The Applied Mind
The Applied Mind
#04 - Professor Alan Brichta - The Hidden Sense: Vestibular Science and Why It Matters More Than You Think
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Tucked away deep in the hardest part of the skull hides the vestibular system, the mysterious unsung hero of the senses. Professor Alan Brichta is its number one fan.
Most of us never think about balance until we lose it. But behind every step you take, every glance you stabilise, and every movement you make, there’s a silent system at work: the vestibular system.
In this episode I sit down with Professor Alan Brichta, a leading neurobiologist from the University of Newcastle, to explore the science of balance—and why it matters more than we realise.
Alan’s groundbreaking research has redefined what we know about the brain’s “hidden sense.” From pioneering semi-intact inner ear models to uncovering how the brain talks back to the ear through efferent pathways, his work sheds light on a system that connects motion, emotion, and cognition.
We dive into:
The biology of balance—why the vestibular system is the unsung hero of everyday movement.
How efferent feedback reveals a two-way dialogue between brain and ear.
What happens when the balance system malfunctions—vertigo, dizziness, and their psychological toll.
The surprising links between vestibular dysfunction, anxiety, and sense of self.
How balance training could support healthy ageing, concussion recovery, and even elite performance.
Whether you’re a neuroscientist, a psychologist, an athlete, or simply someone who’s ever felt dizzy, this conversation will change the way you think about balance and the brain.
This episode is proudly brought to you by GRecovery, the Central Coast's leading destination for health, wellness, and performance recovery. From infrared saunas and compression therapy to ice bars and soft tissue treatments, they've got all the science-backed tools to help you feel and perform at your very best. Head to gerecovery.com.au to book your next session or learn more. That's gerecovery.com.au are you?
SPEAKER_02Thanks for coming on. Thanks for having me on, by the way, Eddie. It was a bit of a surprise, and I was, I've got to admit, a little flattered that uh someone wanted to know about uh the vestibular system. Yeah. It's quite often ignored, and uh there aren't that many researchers, uh basic science researchers like myself, looking at how the system works.
SPEAKER_00So give us a little bit of your background, where are you from and kind of how did you get into the shishu is sure.
SPEAKER_02Um I guess my uh interest in the balance system was piqued uh during a Bachelor of Science degree at the University of New South Wales. And um there was someone who was doing some research on back muscles or neck muscles at the time, and uh it just seemed like this person might be uh a reasonable, how shall I put it, uh, mentor or supervisor if I wanted to look at this balance system, because I was intrigued. Every time I ask somebody about it, uh they didn't know too much, and uh it's a bit complicated. You might want to think about something else. And at the time, um vision was a big uh area in sensory neurobiology, and uh the uh the balance system was almost totally ignored. So I thought, well, this is kind of interesting. I want to find out about things that people don't know.
SPEAKER_00Yeah. So we kind of want to dive into that a bit more today, but give us a bit of a overview on the kind of sensory system and how it works.
SPEAKER_02Yeah, sure. Um okay, well w where to start. Um it's one of those well, let let me begin by saying it's one of the oldest sensory systems that we have in our body. And you might think, oh, isn't vision or hearing really important? And wouldn't they be the first to occur? But if you think about it, um we've always needed to know what was up and what was down. And regardless of whether we had vision or hearing, um we had to know where we were oriented in space or in uh in the environment. So uh balance or at least knowing our spatial awareness has been um a sort of a sense that we've needed to know about um since time immemorial. And yet, I have to say, it's one of the last sensory systems that we've sort of discovered and started to study. And that's mainly because it's it's such a subtle system. Uh we don't really think about it until it goes wrong. And it's actually quite hard to study because it's the the organs are not on the surface of our skin or not on, you know, sort of our ears. We can see where where sound has to come in. The balance organs are deep within the skull, and that makes it tricky to to study.
SPEAKER_00Yeah, yeah, we we're gonna jump into your uh you did a inner ear study with mice. Um we'll jump into that a bit later. Sure. So there's a few effects that we kind of talk about in psychology relation to sensory systems and stuff. Could you explain the cocktail party effect?
SPEAKER_02Oh yeah. Um that that has less to do with the balance system, but it's still the inner ear. And so the cocktail effect is sort of I'm I'm sure most of your listeners and viewers have seen that when you're in a party or in a in a pub, um, the background noise is pretty uh loud, right? In in other words, that's that's an important noise contribution. Uh and yet, uh for certain reasons, you can actually pick out the sound that you want uh out of all that hubbub, um, mostly because it's the person standing in front of you. And it's not because they have to raise their voice too loud, they may have to raise it just a little bit, but that cocktail party is referring to the fact that you can hear somebody despite all the background information that's coming to you. And what you're able to do is selectively pull out the frequencies and the sounds that you want to hear. It's quite a remarkable system. And that's it sort of leads into some of my research. It has to do with the feedback system from the auditory system. In other words, the we normally think of sensory information traveling from the periphery out, you know, wherever it is, back to the brain. But there's a whole pathway in sound and in balance that comes from the brain out to the uh organs, hearing organs or the balance organs. And it's that feedback system that sort of fine-tunes our ability to hear things. Uh it's it's not like a simple volume control, because with a volume control, everything gets sort of amplified. Um, what happens with our selective feedback is that it picks out the things that you want. And I I'd argue that it does it the same way also in the balance system, but we can talk about that later on.
