July 7, 2010, 12:01 am
Phys Ed: Your Brain on Exercise
By GRETCHEN REYNOLDS
NEW YORK TIMES
Jim Wehtje/Getty ImagesWhat goes on inside your brain when you exercise? That question has preoccupied a growing number of scientists in recent years, as well as many of us who exercise. In the late 1990s, Dr. Fred Gage and his colleagues at the Laboratory of Genetics at the Salk Institute in San Diego elegantly proved that human and animal brains produce new brain cells (a process called neurogenesis) and that exercise increases neurogenesis. The brains of mice and rats that were allowed to run on wheels pulsed with vigorous, newly born neurons, and those animals then breezed through mazes and other tests of rodent I.Q., showing that neurogenesis improves thinking.
But how, exactly, exercise affects the staggeringly intricate workings of the brain at a cellular level has remained largely mysterious. A number of new studies, though, including work published this month by Mr. Gage and his colleagues, have begun to tease out the specific mechanisms and, in the process, raised new questions about just how exercise remolds the brain.
Some of the most reverberant recent studies were performed at Northwestern University’s Feinberg School of Medicine in Chicago. There, scientists have been manipulating the levels of bone-morphogenetic protein or BMP in the brains of laboratory mice. BMP, which is found in tissues throughout the body, affects cellular development in various ways, some of them deleterious. In the brain, BMP has been found to contribute to the control of stem cell divisions. Your brain, you will be pleased to learn, is packed with adult stem cells, which, given the right impetus, divide and differentiate into either additional stem cells or baby neurons. As we age, these stem cells tend to become less responsive. They don’t divide as readily and can slump into a kind of cellular sleep. It’s BMP that acts as the soporific, says Dr. Jack Kessler, the chairman of neurology at Northwestern and senior author of many of the recent studies. The more active BMP and its various signals are in your brain, the more inactive your stem cells become and the less neurogenesis you undergo. Your brain grows slower, less nimble, older.
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But exercise countermands some of the numbing effects of BMP, Dr. Kessler says. In work at his lab, mice given access to running wheels had about 50 percent less BMP-related brain activity within a week. They also showed a notable increase in Noggin, a beautifully named brain protein that acts as a BMP antagonist. The more Noggin in your brain, the less BMP activity exists and the more stem cell divisions and neurogenesis you experience. Mice at Northwestern whose brains were infused directly with large doses of Noggin became, Dr. Kessler says, “little mouse geniuses, if there is such a thing.” They aced the mazes and other tests.
Whether exercise directly reduces BMP activity or increases production of Noggin isn’t yet known and may not matter. The results speak for themselves. “If ever exercise enthusiasts wanted a rationale for what they’re doing, this should be it,” Dr. Kessler says. Exercise, he says, through a complex interplay with Noggin and BMP, helps to ensure that neuronal stem cells stay lively and new brain cells are born.
But there are caveats and questions remaining, as the newest experiment from Dr. Gage’s lab makes clear. In that study, published in the most recent issue of Cell Stem Cell, BMP signaling was found to be playing a surprising, protective role for the brain’s stem cells. For the experiment, stem cells from mouse brains were transferred to petri dishes and infused with large doses of Noggin, hindering BMP activity. Without BMP signals to inhibit them, the stem cells began dividing rapidly, producing hordes of new neurons. But over time, they seemed unable to stop, dividing and dividing again until they effectively wore themselves out. The same reaction occurred within the brains of living (unexercised) mice given large doses of Noggin. Neurogenesis ramped way up, then, after several weeks, sputtered and slowed. The “pool of active stem cells was depleted,” a news release accompanying the study reported. An overabundance of Noggin seemed to cause stem cells to wear themselves out, threatening their ability to make additional neurons in the future.
This finding raises the obvious and disturbing question: can you overdose on Noggin by, for instance, running for hours, amping up your production of the protein throughout? The answer, Dr. Gage says, is, almost certainly, no. “Many people have been looking into” that issue, he says. But so far, “there has not been any instance of a negative effect from voluntary running” on the brain health of mice. Instead, he says, it seems that the effects of exercise are constrained and soon plateau, causing enough change in the activity of Noggin and BMP to shake slumbering adult stem cells awake, but not enough to goose them into exhausting themselves.
Still, if there’s not yet any discernible ceiling on brain-healthy exercise, there is a floor. You have to do something. Walk, jog, swim, pedal — the exact amount or intensity of the exercise required has not been determined, although it appears that the minimum is blessedly low. In mice, Mr. Gage says, “even a fairly short period” of exercise “and a short distance seems to produce results.”
