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October 3, 2008
Brain Circuitry — i on NIH — episode #0013, segment 1
Human imaging studies have for the first time identified brain circuitry associated with social status. Caroline Zink is a Ph.D. researcher with the National Institute of Mental Health's Genes Cognition and Psychosis Program. She explains that different brain areas are activated when a person moves up or down in a pecking order, or social hierarchy.
Welcome to “i on NIH”!
Featured in this month's episode are segments about a study that shows how our brains are activated by hierarchy and a segment about the keys to living a long life.
From the national institutes of health in Bethesda, Maryland – America's premiere medical research agency – this is “i on NIH”!
Covering health-research topics important to you and the nation, this public service vodcast is your information source from inside all 27 institutes and centers at NIH.
Half an hour, once a month, we'll show you the excitement of advances and the important information that comes from medical research.
And now, here's your host, Joe Balintfy.
Host: Welcome to the 13th episode of I on NIH. Thanks for tuning in. For this edition, we get to see how our brains are activated by where we think we are in a pecking order. Also, we'll learn about a study focusing on those who live exceptionally long lives. But first, here's our news update with Harrison Wein from the NIH news-desk.
Harrison: Thank you, Joe. In this NIH Research Update, wide waists and death rates, and two studies about quitting smoking.
Doctors have long known that people with extra weight have higher health risks. A new study suggests that even people in the normal weight range have increased risks if their waists are wide.
Having a large waist has been tied to health problems before, but it wasn't clear if waist circumference could give doctors any more information than body mass index could (that's BMI, a ratio of weight to height). A team led by NIH researchers set out to look at the question more closely by studying almost a quarter of a million people.
They found that people with the largest waists had about a 25% higher mortality risk than those whose waists were in the normal range.
The size of the study allowed the researchers to tease apart the effects of BMI and waist circumference. They found that people with a normal BMI but a large waist-for men, that's 40 inches or more; for women, 34 and a half inches or more-had about a 20% higher mortality risk than people whose BMI and waist circumference were both in the normal range.
It's not just weight that counts, but how much fat you have around the middle.
The first study about smoking found that changes in smoking behavior often spread through social networks, with spouses, friends, siblings and co-workers deciding to light up or stub out their cigarettes for good at around the same time.
NIH-funded researchers looked at medical records and other data from more than twelve thousand adults, tracking changes in their social relationships over more than 3 decades. They found that close relationships exert a strong influence on smoking.
The greatest effect was in married couples. When a husband or wife quit smoking, it reduced the chance of their spouse smoking by about 67%. A better understanding of how social ties affect smoking behavior may lead to more effective ways to prevent or reduce smoking.
The other study found that a smokers' genetic make-up influences their chances for successful quitting, and may help determine which treatment is most likely to help them quit.
A team led by NIH researchers searched across the genome for genetic variations among people trying to quit smoking. Their goal was to pinpoint genetic differences between those who successfully quit and those who didn't. The researchers found a set of genetic variations that can be used to be predict whether a smoker has a better chance of quitting using nicotine replacement therapies or the drug Zyban. One day, genetic testing might help doctors prescribe the smoking treatment that's most likely to work for each individual patient.
Read about these and many other research studies in "NIH Research Matters." Go to the NIH home page and look for the link on the right-hand side, under "In the News" that says, "eColumn: NIH Research Matters"
And in this month's health newsletter, "NIH News in Health"… For thousands of years, people have searched for the meaning and beauty of life in music, painting, poetry and other arts. Now scientists are finding that the arts can benefit both your mental and physical health. Read about this and more in the June issue of NIH News in Health. You can find it at news-in-health-dot-nih-gov.
This is Harrison Wein at the NIH Science Desk.
Joe: Thanks Harrison. Now to our first story. It's about a very interesting experiment that showed where we're thinking when we're competing for social status.
VO: Human imaging studies have for the first time identified brain circuitry associated with social status.
VO: Caroline Zink is a Ph.D. researcher with the National Institute of Mental Health's Genes Cognition and Psychosis Program. She explains that different brain areas are activated when a person moves up or down in a pecking order, or social hierarchy.
