Neuroplasticity with Anne-Laure

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Yes. Yes.

Yes. Amazing. So hello everyone. My name is Anne-Laure, and today we're going to talk about the human brain, and more specifically about something called neuroplasticity. So neuroplasticity, which is also known as brain plasticity, is the ability of the brain to change continuously throughout your life. So it's the idea that you're not just born with a brain that's set in stone. During your life, your brain keeps on changing based on your experiences. And as you'll see during this lecture, it can change quite dramatically. So I know neuroplasticity sounds like a fancy, complicated word, but it's actually quite simple once you break it down. It's made of two words. First, neuro, which is a word from Greek origin which relates to the nervous system, and plasticity. The word plastic means several things. There's one you probably know that's the most common meaning, and that's the material, as in when you say something is made of plastic. But there's another meaning of the word plastic, and it's something that is easily shaped, something which you can change easily. So neuroplasticity, as we said, is the capacity of your brain and your nervous system to change easily. Okay, so before we look at how neuroplasticity works and how you can use that knowledge to change how you shape— you learn and how you shape your brain, let's just take a step back and ask ourselves, how does the brain work? Do you ever wonder how this mysterious thing inside your head is generating all these thoughts, these emotions, and even your dreams at night? So we're going to look a little bit at the science behind this. So of course, asking— answering all of these philosophical questions It would take a very long time, and figuring it all out is actually the job of what's called neuroscientists. But let's still try and have a look. For this, we will need to zoom way in to our brain to look at what's going on at the cellular level. So this is a human brain. Let's zoom in where you see the little white square. When you zoom in, you see the brain is made of lots of different cells. 10% of these cells are neurons. Your brain works mostly because of all of these neurons which are connected together, and they're all sending information to each other in a very, very rapid way. The brain has 100 billion neurons. To give you an idea, that's as many neurons as there are stars in the Milky Way. A typical neuron will have 30,000 other neurons communicating with it. So imagine you're standing in the middle of a football stadium and you could reach your arms out and touch every single person in that stadium all at the same time, and they could communicate with you. That's what a neuron can do. It's the equivalent of being that one person in the middle of the stadium and talking and listening to everyone who is seated there at the same time. Thanks to this 100 billion neurons, each communicating with 30,000 neurons. Your brain is basically an amazing communication machine, and it's very good at sharing billions and billions of pieces of information very quickly. Okay, so what does one single neuron look like? Neurons are actually quite weird-looking cells. They have a body with lots of little dendrites branching from it. And a long axon. You can see here the body is called the soma. That's how scientists call it. Neurons, and in particular the axon, can be extremely long. So when you wiggle your feet or move your toes— you can try it now— it involves only two neurons. The first one goes from your brain to the beginning of your spinal cord at the bottom of your head, and then this neuron talks to a second neuron which will travel all the way down to your toes. So neurons can be up to 3 feet long. We mentioned several times neurons talking to each other. So how do they do that? The way it works is one neuron, here the neuron on the left, sends information through its axon, the long part, to another neuron, which in turn will send information to other neurons. So you see the white part here that I have circled where the two neurons connect? We're going to zoom in, in for more on this. So this is where we zoomed in from the previous image. The part where the two neurons connect is called the synapse, and it's where the real magic happens. The first neuron sends little bits of information called neurotransmitters through the synapse. The information crosses the synapse and is received by the second neuron. What's very important is that sometimes the information flows well and sometimes it doesn't. So do you know how sometimes you call a friend but the signal is terrible and it keeps on cutting and you can barely hear each other? And other times you have great Wi-Fi or a great signal and you can hear them and see them almost as if you were in the same room? So that can happen at the synapse, at the synaptic level. There are two things that have an influence on how well the information flows between two neurons. First, the amount of information, or neurotransmitter, that the first neuron sends to the other. So to go back to the idea of you and your friend talking to each other over the phone, sometimes when the connection is bad, you start speaking louder. You do that because your friend may hear you better. You're effectively sending more information. If you were a neuron trying to talk to another neuron, it would be the equivalent of sending more information, more neurotransmitter. The other thing that plays a role in how well the information flows is the number of receptors on the second neuron. So let's say you have the latest iPhone, but your friend has a very old, very slow phone. Even if you send lots of information like a video