Stanford scientists discover the human brain may actually be two separate organs

New Stanford Medicine research has uncovered that the human brain comprises two separate, independently evolved organs, according to a recent announcement. This groundbreaking study reveals that the brain comprises a primitive component governing essential functions like heartbeats and breathing and a distinct, evolved system responsible for human abilities such as creativity, mathematics, and contemplation of our origins.

The discovery's implications extend to laboratory research, as scientists have long struggled to cultivate specific brain cells in the lab. This obstacle has impeded investigations into diseases impacting the brain stem, such as spinal muscular atrophy and amyotrophic lateral sclerosis. The key to this breakthrough lies in understanding the brain's embryonic development, where researchers discovered the hindbrain follows a distinct developmental pathway, running parallel to the formation of other brain regions rather than branching off from them.

By applying this knowledge, the team successfully guided human pluripotent stem cells to transform into functional hindbrain motor neurons for the first time. This achievement sheds light on the brain's evolutionary history, as the study found this two-organ pattern persisting in various species, including chickens, zebrafish, and acorn worms. Remarkably, even jellyfish, which separated from humans approximately 600-700 million years ago, possess two separate nervous systems, one at each end of their body.

Professor Loh explains that evolution initially created two neural systems and later integrated them spatially within the brain, a design that, while efficient, necessitates this unique structure. The researchers' findings offer fresh insights into studying brain stem diseases and could revolutionize our understanding of the brain's intricate organization.