Inside the Brain of a Cadaver

whether you're learning to walk for the very first time or maybe learning how to ride a bicycle without the training wheels or maybe playing instruments such as a guitar or piano or maybe you're learning to jump over a hurdle with the Finesse of a galloping gazelle muscle memory is truly something special I mean how does the brain work with skeletal muscles to not only improve at the movement over time but for you to think less and less about it the more you do it it is seriously impressive on today's video with the help of the cadavers here in the lab we're gonna be looking at the various regions of the nervous system associated with the execution and more importantly the refinement of skeletal muscle activity it's going to be a memorable one let's do this first and foremost muscles do not store memories or at least not in the same sense that your cerebral cortex or hippocampus does and we know this just based off of amputees right if an amputee has a robotic prosthetic they're still able to flex their elbow right it's not as though the loss of biceps brachii meant that they forgot how to flex their elbow but that doesn't mean that muscles don't store important information especially as it pertains to muscle memory but we will discuss that information in a later video in today's video I want to focus primarily on the neurological aspect of muscle memory but so if muscles don't really have memory what are we really talking about here we're talking about motor learning and motor development now motor development is the process of brain maturation and hitting specific developmental Milestones as you age right so you can see from a newborn as they go into childhood adolescence and so on and so forth now it's important to understand that within motor development there is a large genetic component to it as well as some environmental aspects so they've actually done studies looking at identical twins and seeing that they essentially hit the same developmental milestones at the same time even if you give more environmental stimulus to one of the identical twins and not the other so for instance let's say I have a toy we're playing with that newborn trying to get them to grasp it and play with it in ways that we're not doing with the other one well they still hit the same milestones at the same time but what's interesting is you do start to see later on in life that there is some differences they start to separate in some of their motor abilities and some of that could be attributable to what you're doing environmentally with them at a young age so I'm not saying don't play with children or stimulate children for sure do that it's just interesting to see that within motor development a lot of it is just predetermined right the person that child is going to hit those Milestones when they're supposed to it's so what we're going to be talking about primarily today is what's known as motor learning and motor learning is extremely interesting but in order to best understand it we need to understand what's happening neurologically when a muscle is Contracting but real quick I want to thank the sponsor of today's video yoga body Teachers College they specialize in science-based online certification programs for yoga teachers yoga breathing coaches yoga trapeze teachers and stretching coaches if you're interested in starting a new career or a side job helping people improve their health overcome injuries manage stress and live their best lives longer yoga body's courses might be right for you yogabody takes a science-based business positive approach to yoga they turn passionate students into successful teaching professionals since 2007 yoga body has certified over 23 000 teachers in 41 countries they are backed by yoga Alliance American Council on exercise and even American Council on education making them one of the only schools in the world eligible for college credits yogabody has put together a free report for you called how to choose a yoga teacher training program you can access it immediately at yogabody.com forward slash Iha you are looking at a right hemisphere of the cerebrum which is this highly folded area the cerebellum which is going to be down here and then we can also see part of the brain stem now if I flip it around you're going to be able to see these structures in Greater detail so again that highly folded area is going to be the cerebrum down here this really cool structure is known as the cerebellum and we can also see the brain stem but when you look at it from this medial view you're also going to see some internal structures this is what we call the diencephalon but there are also going to be structures that we just cannot see because they're kind of like they're deep right so if my where my fingers would be intersecting all along here there are going to be accessory structures that we're going to be discussing later on now let's go ahead and figure out exactly what's happening if I wanted to wiggle my fingers so in order to do that let's really quickly understand some other landmarks so you'll notice there is a line that goes all the way up like this this line here is what's known as the Central sulcus and what it does is it separates the frontal lobe which is all of this here from the parietal lobe which is going to be here you'll also notice there is a line going sideways right here this is called the lateral sulcus and this separates the frontal lobe from the temporal lobe now if we're looking at the frontal lobe there are going to be specific areas that we're going to be focusing on so again this is going to be a little difficult to tell but roughly about right here because in order to really understand where a lot of these areas begin and end you'd have to be looking at a microscope so generalizing it this macroscopic level is perfectly acceptable but this right here is what we call the prefrontal cortex but this is where I say like um and actually I did an entire video on the prefrontal cortex so we'll go ahead and link above for you to check that out but this is where things like morality empathy rational decision making you just think of it this is where you are located this is where