University of Washington researchers are studying how to control the brain. They might have found the answer in an eel-like fish.

In a paper published in May, researchers at UW Medicine, Washington University in St. Louis and other institutions say they have successfully used a protein called parapinopsin to manipulate neurons and certain neurotransmitters.

The protein comes from a lamprey — a type of jawless fish similar to an eel — and researchers hope it could eventually be used to treat mood disorders, addiction, depression and even pain.

While neuroscientists have used light-sensitive proteins from plants and bacteria to experiment with neurons, this was the first time a lamprey has lent its protein to research.

According to UW Medicine, this type of protein can be found in bacteria and humans.

The lamprey protein, the study found, responds well to light instead of chemicals, and is a new way to inhibit neurons (i.e. turn off brain circuits). Parapinopsin was originally discovered by a lab in Japan, according to the UW Bruchas Laboratory.

“This is a perfect rationale for why basic science is so incredibly important,” lead corresponding author and UW professor Michael R. Bruchas said in a news release. “Because of someone’s hard work of basic biological discovery, we have a new tool for medical research.”