SPEAKER_00Yeah, so I think like when we talk about early stages of cognitive psychology, we kind of used to have this idea that the the brain was very segmented into different parts that had kind of soul responsibilities. And I think it's common now that we see with more and more research coming out that it's all interconnected and everything is kind of firing and working alongside each other.
SPEAKER_02Absolutely, yeah. You know, I've I've heard in the past people say, Oh, we only use 10% of our brains, which is absolute rubbish. We use all of our brains all the time, absolutely.
SPEAKER_00Yeah. So let's talk about balance. What exactly is the vestibular system and why haven't most people heard about it?
SPEAKER_02Well, it's a good question. I would argue uh the reason we don't think or hear about it too often, again, until it goes wrong, um, is it works exquisitely well. In other words, it works in the background, and I maybe I'm attracted to the system because of that. It it sort of works without fanfare, you know. In other words, it's not like vision which tells you all about the world or hearing where you can hear beautiful music. The vestibular system just gets on with its work, it sort of um keeps everything sort of stable. Um, but it also does it without foss, you know, it's sort of working just well, every moment of the day. Um possibly goes a little bit to sleep as we do sleep, but I I'd also argue that it's it's still working then, because uh if there's a sudden shift in the bed or the place that you're resting, it it it wakes you up, right? In other words, the balance system sort of is an alarm telling you uh, hey, this isn't normal, uh you ought to attend to it. So um, okay, uh that's one thing, but that's a balance system doing its work in the background. That's why I'm attracted to it. It really consists of the inner ear. Uh there are two parts to it. There's a hearing part and a balance part. And remarkably, the two never mix, right, unless you've got some sort of pathological conditions. In other words, loud noises don't disturb your balance, and shaking your head doesn't disturb your hearing. Right. So um even though they're sort of locked together in the uh in the inner ear, they have mostly nothing to do with each other. Um, but it means that they're protected and they're actually in the hardest part of the skull, it's called the petrous part of the temporal bone, and petris means uh rock-like, uh, you know, petrified uh wood is is rock wood, right? And so it's in the deepest part of the skull, the thickest part of the skull, I'd say, and it is there for your protection, because uh if you have damage to the balance system, uh you begin to have serious trouble completing just everyday tasks. So is it the same for all mammals? It is. Um, as I said, it's an ancient system and virtually all animals that you can point to, um from uh reptiles, birds, and mammals, um, even amphibians, which are frogs, and fish, have the same basic setup. Um, they have three things called semicircular canals and they detect rotational movements, and then usually have two uh sort of um flat uh receptor areas called the uteric and sacchole. And um every animal uh virtually, with the exception of some very primitive fish, which have a similar system but perhaps only have two canals, but it's remarkably conserved right throughout the animal kingdom. And so what's great about um as as researchers, what's great for us is that we can study this system in almost any kind of animal and it sheds light on how the system works in all animals.
SPEAKER_00Yeah, I feel like the the research is it's so broad as well because there's so many things we don't understand about different kind of areas and and things like that. We had an interesting question that someone wanted to ask you today. Sure. Um I don't know if you'll be able to answer it, but it was how does being in space with no gravity affect the vestibular system?
SPEAKER_02That's a great question. And I I do have colleagues. You see, the nice thing about the well, the nice thing and the uh sad thing about the vestibular field is that there's only just a few of us, right? And so I well, I I'm not bragging here, but I know most of the people in the world that do um studies on the balance system, right? And so I have colleagues who work at NASA and they look at what they call microgravity changes uh in uh the balance system. And it it's true that having sort of less gravity than we have on Earth has significant changes or or appears to affect the balance system uh over time. So for instance, um if you uh think about the balance system as something that gets used to its environment, in other words, normally we're at 1G, uh you know, sort of uh one one uh at sea level would be at one G. But up in space, as I said, it's a microgravity. And so our brain, our balance system has to adjust to that new um really frame of reference because it it's remarkable how the brain itself uses well, let me just back up and say the brain has a voracious appetite for information, right? It will suck in information from wherever it can, right? I almost think that the brain is being locked in inside your skull. Uh no windows, no um uh no way to get information except what's it what it's being fed with, right? And balance system is just one of the things that feeds our brain. Uh but the brain is using this all the time to adjust its sort of perception of the world and what and and the the uh area within it its um interest. And so the balance information in microgravity in space is has to be adjusted. And there's no doubt that uh a lot of astronauts, I'd say probably close to eighty or ninety percent of astronauts get something called space sickness. It's like car sickness or seasickness, and it takes them maybe up to three days to get used to that microgravity situation. And in that time, if they're a payload specialist, in other words, someone who has to do an important job, this is downtime they can sort of barely afford. So some of these people have to work while they're still feeling nauseous and ready to sort of throw up. And it's all because it takes time to adjust to this new environment.
SPEAKER_00The thought that comes to mind for me is orientation. And the example that comes to mind is when you're surfing or when you're diving and things like that. So you you fall off a a big enough wave and you don't really know which way is up. Um Yeah, talk to me about that. How is it difficult to kind of figure out where you are there?
