Ruben Baler, Ph.D., is not your typical neuroscientist. Baler has studied in his native country Argentina, the U.S., and Israel. He is fluent in three languages. His work at NIDA enables him to publish scientific papers and collaborate on presentations and speeches with NIDA’s Director, Nora D. Volkow, M.D. His true passion is teaching young people about the brain. He talks to college students at George Washington University in Washington, DC, and regularly interacts with high school students in and around the Washington, DC, area. Dr. Baler talks in this podcast about the teen brain—how it develops fast, just like teens themselves. And how, sometimes, that growth keeps young people from using their best judgment when it comes to risky behaviors, such as experimenting with drugs and alcohol, driving too fast, or jumping headlong into relationships.
Dr. Baler: Hello, my name is Ruben Baler. I am [a scientist] with the National Institute on Drug Abuse, NIDA. It’s probably helpful to think of the brain as a computer, which in essence, it is. It’s a very complex computer. It’s made up of circuits that affect or mediate all sorts of different functions in the brain. You can think of the learning circuit, the memory circuit, the higher thinking (cognitive function) circuit. There are all sorts of networks in the brain that interact with each other and with the environment. They are the substrates (or key brain areas) where drugs of abuse have their effects. The main substrate in the brain that is impacted by drugs of abuse is called the circuit of reward. It is the area deep inside the brain that influences feelings of reward, feelings of pleasure. Drugs of abuse hijack the normal pathways of reward and lead the brain to think that the drug-induced experience is the highest possible goal from now on.
SBB: What makes the teenage brain so special?
Dr. Baler: One of the main reasons is that different parts of the brain develop at different rates. There are two main parts: one area, called the amygdala, governs our instincts, our gut feelings. That area develops early on and is already mature in a teenager. Then there is another area called the prefrontal cortex, a part of the brain that takes much longer to develop, to fully mature. The teen brain is different because the ability to make good decisions really depends on the balance between these two structures: the prefrontal cortex and the amygdala, part of the limbic system that develops so early on.
So we can say that teenagers make decisions mostly based on this instinctual part of the brain, these gut feelings, because the prefrontal cortex has not yet reached [developed] the ability to fully exert control and keep tabs on the already-mature limbic system.
SBB: Do you think that by studying the brain and knowing how it’s linked to addiction and other high-risk behaviors, teens can learn to “tame” their brains?
Dr. Baler: Well, one school of thought says that by providing fact-based information to teenagers—like the fact that their brains are still developing and they may make decisions differently than adults—may urge them to stop and think, and make better decisions as a result.
There are big, big questions in neuroscience. For example: where is consciousness? Where does consciousness lie? We’d like to understand how this computer (the brain) leads to things like music, creativity, poetry—very complex products of this very complex machine.
*Note: In order to hear the podcast you will need to have a media player on your computer.
Have you ever wondered why you have to be 16 to get your driver’s license or 18 to vote or 21 to legally drink alcohol?
It’s partly because your brain is not ready to take on these responsibilities, since your brain is not fully developed when you’re a teen.
During the teen years, essential parts of the brain are still forming—like the prefrontal cortex, which allows people to weigh the pros and cons of situations instead of acting on impulse. This is one reason why teens are generally more likely to take risks than adults.
For example, with alcohol, teens may be less able to judge when to stop drinking. The Centers for Disease Control and Prevention (CDC) tells us that each year, more than 4,600 alcohol-related deaths occur among those less than 21 years old—that is way too many.
Research shows that alcohol and other drugs change the brain’s structure and how it works in the short and long term. In the short term, drugs affect your brain’s judgment and decision-making abilities, while long-term use causes brain changes that can set people up for addiction and other problems. The brains of people who become addicted get altered so that drugs are now their top priority—and they will compulsively seek and use drugs even though doing so brings devastating consequences for their lives and for those who care about them.
Do yourself a favor and use your brain to make smart choices, reach your goals, and achieve your full potential in life.
The human brain continues to grow during the teen years, well into the twenties. It’s a scientific fact that abusing drugs and alcohol while your brain is still developing can change the brain’s structure and how it works—both in the short and long term.
