That Neuroscience Guy - Neuroscience Myth Busting

Episode Date: October 13, 2023

Do we really only use 10% of your brain? Are creative people more 'right-brained' than everyone else? In today's episode of That Neuroscience Guy, we parse through common neuroscience myths and discuss how mythical they might be. 

Hi, my name is Olof Kreg Olsson, and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to the podcast. So today we're going to talk about neuroscience myths. A lot of people have written in or messaged and sort of said, well, hey, what about this? Is this true? And what about this? Is this true? And I thought it'd be a good idea to focus in on myths and just go through some of the common myths about the brain that you hear. Now, what I'm going to do with this is I'm just going to take you through a bunch of them and tell you the truth. So away we go. So one of the most popular myths about the brain that you hear

about is that you only use 10% of your brain. That's completely not true. You use a hundred percent of your brain. All right. So I don't know where this myth actually started. I tried to do some digging, but the reality is, is that you use all of your brain. All right. So not just 10 percent, all of it. Now, at any given time, maybe the entire brain is not active, but on average, you use all of your brain every day. All right? So not 10%. Promise. All right, here's another myth that you hear about is people say that they're left-brained versus right-brained.

And what they're kind of getting at is this sort of myth that left brain is more logical and the right brain is more creative. Well, this is simply not true. You can't be a left-brained person or a right-brained person. Now, what is true is some things are more right-biased. So, for instance, if you're listening to music or reading poetry, you tend to get more activation in right brain language areas. Whereas if you're reading, say, a textbook or a fiction novel, you'll get more left brain activity in language areas, but none of us are wired to be more right brain or more left brain. We just use the respective sides when we're engaging in those different sorts of left brain or right brain activities. Now, this one came up from a little bit of Googling. I got

curious as I was planning this episode, so I just started putting in neuroscience myths. One that came up, which I've actually heard, is that we know nothing about the brain. The brain is this complete and total mystery. Well, that's not true either. I hate to break it to you. We know a lot about the brain. The human visual cortex, for instance, is really well mapped, and we have a pretty good idea on how visual processing occurs. We know a lot about sensation and how the brain processes sensory information coming in from the limbs, our feelings of pain or cold or heat or touch. And we know a lot about the primary motor strip. We know exactly what's going on in there. Some of the midbrain structures we know a lot about. So we actually know an incredible amount about the brain. Now, do we know everything? No. you know, our fears, our desires for things, the high-level

thinking that we do, concepts like our belief in the supernatural or our belief in religion. These things are a little bit harder to understand and they're only being mapped out now, but it's definitely not true that we know nothing about the brain. So another myth. Another thing that I read and one that came up was a myth was that our spinal cord is dumb. Now our nervous system goes down into the spinal cord, right? But it's not dumb. Now, you can think of simple reflexes like the tendon tap. We've talked about that in the past. All right. The reason the doctor taps your tendon is to get the knee response that you typically see. And if he doesn't see that response, it's actually a

big problem. But the spinal cord is incredibly complex. It does some things. For instance, our complex reflexes are learned. So if you're ever standing on a bus and the bus accelerates and we lean instinctively to offset that acceleration, well, that's a complex reflex, and that's learned, all right? When we're younger, we don't have that reflex. So the spinal cord is actually learned to adapt to that acceleration, and it does that at the spinal level. It doesn't need cognitive processing. Another one that I've mentioned in the past is gait. When we walk, other one that I've mentioned in the past is gait. When we walk, our legs are alternating left, right, left, right, left, right. And modern thinking in neuroscience is that gait is controlled by the spinal cord, something called a central pattern generator. And that pattern generator helps us

alternate the swing of the legs, and we basically turn it on or off when we want to walk. But the point is the spinal cord isn't dumb. It knows these complex reflexes, and it can control gait, our ability to walk. So to say it's dumb isn't really the best statement that you could make. This one caused me to chuckle when I read about this one because we've talked about the amygdala a lot on this podcast. And one of the myths out there is that the amygdala is only about fear. Another one is that the amygdala is the only part of the brain that's involved in emotions. Well, I can assure you the amygdala does more than fear. It also responds to happiness and positive feelings.

