How brain works…
Translator: Jessica Lee Reviewer:
Denise RQ So how do we learn? And why does some of us learn thingsmore easily than others? So, as I just mentioned,I’m Dr. Lara Boyd. I am a brain researcher hereat the University of British Columbia. These are the questions that fascinate me.
So brain research is one of the great frontiers in the understanding of human physiology, and also in the consideration of what makes us who we are. It’s an amazing time to be a brain researcher, and I would argue to you that I have the most interesting job in the world. What we know about the brain is changing at a breathtaking pace. And much of what we thought we knew and understood about the brain turns out to be not true or incomplete. Some of these misconceptions are more obvious than others. For example, we used to think that after childhood the brain did not,really could not change. And it turns out that nothingcould be farther from the truth. Another misconception about the brain is that you only use parts of itat any given time and it’s silent when you do nothing. Well, this is also untrue. It turns outthat even when you’re at a rest and thinking of nothing,your brain is highly active. So it’s been advancesin technology, such as MRI, that’s allowed us to make theseand many other important discoveries. And perhaps the most exciting, the most interestingand transformative of these discoveries is that, every time you learna new fact or skill, you change your brain. It’s something we call neuroplasticity.
So as little as 25 years ago,we thought that after about puberty, the only changes that took placein the brain were negative: the loss of brain cells with aging, the result of damage, like a stroke. And then, studies beganto show remarkable amounts of reorganization in the adult brain. And the ensuing research has shown us that all of our behaviorschange our brain. That these changes are not limited by age, it’s a good news right? And in fact,they are taking place all the time. And very importantly, brain reorganization helpsto support recovery after you damage your brain. The key to each of these changesis neuroplasticity. So what does it look like? So your brain can changein three very basic ways to support learning. And the first is chemical. So your brain actually functionsby transferring chemicals signals between brain cells,what we call neurons, and this triggered a seriesof actions and reactions. So to support learning,your brain can increase the amount or the concentrationsof these chemical signaling that’s taking place between neurons. Because this change can happen rapidly, this supports short-term memory or the short-term improvementin the performance of a motor skill. The second way that the braincan change to support learning is by altering its structure. So during learning, the brain can changethe connections between neurons. Here, the physical structureof the brain is actually changing so this takes a bit more time. These type of changes are relatedto long-term memory, the long-term improvementin a motor skill. These processes interact,and let me give you an example of how. We’ve all tried to learna new motor skill, maybe playing the piano, maybe learning to juggle. You’ve had the experienceof getting better and better within a single session of practice, and thinking “I have got it.” And then, maybe you return the next day, and all those improvementsfrom the day before are lost. What happened? Well, in the short-term,your brain was able to increase the chemical signalingbetween your neurons. But for some reason, those changesdid not induce the structural changes that are necessaryto support long-term memory. Remember thatlong-term memories take time. And what you see in the short termdoes not reflect learning, It’s these physical changes that are now going to supportlong-term memories, and chemical changesthat support short-term memories. Structural changes also can leadto integrated networks of brain regions that function togetherto support learning. And they can also leadto certain brain regions that are importantfor very specific behaviors to change your structure or to enlarge. So here’s some examples of that. People who read Braille have larger hand sensory areasin their brain than those of us who don’t. Your dominant hand motor region,which is on the left side of your brain, if you are right-handed,is larger than the other side. And research showsthe London taxi cab drivers who actually have to memorize a mapof London to get their taxi cab license, they have larger brain regions devotedto spatial, or mapping memories. The last way that your braincan change to support learning is by altering its function. As you use a brain region, It becomes more and more excitableand easy to use again. And as your brain has these areasthat increase their excitability, the brain shiftshow and when they are activated. With learning, we see that whole networks of brain activityare shifting and changing. So neuroplasticity is supported by chemical, by structural,and by functional changes, and these are happening across the whole brain. They can occur in isolation from one or another, but most often,they take place in concert. Together, they support learning. And they’re taking place all the time. I just told you really how awesomely neuroplastic your brain is. Why can’t you learn anything you choose to with ease? Why do our kids sometimes fail in school? Why as we agedo we tend to forget things? And why don’t people fully recover from brain damage? That is: what is it that limits and facilitates neuroplasticity? And so this is what I study. I study specifically how it relates to recovery from stroke. Recently, stroke dropped from being the third leading cause of death in the United States to be the forth leading cause of death. Great news, right? But actually, it turns out that the number of people having a stroke has not declined. We are just better at keeping people alive after a severe stroke. It turns out to be very difficult to help the brain recover from stroke. And frankly, we have failed to develop