Mark, i never knew before that the main function of dopamine was to depress the production of mammary milk, how about that.
the whole thing is interesting, i guess, yet, if somebody had asked me whether or not "an individual will intentionally seek out an aggressive encounter solely because they experience a rewarding sensation from it" .. my answer would have been yes, no doubt; so what does it really say more than there are different mice and different people .. heh, guess just ignore that .. heck to be sure i don't know anything about this ..
regarding the separate experiment, the dopamine the separate experiment in which "no significant changes in overall movement compared to times when they had not received the drugs. This was done to demonstrate that their decreased aggression in the previous experiment was not caused by overall lethargy in response to the drug, a problem that had confounded previous experiments."
well, ok, but brain can be buzzing as you know and yet, physical movement may not be affected at all 'significantly' ..
The Vanderbilt experiments are the first to demonstrate a link between behavior and the activity of dopamine receptors in response to an aggressive event .. ok .. much more to learn ..
“We learned from these experiments that an individual will intentionally seek out an aggressive encounter solely because they experience a rewarding sensation from it,” Kennedy said. “This shows for the first time that aggression, on its own, is motivating, and that the well-known positive reinforcer dopamine plays a critical role.” .. ok .. thanks ..
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Dopamine is a hormone and neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In chemical structure, it is a phenethylamine.
In the brain, dopamine functions as a neurotransmitter, activating the five types of dopamine receptors — D1, D2, D3, D4 and D5, and their variants. Dopamine is produced in several areas of the brain, including the substantia nigra. Dopamine is also a neurohormone released by the hypothalamus. Its main function as a hormone is to inhibit the release of prolactin from the anterior lobe of the pituitary.
Dopamine can be supplied as a medication that acts on the sympathetic nervous system, producing effects such as increased heart rate and blood pressure. However, because dopamine cannot cross the blood-brain barrier, dopamine given as a drug does not directly affect the central nervous system. To increase the amount of dopamine in the brains of patients with diseases such as Parkinson's disease and dopa-responsive dystonia, L-DOPA (levodopa), which is the precursor of dopamine, can be given because it can cross the blood-brain barrier.
Chuck Norris the only WMD in Iraq, say U.S. troops
Hollywood action star Chuck Norris (L) poses for a picture with Staff Sergeant Amy Forsythe during his visit to Camp Falluja, 50 km (30 miles) west of Baghdad in this November 2, 2006 file photo. Norris, known for his martial arts prowess and tough-guy image, has become a cult figure among the U.S. military in Iraq and an unlikely hero for some in Iraq's security forces. Picture taken November 2, 2006. REUTERS/Handout/U.S. military/Files
A cardboard shrine is dedicated to Hollywood action star Chuck Norris is seen at the U.S. military helicopter hub in Baghdad March 7, 2008 REUTERS/Mohammed Abbas
Mon Mar 10, 2008 12:24pm EDT
By Mohammed Abbas
FALLUJA, Iraq (Reuters) - Hollywood action star Chuck Norris, known for his martial arts prowess and tough-guy image, has become a cult figure among the U.S. military in Iraq and an unlikely hero for some in Iraq's security forces.
A small cardboard shrine is dedicated to Norris at a U.S. military helicopter hub in Baghdad, and comments lauding the manliness and virility of the actor have been left on toilet walls across Iraq and even in neighboring Kuwait, soldiers say.
"The fastest way to a man's heart is with Chuck Norris's fist," reads one message at the shrine, which consists of a signed photo of the actor surrounded by similar statements.
"Chuck Norris puts the laughter in manslaughter," reads one and "Chuck Norris divides by zero," reads another.
Known as Chuck Norris "facts", the claims have already become an Internet phenomenon, and scores are featured on www.chucknorrisfacts.com, including "Superman wears Chuck Norris pyjamas", and "There are no weapons of mass destruction in Iraq, Chuck Norris lives in Oklahoma".
The actor has visited Iraq several times and was made an honorary Marine last year. Some 20 U.S. military personnel and support staff spoken to by Reuters could recite at least one Norris "fact", despite many having not visited the Web site.
U.S. troops in Iraq say his support for them and Norris' invincible image has made him their idol and insist the exaggerated and satirical claims are not meant to mock him.
