You Are Here: Proprioception

are we? Where are we in terms of time and space? Where our arms? Just sort of basic stuff that we take for granted on a near constant basis. Yeah, this at first glance seems kind of like a stoner question. Where is my body? It's right here? Um, but you're right if you look at a little bit closer. It's amazing that we can locate ourselves in our body. That we have this meta sense that combines our brains knowledge of what our muscles are doing with a feel for

the size and the shape of your body. Because as we know, um, the way that we take in data and we parse it in our brains is not always. Um, so straightforward, it's not always actually correct. So of course we're going to talk about some weird things happening with appropriate exception. Just to go back to the what you were doing earlier with your nose though, I'm going to try it myself, and I encourage listeners who are not trying Okay, let's see or otherwise engaged to do this

as well. Closing my eyes and then my hand is out to the side, and then I'm going to reach in with my finger and I'm going to attempt to touch the bridge of my nose. And I got it here. Oh I can't there's a headphone over it. But but I would have had the headphone not I was kidding. You actually did get the bridge of your nose. Yeah, okay, good, good, good. So what was that of that all about? How did I find my nose? Right? Because I couldn't see where

my nose was. I couldn't here where my You could use echolocation like a bat to determine where my my hand was and then guided in towards my nose. Um, I couldn't smell where my finger was and then negotiate it into place. Yeah, I was about to say this is not one of those here's one of your five senses. Because we've talked about that, there were pretty limiting to say we have five senses. There's obviously stuff going on beyond that. And if you've ever hovered your hand over

a hot iron, you know that automatically, right. You didn't get that sense of heat from licking that hot iron, from smelling it, from tasting it, from touching it, um from seeing it. There was another thing going on with the nerves and your fingers that were saying, hey, here's some data about that object. So that's what this meta sense appropriate reception is. But you can't get into the meat of it until you kind of talk more about the nuts and bolts of what's happening inside of your

body and how that connects your mind and body. Yes, we're talking about American philosopher and psychologist William James two through nineteen ten. Very important thinker, a lot of ideas that were especially in this case controversial at the time and really ahead of of of his time in terms of the way he was thinking about our experience of reality and how our our brain engages and all of that,

and he came up with a thought experiment involving a bear. Yes, now this was covered in a Radio Lab episode, but we wanted to bring it up because it is so central to our conversation today. This thought experiment was imagine you're walking through the woods and a bear attacks, Okay, or just shows up. Really, that's that's enough for me. That shows up. And he's wondering that feeling, that emotion, that fear, what is that feeling made up of? Where

is it really coming from? And so what he gets into is this idea that it's your body kicking off the sense of fear. In other words, it's not your emotions that you feel at first, it's your body having the response. It reacts to the stimuli first, and then the chain reaction informs your body of how to feel emotionally or your brain how to feel. So this was tested out by the idea that people who are paralyzed

from the neck down wouldn't exhibit fear. This is what he thought, right, because he's again arguing that your body is essentially feeling what's happening and feeling the fear and then informing your brain on how to think. And so if therefore, if the if the body were cut off from sensation, then it wouldn't the brain would not have a body to tell it to be afraid of the bear, right exactly. And so he thought thought, okay, well, if you're paralyzed in the neck down, then this should bear

out right. But he finds out that this is not just as cut and dried as he had hoped. This is not, in fact happened. People who are paralyzed the neck down still experience fear and and could still be eaten by a bear from just a very physical, literal sense. Yes,

not exactly. Yeah, However, some such three years so later, neurologist Antonio Dimazzio, the director of the Brain and Creativity Institute at the University of Southern California, who is a paraplegic psychologist, I thought there might be something to this because he said that his emotions weren't as strong since um becoming paralyzed. And so he conducted studies of able bodied people who became paralyzed and found that they reported this same sense of lessening and feelings feeling less sad

or less happy. As we bring this up because once again we see, as Dimazio says, our being is rooted in a body state. Yeah, it comes back again and again our podcast to that that idea we rolled out of the man on a horse versus the centaur. Right, there's the the old notion that our brain is this rider on a horse and the body just obeys the mind, and that's all there is to it. But the more we understand about how our brain works and how our body works, we see that it's more of a center