Showing posts with label new york times. Show all posts
Showing posts with label new york times. Show all posts
Thursday, July 8, 2010
Tuesday, March 2, 2010
FFF Diva Article Research: "Evidence That Little Touches Do Mean So Much"
February 23, 2010
Mind: New York Times
Evidence That Little Touches Do Mean So Much
By BENEDICT CAREY
Psychologists have long studied the grunts and winks of nonverbal communication, the vocal tones and facial expressions that carry emotion. A warm tone of voice, a hostile stare — both have the same meaning in Terre Haute or Timbuktu, and are among dozens of signals that form a universal human vocabulary.
But in recent years some researchers have begun to focus on a different, often more subtle kind of wordless communication: physical contact. Momentary touches, they say — whether an exuberant high five, a warm hand on the shoulder, or a creepy touch to the arm — can communicate an even wider range of emotion than gestures or expressions, and sometimes do so more quickly and accurately than words.
“It is the first language we learn,” said Dacher Keltner, a professor of psychology at the University of California, Berkeley, and the author of “Born to Be Good: The Science of a Meaningful Life” (Norton, 2009), and remains, he said, “our richest means of emotional expression” throughout life.
The evidence that such messages can lead to clear, almost immediate changes in how people think and behave is accumulating fast. Students who received a supportive touch on the back or arm from a teacher were nearly twice as likely to volunteer in class as those who did not, studies have found. A sympathetic touch from a doctor leaves people with the impression that the visit lasted twice as long, compared with estimates from people who were untouched. Research by Tiffany Field of the Touch Research Institute in Miami has found that a massage from a loved one can not only ease pain but also soothe depression and strengthen a relationship.
In a series of experiments led by Matthew Hertenstein, a psychologist at DePauw University in Indiana, volunteers tried to communicate a list of emotions by touching a blindfolded stranger. The participants were able to communicate eight distinct emotions, from gratitude to disgust to love, some with about 70 percent accuracy.
“We used to think that touch only served to intensify communicated emotions,” Dr. Hertenstein said. Now it turns out to be “a much more differentiated signaling system than we had imagined.”
To see whether a rich vocabulary of supportive touch is in fact related to performance, scientists at Berkeley recently analyzed interactions in one of the most physically expressive arenas on earth: professional basketball. Michael W. Kraus led a research team that coded every bump, hug and high five in a single game played by each team in the National Basketball Association early last season.
In a paper due out this year in the journal Emotion, Mr. Kraus and his co-authors, Cassy Huang and Dr. Keltner, report that with a few exceptions, good teams tended to be touchier than bad ones. The most touch-bonded teams were the Boston Celtics and the Los Angeles Lakers, currently two of the league’s top teams; at the bottom were the mediocre Sacramento Kings and Charlotte Bobcats.
The same was true, more or less, for players. The touchiest player was Kevin Garnett, the Celtics’ star big man, followed by star forwards Chris Bosh of the Toronto Raptors and Carlos Boozer of the Utah Jazz. “Within 600 milliseconds of shooting a free throw, Garnett has reached out and touched four guys,” Dr. Keltner said.
To correct for the possibility that the better teams touch more often simply because they are winning, the researchers rated performance based not on points or victories but on a sophisticated measure of how efficiently players and teams managed the ball — their ratio of assists to giveaways, for example. And even after the high expectations surrounding the more talented teams were taken into account, the correlation persisted. Players who made contact with teammates most consistently and longest tended to rate highest on measures of performance, and the teams with those players seemed to get the most out of their talent.
The study fell short of showing that touch caused the better performance, Dr. Kraus acknowledged. “We still have to test this in a controlled lab environment,” he said.
If a high five or an equivalent can in fact enhance performance, on the field or in the office, that may be because it reduces stress. A warm touch seems to set off the release of oxytocin, a hormone that helps create a sensation of trust, and to reduce levels of the stress hormone cortisol.
In the brain, prefrontal areas, which help regulate emotion, can relax, freeing them for another of their primary purposes: problem solving. In effect, the body interprets a supportive touch as “I’ll share the load.”
“We think that humans build relationships precisely for this reason, to distribute problem solving across brains,” said James A. Coan, a a psychologist at the University of Virginia. “We are wired to literally share the processing load, and this is the signal we’re getting when we receive support through touch.”
The same is certainly true of partnerships, and especially the romantic kind, psychologists say. In a recent experiment, researchers led by Christopher Oveis of Harvard conducted five-minute interviews with 69 couples, prompting each pair to discuss difficult periods in their relationship.
The investigators scored the frequency and length of touching that each couple, seated side by side, engaged in. In an interview, Dr. Oveis said that the results were preliminary.
“But it looks so far like the couples who touch more are reporting more satisfaction in the relationship,” he said.
Again, it’s not clear which came first, the touching or the satisfaction. But in romantic relationships, one has been known to lead to the other. Or at least, so the anecdotal evidence suggests.
