Breaking up is hard to do, but it seems the brain may have a mechanism to help get over an ex. Researchers studying prairie voles say the rodents, which form monogamous relationships, experience a burst of the pleasure hormone dopamine in their brain when seeking and reuniting with their partner. However, after being separated for a lengthy period, they no longer experience such a surge. “We tend to think of it as ‘getting over a breakup’ because these voles can actually form a new bond after this change in dopamine dynamics – something they can’t do while the bond is still intact,” said Dr Zoe Donaldson, a behavioural neuroscientist at CU Boulder and senior author of the work. Writing in the journal Current Biology, the team describe how they carried out a series of experiments in which voles had to press levers to access either their mate or an unknown vole located on the other side of a see-through door. The team found the voles had a greater release of dopamine in their brain when pressing levers and opening doors to meet their mate than when meeting the novel vole. They also huddled more with their mate on meeting, and experienced a greater rise in dopamine while doing so. Donaldson said: “We think the difference is tied to knowing you are about to reunite with a partner and reflects that it is more rewarding to reunite with a partner than go hang out with a vole they don’t know.” However, these differences in dopamine levels were no longer present after they separated pairs of voles for four weeks – a considerable period in the lifetime of the rodents. Differences in huddling behaviour also decreased. The researchers say the findings suggest a devaluation of the bond between pairs of voles, rather than that they have forgotten each other. Donaldson said the study could have a number of implications should research show the findings also apply to humans. “First, if that dopamine signal really is crucial for helping to cement and maintain human bonds, it means that doing things that help keep that signal strong have important implications for relationship satisfaction,” she said. Donaldson added the work could also be pertinent to people who had difficulty moving on after a bereavement. “It is possible that, for these people, their partner dopamine signal isn’t adapting after loss, essentially stalling their processing of the loss,” she said. “A larger goal of my research is to identify ways to help those with prolonged grief disorder by identifying the biological changes that help them integrate a loss and re-engage with life.”