Yale University scientists recently explored how some of these changes occur when the brain is exposed to the stimulant cocaine—and learned that some changes result from the brain trying to protect itself.
Your Brain’s Self-Defense
When exposed to cocaine for the first time, the teen brain tries to defend itself against the harmful drug by changing the shape of the brain cells (or neurons) and synapses. This defensive reaction is controlled by a certain pathway in the brain involving integrin beta1, a crucial gene in the development of the nervous system in humans and most animals. The scientists discovered that if they blocked the pathway—and prevented this cell-shape change—the mice became three times more sensitive to the effects of cocaine.
This research may explain why some people who use cocaine end up addicted to the drug while others escape its worst effects. Everyone’s genetic makeup is unique. It’s possible that those with strong integrin beta1 pathways are better able to avoid the dangerous effects of the drug. More research is needed to discover which genes can protect the brain from the effects of cocaine and other drugs.
Good News: Cocaine Use Is Down
Hi, my name is Eric Wargo and I’m a new science writer here at NIDA. Before coming to NIDA, I wrote for an association of psychological scientists, people who study all aspects of the mind and human behavior. I was excited to come to NIDA, because NIDA scientists study the brain, and the brain is at the root of everything we humans do.
The brain is almost like magic: It has the ability to transform thoughts and feelings into real physical actions and physical states like health or illness. And something as simple as an idea or a belief can have a real effect on your well-being or how well you do in school or in your relationships. I’ve always been especially interested in ways people can improve themselves—and even achieve many of the things some people seek through drugs—through activities that change their brains. SBB asked me to write some guest columns on this topic. I hope you enjoy them!
Learning Changes the Brain
If you’ve been reading this blog, you know all about how drugs change the brain. But lots of things besides drugs change the brain, and lots of those brain changes are good.
Learning is the #1 positive thing that changes your brain. Something as small as a new experience or learning a new word rapidly creates or reinforces new connections between neurons, even hundreds or thousands of them, in real time. You aren’t exactly the same person now, after reading the last sentence, as you were before you read it—because your brain changed a little.
And guess what—just knowing that fact can actually make you smarter.
Challenge Your Mindset
A few years ago, I was blown away when I heard a really amazing lecture by a psychologist named Carol Dweck. She has studied how people’s “mindsets”—specifically the beliefs they hold about whether someone’s intelligence is changeable—have a strong effect on how well they succeed in school and in life. People who think that intelligence is just something you are born with (or not) don’t apply themselves as much when it comes to learning. Even if they are told they are smart, they may not try as hard and actually may not ultimately achieve as much or handle challenges as well as those who believe that smartness depends mainly on how much effort they put in.
Dweck tested this idea with junior high school students. It can be a tough period in life, as you may have found out yourself. A lot of kids who were happy and did well in elementary school suffer setbacks when they hit junior high—they become frustrated and unhappy and stressed, and where they were once good students, they suddenly see their grades go down. In one study, Dweck and a couple of her colleagues found that students who held the “intelligence is changeable” mindset were more motivated to learn and actually performed better in math over the course of 7th and 8th grades than did those who believed their intelligence was a permanent, fixed quantity.
So Dweck and her team designed an intervention to help students whose math grades were falling. Over the course of 8 weeks, a group of these students were taught about how the brain works, including the way learning actually builds new and stronger connections between neurons and how the brain is like a muscle that can be strengthened through the exercise of learning. A comparison group also learned about the brain and study skills but without the emphasis on the brain’s changeability.
You can probably guess what happened: The students who learned about how their brains change actually reversed their plummeting math grades—they started doing better! Those who were not exposed to this idea continued doing poorly in math. (Dweck has now taken her intervention, called “Brainology,” and developed it for use by schools and teachers.)
The bottom line: Mindsets are super-powerful in setting people either on a path to success or on a path to something less. People who (correctly) believe their brains change go farther, do more, and adapt better to life’s challenges. So help spread the word to your peers: Your brain changes and you can choose how you change it.
Next time, I’ll talk about some cool things you can do to change and hone your brain.
Eric Wargo writes about the brain and addiction for NIDA’s Office of Science Policy and Communications. He has a Ph.D. in anthropology, and in his spare time, he writes and blogs about science, history, movies, and other cool topics.