SPEAKER_02Well, mainly because you're not tossed around very often, right? And admittedly, as a surfer, you probably get tossed around more than most. But I'd give you the example of an ice skater. Uh, you've seen these beautiful ballerina-like uh moves on ice, and then you see them spin, right? And they spin so fast that you and you and me, um, if we once we stopped spinning, we would be all over the place on the ice. But these people are just manage to sort of glide off as though nothing has happened, and that has taken years of practice to overcome all the normal reactions we would have to, say, spinning. So again, I would say um get tumbled around in the uh ocean often, and you'll begin to feel, oh, I know where exactly where I am, and this way is up, right? So uh I guess what I'm saying is that it's like everything, you have to get used to even the extreme conditions to um respond to it really well. Um my example again, uh, or another example is I used to work with turtles. Um they're really great, fascinating animals. But when I'd come into the aquarium, uh these guys would jump off their logs. And we normally think of turtles as being slow animals, right? I mean, you know, slow as a tortoise or slow as a turtle. Um, these things, obviously they were startled, so they jump off the log. And they I kid you not, they they did about three sixties or seven twenty turns in the water, right? And then sped off. And it wasn't because uh they were disoriented, absolutely not, it was part of their escape response. They knew exactly where they were, right? It was part of their escape system, they had it all figured out, and even though we think of them as being slow uh in the water, it was just amazing, right? And that's the f sort of that was the first time it dawned on me that well, wait a minute, they've got a system, of course, the same as ours. Um, you know, yeah, a lot of the time they're just sort of basking in the sun or crawling slowly to to in and out of the water. But when they want to, they can really move.
SPEAKER_00There you go. I'm picturing Looney Two's as you're saying that in the in the cartoons and they're spinning on.
SPEAKER_02Yeah, well it it's it's that exactly. It's uh amazing.
SPEAKER_00Let's dive into uh a bit more of the science. So talk to me about hair cells and not the hair cells that we think.
SPEAKER_02Ah, right, yeah. It's not the hair cells on our heads or the hair follicles as they're called. Um these are individual cells. Uh they're sort of specialized, uh, and they're just they're just one cell uh tall, and they have these tusks of what we call stereocilia or little um projections from the top surface of the cell. And remarkably what they do is when you bend that hair bundle, as they're called, uh in one direction, um the cell will get excited. If you bend it in completely the opposite direction, they get inhibited. So which means that they whatever they're doing, they slow down. So what you have is really what we call a transducer, something that changes mechanical movement into electrical signals. So uh I could pick up my iPhone and and show you that inside there somewhere are these transducers that are able to tell you where this phone is in space, right? Uh and the same sort of thing we have in our inner ear, we have these little transducers, and and they're sensing fluid motion. Because every time we move our heads, we're moving fluid, and these things are detecting that motion and passing that signal onto the nerves that go back to the brain.
SPEAKER_00Are they directly related? So when you get like a in your ear infection and say you might have like fluid buildup, is that what's affecting your balance then?
SPEAKER_02Uh not quite, no. Um so the the fluid that say builds up in the ear is normally in the inner, uh sorry, the middle ear. And I'm talking about the inner ear. So um we have three parts to our ear, the the outer ear, which we can see, um, the middle ear, which is where all these little three little bones actually called ossicles, uh, they actually transmit sound. And it's actually where we get our infections. In other words, uh something called um glue ear or otitis media is something that gets um where you get an infection, uh, because it actually could there's a tube that goes from your nasal passage up to that middle ear, and so it's a a potential source of infection, and in kids it happens a lot. So that's where the infections and the fluid gets. Um I'm talking about deep within the bone. Uh these things are protected, as I mentioned before, and there's there's special fluid that is, again, remarkable. It it's so different from any other fluids in your body. Um, but it's the stuff that kind of sloshes around. I exaggerate, it sort of moves around. Um, and that's what pushes on the hair cells. It's like if we think about a bicycle inner tube and you don't fill it with air, you fill it with water. And that's exactly like one of these semicircular canals in the uh inner ear. So that when you move the inner tube in uh or the yeah, when you move the inner tube, um the fluid eventually moves, but it gets left behind initially, and and that's how exactly how our inner ear works.
SPEAKER_00So you mentioned before it's a kind of complex process with how much our brain kind of intakes all the information at once. How do we send feedback to the ear and vice versa?
SPEAKER_02It's uh yeah, it's a really well like all questions, uh it's a complicated question. But um the the best way I can sort of illustrate the f feedback mechanism is this that y your you know your inner ear is telling your brain something. Something about your head movements usually. But there's something that your brain wants to tell you balance organs, right? So it's two-way traffic. And what we think and what we've always thought about this feedback mechanism has to do with modulating things. And I don't mean quite like, as I mentioned, a volume control. That that's a little too simplistic. The the brain is too smart for just doing that. Um, and that's unfortunately what hearing aids simply do. They just amplify the signal. Um and but they've got better and better circuitry, which means that they can begin to pretend to do that sort of cocktail party effect that we're talking about. Um, but in in balance, that feedback is modulating the activity of the balance organs. So uh the question is uh why is it modulating and how does it modulate it? And we've got some answers to that, but we're still sort of groping around in the dark to figure out exactly when this feedback is working. So is that the role of efferent signals? Yeah, exactly. It's um there's something um important that the brain wants to tell the the balance organs and also the hearing organs. Um, and also there's actually feedback to our vision as well, but um not from the balance system, but from the brain. So um a lot of sensory systems, when we've looked deeper, uh uh have a feedback mechanism. Somehow the brain wants to tell the organs something or adjust the uh the organs in in some way. And so that's exactly what that feedback or efferent system uh, because we use complicated words like afferents and efferents. Uh efferent just means signals that sort of like if you think about effervescence, right? They're bubbles being given off. And so that's the way I remember it. So this is information given. Off by the brain as efferent information, but afferent is actually the other way around. In other words, it's coming from the external environment and it's going back to the brain. So that's, I think, often we we overlook that sort of important feedback or efferent information. And it's been a mystery. It was sort of, at least in the balance system, it was discovered just after they discovered the balance uh feedback mechanism. And that's you know, close to 70 years ago.
