all right hey everyone um let me know if you can hear me okay I am away from my normal office my setup's a little different here and I don't have a camera available but let me know if you can hear me all right thank you Nicole appreciate you my mom always said i' a face made for the radio so it's probably good you can't see me anyway maybe I'll improve your your uh watching pleasure who could say but uh yeah let's go ahead and um get into it here so we've covered the majority of our motor topics that we're going to or neurot topics I should say that we're going to get into um this is the motor section we're going to talk about and then we'll just have like all the autonomic sort of function for the last one so I'll need to pre-record that for uh tomorrow so if you have questions feel free to ask them now since tomorrow is going to be a recorded lecture but um anyway let's go ahead and get into it here's some of the objectives we've already covered muscle function more specifically so this first one here U I'm not going to talk a whole lot about the neuromuscular Junction just because we've discussed that in the past but I'm going to more so talk about more so like spinal control of the muscles and talk about reflex Pathways and that kind of thing as we get into it so of course I posted a link for the sticky board if you have questions uh otherwise feel free to post them up in the chat and let's get started here so the first which want to talk about is spinal control of motor function um some of this can get a little complicated I'm going to try to hit the essentials but if there's any thing where I'm not clear on something please feel free to ask me otherwise we'll go ahead and keep going so looking at the spinal cord um we're going to be seeing that we're going to be having sensory fibers coming in from places like the skeletal muscle and then we're going to have these motor neurons that are going to be sent out through um into the muscle itself so have these kind of motor neurons on the interior aspect of the spinal cord here and so it's going to be this constant sort of communication of sensory signals coming in we're going to have you know senses coming you some of those senses being sent up into the brain signals coming back down to eventually communicate to the muscle that says hey you know release aolon onto that skeletal muscle and that nicotinic receptor to cause it to contract and so we're going to find this the gray matter here the cord is what we consider be the integrative sort of area so it's taking all this input in from the sensory side of things and then taking all the inputs coming in from the CNS to basically say okay what's the ultimate output and so this is where we're going to see all this integration here so I mentioned you're going to see the sensory signals coming from the posterior the dorsal route right um we'll find that some of this is going to be branching off and going into the higher nervous systems it'll be communicating what the muscles are sensing up into the CNS the other one's going to be sort of terminating here on the gray matter here this and and what this is going to be useful for is providing um the ability to have reflexive actions um so it's basically causing the muscles to move or not move the case may be without even communicating with the brain and so we'll talk about a few examples of those reflect Pathways but that allows for very sort of instantaneous sort of communication based off the information coming from the sensory side of things here um a lot of that's going to be concerning what we call these inter neurons so you're going to see there's a lot of communication between not necessarily the sensory nerves directly onto the motor neurons but there's a lot of players in the middle a lot of kind of middle manager so to speak that can help to modulate that overall signal um either getting up into the CNS or what ultimately gets communicated to the motor neurons there and then finally it'll communicate to the anterior motor neurons that causes the actual the muscle U to contract or not contract as the case may be so looking at this you can kind of see um what sort of sensory information is coming in from the muscle here so what's kind of getting transmitted into that dorsal root gangling here and if you look at a muscle as you can see here um there's going to be both what we call the the muscle spindle and here's a sort of um more exploded or more sort of um expanded view of what the muscle spindle looks like and that's going to be sending information to these dorsal root gangling that basically tells you information about stretch how stretched up or how contracted as that muscle and we'll go into more detail on how that functions here in just a little bit um you'll also notice that we're going to have this Gogi tendon organs as well and that's going to be located within the tendons it will also give information about how much the muscle is actually being stretched and we'll talk about the the role that plays here in just a bit and finally you'll notice here on the interior side you're actually getting the output here the actual motor in plate which is going to be inating the muscle that tells it to contract or relax as a case may be um when looking at the the muscle spindle itself if you'll notice they will have interation by these Alpha motor neurons which are the same sort type of neurons are going to be inating the motor in plate also have these gamma motor neurons and so that's going to have some role to play here um within the middle and what these are useful for is it helps us to control the overall muscle tone meaning that most of your muscles are not just completely flaccid there's some degree of contraction associated with them and so how we are going to be setting that tone is going to be the role of the muscle spindle here so we'll get into more detail on how that will sort of respond and how that can sort of change um you know when we're looking at things like you know putting the muscles underload for example um how that will cause changes the muscle sort of contracts or or lengthens as the case may be I mentioned the intern neurons and so these are going to be found all throughout the cord gray matter there very excitable there's a lot of them many interconnections you can see here and as I mentioned they're integrating a lot of the spinal cord functions so not just from the sensory fibers are coming in signals coming from the CNS all that's going to be playing a role here um and if you notice this line very few sensory signals or signals from the brain in particular terminate on those interior motor neurons it's most likely going to be those intern neurons are going to be responsible for finally sending the signal to the motor neurons that say Hey contractor relax other cells you can find here as well include these Ren Shaw cells these are useful for providing this what we we talked about before called lateral inhibition um instead of having just an all or none sort of contraction of the muscle um we can provide for a little bit more Focus sort of signal by being able to sort of try to quiet out sort of the noise of you know different neurons firing just kind of focus on the main signal that's there basically allows us to have more kind of fine motor control than as opposed to just having the strict all or none sort of contractions and then we'll have this proprio spinal fibers these are interesting because they're kind of running from one segment of the cord over to other places here and this allows us for communication between different areas of the body or different Limbs and I'll give you an example of um what one of those kind of reflexes might look like that could be responsible of the actions of these the proprios spinal fibers here so um proper muscle control requires proper information right because the body needs to know what like the stretch response is happening in the muscle it needs to kind of know the general position of it and so the muscle spindles I mentioned provide majority of that and then the GGI tendon organs are going to be more telling you information coming from the tendons more directly here so um this is necessary for helping us to provide that kind of intrinsic muscle control and again a lot of this is happening unconsciously or subconsciously as a case may be and a lot of that information just doesn't communicate with the interior motor neurons but it's also going to be sent up into the CNS and so we're going to get into more details on how the cerebellum the cortex and all that's going to help to control muscular movement especially under really voluntary sort of um muscular control so if I'm saying hey want to go Shake someone's hand um those signals are going to be taking a lot of that sensory input coming from the muscle spindle and the GGI tendons uh to be able to help me communicate and then say okay well what do the muscles need to do now in order to accomplish whatever my goal is so looking at the muscle spindle more directly here you notice they have these kind of intrafusal fibers and these are found within the belly of the muscles so kind of in the center of it um and so if you will notice here in the very middle you have these Sensory neurons which are going to be able to detect stretch or relaxation of the muscle itself and so this central region here doesn't have any acor myosin so it's not able to contract or release on its own it's just kind of muscle fiber just kind of with the sensoring neurons kind of hanging out but what you're going to see here is you have both ination of the outer portions with the Alpha motor neurons but you also have these gamma motor neurons are going to be involved here as well and so depending on how constricted or relaxed these gamma motor neurons it's also going to be affecting how much stretch is being sensed here in these in the middle portion okay so like I mentioned these are going to be sending sensory feedback to the spinal cord to tell you how much of a degree of stretch is happening within the muscle itself and what stimul these sensory receptors these spindle receptors here so what's going to be the thing that kind of triggers them one lengthening of the whole muscle that will cause a stretch of the central portion here and that'll excite The receptors and tell the brain hey there's some stretching happening within this muscle and then we're also going to find that you can have contraction of the in portions so these gamma motor neurons can kind of pull on either end of the muscle spindle to cause stretch of that as well and that can also lead to excitation and so we're going to talk about some reflexive sort of Pathways in terms of how the gamma murder neurons are going to help to control these the sensory stretch here with the sensory portion in order to allow for proper muscle control so that way for example if I toss you like a heavy load like a