Mind: New York Times
Evidence That Little Touches Do Mean So Much
By BENEDICT CAREY
Psychologists have long studied the grunts and winks of nonverbal communication, the vocal tones and facial expressions that carry emotion. A warm tone of voice, a hostile stare — both have the same meaning in Terre Haute or Timbuktu, and are among dozens of signals that form a universal human vocabulary.
But in recent years some researchers have begun to focus on a different, often more subtle kind of wordless communication: physical contact. Momentary touches, they say — whether an exuberant high five, a warm hand on the shoulder, or a creepy touch to the arm — can communicate an even wider range of emotion than gestures or expressions, and sometimes do so more quickly and accurately than words.
“It is the first language we learn,” said Dacher Keltner, a professor of psychology at the University of California, Berkeley, and the author of “Born to Be Good: The Science of a Meaningful Life” (Norton, 2009), and remains, he said, “our richest means of emotional expression” throughout life.
The evidence that such messages can lead to clear, almost immediate changes in how people think and behave is accumulating fast. Students who received a supportive touch on the back or arm from a teacher were nearly twice as likely to volunteer in class as those who did not, studies have found. A sympathetic touch from a doctor leaves people with the impression that the visit lasted twice as long, compared with estimates from people who were untouched. Research by Tiffany Field of the Touch Research Institute in Miami has found that a massage from a loved one can not only ease pain but also soothe depression and strengthen a relationship.
In a series of experiments led by Matthew Hertenstein, a psychologist at DePauw University in Indiana, volunteers tried to communicate a list of emotions by touching a blindfolded stranger. The participants were able to communicate eight distinct emotions, from gratitude to disgust to love, some with about 70 percent accuracy.
“We used to think that touch only served to intensify communicated emotions,” Dr. Hertenstein said. Now it turns out to be “a much more differentiated signaling system than we had imagined.”
To see whether a rich vocabulary of supportive touch is in fact related to performance, scientists at Berkeley recently analyzed interactions in one of the most physically expressive arenas on earth: professional basketball. Michael W. Kraus led a research team that coded every bump, hug and high five in a single game played by each team in the National Basketball Association early last season.
In a paper due out this year in the journal Emotion, Mr. Kraus and his co-authors, Cassy Huang and Dr. Keltner, report that with a few exceptions, good teams tended to be touchier than bad ones. The most touch-bonded teams were the Boston Celtics and the Los Angeles Lakers, currently two of the league’s top teams; at the bottom were the mediocre Sacramento Kings and Charlotte Bobcats.
The same was true, more or less, for players. The touchiest player was Kevin Garnett, the Celtics’ star big man, followed by star forwards Chris Bosh of the Toronto Raptors and Carlos Boozer of the Utah Jazz. “Within 600 milliseconds of shooting a free throw, Garnett has reached out and touched four guys,” Dr. Keltner said.
To correct for the possibility that the better teams touch more often simply because they are winning, the researchers rated performance based not on points or victories but on a sophisticated measure of how efficiently players and teams managed the ball — their ratio of assists to giveaways, for example. And even after the high expectations surrounding the more talented teams were taken into account, the correlation persisted. Players who made contact with teammates most consistently and longest tended to rate highest on measures of performance, and the teams with those players seemed to get the most out of their talent.
The study fell short of showing that touch caused the better performance, Dr. Kraus acknowledged. “We still have to test this in a controlled lab environment,” he said.
If a high five or an equivalent can in fact enhance performance, on the field or in the office, that may be because it reduces stress. A warm touch seems to set off the release of oxytocin, a hormone that helps create a sensation of trust, and to reduce levels of the stress hormone cortisol.
In the brain, prefrontal areas, which help regulate emotion, can relax, freeing them for another of their primary purposes: problem solving. In effect, the body interprets a supportive touch as “I’ll share the load.”
“We think that humans build relationships precisely for this reason, to distribute problem solving across brains,” said James A. Coan, a a psychologist at the University of Virginia. “We are wired to literally share the processing load, and this is the signal we’re getting when we receive support through touch.”
The same is certainly true of partnerships, and especially the romantic kind, psychologists say. In a recent experiment, researchers led by Christopher Oveis of Harvard conducted five-minute interviews with 69 couples, prompting each pair to discuss difficult periods in their relationship.
The investigators scored the frequency and length of touching that each couple, seated side by side, engaged in. In an interview, Dr. Oveis said that the results were preliminary.
“But it looks so far like the couples who touch more are reporting more satisfaction in the relationship,” he said.
Again, it’s not clear which came first, the touching or the satisfaction. But in romantic relationships, one has been known to lead to the other. Or at least, so the anecdotal evidence suggests.
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