SciCafe: Exercise Your Brain

Wendy A. Suzuki (Neuroscientist, New York University):
We're going to be talking today about a topic that affects every single one of you—practical neuroscience for everyday life. We're going to be talking about exercise and the brain.

I want to start with the question of, how did I ever get interested in the brain in the first place? It really started the very first day of my freshman year at UC Berkeley and I took a freshman seminar class called "The Brain and Its Potential," taught by a really amazing professor, Marian Diamond. Can you tell which one she is? Marian.

This is a little bit earlier than when I was there, but she was so memorable that very first day. You can't tell, she's very tall, she's very statuesque, very athletic-looking. And I'll never forget, she was standing in front of that classroom—there's only 15 of us—and she had a hatbox, just like this, in front of her.

She started telling us about why we should be studying the brain. She said we should study the brain because by studying the brain, we'll learn more about ourselves: about how we see the world, how we feel the world, how our emotions work. And as she told us all this, she slowly and dramatically opened that hatbox and pulled out a real, preserved human brain, just like this.

We freshmen went, "Oh, my God." And every time I pull it out of this hatbox, I am struck with how dense it is. We all have one in our heads, and it is defining how we think and feel and smell and taste the world. So let me give you a quick tour of the brain, okay?

If the brain was sitting in my head, it would be right here. My eyes would be right here. So this is the frontal lobe, right behind your forehead. Critical for what's called "executive functions"—planning what you're going to do in a day, the order in which you're going to do it. Critical for decision-making. Also very important for your personality. Your sense of humor is thought to reside in this frontal part of the brain.

Let's go to the very back: occipital lobe, right behind the back part of your head. Now, you see with your eyes, but with damage to the primary visual cortex back here, you would be blind. That tells you that the brain is defining how you see the world. In fact the eyes, the back of the eyes, the retina, is an outcropping of the brain. So with that, it brings in the light information. But that all has to be processed by this occipital lobe of the brain.

Next lobe, parietal lobe. Sits between the occipital lobe and the frontal lobe. Critical for visual-spatial information. For example, you can see that there's two halves of the brain: the right half and the left half. The right side of the brain controls everything on the left side of the body, and it also brings in sensory information from the left side of the body; and opposite for—the left side of the brain controls and brings in sensory information for the right side of the brain.

So if I have damage to the right parietal cortex, what happens is I could see my whole world. But if I had a plate of food in front of me, damage to the right means that the left side is impaired. I will only eat what's on the right side of the plate, because I ignore everything on that left side, because I have a right-side parietal lesion. That's what we mean by visual-spatial functions.

Finally, temporal lobe, down here. The temporal lobe is basically right behind this area right here. Temporal means time. So can anybody think about why you would name a lobe right below this region right here having to do something with time, or the passage of time? Memory. Gray hair, right.

This spot here is one of the first places where you get gray hair that shows, for some of us, the passage of time, and so that's how this lobe got named. It houses one of my favorite structures in the brain, critical for long-term memory. The structure is called the hippocampus. And without this structure, you can't form or retain new long-term memories for facts and events. We're going to come back to that in a little while.

The rest of the temporal lobe is really important for processing high-level visual information. So there's an area right about here called the peri-hippocampal face area. Critical for processing information about faces. So if you have damaged this area, you have a syndrome called prosopagnosia, which does not allow you to recognize different faces.

That was my introduction to the brain that very first day. But that in fact was not what made me want to become a neuroscientist. What made me want to become a neuroscientist is what Marian Diamond said next. She said that "One of my fundamental findings was asking, could the adult brain change in response to the environment?" We call that brain plasticity.

And remember, these studies were being done in the early 1960s when nobody had any information about how plastic or how malleable the adult brain was. And she did a very simple yet elegant experiment. What she did is she raised a group of rats in a very souped-up rat cage with lots of toys, lots of other rats. Think of it like the Disneyworld of rat cages.