or some photos, it's going to take a long time for your friend to receive it. So the number of receptors on the receiving neurons is very important too. So there you have it: the brain on the left, which is made of neurons, which you can see in the middle, which communicate with each other through the synapse, which you can see on the right. So now you're probably wondering why I haven't talked much about neuroplasticity in this lecture about neuroplasticity. Well, the synapse is actually absolutely central to neuroplasticity. When your brain changes, a lot of it happens at the synaptic level. How does it work? It's a bit like a muscle. The more the first neuron will send information, the more the second neuron will add receptors to better receive this information. So imagine you and your friend. After a while, you both get annoyed because it's taking a lot of yelling on your part and it's very slow to receive what you send on their part. So maybe they decide to upgrade to a better phone. It's the same with neurons. As the first neuron sends more and more information, the receiving neuron will become even more efficient at receiving information by adding new receptors. This is actually how memories are formed. The first neuron sends information to the second one. Maybe the information is very important. For example, you probably touched some fire when you were younger and you burned your hand. That, I think, has happened to everyone. That's very important information to remember because you don't want to touch fire every time you see it. And usually you don't need to do it twice to remember it. So the neuron sends information through the synapse to say, hey, this is important, let's make sure to remember. And the other one goes, "Okay, I'll add more receptors so it's easier to remember." Next time the first neuron talks to the second one about fire or something related to fire, the memory of how it burned will be accessible there. Sometimes though, it takes more than one repetition to learn. Let's say you want to learn how to play the guitar or how to play chess. You will have to practice a lot. You need the information to go several times through the synapse before it becomes a long-term memory. The more you practice, the stronger the connections will become, and over time you may even have new connections appearing between the neurons. But even once you've learned something, you need to keep on practicing. Remember how I told you the more information is sent, the stronger the connection? The louder you yell, the better your friend will hear you? It goes the same the other way. If you start sending less information, if you start whispering, or in the case of learning, if you stop practicing, the connection will become weaker, and you will start forgetting what you learned. Okay, so you know a lot about neuroplasticity. How can you use what you learned in your daily life? So first, the very important— the very first thing to remember and to understand is that your brain is not fixed. Your brain keeps on changing during your life. Some connections will become stronger and some will become weaker, and you do have a say as to which ones are stronger and which ones are weaker. You can basically learn anything you want. There is no limit, and it's all about practice. Which brings me to the second point that is important to remember about neuroplasticity: you need to practice to learn new things. Except for very vivid experiences, as we mentioned, for example, touching fire, burning your hand, when you want to learn something else, you will probably need to repeat most things like playing the guitar or learning to play a new video game, you will probably need to do that several times. You will need a lot of repetitions over a long amount of time. It doesn't happen in one go. And the last thing, remember the bit where I told you that the more you use that memory muscle, the stronger the connection becomes and the better the memories are? And that it also works in the other way: the less you use it, the more you're going to forget. So it's very, very important that you keep on exercising that memory muscle. Memory is generally like a muscle: you need to keep on using it to remember what you learned. That's it, thank you, and I'd love to discuss and listen to your questions. What do you think the best way to practice our memory muscle is? Yes, so there's actually something called spaced repetition. It's one of the very few techniques that have been proven by scientists to work. The idea is that Instead of trying to cram everything in your head, for example, let's say tomorrow you have an exam and you try to learn everything in one go. Scientists have found that that doesn't work at all. You will maybe be able to answer a few questions for your exam, but then the memory will be gone because you will be using your short-term memory. If you want to use your long-term memory and remember the things for a very long time, spaced repetition is a very good technique. It means that you study a little bit today, and then a few days later, you check how much you remember what you studied. And then you look at what you, you practiced. And for example, if there's something you had a really hard time to remember, maybe you need to practice it more often. But something you remember very well, you can check on a little bit later. And a good system to do this is called flashcards. It's very easy to make your own. You can write the question on one side, write the answer on the other side, and you can test yourself like this. You can do it on paper, or there are many free applications that you can download and that will help you do this. And so this has been proven to be a really good way to learn.

