Afterglow. Brain scans are taking some of the mystery out of love and sex.

Caudate-Over-Heels in Love

NEW ORLEANS--Giddy, passionate, mad. When people speak of the early days of romantic love, this state comes across as highly emotional. But a brain-imaging study presented here 11 November at the Society for Neursocience meeting suggests that the brain treats the experience more as a drive or motivation than an emotion. Meanwhile, another study discovered that an orgasm activates mostly the same brain regions in men and women.

College students participating in the study of romance had been with their One True Love for between 2 to 17 months and they displayed all the classic, feverish, delusional symptoms: obsessive thinking about their partners, sleeplessness, euphoria when things are going well. They topped the charts of the standard lab measure of such things, the Passionate Love Scale, which asks how strongly participants agree with statements such as: "Sometimes my body trembles with excitement at the sight of [my partner]."

These lovebirds--seven men and 10 women--then went into a functional magnetic resonance imaging scanner, watched closely by a team including psychologist Arthur Aron of the State University of New York, Stony Brook, neuroscientist Lucy Brown of Albert Einstein College of Medicine in New York City, and anthropologist Helen Fisher of Rutgers University in New Brunswick, New Jersey. The subjects saw pictures of their loved one interspersed with pictures of another familiar but emotionally neutral face. Regions of the brain involved in the motivation and reward system lit up in response to the loved one, including parts of the caudate nucleus and the ventral tegmental area. The men's and women's brain activity patterns were very similar, with an additional area lit up in men that had previously been linked to penile erection.

These results differ from those of a previous study of romantic love, which imaged the brains of people who'd been in relationships for more than 2 years, on average, and found lots of activity in emotional areas such as the insula and anterior cingulate. Fisher's team reexamined their data and found that the subjects in relatively longer-term relationships also activated these emotion centers when viewing their loved ones.

"It's a very thoughtful study," says cognitive neuroscientist John Gabrieli of Stanford University, pointing out that the researchers controlled for many variables that might have made the findings suspect, such as the attractiveness of the comparison faces.

But that's not the end of the romance at this year's meeting. Finally, the classic postcoital question of trashy novels everywhere--"How was it for you, dear?"--has an answer: "The same as it was for you." A brain-imaging study shows that, during orgasm, women's brains have about the same pattern of activity as men's.

Neuroscientist Gert Holstege and colleagues at the University of Groningen, the Netherlands, reported earlier this year the brain regions that glow under a PET scanner when men ejaculate. For the new study, eight female subjects lay in the scanner while their male romantic partners manually provided the necessary stimulation. Four reached orgasm and some did so repeatedly, for a total of eight data points. Compared to clitoral stimulation alone, orgasm caused greater activation in several parts of the brain, including the same reward region tickled by romantic love, the ventral tegmental area. The main difference between the sexes was a deep brain area called the periaqueductal gray. It's also the sine qua non of the female sexual response in cats, rats, and hamsters; if it's damaged, the animals don't assume a mating position. Other than that, the brain activity "is very much the same as during ejaculation in males," says Holstege.

Related sites
The romantic love abstract
The female orgasm abstract
The male orgasm abstract
More about the psychology of love