How do scientists unravel the secrets of love? By looking at the brains of prairie voles while they woo each other and have sex, obviously.

Neuroscientists from Emory University have managed to “crack the neural code” of love by finding the specific brain connection that makes the brain’s reward system pump with lots of juicy feel-good chemicals, such as oxytocin and dopamine, when voles are romantically bonding. They even managed to artificially stimulate this network using light, effectively making the voles fall in love. Whether this is can be considered true love, however, remains to be answered.

In the study, published yesterday in the journal Nature, the researchers used a probe entering the vole’s brain to “listen in” on their neural communication while they were socializing, huddling up, and bonding in the run-up to sex.

This pinpointed the “love circuit” in the brain. They found that bonding rhythmically excites the area of the brain involved in decision-making, the prefrontal cortex, and the brain’s reward HQ, the nucleus accumbens.

"It is remarkable there are neural signatures of a predisposition to begin huddling with the partner,” Larry Young, co-author of the study and director of the Conte Center, said in a statement. “Similar variation in corticostriatal communication could underlie individual differences in social competencies in psychiatric disorders in humans, and enhancing that communication could improve social function in disorders such as autism."

Using optogenetics, a technique that inserts genes that code for light-sensitive proteins, creating a bundle of neurons that respond to light, to stimulate this particular network in the brain and observed the animals being considerably more keen on bonding with fellow voles.

"It is amazing to think we could influence social bonding by stimulating this brain circuit with a remotely controlled light implanted into the brain," added co-lead author Zack Johnson.

You might be wondering: why voles? And, no, it’s not because "vole" is an anagram of "love" (though points to you if you noticed that). Scientists actually use this North American species a fair amount in studies looking at love, sex, and animal behavior because they are monogamous, meaning they mate for life and share nests with their partners.

"Prairie voles were critical to our team's findings because studying pair bonding in humans has been traditionally difficult," explains Dr Elizabeth Amadei, a co-lead author on the research. "As humans, we know the feelings we get when we view images of our romantic partners, but, until now, we haven't known how the brain's reward system works to lead to those feelings and to the voles' pair bonding."

The researchers think their results could be applied to improving social skills and abilities of those with impaired social function.