back of flower or something um your muscles just don't completely drop it you're able to have a reflex that allows you to have that muscle tone necessary to be able to hold on to that heavy object instead of just dropping it for example so the sensory endings you're going to have these kind of primary sensory fibers here and then you're going to have these secondary fibers as well and so what these are going to do for us is they're going to help us to determine are we having like really sudden changes in muscle length or are we having more of kind of a slow and steady change and so a term we're going to use here is going to be static versus Dynamic changes so a dynamic change is something that's happening very acutely happening very abruptly so in the example there if I were to to throw you a heavy load in your arms all of a sudden as that heavy load causes your biceps to stretch for example as you're trying to hold it um that will send a dynamic signal to the brain saying oh this muscle just got stretched versus if it's more of kind of a slow steady sort of thing here we call that more of a static sort of change and so in the case here where you have a dynamic sort of change happening in the muscle link the primary these kind of 1A fibers are the primary ones are going to get stretched initially or sending that signal that the muscle fibers are stretch there the muscle spindle I should say so sudden increases in the length affect the primary nerve endings initially and then we're going to find that as that change starts to be less abrupt um it'll be kind of like dying down into going more of these into more of a static sort of signal um the secondary fibers are going to be more so activated when you have more of those static sort of changes happening there okay and sort of what that would look like with a stretch reflex so again if I were to throw you a heavy load in your bicep stretches as you're trying to hold that load there um you're going to find that the reflex function here is trying to oppose sudden changes of muscle length because your brain has said okay this is the tone I want to have for your bicep but now that this has changed due to this new load that's being added onto the biceps itself um we want to oppose that sudden lengthening of the bicep and so this is the reflex that's happening here and so basically once you will see this stretch here of the muscle spindle this will then send the signal that's going to cause a reflexive contraction of the muscle itself so again it's an instantaneous subconscious kind of thing is happening here and so what this picture would look like on um the a portion this is what normally happens so if you notice the stimulus that's coming into the muscle itself that tells it to contract if you notice you get a big uptick all of a sudden that's that Dynamic Factor that's the thing that you know you just caught the big heavy load and your spinal cord is telling the muscle hey don't stretch out contract and you'll notice that it then starts to die down to where you have more of a kind of consistent or a static sort of signal here so you get the initial reflex those primary sensory fibers are firing off tell hey o muscle stretching cause a contraction you get that Dynamic response initially and then it sort of dies out picture B here um is less relevant but this is an example if you go back to the textbook um it talks about someone who was uh basically that muscle that was denervated of these primary sensory fibers and so essentially what this is is someone who is unable to not have those Dynamic responses or they only can have Dynamic responses and you can see here that the muscle contract and relax and contract and relax and it's not very steady a is where we want to be from a normal sort of standpoint we have the initial contraction that initial signal to contract really hard and then it kind of dies down to more of a steady sort of signal that allows you to continue carrying that heavy load as the case may be so that's under involuntary action so the muscle spindle gets stretched out sends a response back to the spinal cord that says to contract similarly if you're having like a relaxation of the muscle the muscle is shortening it can also send an inhibitory signal as well through the spinal cord in order to help control that tone but let's think about what happens with voluntary activity because if I want to go and reach out and Shake someone's hand the bicep is naturally going to be stretching during that time frame but I don't want that reflex to cause my muscles to tighten back up because I'm trying to do a voluntary action so what do we do or what happens in order to control that to allow for voluntary actions to happen here without the reflexes taking over okay so what happens so basically by anything that stimulates the Alpha motor neurons they also stimulate the gamma motor neurons too so what does that mean well basically if you were to have the Alpha motor neurons tell the muscle to contract the gamma motor neurons are also going to tell us to contract as well so as the Alpha motor neurons contract the muscle everything is shortening right so you'd expect the sensory fibers to be able to detect that that's shortening as well to send that reflex signal but the operative thing here is is that the gamma motor neurons are causing activation of the ends of the muscle spindle as well so as the muscle is shortening the gamma fibers are also causing this to pull apart so it opposes that shortening reflex that you would expect to see similarly if you were to have relaxation of the Alpha motor neurons telling the muscle to lengthen because it's Rel on the contraction the gamma motor neurons also turn down their signal so that then as the muscle lengthens as a result of less signal to contract you would also see that this relaxes as well and it causes a shortening of the overall distance between the gamma motor neurons so this really really important to get this co-activation here it's preventing that muscle spindle from activating its reflex there so we call this sort of a damping function which is helping to prevent The Reflex from taking over so very very important that these are working together and keep in mind that in the middle here there's no AC inom that muscle is unable to contract on its own it's really as a matter of um how stretch out is going to be is going to be the gamma motor not either relaxing or pulling it apart essentially right think about like a Chinese finger trap if you ever had those you stick your fingers on either end you try to pull it apart and it just you know holds on to your fingers it's kind of similar for whatever reason my brain goes to that um so the central control for these gamma Vons helps us to stabilize our joints okay so when we see increased activity on both sides of the joint it's going to stretch that receptor and it causes the contraction to occur there between the two ends um this is really good for anti-gravity muscles in particular so for example um if you're standing up if you're cashier at public for example and you're standing up for eight hours a day um you're using a lot of muscles in order to keep you upright so your abdominal muscles and your quadriceps and your uh calves muscles and all that working to keep you standing upright and so there's a lot of interplay here in order to maintain um your your posture maintain your your ability to stand up there so pretty pretty interesting stuff I'm going to get down to but just kind of think through the process here and if this isn't clear let me know when I can try to explain it uh maybe a different way there but it took me a little bit of time initially to kind of grock this but um let's look at a few examples of this happening in action here so one thing we can do is we can try to determine sort of the sensitivity of these stretch reflexes here and so for example we could do something like a patellar tendon uh reflex action here so by striking the pallar tendon that causes that muscle to expend you know so it's lengthening because you've now caused this lengthening of it the reason why the knee jerks is because that muscle spindle detects that the muscle has lengthened so its response is to contract to avoid that so you get the kneejerk that happens there because now you've caused a temporary change in the length of that muscle so it's a very fast response to that you can see there um some cases you may see some of these diminish impulses and that can cause the jerks that happen to either be weakened or absent um in some cases it may be more exaggerated depending on um you know the the patient how responsive they are to that sort of thing there um in some cases you may see sort of this oscillation of muscle jerks that can happen uh so this is called clonus you can see this in certain conditions I would see this mostly when I had patients who were experiencing something called serotonin syndrome which is a condition can develop from an overdose on certain types of anti-depressant medications and we wouldn't be able to observe this ankle clonus that happened as a result of for whatever reason um this serotonin actions here that were causing changes and how the muscle is responding so okay so we talked about the muscle spindle and how that's going to be functioning there then we get into the GOI tendon reflex and if you can see this is located within the tendon itself and so this is going to be also trying to sense stretch and it's both happening in a dynamic and a static sort of response similar to what we saw with the muscle spindles there um but this one's kind of interesting because when we see increased tension its reflex response is to tell the muscle to relax and why does this happen well we're trying to prevent putting excessive tension on the tendons um and hopefully trying to prevent aulion from happening so we don't want that tendon to detach from the bone uh so by it sensing that Big Stretch there it says oh wait a second we don't like this let's cause the muscle to relax to prevent putting too much tension there so just another way that the muscle itself can send sensory information into the spinal cord to get these reflex responses those signals are also being sent up into the CNS to tell the brain and the cerebellum you know what what's happening within uh the body in terms of like position and you muscle contraction all of that but this is the kind of quick adaptive reflexive response as you can see we have much kind of quicker sort of communication just within the spinal column without the scene that's really getting involved okay another example of a flexor response and so this would be a case here where you're actually seeing a reflex going from one side of the body to the other and so this is something also known as a no ceptive reflex reflex um and so we call it the NOP because it's usually elicited by pain and so pain can be a very