Like many around the world, the lab of Professor Mriganka Sur in The Picower Institute for Learning and Memory at MIT has embraced the young technology of cerebral organoids, or ‘minibrains,’ for studying human brain development in health and disease. By making a surprising finding about a common practice in the process of growing the complex tissue cultures, the lab has produced both new guidance that can make the technology better, and also new insight into the important roles a prevalent enzyme takes in natural brain development.