I’ve always been a huge Star Trek fan. When I was a teenager, my hero was Mister Spock—cool, analytical, even-tempered, and smarter than everyone around him. Being raised in his ancient society of the planet Vulcan made him a force to be reckoned with. He was kind and compassionate, but his mind was unswayed by human passions and fears, and he was always in control. When he was alone, he often sat, eyes closed, deep in meditation.
Vulcan is a fictional planet, but I later came to learn that there are real people on Earth kind of like Mister Spock, who possess many of his qualities and abilities because they have trained their brains in ancient Eastern mental arts.
Going to a “Zen Place”
A German philosophy professor named Eugen Herrigel discovered the power of a calm mind when he went to Tokyo in the 1920s. One day, he was having lunch with a Japanese colleague when an earthquake struck. Panic quickly broke out, and most of the diners (including Herrigel) jumped up and hurried out of the restaurant.
But the man Herrigel was having lunch with remained seated with his hands folded, his eyes nearly closed, completely undisturbed by the shaking going on around them. Fascinated by his companion’s trance-like calm, Herrigel sat down too and felt strangely safe. When the earthquake was over, the man continued the conversation exactly where it had broken off, saying nothing about what had just happened.
A few days later, Herrigel learned the source of his lunch partner’s amazing, infectious calm—he was a Zen Buddhist. His emotional steadiness came from practicing meditation.
Buddhist literature is full of stories of people achieving amazing feats of insight, courage, and even control over their own bodies after years of practicing simply sitting and focusing their minds. Such people often become rocks of support, giving strength to those around them, or even become calmly inspiring leaders themselves.
Meditation’s Effects on the Brain
Brain scientists have gotten really interested in the effects of meditation on the brain. A Harvard psychologist named Richard Davidson has done brain scans on dozens of Buddhist monks and found that their training has permanently altered their limbic systems, giving them heightened empathy—or the ability to understand and identify with another person’s feelings.
A recent study of “beginner” meditators by another Harvard researcher found that 8 weeks of training in techniques like mindfulness meditation and yoga increased gray matter in brain regions involved in memory, learning, emotion, breathing, and motor control.
[Caption: These high-resolution brain image scans show where gray matter increased in different parts of the brain for those who practiced mindfulness.. A: The posterior cingulate cortex and cerebellum; B: The left temporo-parietal junction; C The cerebellum and brainstem.]
The bottom line is, the brain is a powerful instrument, and you can make it do even more amazing things when you sharpen and enhance its powers. Wouldn’t it be cool to have a tough, disciplined, compassionate, and fearless brain like a Buddhist monk … or Mister Spock? P.S. After his remarkable experience with the Zen man in the earthquake, Eugen Herrigel promptly decided to learn Zen himself, and went on to study with a Zen master for 6 years. He then wrote a classic book about his experience, called Zen and the Art of Archery, as well as a short introduction to Zen philosophy and meditation (which I highly recommend, if you are interested) called The Method of Zen.
Eric Wargo writes about the brain and addiction for NIDA’s Office of Science Policy and Communications. He has a Ph.D. in anthropology, and in his spare time, he writes and blogs about science, history, movies, and other cool topics. Read his previous SBB guest post, Mindset Over Matter.
I'm sure you've heard that abusing alcohol hurts your health. But how many years of drinking do you think it takes to visibly affect your brain? Ten years? Twenty?
It turns out that it doesn't take that long at all—in fact, scientists can already see changes in the brains of teenagers who drink.
In a new research study, Professor Susan Tapert of the University of California at San Diego used an imaging machine called an MRI to scan the brains of teens who binge drink—defined as drinking 4 or 5 (or more) drinks in a couple of hours. Dr. Tapert found that the "white matter" in their brains—the part that transmits signals, like a television cable or a computer USB cord—was abnormal when compared with the white matter of teens who don't binge drink. Transmitting signals is a big part of what the brain does, so affecting the white matter in this way could also affect thinking, learning, and memory.
The really scary part is that these teens weren't alcoholics, and they didn't drink every day. All they did (to be considered "binge drinkers") was drink at least four (for women) or five (for men) drinks in one sitting, at least one time during the previous three months.