"The jokes all add to his legend. They're not derogatory. He's an icon," said Sergeant Joe Lindsay at a base in Falluja in Iraq's Western Anbar province, which Norris has visited.
AN IRAQI NORRIS
Bearded and muscled, Norris shot to fame fighting kung fu legend Bruce Lee in the 1972 film The Way of the Dragon, and later films show him devastating groups of men with one kick.
"Norris visited Iraq when violence was its worst and other celebrities were skittish. He's one of the guys," U.S. military public affairs officer Specialist Mark Braden said in Baghdad.
"The Marines love him. He's like a mythical legend," Staff Sergeant Amy Forsythe in Falluja said.
Soldiers cited many reasons for his appeal. Some appreciated his films and fighting ability -- Norris is a martial arts guru, and many of his films have military themes.
Others said the masculine and plainly dressed actor was an antidote to the preening and moisturized metrosexual male.
Some praised his Christian and political values. The actor recently endorsed Republican Party presidential hopeful Mike Huckabee, though in the spirit of the Norris "facts", Marines argued it was Huckabee who endorsed Norris.
"He's helped us a lot. The appeal is also his martial arts, and sheer physical presence ... I don't think I go a day without hearing a Norris joke," said Corporal Ricardo Jones in Falluja.
Norris' appeal is not restricted to U.S. troops either. At an Iraqi police graduation ceremony in Falluja, graduates called out for their "Chuck Norris" to pose with them for photos.
"Truthfully, I didn't know who he was. I asked the Americans, and they said he was a great fighter, and that's why they named me after him. They showed me a video, and it's true, he's a great fighter" said police trainer Mohammed Rasheed.
With his handle-bar moustache, Rasheed has a vague resemblance to Norris.
Another police trainer said Chuck Norris was a role model for the police in Falluja, which until 2007 was an al Qaeda stronghold and the scene of fierce battles with security forces.
"I've seen his videos, he's a hero. He saves the city, he protects women and children and he fights crime wherever it is. We should all be like Chuck Norris," Khaled Hussein said.
A salesman takes a rifle off the rack to show a customer at the Cabela's store in Fort Worth, Texas, March 7, 2008. The American affinity for guns may puzzle foreigners who link high ownership rates and liberal gun ownership laws to the 84 gun deaths and 34 gun homicides that occur in the United States each day and wonder why gun control is not an issue in the U.S. Presidential election. The owners are not just urban criminals and drug dealers. There are hunters and home security advocates, and then there are the gun collectors. REUTERS/Jessica Rinaldi
A customer holds a hand gun at the Cabela's store in Fort Worth, Texas, March 7, 2008. REUTERS/Jessica Rinaldi
Gun collector Lynn Kartchner takes aim with an AK-47 assault rifle at his gun shop in Douglas, Arizona, February 29, 2008. REUTERS/Tim Gaynor
A customer browses for guns at the Cabela's store in Fort Worth, Texas March 7, 2008. REUTERS/Jessica Rinaldi
Customers look at the trophy mounts shot by hunters in Africa displayed at the Cabela's store in Fort Worth, Texas, March 7, 2008. REUTERS/Jessica Rinaldi
A customer browses for guns at the Cabela's store in Fort Worth, Texas, March 7, 2008. REUTERS/Jessica Rinaldi
Cabela's salesman Larry Allen shows a customer a gun at the Cabela's store in Fort Worth, Texas, March 7, 2008. REUTERS/Jessica Rinaldi
Guns are put up for sale at the Cabela's store in Fort Worth, Texas, March 7, 2008. REUTERS/Jessica Rinaldi
By Tim Gaynor Wed Mar 12, 2008 8:51am EDT
DOUGLAS, Arizona (Reuters) - An odd contraption in retired firefighter Alex Black's cluttered garage looks a bit like the hand winch at the top of a well. In fact, it is a machinegun.
Turning the shiny brass handle spat out a withering hail of bullets that transformed modern warfare.
"You march in to battle in straight lines against this, and nobody comes back," said Black, standing beside the hefty, carriage-mounted Colt Gatling Gun, which he restored over the course of a decade.
Black, who lives in this sleepy ranching town on the Arizona-Mexico border, is one of millions of gun collectors in the United States, where authorities estimate that there are more than 200 million firearms held in private hands in a country of 300 million people.
