ventral spinal cerebral pathway okay there that also has to take information from spinal cord to the cerebellum those fibers start ventrally more interiorly go upward they are going to cerebellum right the only thing is that when ventral fibers enter they didn't do a mistake here they cross to the opposite side they were suppose look information should go to ifc lateral cerebellum is that right but ventral spino cerebral fibers when they end their first order neurons enter second order neuron ideally should go fc laterally but unfortunately they cross right and from this side also the fibers cross now what are these these are ventral spinosad viral fibers which are crossed fibers and going to the cerebellum now this is a little bit naughty pathway first naughty thing what did it do it crossed there was no need of crossing it because information should go if still laterally so this was first naughty thing they crossed second not a thing they are coming from spinal cord in a decent way they should enter through which inferior cervical but they are very naughty they will go all the way up so that you don't have to remember in difficult ways and enter into cerebellum through superior cerebral peduncle is that right they enter into cerebellum through where superiors are barrel protector once they enter into cerebellum they remember oh my god they have gone to the wrong slope of the cerebellum they were supposed to go excellently but they have gone to wrong side so after entering they again move within the cerebellum to the opposite side and end up on contralateral side very naughty this is ventral spinosary barrel pathway right up to now i've told you how many pathway for to the spino cerebellum spinal cerebellum is constituting verbal and parabola region well thermal region is for the axial system and paravermal for the distal part of limbs fibers are this verbal and parathermal region of cerebellum they are supposed to collect information that what are the actual movements going on that information will come from where from the golgi tendon organs and from the muscle spindles as the action is going on right so information is coming through dorsal spinosary parallel tract through curiosity parallel track and through ventral spinosary barrel track is that right now there's one more thing i told you this is a naughty pathway which one ventral spinal cybara it did funny thing first it enters rather than simply going if see laterally it go across then cross go up then through superior cerebral uncle it enters then re cross is that right it does another funny thing you know what it does i told you previously when corticospinal fibers are coming down and they're bringing the final motor information right this pathway takes that information also to the cerebellum in the previous lecture i told you that cerebellum has information at three levels at least number one when movement is planned you should know where's the body position and what are the actual movements going on in the body that information is coming from where dorsal spinous cerebral system ventral spinal cerebal system and curiosity viral system is that right and spino library and spino rectal a spinal reticular y rectal i don't know spinal reticular system right these are ascending fibers is that right okay this is one thing secondly i told you siri balance should know what is the intended movement thirdly even information goes down right from the top story motor information is going down before upper motor neurons stimulate the lower motor neuron whatever final information has come here that information is again taken up to the cerebellum by the ventral spinal steady barrel track are you understanding me i'm teaching myself you understand it why you're making so sad faces all of you is it clear okay now it means these ascending fibers are giving two type of information number one what are the actual movements are going on number two from here they also take the information what is the final motor orders going on to the spinal cord and they are coming to the cerebellum in the cerebellum these fibers will eventually end up into as much fiber climbing or mosey all of them will be mostly fibers isn't it and once they will go in of course there's no fun in telling they will activate the deep nuclei and they'll also activate the granular cells and they will then stimulate the percentage of cells and percentage cells will come back you know it and stimulate the deep nuclei inhibit the deep nuclei again right anyway now this is what spinosa cerebral connection input now where is the output of spinal steady barrel system this is the input let's look at the output of spinosary barrel system these are the deep nuclei right now deep nuclei i'm making a section of cerebellum horizontally now this is the brainstem here this is right cerebral hemisphere this is the left uh the most medial are fastidious or let's start with the most lateral lateral is like a teeth of what is this teeth of an alligator this nucleus is deep nucleus is called it's having these like arrangement dentate nucleus right then there are yes emboli form nucleus this is dented dented then emboli form and bolly form then more medial is globose and eventually fastidious is that right all of you must be knowing there's a mnemonic called don't don't eat greasy food don't eat greasy food dentate boliform nucleus globulus glubose nucleus and festigias now here i want to make it clear this nucleus which is prestigious it is intimately related with what vestibular system is that right it was a most primitive system more lateral to that these nuclei these are deepsea globe blue globus and what is the symbolic form these are related with spino cerebellum right more laterally these deep nuclei are related with most modern cerebellum what is that cerebral cerebellum now listen again don't eat greasy food dentate emboliform globose and festigious right but actually from medial to lateral it is nuclei concerned with the archaea cerebellum more laterally with the paleocerebellum most literally neo cerebellum is that right now most medial are fastigious which are concerned with vestibular system in after that there is what is that globose and emboliform together these two are called interposed nucleus this globus and emboliform or together they're called interposed nuclei these are concerned with spino what cerebellum and outermost is neo cerebellum or cerebral cerebellum now it's so easy to understand