How could it be possible for just a few sessions of heavy drinking to affect the white matter of the brain? Well, science has shown that alcohol can poison brain cells and can alter the brain's white matter in adult alcoholics. Dr. Tapert thinks that teenagers' brains are even more susceptible this way. She says, "because the brain is still developing during adolescence, there has been concern that it may be more vulnerable to high doses of alcohol."
Many questions still remain, including how long it takes before these changes occur, and how much they affect the function of the brain. To figure this out, scientists would have to look at the binge drinkers' brains before and after they started drinking. That way, they can tell if the differences might have already been there before the teens started drinking. It's possible that having abnormal white matter in the brain somehow increases the chance of being a binge drinker. In order to answer that question, Dr. Tapert says they need to do longer studies that follow teens' brain growth over time.
The bottom line? If you're a teen, drinking to the point of getting drunk could damage the white matter of your brain—even if you do it only once in a while.
Find out more through the following resources:
- SAMHSA Fact Sheet on Binge Drinking
- NIH Fact Sheet on Underage Drinking (PDF, 305 KB)
- USCD News Release: Binge Drinking May Hamper Information Relay System in Teen Brain
- Dr. Tapert's Study: Altered White Matter Integrity in Adolescent Binge Drinkers
- NIAAA's Rethinking Drinking Web page
Many teenagers assume smoking weed is harmless because of all the myths floating around saying it’s safe. What few people know is that the age you start using marijuana actually makes a difference. In fact, if you start smoking it as a teenager, there can be some serious problems for you down the road.
Although we already knew from past research that if you start smoking pot as a teen, you’ll be more likely to get addicted, new research (just published in a well-known journal called Proceedings of the National Academy of Sciences) now says if you smoke marijuana heavily as a teenager, it can actually lower your IQ!
Scientists looked at more than 1,000 people born in 1972 and 1973. When they were 13 years old, they were given IQ and other kinds of intelligence tests. They were interviewed every few years about their use of marijuana and then tested again when they were 38 years old.
The results? Those who smoked weed heavily as teens showed mental decline even after they quit using the drug—and had, on average, an 8-point drop in their IQ scores. An 8-point loss could push a person of average intelligence into the lower third of testers. Those who started smoking pot after age 18 also showed some decline, but not as much.
This was an interesting study because it also collected information from people who knew the study participants. They reported that people who smoked marijuana heavily had more memory and attention problems and did not organize their lives as well, misplacing things and forgetting to keep appointments, pay bills, or return calls. This highlights the lasting effect marijuana can have on the teenage brain, which is still developing and still wiring itself to handle the onslaught of information it gets every day. The toxic chemicals in marijuana can mess up that wiring process and hurt your ability to do well in school and in life.
Carol Krause is the Chief of the Public Information and Liaison Branch at NIDA. Since arriving at NIDA in 2006, Ms. Krause has launched several new innovative programs for teens, including Drug Facts Chat Day (an annual live Web chat between NIDA scientists and teens), National Drug Facts Week (to stimulate community events between scientists and teens), and the first Addiction Science Awards for high school participants in the Intel International Science and Engineering Fair.
At NIDA's last Drug Facts Chat Day, mendythepenty asked this question:
"is it possible that you do so much drugs, that your brain can change into the size of a pea?"
When you do drugs, your brain changes. According to NIDA scientists, the brain weighs about three pounds and doing drugs, even for the first time, can change how our brain looks and works. Assuming you're serious, does this literally mean it can shrink to the size of a pea? Probably not, but the fact that drugs can change your brain, never mind damage or kill brain cells, is enough for me! I want to be smart. To me, smart means cool, and it means healthy. And healthy means being able to live the life you choose, whether that's trying out for the basketball team, skateboarding with friends, or going to the school dance.
Can you put yourself in someone else’s shoes? Developing empathy—being able to read someone else’s feelings and relate them to your own—depends to some extent on brain development.