SPEAKER_00There you go, yeah. Yeah, excuse my poor prun pronunciation on that one. You mentioned balance organs and things like that. We're gonna kind of dive into what kind of happens when the system fails or what can go wrong. Before we do that, just for kind of people that don't have uh maybe the broader kind of understanding of it, what are our balance organs and sure.
SPEAKER_02Yeah, um so the our balance organs, as I mentioned, uh are deep within the ear, as I said, three semicircular canals, uh a uterical and a sacchole. And what's remarkable about all five organs, and that's just in one ear, you've got a uh the same set in the other inner ear, um, is that they're all sort of oriented precisely. In other words, if we look at the three semicircular canals, they're all right angles to each other. So what does that mean? Well, it means that absolutely any head movement will be detected. In other words, that rotation that you make with your head, one of those or more of those canals will detect that motion, right? So it's a remarkable piece of biological engineering. It's just um it always blows me away when I see these three uh sort of um planes that are represented by these semicircular canals. And you know, that's how modern inertial organs and sort of instruments work, right? Um and then the two other things are uh the uterle and saccule. The uterle is really good at sort of backwards and forwards motion, side to side, that sort of stuff. So in l what we call linear motion, right? Um backwards, forwards, side to side. And then the sacchole is really good at up and down motion. So it's it's actually very good at detecting gravity. So it's a gravity receptor. So with the three semicircular canals, the utero and saccular, they've got you covered. Any possible movement you can make uh will be detected by one or more of these organs.
SPEAKER_00And so do they work to balance each other out? Like I think we spoke before we did the podcast, and we kind of used the analogy of a uh a camera stabilizer.
SPEAKER_02Oh yeah, yeah. Well that that I mean that's what's great about watching this new technology come on board. I don't know if you've ever had one of those handheld sort of uh uh I you know iPhone holders that actually adjust every time you move your hand, it sort of moves. Gimbals. Yes, that's gimbal. Exactly. And also, I think I was just watching the um uh not State of the Union. Oh um State of Origin. State of that's right, exactly. State of origin football. And um there was a lot of cameras that were handheld, but they were steady cams, right? In other words, um the guy could be running along or probably on one of those segues or something like that, and they could keep a smooth um and um uh how should I say, um n not a handheld feel to it, right? And that's exactly what we do with our own eyes, is with the help of the balance system, every time we're walking, normally you would think, and if you held just a camera uh in in space as you were walking, you'd actually realize it goes up and down. That's that's what we do. But you never detect that. And the reason is uh your eyes are making these little adjustments up and down as you walk. So everything's smooth, just like that steady cam. And that's why you, while you're jogging or while you're walking, you can read signs. Someone who has that balance system issue um has to stop walking, and then they can read because everything's blurred, just as it would be with a handheld camera. Um sorry, I digress. I I'm so excited about this subject. Anybody wants to talk to me about it, I just can't believe it. So uh yeah, so I I um yeah, I sort of digress. But um what I'd say is that that the balance system itself is then just passing those signals on to the brain, and it's a direct connection straight into um, again, w what we'd call almost primitive parts of the brain that were there long established, uh long before we had areas that were established for vision, or and certainly long before we had areas established for hearing. Hearing is actually a very recent acquisition.
SPEAKER_00There you go. You've done a bit of work with geriatric patients on Meniere's disease.
SPEAKER_02Um we've done some work, yes, absolutely. Um and and we're sort of looking to see uh Meniers, uh I might add, is is a debilitating um uh disease of balance. But it's also of hearing too. And quite often uh it's the hearing that takes most of the um uh sort of spotlight when when people are thinking about meniers because they hear uh ringing in their ears, they hear um uh you know sort of roaring sounds, um, but it's the balance or loss of balance that is the key to meniers, I think. And it it really makes the people who've got meniers uh reluctant to leave the house at times because they're not they're not sure when it's gonna happen. There's this attack. Um they sometimes feel it coming on, uh, and therefore they can take appropriate action. But it's it's uh certainly a disease we think of the inner ear and in particular uh the balance organs. And the work that we did was actually look at um uh we got the the generous uh approval of patients uh to um sometimes it's so intractable that surgeons actually have to remove their inner ear on one side uh so that they're then really just relying on on the good side, because it usually does affect one side rather than both sides. And um what we were able to do with the help of of of uh um cooperative patients, friendly cooperative patients and an assertion is to remove that tissue um from the inner ear because it's no use to them. In fact, it's contributing to their loss of balance because it's giving the brain wrong signals, and the brain doesn't know what to do with two different signals. Uh, it gets confused and and so it it it throws up its hands and says, I don't want to know about this, I'm just gonna make you feel ill so you don't move in the head, right? And so we take that tissue, uh, we we took it back into the lab and we did two things with it. We were able to keep that tissue alive long enough to record electrical activity from those hair cells we talked about earlier. And what we found was actually those hair cells were were normal. Um what was left, now there weren't many of them, um, which means that, at least to us, is that many airs doesn't it certainly affects the balance organs, but it doesn't um uh kill the activity or alter the activity of the fundamental units in there, those hair cells. What it does, it does kill them because of increased pressure, as it turns out. Um but if we could say reduce the pressure, um find out a way to encourage those cell hair cells to either uh regrow or get the nerves to grow to them, then we've got a potential cure for menus. But I I certainly don't want to raise any hopes because that that's obviously a long way away.