model where the rider and horse are one. You can't you can't take the brain apart from the body without losing a part of the overall self. Yeah. I was thinking about this morning when I was driving in I thought, when was the last time I felt like I was just punched in the gut from information I was taking in? And actually wasn't that long though, And uh, I thought, you know what that was exactly it? I felt that physical in my stomach and then I had a cascade

of emotions that followed it. Yeah. I think they brought this up in the Radio Lab episode. Well, they were talking about our own memories of feeling fear. But it made me think about reading stories in which someone encounters something fearful, which which I frequently find that because I read a lot of horror and suspense. But but when you when you read these stories, it's never something like and then Randolph encountered a ghost and had the idea

in his head that he should feel afraid. No, it's always the author always describes a visceral reaction to something horrifying. You know, hearts are leaping, skin is crawling, um bowels or maybe avoiding. But but but that stuff comes immediately before, sometimes separated by seconds, minutes, days, hours, whatever, before they actually are able to assemble what's happening in their mind. Yeah, that's why that that cliche of being punched in the gut is so true, because we have an innate sense

of this pre pre reception working on our emotions. Right. Um, so again, let's talk about approprioception. What is it? It is actually stimuli relating to position, posture, equilibrium, or our

internal conditions. Um. It is the sense or rather senses of position and movement of our limbs and trunk, the sense of effort and the sense of force and the sense of heaviness, and all of this information coming together in the brain to form a picture of who we are, well, not well, not as much who we are in this scenario, but what we are, what are parts are composed of, what those parts are doing, and where we physically are.

And it's interesting because if you, if you just take any given moment, we tend to fall back on a visual understanding. If you, if you ask yourself the question, well, what's my body doing and where am I? We think, oh, well, this is me because I see me and I see my surroundings, so I know where I am. We tend to think just visually about it. But it's far more complicated than that. Yeah, and that comes down to body schema,

in this sense of body ownership. So you in body schema, you have this model of where your mind thinks your body is in time and space. And in the paper and an implicit body representation underlying human position sense, authors long Goo and Haggard say that human position sense must refer to a stored body model, and this model has the body's metric properties like body parts, size and shape.

And in their study they found that without cues from a person's environment or their own muscle movements, and we'll talk more about that, that a person's implicit mental map to say, their hand when they tried to recreate it for the researchers was greatly distorted, and it bears out this idea that you can't have just the mental map alone of the body schema to to really know where you are in time and space, you have to have other clues. Yeah, it made me instantly think of Game

of Thrones for some reason. Um, have you watched any of the show? Well, you know there are a lot of scenes, inevitably, especially when things get a little more warlike, where you'll have general staring down at a map and then they'll be pieces on the map representing where the army is. Now, for a general to command an army, you're having to depend on that general sending out messages to the to the army to command where they're going

to go. And then those individual units in the in the army, you're sending back messages to the general to let uh he or she know where the army is. And then all of that is put on a map, and then the general has a has an idea in his or her head regarding the shape of the army, the formation of the army, where the army is and where it is going, and not to encourage a horse and rider view of the mind body connection. But that's

kind of what's happening here. There's all this data coming together and it's an assembling too, and it's really kind of a complicated, um, cognitive process. I mean, the human experience is more like a tapestry the more we look at it. But but that's kind of what's going on in this in this body schemma. Well, yeah, because if you're looking at this map that these men on the field, right, you could kind of look at the vestibular and kinesthetic

systems as being some of those men. However, they are not appropri reception, right um, you know alone. They have to be working in tandem to create that picture. So when we talk about the vestibular system, we're talking about the master controller of our balance and spatial orientation. And when we talk about kinesthetic system, we're talking more about motion and behavior, or rather even the habits of movements, like your eyes between the computer screen and your keyboard.