And she compared the brains of those rats to rats raised in impoverished environments—think of a shoebox, with just rats and maybe one other rat, no toys. And she let them live there for several months.

What she found was at the end of that period, the rats that lived in Disneyworld, their brains, the outer covering of the brain called the cortex, was actually physically thicker. The brain grew. And that was the very first demonstration of how an adult brain could actually change in response to the environment. This was a positive change.

Now, I didn't know it at the time, but I happened to step into the classroom of one of this generation's best teachers. They just made a documentary about Marian Diamond. Did anybody see this on PBS the other time? This was Marian Diamond, and you can find it on PBS, you can look it up. But I'd highly recommend it. "My Love Affair With the Brain," yes, that's the title of it.

I was very lucky, inspired me. I walked into the classroom and I said, "I want to become a neuroscientist." Well, I did. And I decided to study another form of brain plasticity, that is, memory. Every time we form a new memory something changes in the brain and I wanted to understand that.

We're jumping fast-forward to 1998, when I started my lab at New York University. And when I think about that time, I think of an image like this: a dinner party that you never want to leave, because there's always something interesting to talk about and always somebody interesting to talk to.

It was a great time during that period, the first six years. I was developing my first lab. But if I think back on that same time period and I think about my social life, the picture that comes to mind looks like this. It's hard to get tenure, and I was working so hard, and I only knew people in my lab, and I ate a lot of takeout and I gained 25 pounds, and it was really bad.

So at some point I said I need to get back into shape. And so that's what took me to the gym. And I went to the gym, and the one thing that got me to stay and keep exercising was this class that I walked into one day. It's called intenSati. Who has done intenSati before? Yes, I have one of my students over here. So intenSati pairs physical movements from kickbox and dance and yoga and martial arts with positive spoken affirmations. Hassan is going to be giving me eight beats so I can demonstrate what this looks like.

Looks like five, six, seven, eight. One, two, three, four. I am strong now and I am inspired now. Done. Thanks. Okay. Hassan, amazing drummer.

Okay, so that's what you did. And I can tell you, the very first day I wandered into this class—I felt idiotic, saying these affirmations out loud. But by the end of the class, I was saying them out loud.

What it does is it not only kind of shifts your negative thoughts to these positive affirmations, but it actually increases the cardio output of the workout. So you end up shouting out affirmations with a whole bunch of other sweaty affirmation-shouting people, and it's great. And I walked out of the class and I thought, I feel amazing. I can't wait to come back to the next class.

So, mood change. Met a lot of new people at the gym. Another big kind of change in my life. Time rolled on. A year, year and a half went back, and I noticed something that really made me sit up and take notice. That is, I was sitting in my office and I was writing a grant. I'm a professor. I have to write a lot of grants. And a thought went through my mind that I had never had before. That thought was, gee, grant-writing is going well today. I'd never had that thought before.

It really struck me by surprise. It's never easy. But it wasn't just one day. I noticed it was going well. It was going better than it had before. And when I thought about it, I realized that it was because I was able to focus my attention longer and deeper than I had before. I didn't get distracted as much. And I was studying memory, remember. My memory was better, okay?

And that really made me sit up and take notice, and go back to the scientific literature. What do we know? I'm a neuroscientist. What do we know about the effects of exercise on the brain? Let me ask you: How many people have noticed that when they go and exercise in any way, shape or form that their mood gets better? Anybody notice that? Yes. Okay, that's probably why you came to this talk.

I can tell you why. Exercise improves your mood because even a single bout of exercise will increase levels of neurotransmitters that we know are very strongly associated with good mood. Dopamine goes up. Serotonin goes up. Noradrenalin goes up. Endorphins go up, even after a single bout of exercise, and that's why we get this boost of good mood. I noticed that immediately.

But what about my attention and my long-term memory? It turns out, when I went back to the literature, the most common effect in clinical studies in people, looking at the effects of exercise, is increases in your ability to shift and focus attention. So I said check, that's happening to me.

