【TEDx演讲004】看完这个，你的脑子就不一样了

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00:00

Translator: Jessica Lee Reviewer: Denise RQ

00:14

So how do we learn?

00:16

And why does some of us learn things more easily than others?

00:21

So, as I just mentioned, I'm Dr. Lara Boyd.

00:24

I am a brain researcher here at the University of British Columbia.

00:28

These are the questions that fascinate me.

00:31

(Cheers) (Applause)

00:35

So brain research is one of the great frontiers

00:38

in the understanding of human physiology,

00:41

and also in the consideration of what makes us who we are.

00:45

It's an amazing time to be a brain researcher,

00:47

and I would argue to you

00:49

that I have the most interesting job in the world.

00:52

What we know about the brain is changing at a breathtaking pace.

00:56

And much of what we thought we knew and understood about the brain

00:59

turns out to be not true or incomplete.

01:03

Some of these misconceptions are more obvious than others.

01:06

For example, we used to think

01:09

that after childhood the brain did not, really could not change.

01:14

And it turns out that nothing could be farther from the truth.

01:18

Another misconception about the brain

01:19

is that you only use parts of it at any given time

01:23

and it's silent when you do nothing.

01:25

Well, this is also untrue.

01:27

It turns out that even when you're at a rest

01:29

and thinking of nothing, your brain is highly active.

01:33

So it's been advances in technology, such as MRI,

01:37

that's allowed us to make these and many other important discoveries.

01:40

And perhaps the most exciting,

01:42

the most interesting and transformative of these discoveries

01:45

is that, every time you learn a new fact or skill,

01:49

you change your brain.

01:51

It's something we call neuroplasticity.

01:54

So as little as 25 years ago, we thought that after about puberty,

01:58

the only changes that took place in the brain were negative:

02:01

the loss of brain cells with aging,

02:03

the result of damage, like a stroke.

02:06

And then, studies began to show remarkable amounts

02:09

of reorganization in the adult brain.

02:13

And the ensuing research has shown us

02:15

that all of our behaviors change our brain.

02:19

That these changes are not limited by age,

02:23

it's a good news right?

02:24

And in fact, they are taking place all the time.

02:27

And very importantly,

02:29

brain reorganization helps to support recovery

02:32

after you damage your brain.

02:34

The key to each of these changes is neuroplasticity.

02:39

So what does it look like?

02:41

So your brain can change in three very basic ways

02:44

to support learning.

02:45

And the first is chemical.

02:48

So your brain actually functions by transferring chemicals signals

02:51

between brain cells, what we call neurons,

02:53

and this triggered a series of actions and reactions.

02:57

So to support learning, your brain can increase the amount

03:00

or the concentrations of these chemical signaling

03:03

that's taking place between neurons.

03:06

Because this change can happen rapidly,

03:09

this supports short-term memory

03:10

or the short-term improvement in the performance of a motor skill.

03:15

The second way that the brain can change to support learning

03:18

is by altering its structure.

03:21

So during learning, the brain can change the connections between neurons.

03:25

Here, the physical structure of the brain is actually changing

03:28

so this takes a bit more time.

03:30

These type of changes are related to long-term memory,

03:33

the long-term improvement in a motor skill.

03:37

These processes interact, and let me give you an example of how.

03:41

We've all tried to learn a new motor skill,

03:44

maybe playing the piano,

03:46

maybe learning to juggle.

03:48

You've had the experience of getting better and better

03:50

within a single session of practice,

03:53

and thinking "I have got it."

03:55

And then, maybe you return the next day,

03:57

and all those improvements from the day before are lost.

04:01

What happened?

04:02

Well, in the short-term, your brain was able to increase

04:05

the chemical signaling between your neurons.

04:08

But for some reason, those changes did not induce the structural changes

04:13

that are necessary to support long-term memory.

04:17

Remember that long-term memories take time.

04:20

And what you see in the short term does not reflect learning,

04:23

It's these physical changes

04:25

that are now going to support long-term memories,

04:27

and chemical changes that support short-term memories.

