In this solo episode, I attempt to make the nervous system less intimidating by sharing some concepts and models that can help us all understand the nervous system. One of those concepts is the “black box,” a theoretical object that accepts inputs, processes them, and creates outputs. We can view the nervous system as a big feedback loop that operates in this manner, and I share several examples of how the loop works to bring it to life. Another concept that helps us understand how the nervous system works is to understand that the brain’s #1 priority is survival and protection. Because of that priority, the brain would rather have us do less and not more in order to keep us safe, and our brains often impose limitations on our bodies. Finally, we’ll discuss how the purpose of functional neurology is to impact this loop by providing the right inputs, and what that can mean for rehabilitation and performance. Focusing on the software of the body, the nervous system, opens up breakthroughs in healing. This episode will help you better understand how to make those breakthroughs in your own lives and the lives of your patients/clients.
Garrett Salpeter: 00:00 – 05:48
Hello, Neufit nation. Welcome back to the undercurrent podcast. We’ve been on a break for a few months and are really excited to get back into, we can call it a new season, just like there was a break between seasons of your favorite television show. So, we’re excited to be back here. We got some new content coming down the pipeline and one of the things that I’m going to do a few more of are these individual kind of solo in between episodes, where I’ll talk about a particular topic that comes up in conversation that we get questions about, that might be interesting or educational and today, that topic is going to be the nervous system. I’m going to ask are you nervous about the nervous system, because we want to help demystify it and although in neuroscience on the frontiers of neuroscience, there is still a lot to be learned about the nervous system.
There are also some basic principles and concepts that we can share with you that I think will help to make the overall topic of neuroscience less intimidating, and some different models that we use a lot, that are really helpful because they lead us to be able to make interventions or come up with strategies and tactics that can help actually make people feel better, recover faster, get better outcomes, in their rehabilitation, in their fitness journey, whatever it might be. So, the first component of this when we’re talking about the nervous system, trying to demystify it, first component I want to talk about is to draw the distinction between the hardware and the software of the body. So, many techniques, methods and systems are focused on the hardware of the body, the bones, the connective tissue, all the different structures, the muscles, skin, everything there and that, of course, is important our hardware has to be working functionally and oftentimes, that can be a limiting factor.
But there’s also a really interesting world in software, the other side of that software, the nervous system, the control system of the body, there’s this whole other avenue for effecting change and it’s really interesting, because that’s a huge breakthrough that I noticed in my own journey, and that we see with patients all the time is that by focusing more on the software side on the nervous system, functional side function, in addition to structure, that those functional improvements often help people make changes much faster, much more significantly, because a large part of the problem when it comes to recovering from injury, reversing chronic pain, restoring movement, it was especially with orthopedic injuries, and chronic pain, the biggest problem is not necessarily the original insult or injury. But it’s the neurological response to that, which is the thing that makes it so difficult to recover, that makes it take so long, that keeps people locked in pain or locked in a cycle of dysfunction or limitation and so focusing on the functional side, the nervous system, and the principles, and these models that we’re going to share in this episode can allow for these really significant breakthroughs in rehabilitation, recovery, and therapy. So, definitely want to want to tee up the importance of that there, and then go into some of the high-level principles of how the nervous system works and there’s a really meaningful way to simplify it and that is to think of the nervous system as a black box. So, the number system, it’s a big feedback loop, essentially, we have inputs, we have outputs, and it’s all operating conceptually, in this, this model, you can think of as a black box, a black box is a scientific, you know, theoretical construct where you put something into the box, and then there’s something that happens, and then you get an output. So, thinking of the nervous system is a black box, let’s look at the inputs that might be given or provided into the nervous system.
So, the biggest inputs that we get are, of course, the five senses, what we see hear, touch, taste, and smell, vision, especially is a is a big one, we get more brain area devoted to vision than to any other senses there and then of course, touch our is how we interact with the world feeling our feet on the ground, being able to grasp and maneuver objects with our hands and then also related to that is the internal sense of, of where our bodies are in space. So, touch helps us feel where we are in the external world. Proprioception helps us feel where we are in the internal world is our internal sense of where we are in the brain how the brain makes a map of itself.