So that's some of the data that comes in. But according to Joseph Bennington Castro and he's writing for Ion nine quote comparatively pro pri reception has more to do with body position and focuses on the cognitive awareness of the body of space, so it's not just those two

elements of the stibular and kinesthetic. And this kind of gets us into this weird area too, because people will sometimes say, well, sure, pro preeception is kind of a medicine, but it couldn't be like alongside one of the five senses, right, because when we talk about the five senses, we're talking about experiencing the outside world, whereas pro preeception allows us

to understand the physical place within that world. So that's I just want to bring that there's a bit of quibbling when we talk about this as it's well, one thing about it, though, I feel like with with site, with smell, with hearing, these are all process processes that that seem a lot simpler based on that sort of

take it for granted every day um experience. But as as we've explored on the show, when you start looking at site in the way site works, or how smell works, or or how hearing works, all these are are far more complicated than we give them credit on a daily basis. I mean, just on hearing alone, you get into the two different ways that you hear the world hearing with

the with your inner ear hearing with your skull. You can you can take just about any of these these senses and you can divide them up into into more complicated systems, especially touch, as we mentioned earlier, you can get into all the various ways that are our sense of touch interacts with the world. I agree. I think that pro preception is just right there alongside with the other senses in the way that you can view it as pointill is um right um. Each one of those

dots creates that picture of whatever that sense is. So it gets us to this idea of how does our brain keep track of our body? Anyway? Yes, how does it do that thing that it does? We're gonna take a quick breaking when we come back. We're gonna jump into that question. All right, we're back, and we're gonna talk about how our brain keeps track of our body. So we're gonna go sort of into the nitty gritty

in a second. But let's get this obvious part out of the way when we talk about equilibrium and orientation, because in humans, gravity, position, orientation, those are all registered by tiny greens called odo life moving within two fluid filled sacks in the inner ear in response to any change or position and orientation and their motion is detected by sense hairs. So rotation is detected by the inertial lag of fluid and the semi circular canals acting on

the sense hairs. Okay, let's getting the weeds with all that stuff. So you have central nervous system integrating signals from the canal to perceive rotation in three dimensions. In the meantime, if you're saying getting off an elevator, let's slow mo this and figure out how your brain is then figuring out how it's transitioning from one place to another and where it is, right, because we've mentioned before

the elevator's magic. The door opens and we're in a different setting, and I suddenly have to figure out where I am, which way is right, which way is left, which way leads to the castle, which way leads to certain death, at least that's how it is in our building, right. So that's when you get into this idea that pro prereception uses receptors located in the skin, muscles and joints.

And if we slow mo this, we can see when we've got a microscope here, Uh, we're inside actually the muscle, now, muscle spindles, signaling the angle of related joints and telling the brain, hey, this is going on. And then you get stretch receptors getting in on the game. Yeah, and these are detecting small movements of the limbs. So again it's just general ideas of what are the limbs doing, what kind of what kind of movements are taking place,

what kind of force is taking place? Yeah, just another dot in the point as um picture. And then within the tendons that attached to muscles two bones, there are PreO pre aceptors called Goldie tendon organs, which would be clocking the muscle tension and reporting about that. Yeah. This gets into how much force am I exerting? Right, So, which is something that can get a little out of whack if you are, say, really worn out or maybe inebriated, but you need to know how much if you're putting

into your efforts. Yeah, you get that sense of effort because all of those different processes are informing like, okay, this is how much force I'm exerting, as you say, and then that's getting reported to the cerebellum, which would then take that information and try to determine the location and the movement of body. Parts, and finally it would match that up to the body schema or that stored body mob well that we talked about. But and here's

the rub body schema. Appropri Receptive cues aren't always reliable, Yeah,

because especially body schema. We've we've discussed before how the fact that body schema is notable is key to our success as they cool using organism because if you remember from our our episode on tool using tool use, when we use a tool, be it an ink pin, a hammer, or a battle axe, the brain adapts to that tool and incorporates it into the body schema, which works to our advantage this particular life hack, if you will, when we need to write something hamm or something, or chop

someone's head off. So you can see how when someone looks at a rubber hand, for instance, they might think that it's their own. Not initially, of course, but as you say. This idea that something becomes part of you um is steeped in a study by Marcello Constantini who had subjects view stimulation of a rubber hand and at the same time their own hand was touched in the same manner. Okay, so there succeeded at the table. Have your own hand. Here there's another rubber hand next to it.