Zink: We've known behaviorally how important social hierarchies are when virtually everything we do; they basically define normal behavior. The way you act towards your boss is probably different than the way you act towards your best friend. But we've just never known what parts of the brain are processing this information and handling this information. And it's also known that hierarchies and someone's status in the hierarchy can have huge impacts, health wise with stress related illnesses. And so we're hoping that by showing the brain regions that are sort of underlying this processing, these may be the brain regions that should be target to sort of help with the stress related illnesses that we see related to social status.
VO: Dr. Zink and fellow NIMH researchers created an artificial social hierarchy in which 72 participants played an interactive computer game for money. She explains they did two different studies.
Zink: In one they had to do a very simple reaction time test, they just had to push a button when a circle turned green as fast as they could. If they did it fast enough they got a dollar, if not they did not get a dollar. And the other study we had two boxes with dots in them, and we asked them to identify which box had more dots in it. But they only had one second; it was very difficult to do. So with the button they just indicated which one they thought had more dots, and if they got it right they get a dollar, and if they did not get it right they did not get a dollar.
VO: In fact, the game outcomes were predetermined, and the other “players” were simulated by computer. All the while their brain activity was monitored by a functional MRI. The results were clear.
Zink: We showed that looking at a superior individual, someone that is higher than you in the hierarchy, elicited a profound brain network of activations in areas related to attention and value and social emotion. And basically all the activity was always greater when looking at someone higher than you compared to lower than you. And we also showed that when we made it so the hierarchy was able to change, so throughout the game if the participant started doing very, very well they could move up in the hierarchy, and if they started performing worse they would move down in the hierarchy.
And we showed that when they saw the outcomes, for example performing better than a superior player, so they saw, they got the dollar and the superior player did not get the dollar, that indicates that they will be able to move up in the hierarchy. We saw huge activations in another network of activity. But what was most interesting was this pre-motor activation that's related to a sort of an active stance, an abstract active stance, suggesting when you move up in the hierarchy you espies towards sort of an active state of mind.
On the other hand if they did worse than the inferior person so the participant did not get a dollar and someone who's supposed to do worse than him did get a dollar, then we saw an activation in areas related to sort of value and saliency as well as in the insula, which is a region that processes emotional pain and frustration, sort of with falling in the hierarchy.
VO: Prior studies have shown that social status strongly predicts health. Dr. Zink points out that in fixed, stable hierarchies, the person in the inferior position has the most stress, which leads to the most stress related illnesses, like cardiovascular disease or immune deficiencies and even in mental illnesses.
Zink: But when you make a hierarchy unstable so there's times when the hierarchy can readjust, which is what we did in a second study, actually the opposite occurs. The person who is in the top position becomes the most stressed during these times of reorganization because they are the ones who can potentially lose the position. If you're already at the bottom you have nothing to lose, so it's not very stressful when it's reorganizing. But if you're at the top it becomes very, very stressful in these unstable hierarchies. So we looked at both conditions to see, to sort of separate which part of the brain was responsible for processing stable hierarchal information and unstable information which may be related in underlying these stress related illnesses.
VO: Dr. Zink says the most surprising result from the study was that even when participants were told that the point of the task was just to earn as much money as possible - were even instructed to ignore other players – the participants brain activity and behavior were highly influenced by their position in the implied hierarchy.
Zink: And it was quite outstanding to see this enormous processing of the brain, by the brain of social information, social hierarchy information even though it was irrelevant for how much money the participant was getting.
VO: Dr. Zink concludes that the processing of hierarchical information seems to be hard-wired, underscoring how important it is for us.
VO: For more information on this and other studies by the National Institute of Mental Health, visit www.nimh.nih.gov.
Host: In our next report, we talk in-depth about the trends and studies that may help us understand the keys to long life.
Text: How many people in the U.S. are 65 and older?
Rossi: Currently there are about 37 million people in the United States who are 65 and older, and by the year 2050 that number is expected to probably double to more than 71 million, which is a huge increase, and that will make that about 20 percent of the total population of the U.S. that would be over age 65.
