A new study finds that miniature brains could revolutionize future testing of drugs and reduce the need for animals to be subjected to testing.

A tiny portion of human brain cells, no bigger than the head of a ballpoint pen represents about a two-month-old brain of a fetus and has spontaneous electrophysiological activity, according to a Guardian report.

The findings, produced by Johns Hopkins University and presented at the American Association for the Advancement of Science conferences, finds that these tiny brains can produce a primitive type of thinking, albeit only mechanical, and his team saw signs of the neurons trying to communicate with each other.

The brains were developed in test tubes back in December 2013. Professor Thomas Hartung, who made the presentation, said that the research team found a way to grow hundreds of uniform brain cultures in one petri dish, all with the same genetic codes.

It’s an important finding because researchers will be able to examine not only how drugs impact the health and function of brain cells, but also how they impact neural activity.

The brains were grown from the skin cells of five donors. They were reprogrammed to become similar to stem cells and then stimulated into brain cells. Then, they were recreated with the conditions of Parkinson’s disease. These mini-brains could help scientists study brain conditions like Parkinson’s and Alzheimer’s, possibly leading to huge breakthroughs down the road.

“Ninety-five percent of drugs that look promising when tested in animal models fail once they are tested in humans at great expense of time and money,” Hartung said in a statement. “While rodent models have been useful, we are not 150-pound rats. And even though we are not balls of cells either, you can often get much better information from these balls of cells than from rodents.”