And then what about the long-term memory function? This is where it got really interesting. Because when I went back to the literature, I found a very, very familiar figure. That figure was Marian Diamond. It turns out that all those studies on enriched environments and those Disneyworld rat cages, later people asked, what was it about that Disneyworld of rat cages that made all those brain changes happen?

So they systematically looked. Was it the social interactions? Was it the games that they were playing? And they came up with one major factor that caused all those brain changes that she first identified in the 1960s. That one factor was exercise. The rats in Disneyworld were getting significantly more exercise than the rats that were in that shoebox with no way to really exercise.

And so I thought, this is fantastic. I want to really—I'm fascinated with this, because I'm seeing it in myself. I want to learn about it. And so I thought, the best way to learn about a new topic is to teach an undergraduate course on it. So I developed a new class for neuroscience majors at NYU called "Can Exercise Change Your Brain?" And I was going to go over all of the data that I just explained for you, in more detail.

But then I thought, wouldn't it be cool if I could actually get the students to exercise themselves, so they could actually feel the effects of exercise on their brain. So I went to the administration and said, "I have a great idea. All you have to do is give me some money to pay for an exercise instructor and then they'll teach the exercise, they'll do exercise, and then I'll do the academic part."

And they said, "Well, we pay you to teach the class, so no extra money." So I did the next most obvious thing: I went to the gym and got certified to teach the exercise part of the class myself. So I went and I did five days of teacher training. But you can't—just five days doesn't really help. You have to really train. So this started the longest class preparation that I've ever had in my entire career. It was six months of training.

And I had individual friends come over, begged them to let me teach them how to do this exercise. I did it for my cat. I did it for large groups, small groups. I practiced, because I was going to be doing this all semester.

And then I realized that I was going to have a whole classroom full of undergraduates exercising more for an entire semester. They were going to be my first subjects for research. So all I had to do was test them cognitively at the beginning and at the end of the semester.

But I needed a control group as well. So I went to one of my colleagues and I said, hey, do you make your students exercise during class? And they said no. And so I said, can I test them at the beginning and end of the semester? And they said yes. So I had my control class.

So six months, I'm doing all the research to develop the academic part. I'm training with intenSati, and the day arrives. September 7th, 2009, the first day of fall semester. And three things are very different. One is I'm clad head to toe in spandex. Because I have to teach an exercise class. I usually don't come to school in spandex.

Second, I was really nervous. And I give a lot of—I lecture all the time, I'm not nervous when I lecture. But I'd never taught students exercise, and I really wanted them to like it, so I was very nervous.

And the third thing that was different is the students themselves. First day of fall semester, they're really excited and don't know what's going to happen. These students looked scared. They knew they had to exercise, but they didn't really know whether they wanted to exercise with me. But I knew that the only way I would know if this would work or not would be to actually get them to exercise.

So I want to bring you all back to that day on September 7th, 2009, and ask you all to stand up. Okay. Put your drinks down. Make sure they don't spill. Okay, get a little—go like this, make sure you're not touching anybody, okay? Actually, first thing to do, turn around and high-five at least three of your neighbors, and tell them, "You are awesome. You are awesome. You are awesome. You are awesome. You are awesome."

Okay. Are you ready? Here's your little test, without music, okay? We're just going to do punches, right and left. It is right, left, right, left, right, left, right, left. I am strong now. You say it.

Audience:

I am strong now.

Suzuki:

Done. Okay, you were great.

Now, we have to add the special sauce. The special sauce is Hassan. Okay, here we go. Five, six, five, six, seven, eight. It's right, left, right, left. And I say, I am strong now. You say it.

Audience:

I am strong now.

Suzuki:

I say, I am really strong. You say it.

Audience:

I am really strong.

Suzuki:

Just the girls: I am Wonder Woman strong. Let's hear you.

Audience:

I am Wonder Woman strong.

Suzuki:

Yeah. Guys, I am Superman strong. You.

Audience:

I am Superman strong.