And it's not the only part of the brain involved in emotion. And we've walked through that in the past, but the amygdala comes up a lot because if you run fMRI studies, you see activation in the amygdala quite frequently in emotional tasks, but it's not the only part of the brain involved in emotion. And we've talked about emotion a lot, so I won't go through all of it. But for instance, we know that the insular cortex plays a role in emotion. We know that there's midbrain structures that play a role in emotion. So the amygdala is not only about fear. One that I've also mentioned in the past that comes up is this idea of superfoods, that there are these foods out there like acai berries that are, you know, really,

they just make your brain function so much better. I always like to use a very simple logic statement when I think about these things. If there was a food out there that made your brain function better, and it was superior to all other foods, why wouldn't everyone be eating it? Your doctor would prescribe it. If acai berries were this magical thing that made your brain function better, everyone would eat acai berries, like it would be part of your diet every single day. So by logic, you can deduce that superfoods aren't a thing. These are trends that appear, and it's designed to sell things. Now, is a healthy diet good for your brain? I've talked about this countless times. But a healthy diet is just quite simply a well-balanced diet.

And if you eat a well-balanced diet and follow modern nutritional guidelines, that's good for brain health and brain function. This one is kind of related to that, and it actually stems from a talk I went to a long time ago. I was talking to someone who was talking about education and helping people learn more, and it was someone that I would suggest doesn't have the best background in neuroscience. Jess doesn't have the best background in neuroscience. And the talk was about getting myelinized. To learn more, you need to get myelinized.

And that was actually a catchphrase. It's possibly the most ridiculous thing I've ever heard in neuroscience. So just to review this one, what's myelin? Well, we talked a lot about neurons because it's a podcast about neuroscience. And if you remember the basics of how a neuron works, information, neurotransmitter arrives on a dendrite, it binds, it creates small electrical signals. We call these excitatory and inhibitory post-synaptic potentials. Those voltages are basically summated in the cell body.

And if there's sufficient voltage, the neuron fires, it sends its signal out detecting something. And we call that the action potential. And the action potential goes down the axon of the neuron. And the way it transmits is it basically hops because the axon is coated in myelin. It's a fatty sheath. One way to think of myelin is fat. It's kind of true, but it's the simplest way to explain it. And there's gaps in the myelin, so every little distance there's a gap, and we call these the nodes of Ranvier.

And the electrical signal basically hops from one node to the other so what the fat's actually doing is it's making the electrical signal move more quickly so this is a good thing and in fact if you talk about diseases like ALS what's happening in ALS is actually a degradation of the myelin sheath. And this is why people with ALS can't control their limbs that well, is because literally the signals to the muscles aren't being transmitted effectively because of the lack of myelin. Now that's myelin, but there's nothing you can do to get myelinized. As you develop, so as you move from being born into your teens into adulthood, the myelin on the axons is there and there's not much you can do to

get more myelinated. Now, if you live a healthy lifestyle and you have a well-balanced diet, then your body will support the myelin and that sheath will be what it is. But there's nothing that you can do to get more myelinated. So if you hear someone telling you to get myelinized or myelinated, feel free to laugh it off. Now the last one I'll talk about is one that's near and dear to my heart because we've done a little bit of research in my lab on this subject, and that's cognitive fatigue. And where this comes up is people believe in a second wind. They believe that as their brain gets tired, at some point they'll get their second wind and they'll be able to keep performing at a high level or their performance will improve. Well, that's basically not true. When you get to a certain level of fatigue, performance begins to

drop and it just keeps dropping. Now, while people report they're having a second wind, so they're telling you, hey, I feel better. I've got my second wind. If you actually chart their performance, they just keep getting worse and worse and worse. So don't rely on your second wind to recharge. What you need to do is take a brain break, go for a walk, take some time away from the task you're doing, make sure you're getting sufficient sleep.

Anyway, those are an array of neuroscience myths. I hope those little quick tidbits helped you a bit. If you want to know more, these are things you can Google. And if you go back through our episodes, we've actually talked about a lot of these things in more detail. I just wanted to summarize some of these classic neuroscience myths and tell you that, yes, they are neuroscience myths. All right. As you know, check out the website, that neuroscience guy.com links to Etsy, where you can buy merch links to

Patreon, where you can support us. Thank you so much. Patreon really helps us out because all that money goes to graduate students like Matt, who does all the sound production for the podcast. None of it goes to me. So it's a great way to support the podcast without supporting yours truly. Of course, you can follow me on ex-formerly Twitter at that neuroscience guy. Feel free to DM me your ideas for episodes and things you're curious about because we want to know what you want to know about the neuroscience of daily life. And there's our Gmail address, thatneuroscienceguyatgmail.com. We check it reasonably frequently and we just make a list of all of the cool ideas you send in.

And of course, the podcast itself. Thank you so much for listening. Please subscribe if you haven't already. It really helps. My name is Olive Kregolson and I'm That Neuroscience Guy. I'll see you soon for another full episode of the podcast.