That hand is being stroked. Your hand is being stroked. So you have the visual information of these two arms being stroked, and then you have the sense data reaching your brain as well of a hand being stroked. Yeah, I mean they come to feel like that rubber hand

is part of their own body. And this is called appropri receptive drift, and it's an example of how easy it is to have a spatial mismatching and um in the abstract of the paper that Constantini has says, current sensory evidence about what is me is interpreted with respect to a prior mental body representation, meaning that this idea of where we are who we are is kind of

easily messed with. In act, you can take the same idea and you can you can extrapolate it a little more and actually make the test subject feel as if they have three arms. And for this we look to a two thousand eleven study from Sweden's Carolinska Institute UH and this this is pretty pretty amazing against similar in a sense to the rubber hand illusion. They created an experiment where subjects had a prosthetic but realistic rubber arm

placed right next to their right arm. And then the experimenters started touching both right arms with a brush in the same location, trying to make identical brushstrokes in time and location, so similar again to what we saw we saw in the rubber arm. And I remember this is a first person view of this. They're they're seeing this

as their arms. Imagine across the room, right, I manage yourself at that table, looking down at your one left arm, your right arm, and then this plastic right arm there as well, and some stranger is stroking it um And what happens is is pretty crazy. According to head researcher Arvid Gurtustan, what happens is a conflict arises in the brain concerning which of the right hands belongs to the

participant's body, which one could expect. What one could expect is that only one of the hands is experienced as one's own, presumably the real arm. But what we found, surprisingly is that the brain solved this conflict by accepting both right hands as part of the body image and the subject experience having an extra third arm. So again it gets into that same idea of the body scheme is saying, all right, my the end of my left hand is a battle axe. Now, okay, we can roll

with it. And here the body schema is updating and saying, all right, is a third arm. It's psychologically before to like, how do people accept some some piece of information that is starkly different from what they thought was happening. Well, they just accept it, right, Um, So it's kind of not to you know, surprising that this would happen. But how do the researchers know for sure that the participant

is really accepting this body part as their own. Well, you've got to you've got inflict little pain, you gotta at least bring out a knife. And that's what they did. Uh, They threatened the arm with a knife, and they saw the participants a lynch and then you know, maybe it was just because they saw a knife. So how else would they measure that response? Well with a goalvonic skin response, which would measure the amount of sweat um, which of course is one of those things that's a telltale sign

of fear. Now you watch the video. I didn't. Now I'm imagining the researchers are there gathered around this individual with the third plastic arm there, and they've done some gentle stroking of the real arm and the plastic arm to to inspire this sense of of of having three limbs.

And then imagine one of the researchers reaching under the table, pulling out a dagger and just stabbing, just nailing that that third plastic arm to the table so that the dagger, you know, vibrates and quivers, and then the test of you just shrieks and uh and away. Is that what happened? Exactly what happened? No? No, but yeah, kind of except for like they didn't like, you just did this big arm movement that was big, overarching. I mean they brought out the knife and then they brought it up to

the hand. Um, so it wasn't any sudden movement. But you know, obviously there was an implied threat there. Well, they're probably standards in practice for the sort of experiment. There's a certain way you have to threaten your test subjects with a knife. Well, and they explored that. They explored this idea more by having someone have a mannequin right across from them and then having these little goggles on that gave them the vision of being the mannequin.