festival nuclei must be having connection with vestibular system interposed nuclei or globus and emboli form should have relationship with the what spinal cerebellum outer most should have relationship with the neo-cerebellum now come back here okay go to the same okay this is the diagram okay what is this verbal paravermal now actually all the floccular nodular cortex for flocculone nodular cortex that should be connected with what fastidious is that right because it is r key what are these what is this vermal and para vermal they are concerned with what spinal cerebellum so they should be connected with which deep nuclei yes yes globals and emboli farmers globos and bully form very little connection here also for festivities and outermost this cortex of cerebellum that should be connected with which deep nucleus dentate indented is that right now just to check your knowledge i'm going to make a cerebellum right this is flocalo nodular right and what is this nucleus now connected festigious and this is vermal and paravermal areas they should be connected with which nuclei volume formant and this cortex is and that should be connected with which nuclei lateral most is it difficult it's easy isn't it right now let's go back now if we were talking about spino cerebellum we have already discussed the information will go through dorsal spinal steady barrel system we'll also go through ventral spinosary barrel system is that right will also go through olivo sorry cuneo cereberal system is that right this was input to vermont and paravermal region because that was fine suppose this is verbal and paravermal region i draw it here so all of them fibers right they are acting as entering as mosey fibers and they will eventually connect it to this verbal and para thermal region from there when parking a fiber will fire they will go to which nuclei global's hand and volley form from here information will come out is that right now when this information will come out where it will go it will go up and down up when it will go it will go to the red nucleus so cerebellum rubral pathway now we are talking about output of spinal cerebellum input of spinosary balance system you know it now output of spinocerebellum right this is going to what is this cerebellum rubral fiber and some of these fibers go to the thalamus ventro anterior nucleus of thalamus and ventro lateral nucleus of thalamus right some fibers go to red nucleus and then here some fibers go directly there so how you will call them cerebellum rubra thalamic fiber or cellulothalamic fibers is that right when these fibers will reach over here from here next fiber will go to the thalamo cortical fibers and they will influence the motor area primary motor area somatosensory cortex and from there eventually corticospinal fibers will come down now you look at the total loop muscles were let's suppose attention please suppose muscle was firing more strongly than needed if muscle was contracting more strongly then as muscle was for example my hand is here suddenly and it is going should it stop or not if cerebellum is intact now how it will stop when it was moving rapidly information went to cerebellum is that right cerebellum process it and sent to the red nucleus end to the thalamic is that right and then information went to the top from there this output of cerebellum modifies the higher center motor center and now modified information will come down and alter the movement rate and correct it if it need to be accelerated it will be if it need to be movement will be reduced you are understanding so what happened from spinal cord information you're going to cerebellum cerebellum going to the higher centers and then from there corrections come down now some fibers from red nucleus come down what is this pathway called rhubarb spinal now let's make it very simple does spino cerebellum work spino cerebellum is verbal and paravermal region right with associated deep nuclei vermal and para vermal cerebral cortex has associated deep nuclei which are globosis and emboli form just listen to me is this globosis and both everything is written in books and nodes just understand it here globosis and bully form are also together called nucleus interposed right this is nucleus for what spinal cerebellum now what will happen from spinal cord information will go to the spinal cerebellum through the dorsal spinal steady barrel pathway through the curiosity barrel pathway to the ventral spinosate barrel pathway right and all this information when it goes to cerebellum put an input after internal processing output will come out right from which nuclei mainly from globus and bolly form these fibers will come out at cerebellum rubra fiber and come down as rubra spinal and correct some fiber will go even upward to correct the top story fibers will go what is that cerebellum thalamic or cerebellar thalamic ventral ventral lateral nucleus then going to the premotor area for primary motor areas metal sensory area and corticospinal information is corrected is that right this is spinocerebellum compare it with vegetable oil cerebellum very simple vegetable cerebellum taking information from vegetable nuclei vegetable operators vestibular nuclei yes vestibulo cereberal fiber floccular nodular cortex coming to festivious nucleus coming to vestibular nuclei this is output coming and then going down as vestibular spinal going up as medial longitudinal fasciculus to altering the third fourth sex nuclei to regulate the eyeball movement so vestibulo cerebellum and spinal cerebellum is clear anyone who is confused raise your hands no one is confused are looking so tired i should be looking tired you are so young but tired what happened it's so easy there's not a lot of information so easy in five minutes it can be repeated what we learned what did we learn after now cerebellum has yes vermal area in the center paraverma on the side and lateral hemispheres on the side and floccular neutral area done it has three rc cerebellum which is vestibular cerebellum spinal cerebellum of paleocerebellum neo cerebellum cerebral cerebellum or pontine cerebellum done all the fibers which come inside they are either mosey or climbing if they are coming from olive they are what climbing and if they are coming from all other sources they are mosey when moses and climbing fibers pass near the deep nuclei they stimulate them and then they go into climbing go directly to kenja cell stimulation and moji go through