SPEAKER_00I know for a lot of people kind of having balance issues, and even when you're kind of entering like a a panic state, you'll lose kind of your sense of balance and your orientation. And what's the kind of correlation between patients that you've sat with and their their experience with anxiety? Is that related to their balance, do you think?
SPEAKER_02Yeah, uh it is. And I and and again, the more we know about balance systems, the the more remarkable it is. In other words, um there are studies to show now that the information um of balance doesn't go to a special part of the brain, right? In other words, if we think about vision, it finds its way to the back of the brain, the what we call the occipital lobe, and there's um basically uh we have a visual cortex there. And uh same with hearing, uh that there has special special areas uh on the brain, uh which we call sort of primary sensory areas. The balance system um doesn't have a special area. Uh in fact, I would argue it has all the brain. It it distributes itself to places like the hippocampus, which is known to uh deal with spatial orienting, you know, in other words, and it's often affected badly by Alzheimer's. So quite often um dizziness um in in Alzheimer's patients is as a result of the connections between the balance system and the hippocampus uh being reduced or or being um sort of uh altered. And the same thing happens in Parkinson's. Um it's tur it turns out that there's connections between the balance system and the striatum, which is a uh area deep in the brain that has to do with uh coordinating our movements. So as I'm throwing my hands around here, um I'm using part of that, the basal ganglia and the striatum to sort of coordinate smooth movements. And it's precisely um that uh balance information that's required to help us with that smooth information or smooth translation into smooth movements. And if you destroy or alter that balance system, then then you get difficulty sort of making movements, um, being aware of where you are spatially, and also now um sort of reducing those movements as as it happens in uh Parkinson's.
SPEAKER_00Yeah, I think you could see why it would be so debilitating. I think that's one of the things that kind of stands out to me about it is you said earlier on, like you don't we don't really look at it until something goes wrong with the system. I think yeah, it's one of those ones that's so central to everyday life and we don't think about it because we take it for granted or whatever reason. And then when it goes wrong, it's like you said before, people aren't even leaving their homes.
SPEAKER_02Yeah, you're right. And and that's um that's where you know where when I go to work every day, I I guess that's what I think about is that there are people and and I I live in Newcastle and there's a a great uh meny air support group there. And if anybody uh sort of lives in that area, then I'd I highly recommend them uh joining if they have that kind of uh problem. Um it it's people with many airs and people interested in many years, uh the get together. Um but it's it's very compelling and it and it sort of for me as a researcher, it it sort of grounds me in, you know, this is where this research is hoping to go. In other words, help people who at the moment have uh no recourse, um, no drugs, no real operations can can help.
SPEAKER_00Yeah. Talk to me about sedatives, and um I think there's been a bit of kind of controversy in in treatment with sedatives and people five.
SPEAKER_02Yeah, um that's mostly to do with uh treatment of dizziness. I mean, w we're in the dark ages when it comes to treating balance disorders, and uh what I mean by that is that the common treatments for, say, motion sickness or even balance disorders, is to give someone a sedative. In other words, you know, uh take two pills and call me in the morning kind of thing. And and usually there are things like uh anti-histamines uh or um uh I'm I'm just trying to think of um there's uh scopolamine, which is uh uh anti-muscarinic, um it's that's an important blocking agent in the nervous system. Um so there's scopolamine, there's promethazine, these are typical um and and we've used them for you know 50 to 100 years or more, uh, just to suppress the the the nausea, the anxiety, as as you mentioned, um, and and it's really that's the way it works. It doesn't actually attempt to uh cure the dizziness or or the um the um imbalance that we have. And it's so as I said, it's treating the symptoms um not too well because then it means that if you have to take a lot of it, you can't drive drive, you can't do important sensitive things if you're sort of sedated. Yeah, well we're not fixing the core issue, aren't we? No, you're just sort of papering it over and say, well, you'll get over it. And of course, most people do get over motion sickness once they get out in that environment. But if for instance they're on a a ship, um, you know, a s a submariner, you know, in a submarine, um, you know, it it it it's um say on a ship, I'm thinking on the surface where you've got sort of fairly violent movements, you know, the crew has to be there for security as well as service, right? And and safety. And so um it it's much like space sickness, you don't want them out of commission on on rough seas, um, but a lot of them are. And so that introduces um a level of um safety that needs to be addressed.
SPEAKER_00So we kind of mentioned before the the the part that you study in the inner ear is so hard to get to. And you did a study with mice. Um did you develop the semi-intact model?
