As we reported recently, scientists at Johns Hopkins University have come to a tremendous discovery regarding “mini-brains” that could change how we test drugs in the future — but what are mini-brains and what makes them so useful?

The findings, which were presented at a conference recently found that these tiny brains are capable of neural signals and could allow for testing of drugs without using animals. Professor Thomas Hartung, who led the study, said that they were able to grow hundreds of brain cultures in the same petri dish back in December 2013.

Why the excitement over them? These mini-brains have functioning nervous tissue and could be quite inexpensive — costing just 25 cents each to produce, according to a ScienceAlert.com report.

The mini-brains would be perfect for testing drugs without having to use animals or people for that matter. They could also be used for stem cell experimentation and for neural tissue transplants.

Mini-brains are a bit of a misnomer, as they are not a fully functioning brain. They are quite small, just a third of a millimeter in diameter, and just a tiny bit of living tissue can produce thousands of mini-brains by concentrating the cells and seeding a cell culture, according to the report.

The brain tissue forms just a day after seeding, and after two or three weeks, it develops a neural network. After that, the mini-brains are ready to act as a test bed in the lab.