Most of us know how terrible it feels to be in the throes of a breakup. Now scientists know what it looks like, too. Helen Fisher, an anthropologist at Rutgers University, and several neuroscience colleagues found some interesting correlations after scanning the brains of 10 women and five men who were still heartsick over losing a lover.

The investigators positioned each jilted subject in a functional magnetic resonance imaging scanner. When they asked the volunteers to look at a photograph of their former lover and at a neutral picture, they found that the same areas at play in new love — for example, the nucleus accumbens that governs reward — were still active when the forlorn looked at their lost love. But new areas were also activated, including those that regulate obsessive-compulsive thoughts and anger, suggesting a torrent of mixed emotions.

Stress regions also lit up strongly. “Being rejected in love is among the most painful experiences a human being can endure,” Fisher says. She suspects that such brain reactions moderate over time, probably by biological design, perhaps to aid self-preservation. Yet if the individuals are lucky, they will meet someone new, and the biological processes will start all over again.