Although it sounds simple to be able to imagine the nervousness your friend felt about playing her first JV soccer match, for example, it may be hard for teens to have empathy because their brains aren’t yet hard-wired for it. Brain imaging studies show that teens and adults may use different mental strategies for figuring out someone’s intentions or motives for doing something. The ability to understand what others are feeling is important in forming close relationships, tolerating differing points of view, and keeping us from hurting others because of misunderstandings.
Even more, some people seem to be inherently better at empathizing than others. Dr. Abigail Marsh, a researcher at Georgetown University, studies empathy—or the lack of it—in teens. Dr. Marsh measures this quality by using brain imaging technology to look at activity in the brain’s amygdala while showing both groups of teens pictures of fearful faces. She theorizes that “exposure to and correct interpretation of certain distress cues may predict the likelihood” of developing behaviors like empathy.
According to Dr. Marsh, you can aid the development of empathy by practicing the following three ways of tuning into others’ feelings:
- Put yourself in someone else’s shoes. Is it possible that it hurt your friend’s feelings when you said her choice of birthday presents “sucked”? Can you share in your sister’s excitement for acing her physics exam?
- Recognize others’ emotions if you have felt them yourself. How do you feel when someone makes you mad? Have you ever noticed when something you said out of anger or frustration had that effect on someone else?
- Pay attention. Are you too busy tuning into how no one “gets you” to notice the needs of other people around you? Other people may need your understanding as much as you need theirs.
NIDA scientists are always saying that teens shouldn’t use drugs, tobacco, or alcohol. But do you know why they say that? Because of scientific studies like this one by Dr. Jay Giedd, which shows that your brain won’t reach its adult potential until you’re over 20 years old. If you’re a teen—even if you’re a high school senior—your brain is still maturing. Your neurons are still developing, and connections between different parts of your brain are still forming. Drugs and alcohol may mess up that process.
Along with his colleagues at the National Institute of Mental Health, Dr. Giedd created this scientific figure.
This picture is a cartoon depicting how the human brain continues to change between the ages of 4 and 21 years. As you move from left to right along the red arrow, the brain gets older. Above the arrow are side views of the brain (as if someone was standing in front of you, looking toward your right shoulder). Below the arrow are views of the brain from the top (like you are looking down on someone’s head).
So what’s with the rainbow colors? The colors represent the amount of “gray matter” (or active brain cells called neurons) that the researchers found in brains of different ages, using a brain imaging technique called MRI. Gray matter isn’t usually this colorful (hence the term ‘gray’ matter), but these brain pictures have been color-coded to show areas of more or less gray matter. Pink and red areas have the most gray matter, while green and blue areas have the least.
So, who do you think has more gray matter—you, or your parents? What does the figure show?
Yep—you do! It turns out that the number of neurons in your brain actually decreases as you get older. Younger brains have more gray matter (represented by the pink and red areas) than older brains (which are more green and blue). But wait—if the number of neurons in your brain is going down as you age, does that mean you’re getting dumber?
Fortunately, no. The total number of neurons in your brain isn’t as important as how your neurons connect to each other. As you get older, everything you learn and experience shapes the connections between the neurons in your brain. Over time, the connections between neurons become stronger. Your brain also develops more myelin—a white substance that wraps around neurons, insulates them, and helps them communicate more effectively. It’s like starting with a blob of clay and carving it away to make a sculpture: eventually you get a sleek, smart, mature adult brain, like the blue brains on the far right of the figure.
This figure also shows which parts of the brain mature first and which mature last. One of the very last areas to develop is the prefrontal cortex—the part of the brain located just behind your forehead. This part of the brain is responsible for helping you make good decisions, and isn’t fully mature until well after you graduate from high school! Scientists think this might help explain why teens tend to take more risks than adults, including experimenting with drugs.
Does all this mean that teens can’t make smart decisions? No. Teens can and do make good choices all the time. What this figure shows is that your brain doesn’t reach its full potential until you are in your mid-twenties. Basically, teenagers have a lot of brainpower still to come online—good reason to avoid stunting your potential brain power now with drugs or alcohol.
Watch some cool time-lapse movies showing how the brain changes with age.
What’s your new geometry teacher’s name? How do you get to your friend’s house? Where did you put your smartphone? Have you noticed that practice makes you play the piano better?
