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  • Hi, thank you.

  • I love, love, love your enthusiasm.

  • Your energy and excitement is really what makes me love my job,

  • and my job is to study the adolescent brain.

  • I'm a scientist at UCLA, as Jake said.

  • So scientists have studied the brain for centuries,

  • but it's only been in the last 15 years or so

  • that we've discovered one of the most fascinating things,

  • and that is that your brain changes every single day.

  • As you sit in this room,

  • your brain is changing in response to my voice,

  • in response to the person next to you,

  • and your experiences and the people you affiliate with

  • shape the way your brain ultimately develops.

  • We also know that the brain matures

  • and continues to do so past childhood and into the teenage years

  • and well into your mid-20s.

  • So most of you in this room today,

  • as middle and high school students,

  • don't yet have a fully mature brain.

  • But this is actually really beneficial,

  • if we think about one of the functions of adolescence,

  • which is to establish your independence from a caregiver,

  • because your brain as an adolescent

  • is built to help you do that.

  • Compared to children and adults,

  • the teenage brain is really good at seeking out new experiences

  • enjoying thrills and seeking out risks.

  • It's also really good at recognizing social

  • or being sensitive to social and emotional information.

  • And so for that reason,

  • the teenage brain is really responsive to rewards and emotions

  • when making decisions.

  • And in my laboratory at UCLA, and in laboratories all around the world,

  • we're interested in uncovering that very question:

  • How does a teenage brain make decisions?

  • One of the first discoveries relevant to this topic

  • was made when we discovered

  • that the part of your brain in the very front,

  • called the prefrontal cortex,

  • which is the last brain region to develop,

  • because your brain develops from the back to the front,

  • continues to change up until the mid-20s.

  • And the reason this is relevant

  • is because the prefrontal cortex is a part of your brain

  • that helps you think about the consequences

  • or potential consequences of your actions

  • before you do them.

  • It helps you regulate your behavior and your emotions.

  • And so it makes sense that if this part of the brain

  • isn't fully available until well past adolescence,

  • then teenagers may make more impulsive decisions

  • with less regard for the potential future consequences.

  • But we now know that the stories

  • are far more interesting and complicated than that.

  • And in fact, what we really need to do

  • is think about how brain regions that are not at the surface of your brain,

  • but in the deeper layers,

  • how they change.

  • And one region we focus on is called the striatum.

  • And the striatum is the key component of the reward system.

  • So when you receive something that you find rewarding,

  • your striatum is very responsive

  • and it releases something called dopamine.

  • And this is the case not just in humans,

  • but in kids, in mice, in rats, in monkeys.

  • All of these organisms respond

  • really with a lot of excitement in their brain

  • when they get something they like.

  • So in my lab, we study this reward system across development,

  • especially in teenagers.

  • And we do that by asking people to come to the laboratory

  • and perform what is called

  • a Functional Magnetic Resonance Imaging Scan, or fMRI

  • And the beauty of fMRI is that

  • you can take a snapshot of the brain in motion.

  • So while you are experiencing something you like,

  • or while you are making a decision,

  • we capture how your brain is responding to that,

  • how your brain is active.

  • And so, to study the reward system,

  • what we did is not simply show people pictures of reward,

  • which is what mostly happens in brain imaging studies,

  • but instead what we did is we actually gave someone a reward

  • and what's something that people find rewarding?

  • Sugar.

  • So what we did is we asked people to come to the lab,

  • we asked a group of teenagers and a group of adults,

  • and, while they were in the MRI, we hooked them up to a straw

  • and we fed them squirts of sugar water ever so often.

  • And first we asked them whether they liked it.

  • Maybe they weren't going to like the sugar as much as we thought.

  • But they actually did.

  • This is the rating scale asking them, "How much do you like the sugar?"

  • And the average response is in red for the teenage group

  • and the adults is shown in white,

  • and you can see that everybody liked it,

  • but it's the teenage group that showed this exaggerated sensitivity.

  • They really liked it.

  • So we started to wonder whether there was something neurobiological

  • that represented this difference.