powerful sort of um you can sort of stimulus for response of these reflexes here and so this is interesting so imagine you have both your arms and let's say for example you were to touch something painful like say a hot stove uh for example that you're initi sort of response would be to pull your hand away right so you would expect to see um your bicep being excited to pull that hand away whereas the tricep relaxes well you'd end up seeing the opposite response through these inter neurons to be able to tell the other hand to extend so that way you could push yourself away from whatever the painful stimulus was and so that's another just example of a reflex of response that occurs Without Really any sort of CNS sort of uh or you know higher you know functions of the CNS like your somat sent cortex and things like that it's all happening within the spinal cord itself okay kind of more quick knee-jerk sort of reactions quite literally okay so let's talk about then how we can see cortical and brain stem control of the motor function so we talked about spinal control of muscle function let's look to what happens when we actually get the signals being sent up into the brain and then how the brain is going to be able to process that and then use that information to then make decisions about what kind of muscle function should happen here so we're going to see that most voluntary movements occur within the cerebral cortex during its activation here and we'll find that the sort of patterns of function is stored in the lower sort of areas um so for example more kind of like clunky large body movements will not necessarily be controlled by the primary cortex necessarily but for example if we want to do something very fine or delicate like if we're suturing you may see a little bit more direct sort of um input coming in from the cortex here um we'll talk about that pathway in just a little bit here but if we had fine movement of the hands and fingers that's typically more so of like kind of like a direct interation otherwise most of the sensory information coming in from the sematic area gets transmitted over to the primary motor cortex and that will usually send signals to places like the basil ganglia and and the cerebellum and other places like that which we'll talk about more in detail as we go forward here but generally speaking you're going to see we have the primary motor cortex which is in direct sort of contact with the smat sensory areas that we discussed before and you'll notice as well that the sort of organization is very similar in terms of like okay well the leg area here is going to be communicating with the leg area of the somat sensory area so they're all very kind of closely associated with one another um then get your premotor cortex down here and then the supplemental motor cortex as well so we'll talk about the general function of these as we go through so the primary motor cortex the stimulation of individual neurons rarely stimulates single muscles right so generally what you're going to be seeing though it's more so exciting patterns of separate muscles so it's not going to be like direct individual things unless it's like places like your hands and fingers like I mentioned before they can can generally see here that we're going to have a lot of lot of um neurons that are going to be dedicated to places like the hands where you're going to see a lot of like fine delicate motions can be taking place there um you know places like the face as well because we need to be able to communicate and talk and do all these sorts of things there's going be a lot more intervation here uh to provide those movement patterns that are necessary for speaking or suturing or performing surgery whatever the case may be there places like the legs for example don't get as much real estate so to speak because they're going to be much more I want to say clunky but it's much more uh less delicate in terms of like the fine control that we're going to need there the premotor area will have similar sort of organization as the primary motor cortex in terms of how it is um organized in terms of like which neurons are going to go to which parts of the body there um here we're going to be seeing more complex movement patterns so if we needed to position the shoulders to get ready to throw a baseball for example or if we need to set our hands up in order to play the guitar or piano or something like that the premotor cortex is very useful for this and basically you get this sort of like motor image of like generally what the total muscle movement needs to be that will then send signals into places either the primary cortex which can then send the signal down to the muscles in some cases or to place like the basil ganglia so I'll talk more about that towards the end here but the basil ganglia is going to be really important for um a series of complex movements so if you're thinking through you know um how to stand up walk over pull the door handle go out grab my keys like that kind of stuff is going to be um sort of envisioned by the premotor CeX but then sent out to other places to actually carry it out like the basil gangle so we'll talk about that function there in just a little bit uh then you have the supplementary motor area here so this is going to be causing generally things like bad lateral movements and is going to be working along with the uh premot area for helping out with things like attitudinal movement so if you're like repositioning like the whole body T twisting at the hip for example head rotation things like that are where you're going to see uh those are going to be involved there so then how is the information or those signals then transmitted back out into the muscle so these are going to be kind of the eer signals these are going to be the outputs coming from the motor cortex and other places um we'll see here as well places like the basil ganglia and the cerebellum and there's also a couple of different nuclei we're going to talk about they're going to be communicating a lot of these signals along with the cortex itself um to be able to send that information down and again similarly like we saw with the um AER signals we know that there's a crossover that happens at some point so we're going to see the information from say the right hemisphere is then going to travel over to the left side of the spinal column at a point um and so that'll having that control there so it always seems a little opposite but that's kind how it's designed um and again the more direct pathways are going to be for those really detailed discret movements so if you're doing something very detail oriented with your fingers for example as opposed to more complex you know movements requiring a lot of different muscle groups and things like that that's going to be more so coming from places like the basil ganglia cerebellum and things like that so for these corticospinal or what they call the peramal tract so they call them peramal because they're kind of pyramid shaped in in terms of how they're organized within the spinal column there so we'll get this signal sending from the cortex over the posterior limb of the internal capsule so this is little area between the codic nucleus and pamin and it we get into the basil gangly function the different organs there in just a little bit and then they form these pyramids within the medula so that's where they get the peramal track from in terms of the name there and so we'll see that the fibers are mostly going to cross over in the lower medula and they're going to then descend on this lateral cortical spinal tract and then they can terminate usually on places like the inter neurons but they can also communicate with the sensor relay neuron so it would be like information coming from the GGI tendon uh signals or coming in from the muscle uh spindles there and then they can also then cause acute stimulation of the anterior motor neurons so probably far in away the most common would be communication to the inter neurons but you can see some direct interation and that would just in a straight signal say hey contract the muscle or if it turns it off say no don't contract the muscle a lot of complicated Pathways here but I'm trying to give you just kind of the essentials here so if you incoming sensory fibers to the motor cortex so this is be signals sent um from the muscle spindles from the GGI apparatus for example here um so these sub cortical fibers they're going to be coming from the somata sensory cortex but other places as well it's not just information coming from the muscles but it's also going to be like auditory information we're also going to see information coming from the visual like from the occipital lobe for example because we talked about how Vision the signals get transmitted back to the occipital loob there but also information from the frontal cortex as well so the motor cortex is getting all the sensory information coming in from all these different places to be able to get a whole picture of like okay what's going on what am I hearing seeing feeling all that can be important information to then decide what am I going to do in terms of movement there and so we'll see the subcortical fibers from the Corpus kosum coming in from the opposite central hemisphere or cerebral hemisphere so he's getting information from the other side of the brain as well and then we can get some signals coming from the thalamus so this could be things like touch for example um this could be information from the joints or the muscle signals here it's also getting information from the basil gangle and the cerebellum so we'll talk about those more in detail in terms of their function as well and then we'll find these kind of intamin or nucle the thalamus helps to control kind of General overall level of excitability so there's a lot of different things you're going to be inputting on the motor cortex not just muscle signals but like everything else so frontal cortex we doing a lot of like decision making critical thinking get information from the visual cortex all these different places are all feeding into the motor cortex and say okay this is what we want to have happen and then make it happen Okay so some ways that we can have that then occur is partly through this red nucleus and so this is sort of an alternative pathway where we can get these sort of cortical signals down into the spinal column itself so this is sort of skipping places like the cerebellum and the basil ganglia U and this is more so for like really discret activation of certain muscles so I think a lot about um things like f control of the hands and and fingers a lot of that can be transmitted from the motor cortex through that red nucleus directly to those muscles to cause individual contractions and relaxations here um if you have destruction of this part of the brain you will have an inability to have that kind of fine