Does that make sense? Yes, they're they're wearing basically virtual reality goggles. They put them in the point of view of the mannequin. Yes, they see the mannequin, and you can. The video is great because it shows how they're this view of looking down at their mannequin body, and so the same sorts of things happened. They have a paint brush that's stroking them gently, and then of course all

of their responses are being measured. Uh, and then the knife comes out and it goes right straight across the stomach. And so again, what you're doing here is you're removing that distance. Um, you're changing it from a third person narrative, as we discussed before, a first person narrative. This is fascinating. I recently wrote a blog post about a recent study

where they took a similar situation. They had a lecture giving a lecture about some some topic, and they had individuals that were, uh that we're in a everyone is in a virtual reality environment to view this lecture. But some people have that third person sort of like that over the shoulder video game persona like like looking at a mannequin setting in front of you, and the other

said that first person view. And they found afterwards that the people with the first person view had better comprehension of the material and the lecture versus the third person, which, again you take the human experience out of the body experience and lose something in this case, um, memory comprehension of what is experienced in that body, right, so that that distance, that objectifying doesn't mean it's part of you,

so it's not as important. So the same thing with mannequin, and all of a sudden, if you are looking at yourself as a mannequin, you're the first person. You're you're the one who's having the knife dragged across your chest, and you're going to show that in a fear of response. Um. So we're actually gonna be touching on this a little bit in the sense of unconscious commonality in the next episode in which we talk about nominative determinism essentially names

forming our personalities. But but even then, when you see someone having the same name as you, you feel connected to them. You get a little bit closer to that

first person experience, right. And we see this in our body schema, and then we see it play out in our unconscious which brings us to the subject of out of the experiences because ultimately an out of body experience, which which does exist as an experience, Um, you know, it's it's not a situation where your soul is drifting away from your your body or your your you know, your your mind is about to travel the astral plane.

But the experience of existing outside of your body for brief periods is is a reality and it's kind of the the ultimate uh in in leaving the body scheme, leaving prop prio sception behind, right because um, we we've talked about us in different senses before, Like, um, if you have ever experienced sleep paralysis, what is that? But in misfiring of your brain and your muscles, you're waking up, but your brain is not quite there yet and so you can't move your body yet. Um. In the same way,

proprioception can go awry in out of body experiences. Essentially, that is the basis for them. And this has been looked at in pilots because pilots they can experienced the sensation of being outside of their bodies in something called g lock. That's called gravity induced loss of consciousness, and this occurs frequently with fighter pilots. Right, Yeah, if you've ever played a fighter simulator, which is my main uh tie into this sort of stuff since I've never powered

it a plane. Uh. You you know, if you you pull too many g's, you can experience, say a red out where all the blood surges to your head. You can get a gray out or even a blackout. Is the brain is the blood leaves your brain and heads towards your abdomen. Uh. And of course our brain needs to have blood to function, and so if enough blood leaves the brain, if you pull too many gs, you black out, you lose consciousness. But some other interesting stuff

can occur there as well, as explored by Dr James Winery. Um. And this is the the the individual who was interviewed on that episode of Radio Lab. We were mentioned earlier, specifically in a section of that episode titled Out of

the Body. Roger. Yeah, he looked at these pilots experiencing visions. Okay, because as you say, they get through these different red, gray, and then blackouts of consciousness, and along with them, they get different ideas of what's going on or their brains are presenting maybe a a tunnel sort of vision going on in a gray blackout. But with those people, those pilots who experience blackouts. Some of them said, hey, I

had some weird vision. Yeah, like it's it's one thing to like some of the examples where I found myself on the wing of the plane looking at myself, and that's that's weird and interesting, but it's more based in, alright, the reality of where you were. You just saw yourself outside of yourself. You were kind of viewing that model of the self that we talked about earlier, instead of experiencing it from within or or simply blacking out. Right.

That's fine too, But but some of the stories, for instance, we're you're blacking out and suddenly you're fishing on a river somewhere, which sounds so cinematic made up that it. Uh yeah, I wouldn't need to have they even bought that idea. Had I seen it in a movie, like our hero blacks out wall fighting the Germans in the air, and suddenly he's back home fishing, I would have said, that's complete hueie. But that's exactly the type of experience

that Winery came across in his studies. Yeah, they're fishing. There's another one which the guy was shopping for ice cream. So what I thought was interesting about both of these examples is that in this dream or what they call vision um, they were struggling with motor control. They were struggling with the real they were struggling to try to reach into that ice cream freezer to extract the ice cream.

