The science of romance: Brains have a love circuit

SETH BORENSTEIN, AP Science Writer

WASHINGTON – Like any young woman in love, Bianca

Acevedo has exchanged valentine hearts with her fiance.

But the New York neuroscientist knows better. The

source of love is in the head, not the heart. She's one of

the researchers in a relatively new field focused on

explaining the biology of romantic love. And the unpoetic

explanation is that love mostly can be understood through

brain images, hormones and genetics.

That seems to be the case for the newly in love, the long

in love and the brokenhearted.

"It has a biological basis. We know some of the key

players," said Larry Young of the Yerkes National Primate

Research Center at Emory University in Atlanta. There,

he studies the brains of an unusual monogamous rodent 

to get a better clue about what goes on in the minds of

people in love.

In humans, there are four tiny areas of the brain that

some researchers say form a circuit of love. Acevedo,

who works at the Albert Einstein College of Medicine in

New York, is part of a team that has isolated those

regions with the unromantic names of ventral tegmental

area (VTA), the nucleus accumbens, the ventral pallidum

and raphe nucleus.

The hot spot is the teardrop-shaped VTA. When people

newly in love were put in a functional magnetic resonance

imaging machine and shown pictures of their beloved, the

VTA lit up. Same for people still madly in love after 20

years.

The VTA is part of a key reward system in the brain.

"These are cells that make dopamine and send it to

different brain regions," said Helen Fisher, a researcher

and professor at Rutgers University. "This part of the

system becomes activated because you're trying to

win life's greatest prize -- a mating partner."

One of the research findings isn't so complimentary: Love

works chemically in the brain like a drug addiction.

"Romantic love is an addiction; a wonderful addiction

when it is going well, a horrible one when it is going

poorly," Fisher said. "People kill for love. They die for

love."

The connection to addiction "sounds terrible," Acevedo

acknowledged. "Love is supposed to be something

wonderful and grand, but it has its reasons. The reason I

think is to keep us together."

But sometimes love doesn't keep us together. So the

scientists studied the brains of the recently heartbroken 

and found additional activity in the nucleus accumbens,

which is even more strongly associated with addiction.

"The brokenhearted show more evidence of what I'll call

craving," said Lucy Brown, a neuroscientist also at

Einstein medical college. "Similar to craving the drug

cocaine."

The team's most recent brain scans were aimed at people

married about 20 years who say they are still holding

hands, lovey-dovey as newlyweds, a group that is a

minority of married people. In these men and women, two

more areas of the brain lit up, along with the VTA: the

ventral pallidum and raphe nucleus.

The ventral pallidum is associated with attachment and 

hormones that decrease stress; the raphe nucleus pumps

out serotonin, which "gives you a sense of calm," Fisher

said.

Those areas produce "a feeling of nothing wrong. It's a

lower-level happiness and it's certainly rewarding," Brown

said.

The scientists say they study the brain in love just to

understand how it works, as well as for more potentially

practical uses.

The research could eventually lead to pills based on the

brain hormones which, with therapy, might help troubled

relationships, although there are ethical issues, Young

said. His bonding research is primarily part of a larger

effort aimed at understanding and possibly treating social-

interaction conditions such as autism. And Fisher is

studying brain chemistry that could explain why certain

people are attracted to each other. She's using it as part

of a popular Internet matchmaking service for which she

is the scientific adviser.

While the recent brain research is promising, University of

Hawaii psychology professor Elaine Hatfield cautions that

too much can be made of these studies alone. She said

they need to be meshed with other work from traditional

psychologists.

Brain researchers are limited because there is only so

much they can do to humans without hurting them. That's

where the prairie vole -- a chubby, short-tailed mouselike

creature -- comes in handy. Only 5 percent of mammals

more or less bond for life, but prairie voles do, Young

said.

Scientists studied voles to figure out what makes bonding

possible. In females, the key bonding hormone is

oxytocin, also produced in both voles and humans during

childbirth, Young said. When scientists blocked oxytocin

receptors, the female prairie voles didn't bond.

In males, it's vasopressin. Young put vasopressin

receptors into the brains of meadow voles -- a

promiscuous cousin of the prairie voles -- and "those guys

who should never, ever bond with a female, bonded with a

female."

Researchers also uncovered a genetic variation in a few

male prairie voles that are not monogamous -- and found

it in some human males, too.

Those men with the variation ranked lower on an

emotional bonding scale, reported more marital problems,

and their wives had more concerns about their level of

attachment, said Hasse Walum, a biology researcher in

Sweden. It was a small but noticeable difference, Walum

said.

Scientists figure they now know better how to keep those 

love circuits lit and the chemicals flowing.

Young said that romantic love theoretically can be 

simulated with chemicals, but "if you really want, you

know, to get the relationship spark back, then engage in

the behavior that stimulates the release of these

molecules and allow them to stimulate the emotions," he

said. That would be hugging, kissing, intimate contact.

"My wife tells me that flowers work as well. I don't know

for sure," Young said. "As a scientist it's hard to see how

it stimulates the circuits, but I do know they seem to have

an effect. And the absence of them seems to have an

effect as well."

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