So, if my brain is watching my body move, it’s sort of like, like me watching someone move around in a room on a surveillance camera, that’s how the brain sees your own body moving around in space and proprioception can improve by or if proprioception improves, it would be like turning up the brightness on that camera or if you’re the person walking around in the room, and being observed by the brain or the camera, that sense of proprioception, it would be the difference between walking around a room with your eyes open, versus with your eyes closed. If your eyes are open, you can see where you are in space so much more clearly and you can avoid objects and different things like that. But if you have your eyes closed, you’re not going to be able to walk around the room as fast, it’s going to affect the inputs that proprioception into that loop, which will affect the outputs and we’ll get to that.
05:48 – 10:29
There’s also other inputs, specifically about that monitor muscle stretch. So, the muscle spindle that measures the stretch and speed of stretch of all the muscles of our bodies, the Golgi tendon organs not that you have to worry about the terms. But there’s a sensor in every tendon of the body that senses the load on that tendon and if it gets to be too great, if it reaches a certain threshold, then the body will shut down that muscle inhibit or turn off that muscle so that it doesn’t contract too hard and pull itself off of the bone. So, it leads to these protective mechanisms. The other sources of input are the thermo receptors, chemo receptors, bairro receptors, the sensors, the receptors that perceive changes in in temperature, or chemistry, like the presence, the pH, or the presence of carbon dioxide, those are two things that are very tightly monitored by chemo receptors, chemical receptors, bairro receptors measure pressure. So, there’s all these different inputs, and they’re all being processed. So, in the black box, we’re getting these inputs, and then they’re all being processed. Actually, millions of bits of information are being processed every second, from the internal and external environment. It’s a phenomenal amount of work at these lower brain’s subconscious levels.
So, it takes energy to do this is one thing that we want to consider, takes energy to just keep those parts of the brain working and that’s even before we get to the higher-level cognitive function, you know, the ability to do math or write poetry or make, you know, executive function, make good decisions, think, really, at a high cognitive, highly intellectual level. We got to be able to do these lower brain activities first. So, the brain is constantly monitoring every one of these inputs literally millions per second, constantly monitoring them, and running them through the filter of, is this safe, or is it threatening, because the brain’s number one priority is survival and protection and other big principle of the nervous system. The brain is constantly monitoring for safety and threat and his number one priority is survival and protection. So, it would much rather limit our performance, it would much rather cause us to not run as fast or throw baseball as hard or jump as high, if it thinks that we might get injured, and that injury could be a threat to our survival.
Our brain would also have us rather have us conserve energy spend less energy in case there’s a famine tomorrow, rather than expending all of our energy now and having us be at risk of ultimately starving. When we look then at what comes out of the black box, we get to the outputs, there’s a few different ones that are gonna be relevant to the types of conversations that we’re having in the worlds of therapy and fitness, and performance and a lot of those have to do, of course, with muscle function. So, range of motion, flexibility, tension, or relaxation of muscles, speed, or lack thereof, strength or lack thereof muscles, these are going to be based on neurological outputs and so when we see changes here, there’s going to be changes in the nervous system signaling and these outputs exist along a continuum between protection where the body will really limit.
So, if you think about the reduced proprioception, example, think about yourself walking around in a room where there’s a bunch of obstacles on the floor, or people you might run into, but you’re doing it with your eyes closed, you’re going to because of that lack of proper input, inability to see where you’re going to predict when you might run into something threatening, you are going to be able to or you’re gonna be forced to move around really slowly really guarded. You’re going to have more tension. Your movements are going to slow down. Your range of motion is going to reduce. You’re going to be moving around in this really guarded way. Whereas if you open your eyes, you are going to be able to see much, you know, obviously much, taking much more information be much better able to predict. When you’re gonna run into something be much better able to adjust your course. You’re gonna be able to move around with less tension, more range of motion, greater ease more gracefully, and your outputs are going to shift a lot more towards the higher performance end of that continuum.