The American affinity for guns may puzzle foreigners who link high ownership rates and liberal gun ownership laws to the 84 gun deaths and 34 gun homicides that occur in the United States each day and wonder why gun control is not an issue in the U.S. presidential election.
The owners are not just urban criminals and drug dealers. There are hunters and home security advocates, and then there are the gun collectors.
"People are 'Oh, you collect guns, you must be bad.' That's nonsense. Gun collectors aren't criminals, they are nobody to be frightened of," says Black, one of several hobby collectors in this small Arizona town.
"I love machinery, and I love history, and history was written with firearms," he said. "They were probably the most spectacular things ever built."
Aside from the rare 1895 machinegun, similar to ones used by Teddy Roosevelt in the Spanish-American War in Cuba, the soft-spoken retiree has a large selection of antique military weapons from the 19th and 20th centuries at his home.
The arsenal of revolvers, semi-automatic pistols, rifles and carbines spans conflicts from the American Civil War right up to World War Two, and all the guns are legally held.
A LOT LIKE GOLF
Black's friend Lynn Kartchner is another self-described "gun nut" who lives in Douglas. He has a private arsenal of around 100 handguns, shotguns and rifles of all sorts which he uses for everything from hunting prairie dogs and rabbits to target shooting.
"The richer the golfer, the more clubs he owns," he told Reuters at a Sunday morning pistol shoot at the Douglas Rifle & Pistol Club, where he can usually count on meeting up with a number of like-minded enthusiasts.
"You have a golf club for every angle and range, whether you're lying in the grass or lying in the sand trap. It's the same with gun nuts," he said.
When he is out hunting, he carries a small .22 caliber pistol in his pocket in case he stumbles upon a coyote or a jack rabbit. He has shotguns of various gauges to shoot springing quail or wild duck, and rifles to pop off prairie dogs over an afternoon in the countryside with a case of beer.
For target shooting he has everything from small bore target pistols to powerful .45 caliber revolvers for quick-draw cowboy shoots, to semi-automatic assault rifles and heavy caliber sniper rifles for precision tournaments.
"It's a humongous gun," he says of one of one of his favorites, an antique Winchester rifle. "It's been putting bullets one on top of the other since 1935. At 100 meters you can hit a golf ball with every shot."
SOURCE OF POWER
Kartchner and Black say they take care to keep their weapons secure in locked gun safes and secure rooms to prevent accidents and thefts.
Both are firm believers in the individual right to bear arms to protect themselves and their families, and have a wide variety of firearms which they say are for self defense. The U.S. Supreme Court begins examining that right on March 18. (For a story on the Supreme Court case click on http://www.reuters.com/article/newsOne/idUSN0722998120080311 .)
Black, in his late sixties, has handguns including a historic Colt 1911 model semiautomatic pistol to protect his home, and says that, while he hopes he never has to shoot anyone, would not hesitate to do so if threatened.
"I like to be self sufficient, I don't want to be a slave to anybody, it's not going to happen," he says.
Kartchner has meticulously prepared the defense of his home.
He keeps a semi-automatic shotgun loaded with buck shot and heavy lead slugs behind the bedroom door, and a high-powered AR-15 assault rifle loaded in the next room.
"Guns are for projecting force," he says matter of factly, distinguishing firearms from other collectibles.
"Mao Zedong said 'power grows from the barrel of a gun,' and indeed it does."
Pain [of Others] May Be Pleasurable for Some Bullies
Brain scans of subjects with conduct disorder show activity in the ventral striatum -- the brain's pleasure center -- when shown images of people getting hurt. (University of Chicago)
Aggressive Behavior May Feel Rewarding for Some Bullies
By RADHA CHITALE ABC News Medical Unit Nov. 7, 2008
There may be some truth to the notion that bullies make other people feel bad to make themselves feel better.
A new study published in the journal Biological Psychology used fMRI scans to compare brain activity in eight unusually aggressive 16- to 18-year-old males to those of eight normal adolescent males while they watched videos of people getting hurt.
While both groups showed activity in the brain's pain centers, the brains of aggressive males, those with conduct disorder, also showed activity in the brain's pleasure centers, suggesting that they may have been enjoying what they were seeing. Normal males showed no such activity.