granular cell to percentage health stimulation through parallel fiber is that right granular can be inhibited by golgi's health and parking cell can be inhibited by basket and stalin right cortex of the cerebellum gave its output through parkinson's fiber which is inhibitory to the deep nuclei deep nuclei give their output to the brain stem and to final destination done then we said there is next step vestibular cerebral pathway it's so easy vegetable apparatus going to flocculate nodular area right coming back into vegetable operators going down as vestibular spinal going up as medial longitudinal fasciculus influencing third force x now done spinocerebellum very simple verma area paravermal area controlling tone and the movement posture and movement in the yes trunkle region in the thermal area and limb distal region by the paravermal area information come from dorsal spinal cerebellum they come from interior spinosady pattern you need a cerebellum is that right verbal paravermal cerebral cortex nuclei are in bully form and globus information goes out to red nucleus of thalamus if red nucleus gives downward fiber rubra spinal and if fibers go to thalamus ventral interior ventral lateral nucleus going up to the motor cortex and corticospinal fiber down going their activity altered any problem in this is it a lot of information it's so easy so do the last part now thank god we are at the end now so now we will do the last part of cerebellum which is cerebro cerebellum right uh cerebral cerebellum if we go over basic diagram of course this was vermal what was this para thermal region is that right again i'm repeating this was your vestibular this was your spinal is that right and here this is the area what is this yes outermost area right the lateral part of the lateral hemispheres you know cerebral hemisphere the there was vermis then there were lateral hemisphere lateral hemisphere area which was just outside the vermouth that was paravermal area or para intermediate zone then outermost area this is called neo cerebellum right or it is called yes cerebellum because cerebral cortex here communicate with the cerebral cortex is that right now let's make a diagram here and get these connections right in our mind this is middle cerebral peduncle now it's very simple you have heard of pontine nuclei a lot of pontine nuclei in this part of the pons is that right now what really happens from the cortex especially from the motor and sensory cortex fibers come to the pontine nuclei right from premotor area supplementary motor area primary motor area somatosensory area plus fiber from almost all region of yes cerebral cortex all these fibers come to the pontine nuclei we call them quartico pontine fiber and then pontine fibers cross to the opposite side and enter pontine fibers cross to the opposite side right this is the pontine nuclei from their fibers cross and through the middle cerebral peduncle they enter into what cerebellum this pathway is called ponto cerebral pathway this is the main pathway through which cerebral cortex communicates with the cerebellum cortico punto cerebellum is that right now this is the input system now when we are talking about neo cerebellum or we are talking about yes cerebral cerebellum this part of the cerebellum does not have connection with the spinal cord or vestibular system it has all the information what is going on in the cerebral cortex coming to cerebellum from here of course you know that information will eventually go to this what is this cerebral cortex then we need to return from parkinson's system into the nuclei the new most important nuclei here was what was this nucleus yes dentate output will come from dentate dental rubral fiber here and then to thalamic fibers ventral interior ventral lateral mostly ventral lateral so dento rubro thalamic dental rubra thalamic are directly dento thalamic they cross to the opposite side from dento thalamic they go to primary motor area supplementary motor area sorry pre-motor area supplementary motor area primary motor areas tomato sensory area so this is the loop starting from the motor motor regions of cerebral cortex to the pontine pontosary barrel then dento rubro this is the loop of information where cerebral cortex communicates with cerebellum this is the pathway when you're planning a movement the information of intended movement through cortical ponto cerebellum pathway come here is that right now listen carefully when you are planning for any movement what is the balance of the body information is coming vestibular cerebellum back to the vestibular system right what are the movement which are planned or movement which are intended to be done particular ponto seri barrel and correction goes back where what is this dento robothalamic or dentothalamic and thalamo particle is that right and movement after that when modified fibers reach here right modified information and the true movement start actual movement start then information is going to wear through spinosary barrel pathways information is going to spinal cerebellum is that right so it means that what is happening in our body if we want to put the cerebellum at perspective cerebellum is the master controller of the movements how it produces precise and coordinated movement and maintain tone and posture appropriately because it knows what's going on in the field and it knows what the high command wants it means at three level it is receiving information balance information through vestibular system what is going on the actual movement and actual position of the body through spinal cerebellum and what the higher center really want through cerebrosary balance and it coordinate all that and according to that it brings output right to modify the motor system do you have any question any question up to this okay class dismiss we will be doing their liens if

Channel: Dr. Najeeb Lectures

Views: 390,574

Keywords: cerebellum, medical videos, medical school, nervous system, dr najeeb lectures, medulla, medical education, neuroanatomy made easy, dr najeeb, usmle, armando hasudungan, neuroanatomy lectures, cerebellum anatomy, cerebellum anatomy lecture, cerebellum physiology, blood supply of cerebellum, central nervous system, grey matter of cerebellum, anatomy of the cerebellum, brainstem, midbrain, usmle step 1, usmle step 1 videos, medulla oblongata, neet, usmle step 2, lecturio, cerebrum

Id: dGJ6QZjCBeI

Length: 132min 3sec (7923 seconds)

Published: Mon Feb 22 2021