A bank vole in the Sonian Forest in Brussels, Belgium.

Frank Vassen via Wikimedia Commons

Love and loss are two of the most fundamental human emotions. But why do we grieve when we lose a partner, and why do some struggle more than others to recover?

CU Professor Zoe Donaldson is trying to figure that out, but not by studying people. Instead she is researching a tiny, monogamous rodent: the vole. It may seem outlandish, but Donaldson has cred -- she just landed $1.5 million from the National Institutes of Health for her work.

Donaldson works with a colony of 100 prairie voles. Only 3 to 5 percent of all mammals are monogamous, a category that includes us and voles. Donaldson's team separates bonded pairs and gives the remaining vole a lever to press. As a control, some of the voles are reunited with their partners when they pull the lever, the others will not.

Each vole has a tiny microscope planted in its head. Donaldson can then observe what neurons are firing when a vole presses the lever to see their mate, and which ones go off when the animal realizes there won't be a reunion.

It sounds sad, but Donaldson says her work could be a lifesaver for people paralyzed by grief. When a person is unable to return to a normal routine and lifestyle after losing someone, it's called "complicated grief." Donaldson hopes one day her research will lead to the development of new therapies and medication to help restart a stalled grieving process.