Suzuki:

New move: upper cut, right and left. Use your abs. Let's go. I am inspired now. You say it.

Audience:

I am inspired now.

Suzuki:

Again, I am inspired now. You say it.

Audience:

I am inspired now.

Suzuki:

One more time. I am inspired right now. You say....

Audience:

I am inspired right now.

Suzuki:

New move: push it out. Push it out. Push it out. I am pumped up now. You say it.

Audience:

I am pumped up now.

Suzuki:

I am pumped up. You say...pumped up. I am pumped up. Your turn.

Audience:

I am pumped up.

Suzuki:

Are you pumped up? You say,

Audience:

I am pumped up.

Suzuki:

Again: I am pumped up. You say....

Audience:

I am pumped up.

Suzuki:

Last move: it is pull it down, pull it down, pull it down, pull it down. I am on fire now. You say it.

Audience:

I am on fire now.

Suzuki:

One more time: I am on fire now. You say it.

Audience:

I am on fire now.

Suzuki:

Done. All right. Give yourself a hand. Have a seat. Have a drink. Okay.

Now, I want you all to think back on your college classes. What would happen if you did an hour of that before your class? Right? That's what we did, an hour. And then I launched into the lecture. So what did that do? Completely transformed my classroom, okay? We went from standard lecture, one person talking and everybody trying to listen, to much, more interactive, much more fun, much more improvisational in class.

And that really changed the way that I taught every other class at NYU since that day in 2009. But more importantly, what happened to my study? Did my students change their brain function because of this exercise? Well, first I have to tell you, we had a wide range of different fitness levels in my class. We had that first year the starting point guard of the NYU men's varsity basketball team; and other students that said this was the only aerobic exercise they got. I mean, they're

New Yorkers, they walk a lot. But this was the only real aerobic exercise that they got.

Despite all these differences, what we found is that their memory didn't improve, but their reaction time actually significantly improved, relative to the class that didn't exercise. Now, that was a subtle effect. But the class was only once a week. And that really lit a fire underneath me. What if I could get students or people to exercise two or three or four times a week? What kinds of cognitive effects would I see? And so that was the start of my shift, from studying memory to studying the effects of exercise.

And I want to end with telling you about what exactly these open questions are. We have lots of information about correlations. If you say that you walk a lot and you've walked for your lifetime, you are significantly less likely to develop dementia when you get old.

But that does not translate. That's just a correlation. That does not translate to tell me exactly today how much I have to exercise. So one of my big questions in the lab is understanding the exercise prescription: how much, how long, what kind of exercise do you need for this age group, that age group, this genetic background, that genetic background, this gender and that gender, to significantly improve this range of cognitive functions that we know that exercise is affecting.

Actually, most people ask me, could you just tell me the minimum amount of exercise that I have to do to get these effects, okay? But that is the question. The second question is, how the heck does moving your body out here end up changing the brain? What are those pathways, those neural chemical pathways and mechanisms that are allowing muscle movement to change the brain?

Let me just tell you about three that are related to each other, but they're just recently described in the last couple of years. These are from studies in animal model systems.

What we know is muscles that are moving in your periphery are actually secreting different hormones. Those hormones can then pass into the brain and stimulate the release of a really important, what's called "growth factor" in the brain. That growth factor actually helps new cells in the hippocampus grow. So that's one of my main motivations, and I want to share this with you.

There's only, in the rodent brain, there's only two brain areas where new brain cells can be born as adults. One of them is in the olfactory bulb, and it's unclear whether that happens in people, but it happens in rodents. And the second is the hippocampus, critical for long-term memory, and that does happen in people. So without doing anything—you can be a couch potato—and you have a few more of these brand-new hippocampal cells being born in your adult brain.

The one thing we know that could increase the birth of those neurons is physical aerobic exercise. So are those new brain cells good? They are. They're like teenage brain cells. They're really super-excitable, and they try and get into all the social networks and they try and get into all the different memory circuits. And they get more engaged or more easily engaged than the older hippocampal neuron that you've had since you were born. So, yes, you do want as many of those hippocampal cells as you can. And that's what helps motivate me to go to the gym all the time. Okay.

