WASHINGTON — The pain of rejection is more than just a figure of speech.

The regions of the brain that respond to physical pain overlap with those that react to social rejection, according to a study that used brain imaging on people involved in romantic breakups.

“These results give new meaning to the idea that rejection ‘hurts,’ ” wrote psychology professor Ethan Kross of the University of Michigan and his colleagues. Their findings are reported in today’s Proceedings of the National Academy of Sciences.

Co-author Edward Smith of Columbia University said the research shows that psychological or social events can affect regions of the brain that scientists thought were dedicated to physical pain. In a way, we’re saying “it’s not a metaphor,” Smith said in a telephone interview.

The study involved 40 volunteers who went through a romantic break-up in the previous six months and said thinking about it made them feel rejected.

MRI’s were used to study their brains in four situations: When viewing a photo of the ex-partner and thinking about the break-up; when viewing a photo of a friend and thinking of a positive experience; when a device placed on their arm produced a comforting warmth, and when that device caused pain.

Thinking about the loss of a partner, and the burn caused response in the overlapping parts of the brain, the study found.