SPEAKER_02Uh we did, yeah. So what that means is that we were able to keep some of the tissue alive. Uh, because as I said, it's deep within the skull. Uh we can't possibly do this on on humans. And and this is where I'd say, you know, some people obviously uh find this um there are sensitive issues, uh, but uh let me say from the the get-go is that there are very strict rules about any kind of animal research. Um there has to be no pain, um, the animal can't suffer. And indeed, the experiments that we do, um w we just take the inner ears out. Um we've already euthanized the animals or the mice, um, and we're able to keep this um tissue alive and we can record electrical activity because unfortunately, no modeling, um, no amount of guessing is going to actually tell us how these things actually work. So we're able to look in in in fact eavesdrop on the communication between those sensitive hair cells that detect motion and the nerve fibers going back to the brain. So we can now figure out the code that's used by these sort of um specialized hair cells and that that then get passed to the nerve. Because in the end, ultimately, we'd love a balance aid like we have a hearing aid to help people who do have balance issues. But we we've got to know how it works before we can bring in sort of ways to treat things or even bring in prostheses or or uh aids to to help us balance. And so while no scientist I know goes to work, you know, thinking that uh that they really want to work uh on animals, it it really is a case where we um th there's no other way to find out how these things work. So in the most humane way, we we do work with animals, um virtually all mice. And it's been um a breakthrough in understanding how the system works.
SPEAKER_00Yeah, I want to dive into the the kind of process of that a bit more. Um but I agree with the ways of studying kind of biology and and even just anatomy scans and things like that just don't they don't work with this path here.
SPEAKER_02Unfortunately, yeah. We we only get so much information and an anatomical information is absolutely valuable. Um, you know, the way things are structured, that's that's great. And that often can lead you to better understand function. But the only way you're gonna understand function is when it's working. Yeah. And that's sort of um what we're doing right now is looking at the way this works in uh awake, freely moving mice. And it's um I I think it's it's been a a revolution. What have you found that's um kind of steering the research here on where we're kind of going to with the with that kind of research, I I think what we're able to do, and and this is technology that's only come about in the last five, maybe ten years at the most, um, where we can eavesdrop um with special mini microscopes. They're tiny, tiny little microscopes, where we can look at the brain in real time as the animals moving around. They're unperturbed by having this sort of mini scope on top of their heads. And we're looking at neurons that have been specially labeled with these fluorescent dyes that show us when they're active. So for the first time we're able to see the brain in action. I mean, it it's I I can't tell you sort of what a um a step change in our understanding this has occurred. And I'm not just talking about the vestibular system. This is um it started in looking at the brain itself, the cortex. Um all we've done is sort of modified it so we can look at the neurons that we're interested in within the brainstem. And for the first time we can see when they're active. And that's always been uh, you know, a mystery. When does this and and as I said, the feedback information, when does it happen? And what we what we've discovered, I think, is that this information in in this feedback system occurs before head movements, which is just blows my mind.
SPEAKER_00Yeah, explain that before head movements.
SPEAKER_02Um yeah, so what we uh are picking up from these and and that's all we're doing, we're just watching these cells, and and we do have these accelerometers, just like you have in your iPhone, um, within the cameras uh uh itself, so we can actually tell when the head's moving, and we can sort of synchronize when do we see the the lights flashing from these neurons and when the head is moving. And what we can see is that it flashes maybe 30 to 80 milliseconds. Now that that that's thirtieth or eightieth of a thousandth of a second, which sounds incredibly fast, but in actually neuron terms, it's it's you know, it's fast, but it's not that fast. Uh, if we think about a synapse, which is a communication between one uh neuron and another, that happens within one to two milliseconds, right? So a 30-second delay means that it could have gone through quite a few neurons before it gets to the neuron that's flashing, but that flash is occurring just before the animal moves its head. So what we think is happening is that just before uh there's a signal from the brain uh to the muscles, neck muscles, to move the head, that signal is already going to this this neuron, and then that's sending information to the balance organs to warn it, saying, hey, you're about to make a big head movement, don't worry about it. It's you that's making it, it's not the world that's changing. It's you that's making the head movement. Uh we'll take that out of the picture, and then if you sense anything else, then that's important. Attend to that, right?
SPEAKER_00So that's how we're deciphering between kind of what's important and what's not.
SPEAKER_02Exactly. Yeah, it's it's the difference between active head movements, which are movements that we make, and passive movements are the things that uh happen when we're not expecting them, right? In other words, you're in a car, you're bobbing up and down, and then you come to a sudden stop. Um, you're not expecting that. So that's a passive motion. Um you're m s some other force is moving your head. Whereas an active motion is something, I want to turn my head towards the camera or uh uh towards the curtain. That's an active head movement. I know I'm gonna do it. So I might as well warn my balance system that that's what's coming up.
SPEAKER_00Yeah, I I think um the thing that comes to mind with me here is uh I spend a fair bit of time in kind of boxing and and competing in that sport and we have like ever-evolving concussion protocols now and when we're kind of taking say uh an external force or external trauma to the head, we lose our balance in that moment. Yeah. Do we know much about that?
SPEAKER_02Um yeah, you're absolutely right. That there's there's been a big force that we even though say if you're in in a in a um in a in a f uh fight or or in a contest, i you're sort of ready for that blow in case it gets past your defense, but but you never know quite when it's gonna happen. Not like a head movement that you're gonna generate because you know exactly when it's passive.
SPEAKER_00Is this what we call passive?