control there so kind of showing you how it has that sort of direct ination that Direct Control of contraction there um generally speaking this is pretty small in humans and other animals and mammals you might see this being much more developed but we don't necessarily rely on this as much because we have nice organs like you know the basil gangling and the cerebellum which can help us with more kind of complex patterns of movements and whatnot okay so looking at this excitation here we can see there's both Dynamic and static signals they're going to be made so like we talked about before and you're going to be sent by these peral neurons right so um you see a lot more of these within the the more higher proportion of dynamic inputs coming from that red nucleus which kind of makes sense because it's causing that kind of direct interation direct activation of the fingers and things like that um and then we're going to get the smata sensory feedback to the motor cortex and that helps us to have Precision so by getting inputs from things like the tendons and the muscle spindles by getting input from the smata sensory cortex telling us about tactile responses so like if we can feel things with our fingers for example or on the skin um and that will allow us to feed all that information in to give us an idea what what the muscles what the body's actually doing there and then based off of feedback we can either cause enhancement or an inhibition of muscular contraction there so for example if we have say the muscle spindle stretch feedback goes to the motar cortex so if it's detecting that the muscle is lengthening that can then send a signal up to the brain that says hey the muscle stretching out then we send a signal back down that says hey cause that muscle to contract part of that will just be that direct spinal reflex that we talked about previously but part of it can also be coming from the central um sort of control of the motor cortex itself then if we're looking at the brain stem control of motor function here we can find that the um kind of the lizard brain kind of these lower brain stem portions here like the medula the ponds the mezan sephin um these help to provide a lot of like Baseline control of body function so things like a lot of unconscious sort of involuntary actions like your cardiovascular system and the GI function equilibrium it's important too we're going to talk about that a little bit later in this section um usually I talk about it with like hearing since it's part of the you know ear but we'll talk about it more specifically for equilibrium in this portion here for the motor control um eye movements all that and really this is kind of like a Way Station this is like where all signals are coming up and down through the spinal cord um and so this provides a lot of interfacing there where you're going to see a lot of help with controlling the signals that ultimately make it back down to the muscles so you can see here this pontine retic nuclei and there's also a medular reticular nuclei so you can see here the pontine and then the meary um reticular spinal tract here um these are going to be antagonistic to one another and so whereas you will have the pontine reticular nucle actually cause excitation of anti-gravity muscles every time I read that I think about people like floating for example but really it's just keeping you standing up against gravity um and so that will actually excite that and then you'll find the medular reticular nucle actually is going to have relaxation of those muscles so if I was going from say standing to a sitting position you might be relaxing certain muscles that could be re mediated this medul particular nuclei for example then we'll have the vestibular nuclei here as well and so this is going to be working based off of the input coming in from the uh Cate here we're going to be able to get this input telling us about things of movement of the body so are we um turning our head are we you know accelerating in a car for example um this is useful from the vestibular apparatus I should say um is helpful for maintaining equilibrium be able to maintain standing so if someone for example comes and gives me a light push on my back that vestibular apparatus will be able to detect that motion and then we can have places like you know the pontine and then the meary um tract here we're going to be able to then stimulate those anti-gravity muscles to keep me from falling over right I'll talk more specifically about function of vestibular apparatus in just a little bit we talking more specifically about how these are going to work uh to send those signals to the brain in the first place all right so let's get into the cerebellum and the basil gangle and some of their functions in terms of motor control surpris I'm not seeing any questions yet so either I'm doing a great job or you guys are still trying to parse through it and you have formulated your questions yet but anyway so um cerebellum we're going to talk about first here is has been known as the silent area of the brain I had to look that up to see like well what does that mean and basically through research um you know if you stimulate places like the motor cortex you're going to cause the muscles to move or if you stimulate It Whatever muscle associated with or if I stimulate of sensory cortex patient will have some sort of sensation um but stimulating the cerebellum doesn't really seem to do anything and so that's why they called it the silent area and for a while they just didn't really know what the cerebellum actually contributed towards now we know that it's really useful for helping us to work on doing things like going from one Progressive motion to another um so I think a lot about like playing guitar this is kind of my touch Point um so if I'm thinking about going from say a c chord to a G chord my fingers need to make a smooth progression otherwise it's going to sound really bad when I'm playing that and so in addition to that it also helps out with making these sort of corrective adjustments based off of what the desire was from the cortex saying oh yeah you want to play that G chord along with sensory input so if all of a sudden I play it and it sounds terrible that auditory signal will also feed in to be like wait a second that wasn't right that motor movement was incorrect and so it's useful for helping to learn from mistakes and useful for helping to provide some of that muscle memory that makes it very easy if you know what you're doing to go from a c to a g to a d and whatever the case may be and this nice Progressive sort of flowing type of motion there also good for planning kind of sequential movements so again if I'm playing chord to chord to chord that's going to be kind of managed here through the cerebellum so you can get see how it gets broken up into sort of three main areas here you're going have the vermis which is going to be right in the middle here um this is going to be controlling functions within the axial body so basically the trunk uh neck shoulders hips those functions are all kind of located there which you can kind of see the different body parts kind of jutting off but generally the actual um portions of the body are going to be relegated to the vermis here the intermediate Zone which is initially kind of right off of the vermis here is going to be more so contractions of like the distal portions of your upper and lower limbs so arms hands and feet things like that and then the lateral zone is going to be basically joining up with that cerebral cortex and is where we see a lot of that planning of sequential movements happening there so going from say one dance moves to another dance move smoothly um that's going to be the lateral Zone communicating with the cortex there again your brain's going to say hey I want this thing to occur and then the cerebellum is going to say okay well we've done this a million times so here's how you do that uh going from this step to this step to this step there's a lot of kind of um inputs and outputs within the cerebellum so these input Pathways of where they're getting their signals from so there's a couple different ones so one we have the quo Ponto cerebella pathway and so this is going to be taking in information from the cerebral cortex premotor cortex and then also the somat sensory cortex so it's going to be passing through the pony nuclei on this Ponto cerebell tract here and'll be terminating again on the opposite side of the brain from the cerebella area so again having that crossover that happens there from one side side excuse me to the other um there's an olivo cbell tract and so this is going to be coming from this Olive portion of the brain kind of shaped like an olive and it'll be excited by fibers run or fibers from the cereal motor cortex basil gangli R taking the formation in the spinal cord so another place where we're going to be seeing a lot of inputs coming in from not just the cortex but also from places like the basil gangl which we'll talk about its function a bit later there's a vestibular cerebella fibers and so these are coming from the vestibular apparatus and so it's going to help us out with detecting movement and changes in movement and um with equilibrium because again if you're doing something like doing different dance moves you probably don't want to fall over on your face and so this is where signals coming from the vestibular apparatus can be useful there and then the reticular cerebellar fibers U these are coming from the reticular formation and then they terminate in the vermis itself so those are kind of the different inputs you're going to be seeing coming from different portions of the brain spinal column Etc and so what we can see here we're looking at adherent Pathways from the periphery here we're going to be seeing that you're getting these signals coming in from sever several tracks like we saw in the past slide there and then we're going to have one track coming out from the cerebellum it's going be this dorsal spino cerebell tract so this is going to be um coming from this uh inferior cell huncle it's always kind of a fun word to say terminating the vermis and the intermediate zones on the same side as origin and what this is going to do is going to be getting inputs from the muscle spindles GOI apparatus um your skin and Joint receptors going tell you tactile stimulation there and what this is good for ultimately kind of the details here are that it tells the cereal about the muscle contraction tendon tension rates positions of movement forces acting on the body so it's really kind of giving the cerebellum sort of a picture of what's going on with the body at the moment what are the muscles doing what kind of position are you in um to be able to then start to incorporate that information to make certain movement patterns happen um we also will have this vental spinos cerebella