How meditation can reshape our brains | Sara Lazar | TEDxCambridge

Neuroscientist Sara Lazar's amazing brain scans show meditation can actually change the size of key regions of our brain, improving our memory and making us more empathetic, compassionate, and resilient under stress.

Good morning.

So when I was in graduate school, I was a runner,

and a friend and I decided that we're going to run the Boston Marathon.

And so we started training and we overtrained,

and I developed knee and back problems.

So I went to see a physical therapist,

and they told me that I had to stop running

and instead I should just stretch.

As I was leaving the phzsical therapist office,

I saw an ad for a vigorous yoga class

that promised not only to promote flexibility,

but also to promote strength and cardiorespiratory fitness.

So I thought, oh, well, this is a great way

that I can stretch, but also remain in shape,

and maybe I could even still run the Boston Marathon.

So I went to the yoga class and I really enjoyed it,

except when the teacher would make all sorts of claims,

you know, all sorts of medical claims, but also claims about, oh, yes,

it will help you...

You'll increase your compassion and open your heart and I was just like...

I remember my eyes would roll and...

I think, yeah, yeah, yeah, I am here to stretch.

(Laughter)

But what was interesting was that after a couple of weeks

I started noticing some of these changes,

I started noticing that I was calmer and I was better able

to handle difficult situations, and indeed, I was feeling more compassionate

and open-hearted towards other people,

and I was better able to see things from other people's point of view.

And, you know, I was like, hm, how could this be,

how could this be?

And, I thought, well maybe, you know, it's just a placebo response, right?

She told me I will feel this, so maybe that's why I was feeling it.

So I decided to do a literature search to see if there's any research on this.

And low and behold, there was quite a bit

showing both yoga and meditation are extremely effective for decreasing stress

they're also very good for reducing symptoms associated with numerous diseases

including depression, anxiety, pain, and insomnia.

And there's a couple of very good studies demonstrating it can actually

improve your ability to pay attention, and most interestingly, I thought

virtually every study has shown that people are just happier.

They report they're more satisfied with their life, and they have a higher quality of life.

And so, this was interesting to me.

And so I decided to switch and start doing this sort of research.

So as a nurse scientists, you know, how could this be happening?

How can something as silly as a yoga posture

or sitting and watching your breath.

How can that lead to all these sorts of different types of changes?

So, what we know is that whenever you engage in a behavior over and over again,

that this can lead to changes in your brain.

And this is what's referred to as neuroplasticity.

And what this just means is that your brain is plastic and that

the neurons can change how they talk to each other with experience.

And so, there's a couple of studies demonstrating

that you can actually detect this, using machines like the MRI machine.

The first study was with juggling.

They took people who had never ever juggled before,

and they scanned them, and then they taught them how to juggle,

and they said, "Keep practising for three months."

And they brought them back after three months, and they scanned them the second time,

and they found that they can actually detect with the MRI machine

changes in the amount of grey matter in the brain of these people

in areas that are important for detecting visual motion.

So, I thought, OK, three months, you know...

Can meditation change brain structure too?

Something as simple as, you know, as juggling.

What about meditation?

So the first study we did,

we recruited a bunch of people from the Boston area,

and these were not monks or meditation teachers,

they're just average Joes who on average practice meditation

about 30-40 minutes a day,

and we put them in a scanner,

and we compared them to a group of people who were demographically matched,

but who don't meditate.

And what we found is this:

That there were indeed several regions of the brain

that had more grey matter in the meditators compared to the controls.

One of the regions I'm going to point out to you

is here in the front of the brain, it's the area that's important

for working memory and executive decision making

and what was interesting about it

was when we actually plotted the data versus their ages.

So here in the red square, that's the controls.

And this is something you see actually,

it's been well documented that as we get older,

not just there, but across most of our cortex,

it actually shrinks as we get older.

And this is part of the reason why as we get older,

it's harder to figure things out and to remember things.

And what was interesting was that in this one region,

the 50 year old meditators had the same amount of cortex as the 25 year olds,

suggesting that meditation practice may actually slow down or prevent

the natural age-related decline in cortical structure.

So now, the critics, and there were many critics,

said, well, you know, meditators, they're weird.

Maybe they were just like that before they started practising, right?

A lot of them were vegetarian, so maybe it had something to do with their diet,

or something else with their lifestyle, you know.

Couldn't possible be the meditation, it's something else, right?

And to be fair, you know, that could be true.

This first study could not address that.

So we did a second study.

In this study, what we did is, we took people who had never meditated before,

and we put them in the scanner, and then we put them through

an eight-week meditation-based stress reduction program

where they were told to meditate every day for 30 to 40 minutes.

And then we scanned them again at the end of the eight weeks,

and this is what we found.

So what you see is that several areas became larger.

In this slide we can see the
hippocampus,

and in the graph, the controls are in blue and the meditation subjects

are in red, and what we see is that the
hippocampus,

this is the area that's important for learning and memory,

it's also important for emotion regulation and it was interesting it was less

grey matter in this region in people who had depression and PTSD.

Another region we identified was the temporo-parietal junction

which is here above your ear,

it's important for perspective taking and empathy and compassion.

And again, these are both functions which people report changing when

they start practising meditation and yoga.

Another region we identified was the amygdala.

And the amygdala is the fight-or-flight part of your brain.

And here we actually found a decrease in gray matter.

And what was interesting was that the change in grey matter

was correlated with the change in stress.

So the more stress reduction people reported,

the smaller the amygdala became.

And this was really interesting, because it's sort of opposite and parallel

of what some animal studies have shown.

So colleagues using rodents,

they took rodents who were just happy, normal rodents,

and they had them in their cage, and they measured

their amygdala, and then they put them through a ten- day stress regimen.

And at the end of the ten days, they measured their amygdala,

and this exact same analogous part of the rat brain grew.

So we found a decrease with stress, they found an increase with stress.

What was interesting was that then they left the animals alone,

and three weeks later they went back and tested them again.

And three weeks later, that same part of the amygdala was still large,

and the animals, even though they were in their original cages

where they were happy, were still acting stressed out,

so they, you know, they were cowering in the corner,

and they just weren't exploring the space the way they had before.

And so, this is the exact opposite of what we saw at the humans,

because with the humans nothing has changed with their environment.

They still had their stressful jobs,

all the difficult problems were still being difficult,

and the economy still sucked,

but yeah, their amygdala got smaller, and they were reporting less stress.

And so, together these really show that the change in the amygdala

is not responding to the change in the environment, but rather it's representing

the change in the people's reaction or relationship to their environment.

And then the other thing that the study shows is that,

it wasn't just the people were saying, "Oh, I feel better."

Or that it was a placebo response, or that they're trying to please us,

but there was actually a neurobiological reason why they're saying they

felt less stressed.

And so the idea that I'd like to share with all of you today is that meditation

can literally change your brain.

Thank you.

(Applause)