SPEAKER_02Yeah, so that the the the hit um would be a passive head motion, but if if we're trying to avoid the movement by ducking on weaving, um then we're making those movements, right? And therefore we're sort of taking that out of the equation and we're we're sort of priming the system to say, well, anything else that you feel or or or sense in terms of that that's been imposed on you, right? So it it so passive is sort of it's not a great word, but it it means motion that's imposed on you. Um and that's what happens sort of say when you're in um uh you know, sort of martial arts or boxing, um, y you're having to make adjustments, your own adjustments, but you're also uh potentially if you're getting struck uh in the head, um, you're receiving these things. Now, what I'd say that momentary imbalance is to do with the force, sure. You you're making compensatory arrangements because you have these reflexes that are able to keep you balanced so that you don't completely fall over just because you've you've had a um a knock to their head. Although that can happen, of course, you can momentarily lose um um uh your consciousness. Um you can also um you know get slightly disoriented by that force. Um, but you quickly recover and you're you're sort of you're for your own survival, actually. The quicker you recover, the better it is. So so we have mechanisms to do that. But what that blow, a very hard blow, can do is disrupt the inner ear. So sometimes uh car accidents or trauma uh or even um a physical contact uh in sports, that like concussion, uh that can sort of alter the balance system or damage it uh because of the forces involved. It's a as I mentioned rather, it's an extremely exquisitely sensitive um set of organs. So you can imagine that uh, you know, a a big hit is gonna potentially cause some damage, yeah.
SPEAKER_00So it's a system that we can train. Yeah. Some people are better than others. Um and we kind of talked about how exposure to more of the disorientating environments you'll you'll adjust over time. Sure. How can we kind of train it? And is it important to train it when we get older for fall prevention and things like that?
SPEAKER_02So that's a great question because um I was talking to a um a a a rehab physio and she was saying that her best patient because she um goes to um a lot of aged care facilities, and she says by far and away the people who are best adapted, um, you know, that that uh get around uh are people who actually dances and uh also people who did a lot of say martial arts or uh or uh you know I hesitate to hate to hate to say boxing, but you know, sort of where you're moving constantly and and mm surfing is is an example of where you're being constantly um stimulated by you know the rock and rolling of the uh the waves. So the longer you can keep surfing, keep surfing, because it it really is a case of use it or lose it. And sitting in front of the TV um for for days on end is the worst thing you can do for your balance system. So yeah, what she was saying was that dancers are the best because they're used to a life of movement, right? And it's that constant movement, constant information going to your brain, and the brain loves it and and it'll it'll latch onto it and and keep, you know, obviously keep things going. So uh I'd recommend uh to all of you listeners and viewers that you know keep moving. Um even if it's jumping up and down on a trampoline, um keep moving.
SPEAKER_00Yeah, we're certainly not recommending anyone take up boxing for their long-term health.
SPEAKER_02Um possibly not. No, mainly because of the the head injuries that you can sustain from it.
SPEAKER_00Yeah. Um where are we going with this? What are you doing now? Where where are your interests?
SPEAKER_02Oh well, uh, you know, it it's all a matter of funding, as always. Um it it's a case of you can only do as much m uh with uh whatever money you can have. So um unfortunately funding is getting tighter and tighter. And so um we're we're just coming to the end of our our funding cycle. So I've just submitted a another grant to the federal government. Um, but uh, you know, um how can I put it, even though I think this is very important and uh very interesting, it it's competing against all sorts of other things, uh including people trying to solve cancer. So it it it's you're in the mix with a lot of people, uh you try and make a good case for these things. Um it it's true, probably no one dies of vestibular malfunction, but I would argue as as um a lot of people do, if your balance system doesn't work, especially as you get elderly, i you have falls. And falls, uh I was surprised to learn this the other day. Falls are the largest injury-related deaths in Australia. In other words, if you've got an injury uh related uh um uh accident, you know, basically uh falls are it, and you know, the result of falls is uh often uh death or um uh uh the ultimately uh or other really significant um health problems.
SPEAKER_00Aaron Powell Yeah, I think it's definitely something that's concerning for especially as we're getting older and we're living longer. I think it's it's one of those things that we need to keep actively pursuing to make sure we're we're engaging with and and being healthy and kind of preemptive with that.
SPEAKER_02Absolutely. I I I think again, um use it or lose it. Um and what we've found, unfortunately, is that that feedback system is is affected by aging. Uh there's no doubt about it. It's what we call cholinergic, in other words, it's it uses acylcholine as a neurotransmitter, and they're notoriously affected by aging. All the acyl choline systems in our uh nervous system uh get reduced, and and this is one of them. And so um what I would suggest, at least our our uh our data suggests, is that if you are sort of getting on in the years, uh I would suggest don't don't move your head too quickly. If if you're up on a ladder, you see your classic sort of male over 50 um falling off ladders, and I would argue that it might be to do with quick changes in head movement where you momentarily lose your balance and then you fall off the ladder, right? So if you can keep your head movement smooth um as you get older, um that's gonna help you enormously. And if you can take up dancing as well, I'll help to.
SPEAKER_00That's a good note. For people that are kind of wanting to hear more about the vestibular system and learn more about it, where can they go? And where can we go to find more of your research?