your personality and just you as a person are essentially located at least the conscious aspect of yourself but for today's video we're going to be focusing more so on these areas right here so again if we find that Central sulcus and we trace it up just in front of it there is a narrow strip that we call the primary motor cortex then if we can look up here and about right on this area here this is what's known as the supplementary motor cortex and then down around right here this is what's known as the pre-motor cortex and then again behind that Central sulcus there's another strip just like here as I'm outlining my probe called the primary somatosensory cortex these four areas are all going to be involved in muscle contractions now I should also really quickly differentiate well what I mean by Cortex versus lobes so for a second ago I said this is the frontal lobe well a lobe versus cortex what we're really talking about is gray versus white matter so if I turn this around again and you look closely you're going to see that there is gray strips on the outside of it you're also going to see a bunch of white strips gray matter is where cellular processing is going to be occurring so this is where neurons are communicating with one another so if I wanted to wiggle my fingers well that is going to actually be happening in those motor areas of the cortex or the gray matter so gray matter is the cortex white matter is where the signal is then sent so what will happen is that signal would travel through the white matter and eventually make its way down and we'll trace this pathway again in just a moment but down to the fingers so if we're talking about the frontal lobe the frontal lobe includes the white and gray matter in that frontal section but if we're just talking about the gray matter we're talking about the cortex and that is just the surface of the brain and it's just going to be that gray matter now the cortex itself is actually layered or has what are known as laminate and there are six layers and I know that doesn't really look like it because again if you go to this and see just how thin this gray area is there are six distinct layers here and what you'll find in these layers are different cell types and just different other kind of proteins and molecules but what we're really going to be focusing on is inside of the fifth layer there is a large cell called a large pyramidal cell that we also can call an upper motor neuron so what's going to happen is this is this is the excitatory cell in terms of muscle contraction so this is what is going to send that signal now initially if you want to you know contract the muscle that's going to originate inside of the prefrontal cortex so the prefrontal cortex says Hey I want to wiggle my fingers so then you're going to then send signals to that primary motor cortex the primary somatosensory cortex and these other ones saying let's wiggle the fingers and what will happen is they will then that large pyramidal upper motor neuron will excite and that will then start sending a signal but there's nothing I do want to quickly clarify you may be wondering well if this area is called the primary somatosensory cortex wouldn't that be sensation why why are we talking about this having motor neurons well this is actually super interesting yes this area of the brain is responsible for processing feeling right as I'm like poking my hand that signal right is being sent to the primary somatosensory cortex and that's where I'm understanding it wouldn't it make sense to also have upper motor neurons that then can respond to that stimulus in the same vicinity and then it can kind of modulate it that's exactly what happens so around 30 percent or so of the upper motor neurons are going to actually be located in your primary somatosensory cortex kind of wild all right so what's going to happen is again we so we want to do it we're going to send that signal and it's essentially and I'm going to kind of skip a few steps because it can get really super detailed but we will address some of them later on that signal is then going to travel through various regions of the brain and go down into the brain stem if I lift this up here this area of the brain stem specifically is what is known as the medulla oblongata and it's here that the signal is actually going to switch sides so let's say I want to wiggle my left finger as well that impulse is going to originate inside of the right hemisphere in those motor areas and it'll travel down get to the medulla oblongata and that's where it'll switch sides then what will happen is the upper motor neuron will descend down the spinal cord in a specific white matter tract way called the corticospinal tract from here it will then synapse or meet up with a secondary motor neuron called a lower motor neuron which that will then exit the spinal cord go through a spinal nerve and eventually make its way to the muscles that can then cause the contraction so this is going to be that typical pathway but this is the thing is that's just saying okay we're sending the signal straight to the muscle but there's going to be a lot of steps that can help modulate and change that so let's go ahead and look at that now now just a moment ago you may remember me saying that this area is called the cerebellum and that just means little brain the cerebrum which is this highly folded region that actually translates directly to brain now the cerebellum is fascinating for multiple reasons again it's just really awesome to look at but this is actually receiving incoming sensory information based around positions so think about it like this every single one of your soft tissue so your joints your muscles your tendons your ligaments all have Sensory neurons inside of them that are relaying to the cerebellum positional information so right now biceps is a certain length triceps is a certain length and that information tells my cerebellum that my elbow is in its extended state but if I move biceps triceps is also along for the ride that change is then processed within the cerebellum and again I now know my elbow is flexed so if I close my eyes it's not as though I feel as like I've disappeared now