  • So, instead of focusing on the prefrontal cortex,

  • which is what a lot of brain scientists who study adolescents do,

  • we looked at the deeper layers of the brain.

  • So in this image,

  • which is actually a real human brain image

  • averaged together among all our participants,

  • we saw that, in the deeper layers,

  • here represented with this yellow activation,

  • the striatum was really excited to the sugar water,

  • and this was across all age groups.

  • But the really cool thing was observed

  • when we looked at the differences between the teenagers and the adults.

  • Here again I'm showing you the magnitude of activation,

  • that is, how excitable the brain was,

  • in the teenagers compared to the adults,

  • to this very simple reward of sugar.

  • And you can see that the teenagers were much more excited

  • to the same exact stimulus,

  • and in the same exact region of the brain,

  • it's the teenage brain that was going crazy.

  • It was really excited to get it.

  • And when we associated that with their ratings of the sugar,

  • it was only in the teenage group

  • where we saw that people who showed

  • greater activation in the brain

  • in response to the sugar

  • also told us they liked it more.

  • So that means that, in real time,

  • at that very moment your brain gets something that it likes,

  • it will make you think that it's better.

  • And you can think or imagine that, in future circumstances,

  • your brain will encode that information and remember that you liked it,

  • so it will bias your decisions toward getting more rewards,

  • and that's what happens during adolescence.

  • But to ensure that this wasn't just specific

  • to something as simple as sugar,

  • we gave people something else that everybody likes

  • and we did this while they were in the MRI.

  • And what's something else that everyone loves to get?

  • (Audience) Money! AG: Money. Right?

  • Everybody likes money.

  • So, we brought in a whole separate group of teenagers and adults,

  • and this time we threw a group of kids in there,

  • who were between about 7 and 10,

  • and we found that, again,

  • the part of the brain that was most responsive

  • was the striatum,

  • shown here on the left.

  • This is a brain scan showing the average activation.

  • But what you can see really clearly

  • is that not only were the teenagers

  • more reactive to the money than the adults,

  • which you might argue

  • is because maybe they have less of it, they like it more,

  • but that's not the case,

  • because the kids probably have even less than the teenagers,

  • and the teens still showed this exaggerated response.

  • So this is telling us that

  • there's something really special about the teenage brain.

  • There's a sharp increase in sensitivity

  • to rewards and novel information

  • from childhood to adolescence,

  • but then there's a sharp decrease from adolescence to adulthood.

  • And that probably has something to do

  • with the fact that the prefrontal cortex is starting to come online,

  • as people transition into adulthood,

  • and regulating the emotional response to the rewarding information.

  • So what does this all mean for behavior and for your everyday life?

  • Well, there are a few things.

  • From my perspective,

  • this is a really exciting time to study the teenage brain.

  • Although scientists have made significant progress

  • in understanding what makes the teenage brain unique,

  • we still have a lot to learn.

  • For instance, we're just now starting to appreciate that

  • this sensitivity in the brain to rewards and to emotions

  • might lead teenagers to make poor choices sometimes,

  • but it also presents an excellent opportunity

  • to seek out new adventures, to meet new people

  • and to confront interesting challenges

  • in ways that people don't typically do later in life.

  • And I predict that,

  • as we continue to conduct more of this research,

  • we will learn to take advantage

  • of the sensitivity of the brain during adolescence

  • to generate new ideas

  • and to promote creative thinking.

  • There's a lot that we can and will learn from the adolescent brain

  • and from adolescence in general in the coming decade.

  • And perhaps we'll learn that taking risks and seeking out rewards

  • are really adaptive behaviors in many contexts

  • that actually lead to really good decisions,

  • and that help individuals navigate

  • the often challenging and intimidating transition

  • from childhood to adulthood.

  • So with that, I encourage you to savor

  • the excitability of your teenage brain

  • and to enjoy all the new people you meet and all the adventures you take.

  • Thank you.

  • (Applause)

Hi, thank you.

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B1 brain teenage adolescence striatum reward prefrontal cortex

【TEDx】Insight Into the Teenage Brain: Adriana Galván at [email protected]

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    Hhart Budha posted on 2014/06/14
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