Xiaomeng (Mona) Xu, a postdoctoral research fellow at the Warren Alpert Medical School at Brown University and at the Miriam Hospital, responds: You're in the midst of a breakup and feel like a different person. You find yourself spending a lot of time longing for your ex, constantly checking her Facebook updates, and wondering what went wrong. This shift in patterns of thought and behavior may be caused by neural changes that occur after a breakup.
Neuroimaging studies have found that being rejected, even by a stranger, activates many of the same regions in the brain as when experiencing physical pain. In one study, biological anthropologist Helen Fisher of Rutgers University recruited brave participants who held still in a functional MRI scanner while they looked at pictures of the person who had recently dumped them. These participants exhibited increased brain activity in several regions associated with reward, motivation, addiction and obsessive-compulsive disorder, which helps to explain why you might struggle to let go after a romantic relationship ends.