Stanford Medicine researchers led by developmental biologist Kyle Loh have found that the human brain develops from two entirely distinct progenitor cell populations, not one unified origin as textbooks describe. Cells expressing the gene Otx2 give rise to the forebrain and midbrain, which handle language, consciousness and abstract reasoning, while a separate population expressing Gbx2 forms the hindbrain, which controls breathing, heartbeat and sleep. The two populations never overlap, diverging from the earliest stages of embryonic development.
Graduate students Carolyn Dundes and Rayyan Jokhai, co-first authors of the study published in Nature Neuroscience on September 18, also showed the same two-origin pattern holds in chickens, zebrafish and acorn worms, suggesting it is an ancient evolutionary feature rather than a human quirk.
The discovery has an immediate practical payoff: scientists have struggled for decades to grow human hindbrain neurons in the lab. Loh's team says its method finally makes that possible, opening a path to study brainstem diseases such as ALS and spinal muscular atrophy in a petri dish for the first time.