SPEAKER_02Oh gosh. Well, you know, I I had sort of looked up chat GTP or um yeah, was a Microsoft Copilot, and I've got to say it it's getting better all the time. In fact, um I'm not so familiar with something called um vestibular uh stimming. I I don't know if you've heard of that, but it it's um the way it's related to uh autism spectrum disorders where where people, for instance, they rock or they do big sort of movements. Um and it it's self-soothing. In other words, these people find it well we find it alarming um watching people say rocking to and fro or um you know doing big movements. Um but for the person that's doing it, it it's almost like they want to stimulate their vestibular system because of perhaps this what we call hyposensitivity. In other words, r because there seems to be some sort of reduced information from the balance system into the brain, and what they want to do is sort of goose it up, they want to uh increase it. So uh in in short, um uh getting that information to the brain is key and it's critical. And I think it more and more information is suggesting that i if you're losing it, you need to sort of try and force it in somehow. And if it means doing more head movements, uh if it means more jogging even, um then do something where you're actively moving your head um so that you can retain or at least maintain what you've got.
SPEAKER_00Yeah, I think in in autism we kind of talk about the hyper and hypos, yeah. Um over and under. Yeah. Like where we have too much of something or not enough of something. Correct. And uh that was a point that we kind of made when we were speaking before we kind of have this overstimulation of of certain kind of senses. Um and you made a great point, I think, uh, when we were talking about how we can introduce other sensory inputs to kind of regulate that out.
unknownYeah.
SPEAKER_02Yeah, give it more. Yeah. Well, um, often they mention, especially uh people with ADHD, a sort of you know, giving them a very vigorous body rub. Um it sort of helps focus their attention, not from all this information that's coming to the brain, but back to something significant that's happening to their body. And that seems to reduce the levels of information and potentially anxiety, because when you're getting bombarded with all this information, you your brain sometimes says, Hey, this is too much. You know, in other words, yes, I love information, I'll suck in as much information as I can. But if you're overwhelming the channels, um, give me something to focus on. And quite often say vigorous stimulation or or rubbing of the the legs or the arms or the shoulders, um, and I would say uh of the head as well, um, that will begin to sort of focus the person's attention on the things that are important, uh in other words, that sensory information coming in, and then automatically that overwhelming information from other senses is then sort of reduced or dampened. And that's that's an important way of uh regulating times because it's not happening all the time, but uh at times when that information is is overwhelming.
SPEAKER_00Yeah, it's like the overactive neurons.
SPEAKER_02Yeah, yeah, yeah. And yeah, rather than taking a ses sedative, as we were saying, um use the system itself and and sort of uh decrease the amount of of information or at least focus it on something, and then that way it'll tend to um sort of diminish the the external uh information that's coming in.
SPEAKER_00What's um two or three points that we can kind of leave our listeners with on the vestibular system to think about?
SPEAKER_02Oh boy, well uh again I would say that um think about your bit just think about it. That's number one. Uh think that that you do have a balanced system. In other words, um there was a time uh I think we mentioned just off camera um about alcohol. And what's uh the interesting about alcohol uh is that that fluid that I mentioned inside the inner ear a has a certain what we call specific gravity or density, right? And what happens is when we drink, um, that alcohol goes everywhere, but it also f finds its way into this fluid and it makes it just a little bit less dense because alcohol is less dense than uh the fluid in our ears. And so what that makes means that the the hair bundles now are not being pushed as much as they should be. Right. So that's that differ. So that's yeah, so it's disorienting, it makes us dizzy, right? And so we go to bed dizzy, right? Um, but uh you can sort of overcome it, you know, it sort of might go away while you're still drunk, and and that that's fine. You go to bed, and what happens is as you're sleeping, that alcohol evaporates and that fluid goes back to normal. But your system, as I mentioned, tends to go to sleep a little bit as well, and because you're not stimulating it very much because you're sleeping, when you get up in the morning and start stimulating the vestibular, it still thinks it should be that lighter fluid because the alcohol it's gone, right? And so quite often people feel dizzy in the morning as well. So you've got the the the nighttime dizziness, yeah, and then you've got the after effect with it, which is dizziness in the morning.
SPEAKER_00I always thought it was related to hydration. I would wake up and or I'd drink, um I don't drink anymore, but I would I would drink a lot of water before I went to bed, but I would still wake up feeling dizzy and I never could crack it. And yeah, now I know.
SPEAKER_02For other reasons to drink water, because you do dehydrate the rest of your body. Um but in this specific instance, as far as balance is concerned, it has to do with that inner ear fluid being changed by the alcohol initially and then changed again when it when it evaporates. Anyway. Sorry, yeah, sorry. Yeah again, I I I get excited and digress. But you mentioned three things. Uh one is just think about our vestibular system and and keep it exercised, right? Um, you know, even if it means sort of moving your head from side to side. The other thing I would say is that uh unfortunately as we get older, it's gonna get less uh less it it's gonna respond less well. And so we've got to be aware that we can't quite do the same things that we used to do when we were teenagers, um, which is probably when we're at our peak. Um and and the last thing I'd say is that it's never too late. In other words, um even if you've got balance problems, i exercising it, doing things that stimulate it, is gonna bring back maybe not full uh function, but it's gonna retain and at least improve what you've got. So keep using it.
SPEAKER_00I love it. Thank you so much for your time.
SPEAKER_02Thanks, Eddie. Cheers. Bye bye.