tract here as well um this is more so going to be um useful for telling which signals have been received by the anterior horns so basically what sort of signals have made it to the interior horns to then activate that movement so the cerebel knows okay I know that they've received that signal appropriately things are good or if things have gone bad it will say okay remember that's not great let's try to fix that for the next time because again this is really helpful for you know muscle memory being able to plan out these things and do things in a sequential sort of manner there all right and then U looking at the actual circuits within the cerebellum itself there's going to be these three nuclei that are located within the Deep sort of cerebellum that will then be communicating out to um the the cortex itself of the cerebellum oh someone said could you re-explain the cortico Ponto cerebell tract yes so essentially what this is going to be doing is getting inputs in from sort of the areas of the brain that are getting making the decisions essentially so you're going to be getting information coming from the cerebral motor cortex preot cortex um and then also getting some of sensory information coming in as well so it's just getting information from the higher brain areas whereas places like the Olo cerebella tract are getting information more so from places like the spinal cord for example so it's just a matter of seeing like where these different signals are coming into this is tracks itself um am I going to get as nitty-gritty or am I going to split the hair or I'm going to say very specifically where each of these tracks are coming from or I probably wouldn't say that necessarily but I'm more so thinking about like what are the functions of these different areas so for example um would I have you memorize specifically the in the retic cerebell OR fibers these terminate in the vermis I don't know that's necessarily as useful for your educ as opposed to more so thinking what the actual function of the things are going to be so for example here you're looking at this Slide the dorsal spinal cerebellar tract what I think is really the ultimately the important information is you're getting inputs from the rest of the body and it's telling the cerebellum what's going on where the muscles are they contracted what position are they in you know what kind of forces are being acting on the body that's what I think is much more important for your understanding than necessarily where each and every fiber is kind of going to and where it's coming from necessarily maybe that's wrong but that's how I kind of think about things um I think you're get the most Bang foreb from this stuff here anyway um so you're G to have these three nuclei hopefully that answer your question if not let me know um so you three deep nucle the dentate the interpose and then the vestigial and so the dentate here is going to help to coordinate these sequential movements so this is also known as a cerebral Bellum um and so that's going to be okay if I'm going from this step to this step to this step that's where that's going to be use there and this those kind of circuits are going to be functioning there on the interpose this is going to be good for cor coordinating reciprocal movements of antagonistic muscles in the peripheral limb so if you're trying to coordinate between like the bicep and the tricep which are antagonistic to one another that's going to be helped and partially controlled by the interposed nuclei and then the fial is where we're going to see mostly help with equilibrium to make sure that as you're carrying out these steps you're not going to then fall over and crack your head on the cement or whatever the case may be right and so um getting signals from the cerebell cortex these deep sensory affrant tracts to the cerebellum so basically you can see where they're coming from going to um so another thing here every signal inin cerebellum splits and both goes to the nucleus right nucleus and it also goes to the cortex in the outer portions here so what that looks like is this and this looks a little overly complicated but basically what I want to break it down as is that we're going to see here that as you have signals coming in from different portions of the brain so you can you see other input areas coming in here um you're going to have signals both coming in and going to the cortex directly which is on the outer portion of the cellum and then you're going to have some direct intervation of some of these nuclei here as well that then send an output signal and so these are typically when you have these input signals coming in are typically stimulatory causing the excitation of the output signal to cause some movement to happen versus if we have the signal when it splits off and goes into the cortex itself this stimulation here actually will help to stimulate an inhibitory signal so these kind of preni cells that will cause an inhibition now why is that important well because we want to control the overall excitation that occurs here and so it's important to have this inhibitory signal so how does that actually work in terms of function well you're going to see rapid movement stimulates the Deep nuclear cells and then so that'll happen first and then shortly after you're going to get this inhibitory signal coming in so it causes a sort of damping sort of effect here where you're not going to kind of overdo the movement that you would intended to do so for example if I wanted to reach out and grab someone's hand I don't accidentally overshoot it and like grab them closer to the Elbow for example because the initial movement signal is coming from the cerebellum to go shake the person's hand but then I get that inhibitory signal from the peni cell so it prevents me from overshooting it and we'll talk a little bit more in detail about what happens when the cerebellum is not working well and that'll sort of illustrate the functions and what the kind of role that the cerebellum plays in the first place um so this also can help out with coordinating kind of onoff states for antagonistic muscles to kind of keep your muscles from locking up so if I don't want my bicep and tricep to be activate at the same time that can help with that sort of signal there and then also helps to correct motor errors so by training these inhibitory signals here it can help to integrate signals where we have a mismatch between what the muscles should be doing and if we have a mismatch where the thing does not happen appropriately um so for example if I'm trying to play a G chord on the guitar but it sounds terrible I'm going to be getting signals coming in from the you know auditory cortex that get sent to that sahell and be like no that's wrong here's how you should do it correctly and it retrains things helps to correct those motor errors as well so it looks more complicated than it probably really is um but that's really what these signals are meant to sort of do so let's think about if we had some clinical abnormalities in the cerebellum let's think about when things go wrong and so here we can have things like dysmetria and a taxia so if we had a missing cerebellum someone went and just chopped it out um you would see that it could prevent the ability to sort of predict how far movements will go so very frequency very frequently the brain will overcompensate and you'll overshoot your mark So if I'm trying to reach out and grab someone's hand I just totally miss it go straight past it right um so part of that this past pointing sort of thing where you get this sort of delayed onoff signal going to the antagonistic muscle group so it be have a difficult time turning on the opposing muscle when necessary and also this other word here which I love this dieta kinesia sounds very fun um this is actually the inability to perform rapid alternating movements so you can't see me but one thing you can have patients do to test for C cerebell function is to have them take one of their hands and keep flipping it over so back and forth back and forth um they will have a very difficult time uh being able to coordinate going from one side of the hand to flip it over to turn it back to flip it over and that could indicate some cerebella dysfunction there uh similarly they could have disar or difficulty speaking because they cannot coordinate those muscles appropriately to make the correct sounds and then things like intention tremor so they're trying to move they start to get very tremulous during that because they're not getting the correct signals coming from the cerebellum so hopefully that gives you an idea of what the general function and what the cerebellum is going to be doing for us normally by evidence of what happens when it's not there doing its job all right about at the 50 minute Mark almost I'm going to keep going um go over halfway through the PowerPoint SL I'm doing an okay job there um so let's look at basil ganglia and motor function here so when we're talking about the basil ganglia is generally this whole sort of area of the brain here kind of deep in the brain we're going to be seeing places like the codic nucleus the paman the Globus paladis substantia and the subthalamic nucleus these are all making up the basil gangle itself and so this is if you thought the cerebellum was complicated wait to see the basil ganglia super complicated in terms of the different inputs and outputs um sometimes I think if you like we to look at my office and the all the cords I have behind my desk it probably looks something like this it's a very jumbled up looking mess there is order to it but I'm not going to get so far into the details to try to have you memorize okay well what's communica with a Thalamus and what does it outputs onto wouldn't get too much into that right um but I can tell you what it does and what it's used for so these are this paman circuit in particular is good for Complex Motor activity in association with the cortical spinal tract what that means is if we need to do very complex movements like writing letters of the alphabet for example if we want to do things like hammering a nail where we need to coordinate where we're going to be aiming the hammer and actually get the Motions or cutting paper with scissors so very kind of like direct skills that are not just necessarily single muscle movements but are patterns of muscle movements that we need to coordinate right um not many inputs from the primary motor cortex necessarily but we do see a lot of outputs on that primary and the premotor cortex so it'll basically develop a picture of what needs to happen and then send that signal over to the primary premotor cortex to then say okay these are the muscles you need to start activating when you have dysfunction and there's a typo in your slides I've reupdated this um it says writing on your slides it should be writhing um but if you have