The scientists also successfully coaxed human pluripotent stem cells to become functional hindbrain motor neurons in the lab.

These lab-grown neurons displayed all the hallmarks of authentic hindbrain cells: they exhibited waves of electrical activity called action potentials and made proteins that identify the segments of the hindbrain that control facial and swallowing muscles.

“Previous attempts to make hindbrain neurons likely tried to coax forebrain and midbrain progenitors into hindbrain cells, which our study shows is not possible,” said Stanford University graduate student Rayyan Jokhai.