10:29 – 15:00
So, this continuum, it’s not on or off good or bad. But it’s a spectrum. It’s are you more in this direction of wanting to protect and limit performance, or are you more in that realm of being able to take the brakes off and express all the potential that you have within you. So, as outputs exist along that spectrum. There’s other elements to this too. So, if you look at hormones, we can have catabolic and anabolic hormones that exist along that spectrum. We can have our stress hormones that we need to meet an immediate challenge our cortisol, adrenaline, and then we can have our more anabolic hormones released as we recover. So, that can be you know, testosterone can be insulin is very anabolic, different growth hormone insulin growth factor different, more anabolic hormones. So, those exists along a spectrum, and we want to have both, you know, in terms that we want to be able to move along the spectrum, same thing with heart rate and blood pressure.
So, those are outputs of the nervous system. Nervous system controls all the organs of the body, of course, the heart rate and blood vessels, and then the digestive elimination organs, reproductive organs. So, the nervous system makes a huge impact on the overall function of the body and then even mental and psychological emotional function. That’s I mean, those outputs of our thoughts, of course, then they can become inputs that influence the black box in this nice, recursive, or iterative way. But it can work for us or it can work against us. So, it’s really important that we understand how these inputs affect the function of that neurological loop or, or what we’re calling the black box here. I want to share a couple more examples of this just so you can kind of see it in action understand how it works. So, one, I want to just ask, have you ever had the experience of your lying down, you transition to standing up and you feel a little bit lightheaded. So, that what’s happening there is when you’re lying down the blood pressure, your body’s horizontal, and the blood pressure is approximately equal between your whole upper body and lower body head to toe, the bloods able to flow there, and then when you go to standing up, if the blood pressure stays even, gravity is going to pull all the blood down to your feet, and there’s gonna be less than your brains, you’re gonna feel lightheaded.
So, part of the neurological loop here, the job of a highly functioning nervous system, is to sense that change in position from horizontal from lying down to standing up and increase the pressure in the lower body so that the blood is supported from below. It doesn’t all pull down at the bottom, but it stays higher up in the body and the better, the more quickly, we can adjust the blood pressure and the blood vessels in the lower body, the better we can preserve blood flow in the upper body, the less risk there is a feeling lightheaded or passing out and the less we’re going to need to compensate by really increasing the heart rate to pump more blood up to the brain. So, that’s a really cool example and that can give you a sense of how robust your nervous system is, you know, at that moment in time, and that can change with different states of stress or fatigue and recovery, etc. So, you know, when you’re tired or worn down, under recovered, you might be more likely to have that experience where you stand up, you feel lightheaded, whereas other times, you know, never happens not an issue for you. Another example when we’re talking about movement is we mentioned the muscle spindle. This slinky like mechanism in the muscles that just monitors that the stretch and the movement of those muscles. So, remember the brain and nervous system want to protect us, that’s number one priority. So, if there’s some sort of setpoint for stretching of the muscle, as we try to lengthen out muscle lengthen out that muscle, we reach that setpoint and then all of a sudden, that mechanism is going to trigger an input in the nervous system of threat, alarm response, and then the nervous system that this is just at the level of spinal cord. This doesn’t even go up to the brain yet. That spinal cord level it’s going to say contract that muscle to prevent it from going any further and prevent itself from being injured or strained or torn. So, it’s a really cool mechanism. I want of course called the stretch reflex and that’s another example of this loop like function within the black box of the nervous system.
15:00 – 22:15
Another way to think about it is that the inputs can all go into a model that we like to use called the threat bucket. There’s a couple really interesting parts about this. So, if you fill up your bucket, if you give inputs like poor sleep, inflammatory diet, dehydration, you’re going to be shifting your movements more towards the protection side of that continuum. So, your performance is going to be down, you’re going to be your muscles gonna be more tense, less pliable, less able to lengthen to accommodate greater range of motion and so in that state, if you go out into that state, for example, and you go out and compete as a weekend warrior, you’re trying to do an intense workout, that’s a state where someone’s more likely to get injured. So, we have to look at those type of inputs as well, because those can all create changes in the black box and the nervous system and in the outputs that happened. One other interesting example of an output is fatigue. So, fatigue, this is a cool concept. So, there’s some research that shows that, of course, there’s local fatigue, as metabolic byproducts accumulate in the body. But there’s also a really interesting concept that fatigue is an output signal of the brain, just like pain is an output signal of the brain. That can be a topic for a whole other podcast.