04:32

Structural changes also can lead to integrated networks of brain regions

04:36

that function together to support learning.

04:39

And they can also lead to certain brain regions

04:41

that are important for very specific behaviors

04:44

to change your structure or to enlarge.

04:46

So here's some examples of that.

04:49

People who read Braille

04:51

have larger hand sensory areas in their brain than those of us who don't.

04:56

Your dominant hand motor region, which is on the left side of your brain,

05:00

if you are right-handed, is larger than the other side.

05:04

And research shows the London taxi cab drivers

05:07

who actually have to memorize a map of London to get their taxi cab license,

05:12

they have larger brain regions devoted to spatial, or mapping memories.

05:17

The last way that your brain can change to support learning

05:20

is by altering its function.

05:23

As you use a brain region,

05:25

It becomes more and more excitable and easy to use again.

05:29

And as your brain has these areas that increase their excitability,

05:32

the brain shifts how and when they are activated.

05:35

With learning, we see

05:37

that whole networks of brain activity are shifting and changing.

05:42

So neuroplasticity is supported

05:44

by chemical, by structural, and by functional changes,

05:48

and these are happening across the whole brain.

05:51

They can occur in isolation from one or another,

05:53

but most often, they take place in concert.

05:57

Together, they support learning.

05:59

And they're taking place all the time.

06:04

I just told you really how awesomely neuroplastic your brain is.

06:08

Why can't you learn anything you choose to with ease?

06:13

Why do our kids sometimes fail in school?

06:16

Why as we age do we tend to forget things?

06:20

And why don't people fully recover from brain damage?

06:23

That is: what is it that limits and facilitates neuroplasticity?

06:29

And so this is what I study.

06:31

I study specifically how it relates to recovery from stroke.

06:35

Recently, stroke dropped

06:36

from being the third leading cause of death in the United States

06:40

to be the forth leading cause of death.

06:42

Great news, right?

06:44

But actually, it turns out

06:46

that the number of people having a stroke has not declined.

06:49

We are just better at keeping people alive after a severe stroke.

06:53

It turns out to be very difficult to help the brain recover from stroke.

06:58

And frankly,

06:59

we have failed to develop effective rehabilitation interventions.

07:05

The net result of this is that stroke is the leading cause

07:09

of long-term disability in adults in the world;

07:13

individuals with stroke are younger

07:15

and tending to live longer with that disability,

07:18

and research from my group actually shows

07:21

that the health-related quality of life of Canadians with stroke has declined.

07:26

So clearly we need to be better

07:28

at helping people recover from stroke.

07:30

This is an enormous societal problem,

07:33

and it's one that we are not solving.

07:36

So what can be done?

07:38

One thing is absolutely clear:

07:41

the best driver of neuroplastic change in your brain is your behavior.

07:46

The problem is that the dose of behavior, the dose of practice

07:50

that's required to learn new and relearn old motor skills,

07:53

is very large.

07:55

And how to effectively deliver these large doses of practice

07:58

is a very difficult problem; It's also a very expensive problem.

08:03

So the approach that my research has taken

08:05

is to develop therapies that prime or that prepare the brain to learn.

08:09

And these have included brain simulation, exercise, and robotics.

08:14

But through my research, I've realized that a major limitation

08:18

to the development of therapies that speed recovery from stroke

08:21

is that patterns of neuroplasticity are highly variable from person to person.

08:28

As a researcher, variability used to drive me crazy.

08:32

It makes it very difficult to use the statistics

08:35

to test your data and your ideas.

08:38

And because of this, medical intervention studies are

08:41

specifically designed to minimize variability.

08:45

But in my research, it's becoming really clear

08:48

that the most important, the most informative data we collect

08:52

is showing this variability.

08:56

So by studying the brain after stroke, we've learned a lot,

09:00

and I think these lessons are very valuable in other areas.

09:06

The first lesson is

09:07

that the primary driver of change in your brain is your behavior,

09:11

so there is no neuroplasticity drug you can take.

09:15

Nothing is more effective than practice at helping you learn,

09:19

and the bottom line is you have to do the work.