Every day, we learn and remember things that we experience in our lives. If we didn’t, we would get lost, not be able to sing along to our favorite song, and not pass that important midterm exam.
But how do we learn new things? And how does the brain store the memories so that we can recall them at a later time?
By studying the process of learning and memory, neuroscientists hope to be able to find treatments for those who lose their memories because of aging or diseases like Alzheimer’s. We may also be able to help those who suffer anxiety and depression that are triggered by bad memories from traumas like childhood abuse, car accidents, or war. We might also help people in drug abuse recovery stay off drugs by extinguishing memories that stimulate their desire to seek and take more drugs.
A Look at the Hippocampus
Neuroscientists are learning more about the process of learning and memory by studying the hippocampus, a brain region involved in forming and retaining memories. Neuroscientists don’t know exactly how learning and memory occur in the brain, but whenever learning occurs, neurons in the hippocampus become active. Learning is thought to be due to an increase in the activity between many neurons that communicate with each other.
How do neurons communicate? When a nerve impulse reaches a neuron, the neuron is activated and releases a chemical, called a neurotransmitter, at the synapse, or the place where two neurons connect. The neurotransmitter crosses the synapse, where it connects to a receptor molecule located on the adjacent neuron. This binding of the neurotransmitter activates the second neuron, which sends a neurotransmitter to the next neuron, and so on. This process continues from neuron to neuron as the nerve impulse travels throughout the brain.
Neuroscientists have discovered that when you are not learning, a nerve impulse will cause a neuron to have a low level of activity, but that during learning, the electrical activity between two neurons will be increased. This phenomenon is called long-term potentiation or LTP, and researchers have found that animals do not learn when LTP is blocked.
One of the goals for neuroscience research is to be able to manipulate LTP and, as a result, also influence learning and memory formation. Someday neuroscientists hope to be able to help your grandmother find her glasses and purse, to reduce the stress and anxiety that is felt by those who have memories of traumatic events, and even to extinguish the memories that cause a person to want to continue to use drugs.
Roger Sorensen, Ph.D., M.P.A., is a NIDA program official who directs a grant program that supports basic science research on the physiological effects of drugs of abuse on the brain and nervous system. He was trained in neurochemistry and expects that someday scientists will be able to determine how this complex organ known as the brain makes us think, feel, and be who we are.
Lots of teens have questions about drugs. Each year, NIDA scientists spend a day chatting online with high school students and answering their questions.
At the last Drug Facts Chat Day, soccerstar0 asked:
“On average how old are kids who start using drugs?”
Research shows that drug use often starts in the teen years. You might have heard that, but here’s something you may not know—the science shows that the younger you are when you start using drugs, the more likely you are to get addicted later on. Doing drugs can also cause problems with friends, in sports, and in school.
Let’s face it—when someone tells us not to do something, that sometimes makes it seem more exciting. But drugs can really do some not-so-exciting things to your body. NIDA researchers discovered that drugs can literally change the way your brain works. And since your own brain won’t finish growing until you’re 25, you probably don’t want to mess with that process by doing drugs.
Your school probably has science classes like biology and chemistry and maybe even ecology, but does it offer a class specifically on neuroscience?
Neuroscience is a branch of biology that focuses on the body’s nervous system—which includes the spinal cord, nerves, neurons (nerve cells) and, of course, the all-important brain.
Work in the neuroscience field is varied and exciting. Neuroscientists might study how messages travel from one area of the brain to the other, or they might focus on how the brain is involved in behavior and decision-making.
Still others might work to find causes of and cures for diseases and medical problems like stroke, Parkinson’s disease, depression, Alzheimer’s disease, schizophrenia, and addiction.
At NIDA, research focuses heavily on neuroscience, considering that drug addiction is a brain disease. Without neuroscientists and the research they do, we would be unaware of some pretty important things—like how the brain isn’t fully developed until a person is well into their 20s and how drugs like marijuana affect the teen brain differently than an adult brain.
So much about the brain is still unknown. That makes neuroscience a particularly exciting field. If you are interested in help shed light on the mysteries of the brain, consider exploring neuroscience as a career. Check out the advice NIDA scientists offered to SBB for teens interested in a future career in science.
Learn more about the brain from these NIDA resources: