Stanford scientists reveal the human brain is TWO separate organs 'cleverly packaged together' by evolution

From the Newshound archive · first published 19 September 2026.

Stanford scientists have found that the hindbrain — a primitive system governing breathing, heartbeat and sleep — followed a distinct evolutionary trajectory from the forebrain and midbrain, which underpin language, consciousness and abstract reasoning. For the first time, the team managed to grow functional human hindbrain motor neurons in a lab dish, unlocking new possibilities for research into devastating diseases. The findings appeared in the journal Nature.

The breakthrough could transform the study of ALS (Lou Gehrig's disease) and spinal muscular atrophy, conditions that have long proved resistant to scientific progress partly because hindbrain cells could not previously be grown in laboratory conditions.

Lead researcher Dr Kyle Loh said scientists had spent decades working from the wrong starting materials — trying to grow hindbrain tissue using forebrain cell types, an approach that was never going to succeed.

The two brain systems may once have existed as entirely separate structures — much like jellyfish, whose bodies contain two distinct nervous systems in separate locations — before merging over hundreds of millions of years of evolution.