Sergiu Pasca at Stanford University has kept a mini-brain alive for two full years. Scientists refer to it as a cerebral organoid. Only about 4 millimeters (0.16 in) in diameter, this small clump of human brain tissue was grown in the lab from stem cells. With the right hormones, researchers can coax the tissue to grow into structures that almost mimic parts of the brain.
The biggest difference between the real deal and these mini counterparts?
The lab-grown brains don’t have blood vessels or white blood cells, and they don’t follow typical neurodevelopment patterns. Instead, they stop maturing at the equivalent of the first trimester of human development. At least that’s the case with cerebral organoid neurons.
There are nonneural cells in the brain called astrocytes that manage to reach full maturity in the lab-grown organoids. Astrocytes are helper cells that create and reduce connections between neurons as needed. They also make connections with blood vessels leading into and out of the brain and play a critical role in sensing injury.
Further study into these brain balls could help unlock the mechanisms behind Lou Gehrig’s disease and several neurodevelopmental disorders