A NEW METHOD FOR GROWING BRAIN CELLS. “Before it grows in one of Lancaster’s dishes, a brain organoid begins as a single skin cell taken from an adult. With the right biochemical prodding, that cell can be turned into an induced pluripotent stem cell (the kind that can mature into one of several types of cells) and then into a neuron. This makes it possible to do things that were impossible before. Now scientists can directly see how networks of living human brain cells develop and function, and how they’re affected by various drug compounds or genetic modifications. And because these mini-brains can be grown from a specific person’s cells, organoids could serve as unprecedentedly accurate models for a wide range of diseases. What goes wrong, for example, in neurons derived directly from someone with Alzheimer’s disease?”