If you’ve had mononucleosis, chicken pox, or cold sores, then you’ve had the herpes virus. Weird, isn’t it? Anna Rothschild explains in the YouTube channel Gross Science that the virus actually stays in your body for a lifetime and goes through a period where it lies dormant in neurons, hiding from the immune system. It turns out, however, it can even sneak into your brain.

Before you freak out about that, it’s important to note that this happens to about two in a million people. The virus can sneak into your temporal lobe and affect you in peculiar ways. For instance, those who survived the viral attack on the brain had specific damage that didn’t allow them to make normal class categorizations that we normally make on a daily basis, like colors or animals.

Making distinctions between different types of animals are things that we take advantage of. But individuals who have this kind of brain damage are special because they are anomalies.

The specific natures of these cases allow scientists to learn more about how the brain categorizes information. It also allows scientists to learn more about manipulating herpes or finding treatment options for the virus. Even now, scientists are using a genetically altered herpes virus to fight skin cancer.

“In just the past few years, they’ve begun to understand how to lure herpes out of the nervous system. And hopefully one day we’ll be able to stop all eight herpes in their tracks,” Rothschild said in the video.