dysfunction in the paman circuit especially like at the GL with padus like if someone had a stroke for example um you could see issues where they have these kind of like writhing movements U particular like on the hands and the neck and the face it can be very uncomfortable um can be very painful in some cases here this is a process called athetosis um hard to describe without giving a picture but just Google athetosis you can find plenty of videos just to see Alum comfortable that looks there um you can also see unintended movements kind of these like kind of flicking movements as Coria that can develop as well um so again this is an important area of the brain we want to be functioning normally to make sure our movements are happening like we want them to the cod8 circuit is going to be more so used for cognitive control of motor activity okay so you're going to see this is going to be extending out to the cerebrum it's getting a lot of signals coming in and where we're going to be integrating things like sensory signals motor information we're taking this and kind of forming these thought patterns so this is more so for things where if I need to do a series of complicated task the cod8 circuit is what's going to be responsible for doing this so if you think about you know things that require more than 5 Seconds worth of movement a lot of this is coming from this cod8 circuit here so I use the example of response to a bear attack and I know recently in social media there's been a lot of um discourse about would you rather you know be caught with a random man or a bear and a lot of women pick the bear because at least bears are predictable but regardless let's say we do have a bear attack about to happen there's several things that need to happen I need to think about okay I want to turn around I want to run away I need to pull out my keys so I can open my car to get in to then close the door to turn on the car so you know things that are going to require complex movement patterns usually things that require a lot of cognitive sort of input of like okay I'm deciding that I need to do these things Cate circuit is going to help to make sure that happens okay a condition where we can have dysfunction of the basil gangly function H when you have Parkinson's disease um in particular dopamine is really important for helping movement to occur um and so this is where you have destruction of these neurons coming from the substantia so we'll talk more about how to treat Parkinson's disease um when we get into you know pharmacology at some point um but you'll notice here because they have destruction of these neurons that cannot release dopamine anymore you see a lot of issues where they have difficulty initiating movements so you can see things like rigidity they have uh this trimmer at rest that they cannot control um this ainia they have difficulty sort of initiating movements um difficulty walking appropriately kind of a shuffling type of gate to them um all because they have dysfunction of the basil ganglia here and just to give you an idea of what this would sort of look like if you look on the left this this is what the normal is and again there's a lot of different inputs and outputs it's very complicated but ultimately what this is saying is that if you have dopamine coming from the substantia ultimately you're going to get a signal from the thalamus heading to the motor cortex that says hey this is the movement I want to have happen on the flip side though if I have destruction of these neurons here that can no longer release dopamine you end up getting this really strong inhibitory signal to the thalamus and that signal never makes it to the motor cortex cause the movement so that's why the patients eventually if not treated Parkinson's patients will eventually kind of just totally freeze up they become catatonic because they cannot send those signals to the motor cortex that says hey start moving start walking whatever they're they're trying to do so again the specifics here are not so important but just it's important to know the difference is from the inputs to the outputs in terms of hey we lost his dopamine here from substantial Niger now we can't do any more movement because we have too strong inhibitory signal okay let's talk about equilibrium we talked about the ear previously when it comes to um hearing more specifically we talked about how the CIA worked by sending those signals um talked about you know the um endolymph and the paral lymph some that's going to come up again here as we're going to see because again the cocal and the vestibular apparatus are very closely situated one another um and so looking at this we can see we have these different canals here they're going to be associated with vestibular apparatus ultimately though they're going to be sending signals here through this cranial nerve number eight vestibular colear nerve um we send those signals over into places like the cerebellum for example they'll give us a sense of what's going on with like positional movement of the body so we'll talk about how that signal actually gets generated in the first place so again talk about hearing but now we're going to be more discussing equilibrium now that's going to be functioning here okay so vestibular apparatus good for balance good for equilibrium um made up of a couple different places here we're going to see the semicircular canals which you can notice here these different portions we're going to have the sacle and the utricle utricle is kind of fun to say and then we're going to have these ooliths which are going to be associated with this sacul and the utricle and helping us out and so these are going to do different things they're kind of detecting different types of movement as we get into it and then finally we know the C is going to be good for hearing but we talked about that already and so if you notice these semicircular canals they're sort of oriented such that they're able to detect changes in position along different axes and so uh depending on how you're moving your head for example or how the body is moving along with the head um you're going to get fluid movement Within These and so we're going to see The receptors are going to respond to that that will then um tell our brain that hey this movement is happening whether we initiated it or not The movement's Happening we need to know that information so a question it said so so many of these Pathways and circuits occur at the same time or is it there a preference for Pathways depending on the action um it's a lot of parallel actions happening at the same time right so you're having a lot of things happening in concert with one another some of which may be inhibitory some of which may be stimulatory but ultimately you're going to get one output that happens whether it's activate the muscle group or don't activate it whatever the case may be but a lot of these circuits are all happening in tand with one another which is why it does get quite complicated at times because you're getting so much sensory information coming into the brain and if recall like 99% of the sensory information we get is useless anyway but we're getting whatever important information is coming in to then integrate those signals to eventually go through these circuits to get an ultimate output to cause the movement to happen so again happening All In Parallel a lot of cases here hopefully I answered your question okay so just you can see here we have the anterior semi circular Canal we have the posterior and then the lateral and so these are going to tell us different types of movement as we get into it so um equilibrium very important we have this otherwise you're going to get nauseous you're going to fall over and not have a good time and so I mentioned the semicircular canals are good for rotational acceleration so if I'm moving my head from left to right or if I'm T tipping it from left to right that is going to be detected by the semicircular canals that rotational acceleration the linear acceleration is going to be responsible um with the or caused by changes in the utricle and the SA so this could either be horizontal acceleration this could be vertical acceleration we'll get more into those details here in just a little bit and the odor list what's going to help us to actually make that happen as we get into it we know that the inner ears consisting is bony Labyrinth I like the a fun word fun turn a phrase bony Labyrinth um it's right about this membranous Labyrinth here and so we're going to see that between the two here we're going to this fluid called the per lymph um if you recall there's also the endolymph as well and so um the difference is there if you remember from the hearing portion because again this is the same fluid that's going to be located within um the the CIA is that the endolymph typically has really high concentrations of potassium par lymph not so much and so we're going to look at that in just a little bit to see how that's going to help us to be able to detect movement and again it's not going to be all that different from the hair cells in the CIA if you recall when you get those sound vibrations being transmitted through uh the m incus and stapes that causes that fluid movement of the endolymph in or at least that um that membrane you're going to see that movement leading to those hair cells being pulled open along potassium to flood in that causes a depolarization similar things are happening here so the the form and function is not going to be all that different it's just doing sending different types of signals whether it be hearing or there be equilibrium type of things anyway um so you can see that depending on the orientation of the semicircular canal you're able to see that by moving the head in certain ways um that's going to cause fluid to shift around these different areas and so the way that's moving again remember you have two of these so one on the left and one on the right um based off of how those signals are being interpreted that it's going to send the signals into the brain that says like hey okay here's how the body is moving and here's how we need to respond to that okay so I mentioned that each Canal of the semicircular canals are going to be filled up with this endol that's going to have a high amount of potassium in it which is not normal for most of the body usually potassium is mostly located within the cells is going to be located within these semicircular canals so all right so each Canal has an ampula and so you can see the ampula located here and if you notice this is going to be filled with that endolymph along through this track here so as you have movement occurring through this fluid Canal it's going to be pushing this ampula left and right depending on which movement is going to be kind of detecting and so as you do that you're going to notice here these little tiny cells and so