Text: How many people in the U.S. are 100 and older?
Rossi: Currently there are about 55,000 centenarians, which is a ten-fold increase over the last 40 years, and by the year 2050 that number could get as high or higher than 800,000 in the United States.
Text: What's the reason for this trend?
Rossi: Well, there's something called the epidemiologic transition that's taken place over the last century where we've had improvements in treatment for infectious disease and elimination of things like infant mortality and death of mothers in childbirth and improvements in sanitation, in nutrition and in prevention of infectious disease, like vaccines and other medicines, so that automatically made people live longer. And then what happened is people then began to live longer with chronic diseases, such as heart disease, cancer, diabetes. And what we are seeing now, though, is tremendous improvements in treatment for heart disease, such as lipid lowering drugs, which contribute to better cardiovascular health, as well as cancer treatments. And so, we have people living longer and living better in many cases, and that has improved life expectancy a great deal.
Text: What are the different factors that are helping people live so much longer?
Rossi: Well, that's a major focus of our research at the National Institute on Aging. We're actually starting a big study called the Long Life Family Study that's examining these questions. And recent work that's been conducted by recent researchers funded by NIA has shown us that centenarians as a group tend to live better than their counterparts in the population. So, for example, for people who were born in the same year as a centenarian, say 1900, some of those people died, say, at age 73, but others lived to over 100 years and the people that lived over 100 years tend to have lived healthier than their counterparts. And then what we found out as well was that brothers and sisters of centenarians tend to live better than their counterparts in the population as well.
Text: How significant is a healthy lifestyle vs. genetics to long life?
Rossi: Well, we know that there are family patterns of it because in addition to centenarians and their siblings, we also know that the children of centenarians compared to their counterparts in the population tend to live longer and healthier, and so we know that there's a family pattern. We suspect that it's a combination of environmental and lifestyle factors. We are now collecting families in the United States and in Denmark that have large numbers of long-lived individuals in them and we're collecting information on lifestyle, on behavior, on health and trying to assess what might be shared environmental things, and we're also collecting some blood to see if we can find out what genetic contributions there might be.
Text: What kind of families are you looking for to participate in the Long Life Study?
Rossi: So, what we're looking for, we have three study centers in the United States, at the University of Pittsburgh, at Columbia University and at Boston University, and we are because of costs for the study and because of the time it takes to go out with a lot of machines, and we have to collect blood so we have samples we have to bring back and get to a lab for analysis quickly, we've restricted the catchment areas to about two hours driving distance within the limits of each of the centers.
However, the best type of families that we're looking for are the bigger the better. The more longer-lived people, the more valuable, the more informative they can be to this study. So, we are trying to get the word out around the country even though we're focused in three areas that if there is a family that has a large number of long-lived people in them, we do have the capability to go out and meet them, but they have to be fairly large in order for us to do that, to make the best use of our resources.
Text: What are some things to keep in mind about healthy aging in general?
Rossi: I think it's a very prominent focus at the National Institute on Aging that we're really trying to learn how we can help all people live as healthy as possible no matter how old they are and that we can find very useful and informative information from people who live extremely long and extremely well and that we really encourage people to join us for this very positive effort in an effort meet our public health goals.
Text: What are some tips to help live a long life?
Rossi: So, what we know are really things that we hear all throughout our lives, things that our mother told us as we were growing up, things like eat fruits and vegetables, don't smoke, exercise several times a week, get enough rest, monitor your health and see the doctor regularly to keep things in check. Those are things we know for sure that work.
Text: For more information on the Long Life Family Study, visit www.longlifefamilystudy.org. Or to participate call 1-877-362-2074.
For more information on healthy aging in general, visit www.nia.nih.gov.
This story was also recently podcast: www.nih.gov/news/radio/nihpodcast.htm.
Host: And that's it for this episode of I on NIH – thanks for joining us! We're still fine tuning this video podcast, so please keep checking back for new material. And look for these and more segments from NIH on You Tube. For now, thanks again for watching and join us again next time. For I on NIH, I'm Joe Balintfy.
This page last reviewed on April 20, 2015