But when the brain perceives that the body’s at risk of running out of energy, when the brain perceives that it’s too hot, that the body might overheat, it’s going to trigger a feeling of fatigue, which is a protective mechanism, where the brain by triggering that feeling of fatigue is creating this emotional state, this output that is going to, again, then act as a new input to try to get you the person experiencing fatigue, to do less, to stop working, to slow down, to take a break and that is the brains way of triggering a feeling just like it triggers the feeling of thirst, if it is trying to inspire you or motivate you to go drink water, it will actually create the output signal of fatigue and it’s based on those inputs, based on energy levels, based on the literal you know, hydration nutrition inputs that you’re putting in, based on temperature, based on your experience, many different things. So, several examples and ultimately, our goal is to find ways to influence this black box of the nervous system. The goal of NeuFit and functional neurology is to impact this loop so that we can improve the software of the body and yes, if there’s hardware damage, if someone has a sprain, strain, tear fracture, of course, we want to be responsible with the hardware, what we’re really adding into the mix here is that focusing in addition to the hardware, focusing on the software, and the functional response, the neurological response to injury and trauma. We can often help people recover. So, one story that I told in my book, and then the NeuFit method, we were in athletic training room working with a college football player, and he had five days prior. He had a grade two, they call it a two and a half AC separation. So, separated shoulder couldn’t lift his arm more than about 30 degrees up from his side and we went through our process with NeuFit. We went through scanning around on the body to identify where there was this elevated perception of threat where the brain was imposing those protective patterns to limit movement, where the brain was creating that output signal of pain and as we did our mapping process and found where those spots were, then we stimulated and we provided those inputs into the black box of nervous system to change outputs and all of a sudden, after eight minutes, he went from his only getting his arm up to 30 degrees with intense pain or just felt frozen to then getting it up to horizontal to then getting up all the way overhead with virtually no pain, like 0.5 out of 10 pain and he was just blown away and we got to ask, okay, what happened? Did his ligaments heal in eight minutes? Or was the problem part at least in large part was the problem the neurological response to injury that was keeping him locked in that state of limited restricted movement and pain? And that by changing function there we restored more range of motion and that I mean, yes, that is of course that is what happened, right?
He didn’t heal the ligaments the change was a functional rather than structural change. So, then, first of all, you know, it was amazing to him and to the athletic trainers and unfortunately they ended up getting a Neubie as well after that, but you also want to ask the follow up here, okay, for balancing hardware and software structure and function, is that going to be responsible? Are we just setting them up to the point where setting them up for greater problems by taking away that protective response? Where he’s gonna go out and injure himself? And thankfully, the answer is no, because in this case, and generally speaking across the board, the protective mechanisms are still going to be in place. What we’re doing is just providing inputs that can allow the brain to recalibrate. So, if he was, was actually, you know, when he got down on the ground to test out push-ups, for example, if those push-ups were going to cause injury, his protective mechanism would still be in place, you know?
We take the machine off, he’s testing it out, but they still exist, they still are going to be there to protect him. He’s just had this barrage of input that has allowed his brain to reset to recalibrate those protective responses, those protective patterns to more appropriate levels and for him, fortunately, that meant that he was able to work out with his team in the gym that day. He was able to practice return to practice the next day, and he was able to go play in a game that next weekend when he thought he was going to miss the next three. So, the structure and function they both matter. But I wanted to record this for you here just to help one, demystify the nervous system a little bit and two, help us see and understand why working with the nervous system, why prioritizing this functional work, working with it not in place of structural work, but prioritizing it more. So, it’s on a more equal footing with the hardware structure-based work, why that can really make an impact on recovery. I hope you found this useful. Thank you so much for tuning into this episode of the undercurrent podcast. Please, any questions, comments that you have here any requests for future episodes or other content that you wish to hear or listen to or see from us, please let us know share in the comments here and one thing that came up we talked a little bit about pain. That is a very interesting topic probably worthy of its own episode 2. So, that’s one that will probably come up and thanks again for tuning in. We will see you on the next episode of the NeuFit Undercurrent Podcast.
