Inside the brains of rats, a mouse lives…sort of. Photo: Tatiana Bulyonkova/Flickr

Your cells can’t possibly live without you, right? Wrong.

Researchers in Italy tested the boundaries of life existing beyond the death of the individual, specifically, brain cells. Scientists inserted mice neurons into the brains of fetal Wistar rats, a rodent species that lives about three years, considerably longer than the donor mice. As the baby rats grew, the mice neurons integrated themselves in the rats’ brains, while keeping their mouse-like traits. When the rats died at around three years, the mice neurons had survived along with the rat brain cells, though they would have died much sooner if they were still in the mouse’s brain.

So what does this prove, other than scientists can do some really freaky stuff? It tells us something new about how our genes work. Up until this point, researchers believed that our cells had our species’ general lifespan printed in our DNA; that if a common mouse never lives past two years, that neither could its cells. By successfully integrating mouse neurons in a rat’s brain, the researchers proved that the lifespan of our bodies and the lifespan of our cells aren’t as inextricably linked as we previously thought.

Maybe Frankenstein’s monster isn’t such a ridiculous notion after all.