effective rehabilitation interventions. The net result of this is that stroke is the leading cause of long-term disability in adults in the world; individuals with stroke are younger and tending to live longer with that disability, and research from my group actually shows that the health-related quality of life of Canadians with stroke has declined. So clearly we need to be better at helping people recover from stroke. This is an enormous societal problem, and it’s one that we are not solving. So what can be done? One thing is absolutely clear: the best driver of neuroplastic change in your brain is your behavior. The problem is that the dose of behavior, the dose of practice that’s required to learn new and relearn old motor skills, is very large. And how to effectively deliver these large doses of practice is a very difficult problem;It’s also a very expensive problem. So the approach that my research has taken is to develop therapies that primeor that prepare the brain to learn. And these have included brain simulation,exercise, and robotics. But through my research,I’ve realized that a major limitation to the development of therapies that speed recovery from stroke is that patterns of neuroplasticity are highly variable from person to person. As a researcher,variability used to drive me crazy. It makes it very difficult to use the statistics to test your data and your ideas. And because of this,medical intervention studies are specifically designed to minimize variability. But in my research,it’s becoming really clear that the most important,the most informative data we collect is showing this variability. So by studying the brain after stroke, we’ve learned a lot, and I think these lessons are very valuable in other areas. The first lesson is that the primary driver of change in your brain is your behavior, so there is no neuroplasticity drugs you can take. Nothing is more effective than practice at helping you learn, and the bottom line is you have to do the work. And in fact, my research has shown increased difficulty, increased struggle if you will, during practice, actually leads to both more learning, and greater structural change in the brain. The problem here is that neuroplasticity work both ways. It can be positive,you learn something new, and you refine a motor skill. And it also can be negative though,you forgot something you once knew, you become addicted to drugs, maybe you have chronic pain. So your brain is tremendously plastic, and it’s been shaped both structurallyand functionally by everything you do, but also by everything that you don’t do. The second lessonwe’ve learned about the brain is that there isno one-size-fits-all approach to learning. So there is no recipe for learning. Consider the popular beliefthat it takes 10,000 hours of practice to learn and to master a new motor skill. I can assure youit’s not quite that simple. For some of us, it’s going to take a lot more practice,and for others it may take far less. So the shaping of our plastic brainsis far too unique for there to be any single interventionthat’s going to work for all of us. This realization has forced us to considersomething call personalized medicine. This is the idea that to optimize outcomes each individual requirestheir own intervention. And the idea actually comesfrom cancer treatments. And here it turns out that geneticsare very important in matching certain types of chemotherapywith specific forms of cancer. My research is showing that thisalso applies to recovery from stroke. There’re certain characteristicsof brain structure and function we called biomarkers. And these biomarkersare proving to be very helpful and helping us to match specific therapieswith individual patients. The data from my lab suggestsit’s a combination of biomarkers that best predicts neuroplastic changeand patterns of recovery after stroke. And that’s not surprising, givenhow complicated the human brain is. But I also think we can considerthis concept much more broadly. Given the unique structureand function of each of our brains what we’ve learned about neuroplasticityafter stroke applies to everyone. Behaviors that you employin your everyday life are important. Each of them is changing your brain. And I believe we have to consider not just personalized medicinebut personalized learning. The uniquenessof your brain will affect you both as a learner and also as a teacher. This idea helps us to understand why some children can thrivein tradition education settings and others don’t; why some of us can learn languages easily and yet, others can pick upany sport and excel. So when you leave this room today, your brain will not be the sameas when you entered this morning. And I think that’s pretty amazing. But each of you is going to have changedyour brain differently. Understanding these differences, these individual patterns,this variability and change is going to enablethe next great advance in neuroscience; it’s going to allow us to developnew and more effective interventions, and allow for matchesbetween learners and teachers, and patients and interventions. And this does not just applythe recovery from stroke, it applies to each of us, as a parent,as a teacher, as a manager, and also because you areat TEDx today, as a lifelong learner. Study how and what you learn best. Repeat those behaviorsthat are healthy for your brain, and break those behaviorsand habits that are not. Practice. Learning is about doing the workthat your brain requires. So the best strategiesare going to vary between individuals. You know what, they’re even goingto vary within individuals. So for you, learning musicmay come very easily, but learning to snowboard, much harder. I hope that you leave today with a new appreciationof how magnificent your brain is. You and your plastic brain are constantlybeing shaped by the world around you. Understand that everything you do, everything you encounter, and everythingyou experience is changing your brain. And that can be for better,but it can also be for worse. So when you leave today,go out and build the brain you want.