there's other aspects of the brain now again we can't see these if you remember me just a moment ago saying that there were deeper down structures we can see like part of it like this hollow aspect of the brain here is called a lateral ventricle and on the walls of the lateral ventricles that's where we if you could see in there we would actually be seeing portions of what are called the basal ganglia or the basal nuclei now the basal ganglia there are three of them you have the caudate nucleus the putamen and then the Globus pallidus now there are other structures that are commonly associated with the basal ganglia like the uh the substantia for instance but those aren't technically basal ganglia now these are also receiving incoming information from all over the body now these are gray matter so they are this is where processing is occurring and what's happening is they are essential for making plans around motor movement and motor Behavior so think about it like this I have all this incoming information going to the cerebellum going to the basal ganglia the upper motor neurons but go back here so those upper motor neurons that were in these motor areas those large pyramidal neurons are going to start sending as they're going down into that lateral corticospinal tract are actually going to send offshoots to the cerebellum and into those basal ganglia in order to modulate because if they're saying look this is where your joints are at this is where your muscles and soft tissues are at how about we contract in this subtle way think about it like in terms of what if you're LeBron James right LeBron James no matter how good he is still has to warm up when he gets onto the court let's say he just woke up and I said LeBron like I woke up LeBron James and I said get out there and start shooting the basketball LeBron I don't know why he'd listen to me in this scenario but let's just go with it Brahma get out there and as he's shooting the basketball he's going to be amazing No Doubt but he still needs to warm up so as his muscles are Contracting information from that contraction is actually being relayed to the cerebellum and and the basal ganglia and they're saying ah we need to tweak that so then they send the signal back up to those motor areas and synapse with the upper motor neurons and modulate tweaks how the signal is sent so you start to get a more efficient signal that is then going to travel down to the spinal nerves this is why warming up is so essential this is motor learning right now think about it like this in terms of uh you know LeBron James is already good so let's say we trace it back in time right back when LeBron is five or six years old I don't know when he started playing basketball but let's just say it's five or six years old when he's doing that and he's first starting to learn how to shoot the basketball well it's a new it's a new Behavior it's a new series of motor tasks all of that is still going to be happening but the more he practices the more the brain is saying oh this is an important task we need to prioritize this pathway how essentially when you are getting good at something when we're talking about the neurological component of muscle memory we're just saying how efficient are you at speaking between these motor areas these motor areas right here and the cerebellum and the basal ganglia the more efficient you are at you speaking all of or having all these speak to each other then the more proficient you're going to be at that task and then the more you do that what ends up happening is that tracked way because if you recall me saying that white matter white matter is actually the signal being sent well what makes that white these are axons of neurons that are wrapped in lipids we call this process myelination the more you use a pathway the thicker the myelination is going to become and the more efficient the signal is going to be transmitted so as LeBron is practicing what's happening is the body's like oh this is an important thing to do it myelinates these Pathways and makes the process more efficient this is what we're talking about with muscle memory but it's not just LeBron James with basketball this is you with all sorts of tasks you know I've been playing guitar for 15 years that makes me sound like I'm really good but I'm not but there are certain songs that I can have a full-on conversation with someone and play it and that's because my body has learned to prioritize that pathway I've played Tom Petty's free Fallen I I'm not even I'm not uh lying here probably around 10 000 or more times I can play free Fallen really well and that's because I have that muscle memory the neurological component of it it's just a very efficient and effective speaking uh between those motor areas the cerebellum and inside and the basal ganglia but like I said this is only one aspect to muscle memory there's so much interesting uh stuff to talk about when it comes to practicing should you practice in more of a block format as in you know I practice at the same time every single day in the same way for the same length or should you do more randomized practices and this goes for plain instruments uh any type of new behavior that you're trying to do all of this Falls underneath that umbrella of motor learning but again we will discuss that as well as the muscular components in a future video thanks for watching everybody I really appreciate you hanging out with me be sure to look at that link in the description below for yoga body Teachers College as always be sure to like comment subscribe if you feel so inclined and I'll see you in the next video [Music] thank you

Channel: Institute of Human Anatomy

Views: 246,811

Keywords: muscle memory, what is muscle memory, motor learning, what is motor learning, motor development, do muscles have memory, how does muscle memory work, cerebrum, cerebellum, motor cortex, primary motor cortex, upper motor neuron, lower motor neuron, basal ganglia, basal nuclei, putamen, caudate nucelus, globus pallidus, thalamus, corticospinal tract, myelination, how does practice work, what practice does to the brain

Id: _8aA6OxMFxc

Length: 18min 43sec (1123 seconds)

Published: Sat Dec 24 2022