How to Know You’re in Love? Brain Scans Tell All
Study Shows Certain Brain Regions Are Activated by Thoughts of Love
By Bill Hendrick
WebMD Health News
Reviewed by Laura J. Martin, MD
couple holding hands on couch

Jan. 4, 2011 -- Romantic love lights up the same brain regions of lovers, whether they’re heterosexual or homosexual or male or female, a new study indicates.

Pictures from functional magnetic resonance imaging scans (fMRIs) show similar activity in cortical and sub-cortical brain regions when lovers, regardless of gender or sexual orientation, see images of their romantic partners, according to researchers at University College London.

These regions are known to be rich in dopaminergic activity. And dopamine, the scientists point out, is the so-called “feel good” neurotransmitter.

Serotonin is thought to be important in regulating emotional relationships as well as in bonding between individuals.

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Brain Regions Light Up

Semir Zeki, a professor in the University College London’s Wellcome Trust Center for Neuroimaging, and John Romaya, a senior programmer, scanned the brains of 24 volunteers as they viewed pictures of their romantic partners.

The participants also looked at pictures of friends of the same sex as their lovers, but to whom they were not attracted.

While some brain regions showed increased activity when lovers viewed images of romantic partners, others shut down, such as parts of the temporal, parietal, and frontal cortex, which are thought to be important in judgment.

That finding lends credence to the adage that “love is blind,” says Zeki.

Half of the volunteers were males, half females, and six of each sex were homosexual and the other six heterosexual. And all told the researchers they were passionately in love with their partners.

The participants ranged in age from 19 to 47, and relationship lengths ranged from four months to 23 years.

All were asked to rate their feelings toward their romantic partners before and again after scanning, and to declare their sexual orientation in groups ranging from exclusively heterosexual to exclusively homosexual.
Visual Impact

“Passionate romantic love is commonly triggered by a visual input and is an all-consuming and disorienting state,” Zeki says in a news release. “Previous studies have demonstrated that despite the complexity of this emotion, the brain patterns triggered when viewing the face of someone you’re in love with are limited to only a few, though richly-connected brain regions.”

Zeki says the study was influenced by a reading of world literature about love, including works by Shakespeare, Plato, and Dante. Their writings describe similar sentiments whether in the context of opposite sex or same sex relationships.

All volunteers provided six to eight picture portraits of their lovers and also portraits of other friends of the same sex about two weeks prior to undergoing their fMRI scans.

The study is published in the journal PLoS One.