What kind of things require more muscle memory?

That's a very good question. So Anything that is hard for you to do the first time you do it is going to require more muscle memory in the long term also. So for example, some people, they struggle a little bit more to learn how to play the guitar. So for them, that's going to require a lot of muscle memory. But maybe that's something that's easier for you, so less muscle memory for you. So it really depends on yourself and your very first experience when you're trying to learn something. The harder the first time, the longer you will need to practice, and the more you will need to use your muscle memory in the long term if you want to remember. Thank you. Yes? I can't see your name on it. Oh yeah, go ahead.

My question is, will it take more muscle memory to try, like, doing something— like, will it take more muscle memory If you're trying to quit smoking, you're like, "Smoke, started smoking." Or does it take more muscle memory to stop doing it or like to do it differently?

That's also—

Differently, which way takes more muscle memory?

That's very interesting. And actually, you're right to ask it because there's one way that is harder than the other. So it is actually harder to quit something than it is to start it. Because especially with something like smoking, if you have seen people smoking, most of them, they do it every day or several times a day. And you remember the part where we say that the more we do something, the stronger the connection becomes? Yes. So in the case of people who smoke, they've done it so much and for so long that the connection is really, really, really strong. So it's very hard to break that connection.

Yeah, but how does the connection get so big?

It's by repetition. The more you do it, the stronger it becomes. So a smoker who smokes 5 cigarettes a day, the connection is going to be weaker. But a smoker who smokes a pack a day, for example, the connection is going to be really, really big and much, much stronger. So the more you do it and the stronger it is.

Yeah, but once they figure out that that's happening, why don't they stop? Why don't they stop? If they've only done it like 5 times, why don't they stop?

Because it has this effect that the more you do it, the stronger it becomes. So for some people, it's already too late and they can't do it on their own.

Yeah, when you eat, when you suck one, it makes you want to do it again.

Exactly, and that's called addiction. Yeah, and that's a process that is called addiction. I don't know if you've heard that word before, but this is exactly this. There are chemicals in some products like alcohol and cigarettes, for example, that make these muscle memory connections become really strong very quickly. So it means that in the future it becomes harder, but also the— you know, only one cigarette can be enough to create that connection, the same way as touching fire. Is there a moment—

Thank you.

Are there moments in your life where the plasticity is like receptive better, and then times where moments or periods of your life where it's more difficult to advance your memory or— Yes, for sure. There's one thing that is really bad for plasticity and for memory, and it's stress. Stress, being stressed and anxious. So when you're stressed, it releases a hormone that is called cortisol, and it basically puts your whole brain and whole body into survival mode. So it means that instead of trying to learn something new or being creative, etc., you're just starting to function automatically because your whole body and your whole brain thinks that you're in danger. So it just looks at, you know, fleeing, running away, and, you know, some people when they're stressed, they start sweating, and you have your heart that beats faster, etc. So all of this comes from when we were living, you know, in nature, in the jungle, etc. Those were very useful responses at the time, but now that we live in safer environments, they're not that useful anymore, and they have a negative impact on learning, on memory, and on neuroplasticity. Thank you. Yes?

Is it harder to stop doing something or to change doing something? Like if you start smoking cigarettes, then you feel like you're bad for you, is it harder to stop doing it or is it harder to do something else instead of it at the same— like when you usually smoke cigarettes, you would eat apples instead. Is it harder to do that or stop doing it in the first place?

So it's actually It's actually easier to change it rather than completely stop it, because when you change it— so remember the connections that we talked about? When you change a habit, you tell your brain to use that same connection in a slightly different way. That's easier. It's like, keep on doing kind of the same thing, but not exactly the same thing. That's easier for your brain. But telling your brain, this connection, I want you to break it completely and to stop using it, especially when the connection is quite strong, this is very difficult to do.

Thank you.

No, thanks for your great questions.