How to make a brain: new experiments challenge existing picture

A new study suggests that two types of precursor cells are required to build the brain, challenging a decades-long theory that a single type of starter cell gives rise to the complex organ. The research finds that one type of precursor cell forms the hindbrain, while another generates the forebrain and midbrain. Not all researchers are convinced by this conclusion, but the work has drawn broad praise for one aspect: the authors found an efficient way to coax stem cells to grow into hindbrain motor-neuron cells, which could aid research into conditions that affect these cells, such as amyotrophic lateral sclerosis (ALS).