"It just dumbfounded us," said Dr. Benjamin Lahey, co-author of the study and professor of epidemiology and psychiatry at the University of Chicago.
Lahey said he expected an emotionally indifferent response to pain from subjects with conduct disorder, a mental disorder characterized by aggressive, destructive or harmful behavior towards other people and animals and can include theft, substance abuse and sexual promiscuity, according to the American Academy of Child and Adolescent Psychiatry.
Instead, fMRI scans showed a strong but highly atypical emotional response.
Different Strokes
It turns out that the brain circuitry in people with conduct disorder is different from a neurotypical person's when it comes to pain.
In the control subjects, fMRI scans showed that the amygdala -- the part of the brain responsible for processing emotional reactions -- activated at the same time as the prefrontal cortex, which is involved in self regulation and, in this case, for holding emotions in check.
Co-activation suggested that activity in the amygdala and the prefrontal cortex is linked when shown something painful. In other words, when normal people see someone getting hurt, they respond with negative emotions.
"But in kids with conduct disorder, that connection isn't there," Lahey said.
Instead, the kids with conduct disorder showed brain activity in the amygdala and the ventral striatum, which is the area of the brain associated with pleasure and rewards, which include food, sex and drug use.
Instead of responding with negative emotions, these children respond positively, suggesting they may be excited and enjoy seeing someone get hurt, Lahey said.
On top of that, subjects with conduct disorder showed no activity in the prefrontal cortex, which could have controlled those pleasurable emotions. The study results suggest that young people with conduct disorder enjoy seeing others in pain and lack the ability to control potentially inappropriate emotions.
"They're not only indifferent to the pain, they love it -- maybe," Lahey said. "They're responding to others being hurt, but in a way that's self-reinforcing."
While the study proposed an exciting new hypothesis about how young people with conduct disorder may respond to certain stimuli, experts caution that it may not be appropriate to extrapolate the results to the garden-variety bully roaming elementary and junior high school hallways.
"CD at a young age is associated with very poor psychosocial outcomes," said Dr. Paul Sagerman, assistant professor of pediatrics at Wake Forest University School of Medicine in Winston-Salem, N.C.
These outcomes include poor relationships, incarceration, depression and suicide.
And conduct disorder is not very common, affecting 1 to 4 percent of 9- to 17-year-olds in the United States, according to the U.S. Department of Health and Human Services. The disorder is also far more common among boys than girls.
Bully for You
Sagerman, who was not associated with the study, pointed out that bullying typically peaks in young adolescence, between the sixth and eighth grades, and may serve to impress peers.
Using aggressiveness to gain something tangible such as social approval versus personal reward is an important distinction between a regular bully and someone with conduct disorder. Indeed, aggressiveness can be channeled constructively to allow a neurotypical person to excel later in life, in business or athletics, for example.
Although the study is not large enough to draw firm conclusions, it does lead to some new hypotheses and questions.
"The question is what's the chicken and what's the egg?" Sagerman said.
Is bullying a learned behavior, creating pathways in the brain that lead to conduct disorder, or is conduct disorder inherent and results in aggressive behavior?
"If parts of the brain are stimulated by an act of pain, can you make that jump and say maybe they'll go out and replicate that pain ... because that stimulates their brain? That, theoretically, makes sense," Sagerman said.
Though it's too expensive at this point, Sagerman pointed out that fMRI could be a useful technique to detect if certain areas in the brain are active when young children begin to show aggressive behavior.
For example, if a young child were to develop a habit of hitting other children, and a brain scan showed no activity in the prefrontal cortex when he or she saw someone in pain but the ventral striatum showed activity, that could indicate the child may develop conduct disorder in the future.
Early intervention and therapy may help reprogram the brain circuitry in a way that could help prevent conduct disorder, or at least keep it under control.
But if this is indeed possible, researchers have yet to devise the best therapies to deal with conduct disorder. And they could have their work cut out for them.
"If we confirm this," Chicago's Lahey said, "people who develop these therapies are going to be scratching their heads for a while."
Bullying tendency wired in brain Bullies' brains may be hardwired to have sadistic tendencies, US imaging research suggests. 7 November 2008 http://news.bbc.co.uk/2/hi/health/7714072.stm
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