February 12, 2009

Love May Not Be A Matter Of The Heart

According to Bianca Acevedo, a New York neuroscientist, love is in the head and not the heart.

Acevedo is part a new field in science that seeks to biologically explain love, and so far they have found that love is mostly understood through hormones, genetics, and brain images, according to a report from the Associated Press.

"It has a biological basis. We know some of the key players," said Larry Young of the Yerkes National Primate Research Center, where he searches for clues as to what goes on in the minds of those who love.

Acevedo, who works on a team at the Albert Einstein College of Medicine, believes there are four areas of the brain that form the love circuit; the ventral tegmental area (VTA), the nucleus accumbens, the ventral pallidum and raphe nucleus.

The VTA is believed to be a key reward system in the brain.

The team saw the teardrop-shaped VTA light up when people newly in love were tested under a functional magnetic resonance imaging machine and were shown pictures of their darling.

The same thing occurred in people who had been together for more than 20 years.

"These are cells that make dopamine and send it to different brain regions," said Helen Fisher of Rutgers University. "This part of the system becomes activated because you're trying to win life's greatest prize - a mating partner."

According to Fisher, love works 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."

Acevedo acknowledges that love's link to addiction sounds horrible. 

"Love is supposed to be something wonderful and grand, but it has its reasons. The reason I think is to keep us together," she told the Associated Press.

To study the idea, the researchers observed the brains of those recently heartbroken and found activity in the nucleus accumbens, which are strongly linked to addiction.

"The brokenhearted show more evidence of what I'll call craving," said Lucy Brown, a neuroscientist. "Similar to craving the drug cocaine."

The team also studied couples who had been married nearly 20 years and still participated in "lovey-dovey" actions such as holding hands.  Researchers discovered that the ventral pallidum and raphe nucleus both lit up along with the VTA.

According to Fisher, the ventral pallidum is linked to attachment and hormones that decrease stress while the raphe nucleus secretes serotonin which calms people.

The combination of those areas in action causes "a feeling of nothing wrong," said Brown.

The researchers hope their studies could eventually lead to medicines that help troubled relationships, and possibly treat social-interaction conditions like autism.

Elaine Hatfield, psychology professor at the University of Hawaii, believes the brain research is promising, but cautions that the findings need to be combined with work from traditional psychologists.

Brain researchers are limited in how much they can test the human brain, so they have turned to testing on the prairie vole, a mouse-like creature that is among the 5 percent of mammals that bond for life.

The researchers began blocking a key bonding hormone, oxytocin, in female prairie voles to see if they would stop bonding.  After blocking the oxytocin receptors, the female prairie voles did not bond with the males.

The researchers found that vasopressin is the bonding hormone in males.  The team took meadow voles, a promiscuous relative of the prairie vole, and put vasopressin receptors into their brains.

The meadow voles soon began bonding with females.

The team also discovered a genetic variation that affects human males, causing them not to be monogamous.

The men with the variation had a lower than normal emotional bonding scale, and reported more marital problems, according to Hasse Walum, a Swedish biology researcher.

Researchers believe they now have a better understanding of how to keep the love circuits lit.

According to Young, romantic love can theoretically be stimulated with chemicals, but engaging in hugging, kissing, and intimate contact is the best way to add a spark to your relationship.

"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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