And so what you see here, I think, is this idea that the brain has trying to square where it is in the motor control necessary to help it try to get its pro pre reception back right the body. The person, the pilot is in a situation where they're trying to pull back on the controls and gain control of the aircraft again, but they're they're losing consciousness, they're

blacking out. The brain is essentially losing not only a visual understanding of where that the individual is, but also a PreO perceptive understanding of of of what's going on, and therefore it has to fill in the blanks. Uh. We've we've run across examples of this in the podcast before, where the brain has to and actually on a regular basis, fill in the missing pieces in its perception of the

of reality. Now, forty of the subjects who reported out of body experiences, a subset of them had that kind of white lights at the end of a tunnel vision and we've heard about this before, right. Um turns out they were out the longest, and again that gives us a clue about the sort of um distance that they were from their bodies. The longer they're out, perhaps the less sort of data that they're getting in, the less that their minds can create a picture of where they are.

And the idea is that they're just so disassilitated, disassociated from their bodies that they're minds can't really pin them to space and time, and in that absence, that's the

story that's created. UM. It's interesting. In a two thousand five study published in the Journal of Neuroscience, the researchers actually used transcranial magnetic stimulation of the temporo parietal junction and they were able to impair the mental transformation of the body and healthy volunteers, essentially inducing an out of body experience. And did a recent episode This was with the guys from Stuff They Don't Want You To Know mind On we did one about shadow people, similar situation.

There uh electrical stimulation of the t PJ, which concerns self processing, self other distinction, multi central body integration. There's no one part of the brain that's involved appropriate reception. But but certainly the TPJ is in the mix. And in this case, in this one particular style you mentioned in that episode, by electronically stimulating this part of the brain, they're able to induce the perception that, uh, that there is another you, a sort of stranger you, just like

a few inches or less away from your body. So just able to take the the idea of who we are and where we are and skew it just a little bit. Yeah, if anybody is interested in reading a bit more about this, John Horgan has a great book called Rational Mysticism, and he interviews Michael Persinger, who was one of the people who uses those transcranial magnets and

who was looked into this idea of ghosts. All right, this is god helmet, the god helmet, right, And and um, I think you can get a good sense of how easy HIT is to kind of mess with someone's reality by by warping in a little bit in the magnetic field there. Um. But anyway, yeah, I mean it's it's it's fascinating to me just because we take it for granted, this idea that we're rooted in our body and we are who we are, and we're just moving through time

and space. But um, you know, to go back to Walter James and that there thought experiment, I think it says so much about how we perceive in color our emotions and experiences of life through our body. Yeah. One of the things I love about appropriate reception is that essentially this is key to this embodied, consistent self, uh, that we perceive at the center of a changing universe, which is part impartial to everything from the illusion of the soul to personal importance. I mean, so much of

the human experience hinges on this sense. Indeed, it does. I'm hinging on it right now, are you okay? Hinge on hingeon? So there you have it. I hope that forces everyone to just take a few seconds during the course of your day to just stop and think about how complicated this, uh, this scenario is in which we we know exactly where we are and what our body is doing. So again, it sounds a bit like stoner talk, but it's it's truly amazing that we know where we

are and know where our body is. Yeah, er minds here. When I was little, I used to do, I guess you would call a thought experiment. I used to imagine myself on a grid, and I imagine myself can tiny, tiny, twenty and then getting huge, and the sense of that scale in my own mind and body. I used to think that I could physically feel those effects because I was insane, um and I was six years old. But but it is kind of one of those things that it's just amazing when you look at it a little

bit closer. And if you guys have any personal experiences with us, whether it's out of body experiences or just ever feeling sort of um, disassociated with your body, we would love to hear about it. Yes indeed, so be sure to get in touch with us and share those stories with your district. General thoughts on this topic. As always, the best place to go for the stuff to Blow your Mind experience is stuff to Blow your Mind dot com.

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