these are going to be getting pulled along depending on how the fluid's moving around in that semicircular Canal so I kind of think about it like if you see like a sea anemon in the ocean I it's pushing that around the fluid uh the currents can push that around similar actions are happening here and so you're going to see with each of the amp get the hair cells and they get embedded in this chista ulis which is fun thing to say and you're going to get this couple here which is the ultimate kind of this thing is going to be holding all this together here so we when you have again notice the endolymph is going to be filled up here and you also have this called a kelum so this is the largest one out of the bunch here and then we have the stereocilia uh the smaller ones and so as you have movement through here by pushing this back or forth um you'll notice these cells right here are going to either be opened up or closed and that's going to then send different types of signals so some of which will be excitatory and some hitory we'll get into so let's say for instance we have some rotation that makes the endolymph circulate around that semicircular Canal okay so what that's going to do is it's going to send uh that fluid wave is going to start to pull that ampula in one direction or another so in this case here if you notice it's going to be pulling in this direction here and that's going to be able to start to open up these cells which allows that potassium to flow in so similar to hearing with the hair cells there a similar function sort of happening and so if you're looking at the overall discharge of signals from the coar nerve vestibular nerve you're going to notice here that you'll have this sort of like Baseline level of discharge so it's kind of our normal no movements happening here and then all of a sudden you have some degree of rotation if you notice the big signal starts to get sent because those hair cells are being pulled open and then as the motion sort of stops it'll start to hyperpolarize and then you get back to your Baseline okay and notice here this is a pretty quickly adapting sort of signal so it'll be initially very strong signal let your body know oh this movement's happening but then as that movement continues to happen maybe it starts to die die down a little bit getting closer back to that Baseline okay once the rotation stops then it's going to go back to normal basically and so looking at this you can see the endolymph has an unusually high potassium concentration and so when those hair cells get pulled open it's going to then cause pottassium to flood in which causes the depolarization that then can release neurotransmitters onto the vestibular nerve to then send that signal over into the brain okay um and what's interesting too is you can see there's sort of a reciprocal sort of action that happens here so this is what's different from hearing is that whereas with the hair cells and the for hearing purposes they can really just be either activated or not here we can find there can be a degree of excitation it can be a baseline or it can be inhibited depending on which direction the ampula is being pulled because if you pull it the opposite direction actually will inhibit potassium in flux and actually will turn off the signal or at least turn it down and so that has to do with this reciprocal motion within the ears on the fact that we have two vestibular apparatus apparati I don't know what the plural apparatus is but if you have this turning motion here you can find that in say the ampula of the left ear you may have increased firing whereas on the right ear it's getting the opposite action because again as I'm moving my head or turning my head it's going to be moving the fluid in sort of opposite directions in each ear here um in the right here you'd actually end up seeing a decrease amount of firing because it's going to get pulled in a different direction I'll show you what that picture looks like here in just a moment to make that a little bit more clear um again potassium getting pumped into the endolymph that's what's necessary for that hassium content to cause these depolarizations to happen so looking at this picture here you get a better sense of what's going to be happening both that rest and then when you have stimulation versus inhibition um so the sterilia and it's got that one kyum associated with it um when you see at rest here you're going to have some degree of potassium coming in leading to kind of a static amount of discharges happening that's just telling your brain hey everything's status quo everything's normal nothing nothing going on here when you were to have that movement push the ampula this direction here we're going to notice the kelum is kind of pulling along with these hair cells pulling the potassium channels open that's going to cause an increased stimulation of signal so if my head was tilting say to the left for examp example my left ear might be seeing this increased signal whereas on the flip side my right side of my head I would be seeing the opposite signal and that's totally normal so i' be pushing the fluid in the opposite direction closing off those potassium channels and thus you see fewer Action potentials occurring there so that's why it's a little different than hearing because it can either not just be on or off but it can be a baseline rest when there's no movement can be turned on or it can be inhibited the case may be I guess I should turn the volume up in terms of signals or can be inhibited there so similar what we talked about just a second ago and stereosy bend towards the kelum potassium channels open and K rushes into the cell and depolarizes the cell once that pottassium comes in and causes the depolarization you're then going to have opening up of these calcium channels here so these are uh voltage gated calcium channels that will then open these up and that will then cause these little vesicles full full of neurotransmitters to release onto that cranial nerve number eight to then cause a signal to be sent over to places such as the cerebellum we talked about um if the bending away from the kelum ends up causing a deactivation so looking at this you can see if it's kind of going towards the kelum it's going to open up and activate those receptors or open up the potassium channels cause a depolarization if it's going bending back the other direction you can then see it's going to be more deactivated okay so kind of keep that straight and again it's helping us to kind of code for that detection of uh of Direction so if I'm tilting my head from say left to right twisting my head left or right um those signals will be reciprocated between left and right to be able to give you an idea of which direction things are moving okay so those were the semicircular canals and their General function now we got the utricle and sacle and so the utricle is good for detecting horizontal motion and then the SACU is good for vertical uh linear acceleration uh so for example if you were to feel um you know you start get an elevator and you're going up couple of floors that initial condensation might be coming from the sacle to let your brain know okay yeah we're heading up upwards right versus horizontal acceleration be with the utricle so always um so I drive a car that has a manual transmission it's always so interesting riding with other people because obviously they don't know specifically when I'm going to shift gears um because again you'll see that slight decrease in acceleration and then you hammer on the gas again and start to accelerate back again and so it's always interesting because I know I know when I'm going to shift and so my body is prepared for that so I don't really move around too much versus say if my wife is in the passenger seat and I'm hammering on the gas she's going to be as soon as that gear change she going to move forward and back um because she's not really prepared for it so again it has to go with being able to detect these signals again making some of this conscious control ahead of time um where you can get these kind of faster sort of responses or reflexes there anyway um Drive the speed limit don't drive dangerously it's my recommendation so you're going to see the difference here the stereosy here are embedded in oolithic membrane basically like those little calcium crystals you can see here and so you can notice the utricle here on the left I believe and the sacle on the right notice the orientation kind of makes sense of the oolith is going to be pulling either direction here for the utricle for horizontal motion St or the sacul is going to be going up and down so it's going to be for that vertical sort of acceleration and so they get embedded in this oolithic membrane it contains crystals of calcium carbonate so that's actually the same as like Tums same U calcium salt there but it forms these little ear crystals ear stones and so if you were to say tip your head down you would see that because these odists have some weight to them um they can start to pull the stereocilia along a direction to open them up to again allow potassium to flow in so the same functions happening here it's just a matter of instead of the semi or semicircular Canal um pushing fluid around the endolymph here instead now we have ooliths that have some weight to them that can pull it open as we start to have changes in our horizontal or vertical sort of motion there so once we get that signal we're going to see that the vestibular coar nerve is going to be sending signals um into the vestibular nuclei that we talked about in the midbrain so the M Meda blata and then also into the cerebell the main placees the signals are going to get sent to um then the medul is going to be sending neurons to the ocular motor area of the brain to control eye movements and down the spinal cord to adjust body movement so this is really critical because as we establish equilibrium it's trying to keep us from falling over if we're say standing up or whatever we're doing um and so it's important that we can be able to send signals down the spinal cord to be able to adjust those anti-gravity muscles as necessary also important that we have this communication between what we're seeing in terms of like changes in motion and what the ears are feeling and when you have a mismatch there between the visual cortex and this vestibular nuclei um that mismatch causes some problems we're going to see and again you can see that these all communicating one another so vestibular apparatus and cerebellum these are going to be communicating that vestibular nuclei the eyes are going to be getting input in the muscles and the joints and then we'll be sending signals both out into the ocular motor Center so we can help to control eye movements and then to spinal cord to help control General body movement especially those anti-gravity type of muscles so like I