Back to those pathways: those hormones released by the muscles are going into the brain and stimulating the release of a growth factor that helps that birth of new neurons in the hippocampus along, okay? So that's part of the reason why that happens.

And then the other really interesting factor identified by my colleague Moses Chao at the NYU Medical Center is a ketone body that, we've known for a long time that this ketone body is released from the liver when we exercise. Everybody knows that. It is looked at in physiology.

It turns out that he discovered that this ketone body also goes into the brain and stimulates the release of that same growth factor. All of these different pathways are heading towards increasing the level of this growth factor called "BDNF" or brain-derived neurotropic factor. So this is one—certainly not the only one, but one of the keys that we know. And one of the ways that we know to increase this is by exercising. Okay, that's a kind of exercise prescription, and the pathways.

Let me just end by telling you the implications that really keep me asking this question for a long time. One of the implications of understanding how exercise affects brain function is education. I have been saying for many years that I want to make NYU the exercise university.

We have thousands, 50,000 students coming through our doors every year, and we just did a pilot study where we looked at the effects of one semester on exercise and relative to one semester off exercise. Do you know what we found? We found that on the semester where we got the students to exercise—I'll tell you, it was not easy to get them to exercise. It took a lot of effort. But they did.

They had better attention. They had better working memory. They had better long-term memory. There was a significant correlation between their grade point average in that semester and how much they had worked out.

This is still a pilot study, but I have thousands of students to explore at NYU. And one of my dreams that you can check back with me is that I'm going to have a program at NYU, a voluntary program, and we're going to be able to give recommendations for what is the optimum exercise prescription to optimize your performance in school.

They're paying a lot of money for all of this wonderful education that they get at NYU. Can this information give you practical information about how to learn better, how to be more creative, how to use that creativity and learning and energy to do better in schools?

Second implication is for healthy adults. I notice these changes and I changed my research because I notice these changes in myself. I'm an N of one. But there's enough research out there to suggest that these effects are definitely there and they need to be honed and need to be optimized for people. And just think about it: If we got everybody to exercise, even at that minimum level, and we got improved mood, improved long-term memory and improved attention, what is the implication for the productivity of people here in the United States? Okay?

And finally, something that also affects every single one of us in the room is aging. One of the things that I am so passionate about is, I didn't mention that one of the reasons why I became so interested in exercise was not only what I was noticing in myself, but at the same time was noticing my own memory and attention and mood improvement.

My father actually developed quite striking dementia. It was very, very clear. And so everything that was improving in me was getting worse in him. He's 85, and he can't run and he can't do that kind of exercise, and exercise would not prevent dementia. But what we do know is dementia and aging is targeting two key brain areas: the prefrontal cortex, important for attention; and the hippocampus. Those are the two first and major ones.

You can think of exercise as kind of a 40l(k) program for your prefrontal cortex and your hippocampus. You're not going to cure Alzheimer's Disease, but you are going to strengthen these brain areas so later on when these pathologies develop, it's going to take longer for them to start manifesting in your behavior and what you can remember and what you can pay attention to. And so that's why I am so passionate about studying exercise.

And I find every possible excuse to exercise. So for example when there's an amazing drummer sitting right next to me, I'm going to end by asking Hassan to play us off, and I ask you to stand up. We're going to do one more round, just for old time's sake. Sorry, put your drinks down one more time. One more round, starting with "strong." Five, six, seven, eight... I am strong now. Let's hear you.

Audience:

I am strong now.

Suzuki:

Inspired. I am inspired now. You say it.

Audience:

I am inspired now.

Suzuki:

I am pumped up right now. You say...

Audience:

I am pumped up right now.

Suzuki:

Last one. I am on fire now. You.

Audience:

I am on fire now.

Suzuki:

Done. Thank you. Thank you.