09:23

And in fact, my research has shown

09:25

increased difficulty, increased struggle if you will, during practice,

09:30

actually leads to both more learning,

09:32

and greater structural change in the brain.

09:37

The problem here is that neuroplastcity can work both ways.

09:42

It can be positive, you learn something new,

09:45

and you refine a motor skill.

09:47

And it also can be negative though, you forgot something you once knew,

09:51

you become addicted to drugs,

09:53

maybe you have chronic pain.

09:56

So your brain is tremendously plastic,

09:58

and it's been shaped both structurally and functionally by everything you do,

10:03

but also by everything that you don't do.

10:07

The second lesson we've learned about the brain

10:09

is that there is no one-size-fits-all approach to learning.

10:14

So there is no recipe for learning.

10:16

Consider the popular belief that it takes 10,000 hours of practice

10:20

to learn and to master a new motor skill.

10:23

I can assure you it's not quite that simple.

10:27

For some of us,

10:28

it's going to take a lot more practice, and for others it may take far less.

10:32

So the shaping of our plastic brains is far too unique

10:36

for there to be any single intervention that's going to work for all of us.

10:41

This realization has forced us to consider something call personalized medicine.

10:46

This is the idea that to optimize outcomes

10:49

each individual requires their own intervention.

10:53

And the idea actually comes from cancer treatments.

10:55

And here it turns out that genetics are very important in matching

10:59

certain types of chemotherapy with specific forms of cancer.

11:04

My research is showing that this also applies to recovery from stroke.

11:08

There're certain characteristics of brain structure and function

11:11

we called biomarkers.

11:12

And these biomarkers are proving to be very helpful

11:15

and helping us to match

11:17

specific therapies with individual patients.

11:20

The data from my lab suggests it's a combination of biomarkers

11:24

that best predicts neuroplastic change and patterns of recovery after stroke.

11:29

And that's not surprising, given how complicated the human brain is.

11:34

But I also think we can consider this concept much more broadly.

11:39

Given the unique structure and function of each of our brains

11:43

what we've learned about neuroplasticity after stroke applies to everyone.

11:50

Behaviors that you employ in your everyday life are important.

11:54

Each of them is changing your brain.

11:57

And I believe we have to consider

11:59

not just personalized medicine but personalized learning.

12:03

The uniqueness of your brain will affect you

12:05

both as a learner and also as a teacher.

12:08

This idea helps us to understand

12:11

why some children can thrive in tradition education settings

12:15

and others don't;

12:17

why some of us can learn languages easily

12:19

and yet, others can pick up any sport and excel.

12:25

So when you leave this room today,

12:28

your brain will not be the same as when you entered this morning.

12:32

And I think that's pretty amazing.

12:36

But each of you is going to have changed your brain differently.

12:40

Understanding these differences,

12:42

these individual patterns, this variability and change

12:46

is going to enable the next great advance in neuroscience;

12:49

it's going to allow us to develop new and more effective interventions,

12:53

and allow for matches between learners and teachers,

12:57

and patients and interventions.

13:00

And this does not just apply the recovery from stroke,

13:03

it applies to each of us, as a parent, as a teacher, as a manager,

13:08

and also because you are at TEDx today, as a lifelong learner.

13:13

Study how and what you learn best.

13:16

Repeat those behaviors that are healthy for your brain,

13:20

and break those behaviors and habits that are not.

13:24

Practice.

13:26

Learning is about doing the work that your brain requires.

13:30

So the best strategies are going to vary between individuals.

13:34

You know what, they're even going to vary within individuals.

13:37

So for you, learning music may come very easily,

13:40

but learning to snowboard, much harder.

13:44

I hope that you leave today

13:46

with a new appreciation of how magnificent your brain is.

13:49

You and your plastic brain are constantly being shaped by the world around you.

13:54

Understand that everything you do,

13:57

everything you encounter, and everything you experience is changing your brain.

14:01

And that can be for better, but it can also be for worse.

14:05

So when you leave today, go out and build the brain you want.

14:10

Thank you very much.

14:11

(Applause)

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