mentioned once you start to have a mismatch here you're going to have some problems so I always like to think about um cruise ships or to think about this fella here you can see is having some issues with virtual reality headset I'll pause this now not be distracting to me but basically um whenever you have this mismatch that happens here between what the eyes see and the ears are feeling you will start to develop some issues in particular a lot of people um will develop vertigo where they have this loss of equilibrium you can also see uh patients start to develop headaches or they can get really nauseous um so for example people go on cruise ships you know those cruise ships are so huge that you may be standing in the middle of the boat and your eyes don't detect any movement your ears still feel it though because you're floating on the ocean you're moving around and so it's very common for patients to complain an NAA vomiting when they go onto a cruise ship they get seasick um so again we may need medications to help treat that um but similarly if someone with a VR headset on their eyes are seeing something completely divorced from what their ears are feeling and so as a result a lot of people end up getting very nauseous or they get headaches um I myself can like use a VR headset for like 20 minutes before I start to get really not feeling great um because of that mismatch that's happening there so vertigo can happen there you can also see these kind of jerky eye movement which was called nagma so this person here this gift would be indicating this nagma kind of jerky movements of the eyes there um so not not a great feeling and so whenever possibly like to keep that information coming from the visual cortex information coming from the um vestibular apparatus to be in sync with one another so that when the ears feeling motion the ey should be seeing the motion too uh to be able to keep things nice and and copasetic as the case may be anyway so that does it for this section for the motor neuro function uh the last section we're going to cover is going to be more autonomic control of things we'll talk about the autonomic nervous system talk about um um things like you know sleep talk about brain waves we'll talk about things like um language like how we detect language and can communicate and how we form those uh the ability to form words and things like that I feel like my vocal areas are not working so well right now after a couple hours of talking but anyway um what questions can I answer for you at this time I feel like this is probably the most complicated sections out of the group there just because it's really easy to get stuck in all these different circuits and inputs and outputs and whatnot but ultim at the end of the day I more care about function than really anything else so as long as you can kind of describe okay what is the point of the cerebellum what is it doing what are the different areas responsible for um I think that's much more valuable than memorizing every specific different input and output uh from the grand scream of things but any questions are Alpha motor neurons only used in voluntary movement uh it's a great question let me go back on the slides here real quick sorry if anyone has a seizure disorder I want to cause any issues there um so if we were to look at something like this I'm trying to a better picture yeah so let's just say we have those Alpha motor neurons um that are located here um it can be for both right because in one situation you could have a signal coming from the muscle spindle and from the GGI tendon that's saying hey the muscle's stretching too much and that can then through these interations here send a direct signal that says oh you better contract that muscle back to oppose the stretching that's happening there so that's more of a reflex of sort of action there that would be involuntary to a degree you also can have the signal being overridden by signals coming from the cortex for example that would also inovate those Alpha neurons usually through the action of those inner neurons right there's a lot of middle management there so to speak that will affect that um so that can also cause activation for voluntary movements as well so it's both and as it turns out that question um any we could hold a review I'll do a cahoot but I don't know if there's any time uh for uh doing a specific review if you have questions please send them to me though I don't think I've ever received a single email from anyone in the class um or receed any from uh Dr Bolton so please please please send me questions even it's something you want me to like kind of just talk through again or um try to explain it a different way yeah I don't have any uh don't know if you have any time scheduled up for for doing a review because otherwise I'm just like I don't know what questions you have like I don't know what you don't know um so that can make it sometimes difficult for a review otherwise people just looking for me like give them like test questions or give them answers it's like wellah who could do that you know um but if you come prepared with something or if you have a list of questions that's much more fruitful when it comes to actually doing some type of review because I don't know what your pain points are where what areas you might be sort of having troubles with unfortunately just reach out I'm more than happy to talk to you I think actually I have got like one or two emails from from you guys uh throughout the semester but that's it uh can you re explain the Sarah balum per Kenji cell interaction slide 35 yes I can let go back to that okay yeah so this one gets a little can be a little difficult um so what we're seeing here here is that you're going to be seeing a lot of input signals coming in from all over the place so coming in from the body itself you know the muscle spindles coming in from tactile receptors in the skin coming from um higher portions of the brain we're getting input from the cortex U motor cortex mitos sensory cortex all that so basically what we're saying is is there's a bunch of input signals coming in and then ultimately it can stimulate some sort of output to occur and so what will happen is let's say for example I am trying to reach out to grab someone's hand so think shaking a hand right um what you're going to find is is that initial movement initial changes in movement between like my bicep and tricep and all that shoulder muscles and everything like that is coordinated right and the cerebellum helps to coordinate some of that um so initially these signals coming in will trigger or will stimulate this output to occur so that may initiate the movement of reaching out to grab someone's hand but it's Poss I for you to over shoot that right because if you have too much stimulation here instead of reaching grabbing the person's hand I'm going to like grab them by their elbow practically which that gets a little awkward so what happens is that because these Branch off and because they initially activate this one of these nuclei there's another signal that branches off and is going to activate these pereni cells and so a split second later once I start that movement once the enough movement has occurred then I get this inhibitory signal and that just prevents me from overshooting what I was meaning to do so in the case of dancing instead of like say trying to bend over to a certain direction instead of overdoing it to where it then causing me made fall over that inhibitory signal from the peni cells will prevent that from happening so it causes a damping it prevents kind of this overshooting effect or this oscillation effect that can happen there uh from happening so that's why those peni cells are so important and again this helps because it also works for um working muscle memory and it helps us to correct motor errors that occur so I mentioned for example if I'm playing a guitar chord and it's incorrect I will have auditory input coming from my ears that says oh that sounds terrible it will then send signals to the cerebellum through some of these inhibitory signals that says oh yeah that was wrong let me correct that for the next time and then when I start to get a signal coming from the ears that says oh that sounds correct Sarah Bell will make note of that and say okay that that works that signal um is appropriate and it makes it easier for that to then happen again later on so if I were to try to do the same thing next time that muscle memory will kick in again the more you practice those motor patterns the more that gets embedded in the brain the more easily you can then call upon that later on to then cause the motor functions that you want so me if that did not answer your question Kyle what other question can I answer so so the cellum portion I think is probably one of the more difficult things the other thing too is go back and look at that muscle spindle information kind of keep in mind how those are working both on an involuntary basis and then also we now want to have voluntary control of the muscles how we make sure that the muscles SP can be sort of overridden through the action of those gamma motor neurons that co-activate with the alpha um can understand the difference between voluntary versus involuntary control any other questions if not you're free to go thank you for joining me today appreciate you all all right I don't see anything so I'm assuming everyone's good to go um so again tomorrow's lecture will be pre-recorded so I'll make that tonight um and then have that available to you uh so the sellum enhances the signal from the penji or the cortex um so going back to this picture here if for looking at this make sure my uh Mouse is showing there so like this top portion here is the cerebel or cortex this is the very outer edges of the cortex here these would be within the the Deep nucle nuclei so if you go back to this past slide here there's like different nuclei like dentate interpose and fial um so this is showing one of those deep nuclei one of the cells there and so what you'll find is is that the nucle nuclei or the nuclear cells get activated first and then the Split Second later the peni fibers and these signals coming from the cortex then have an inhibitory action so this whole thing is a cerebellum there's different portions of the cerebellum that have one the stimulatory actions of the nuclear nuclei and then you'll have these inhibitory signals coming from the cortex to help modulate it to make sure it's not going to be too too big of a signal make sure you don't overshoot your mark if that doesn't answer your question and you're welcome Gabriella all right I don't see any other questions coming in so so thanks so much for joining me have a good one uh and I will you won't I won't talk to you tomorrow but you you'll be hearing me tomorrow because it'll be pre-recorded but have a good one and talk to you soon bye