Our research suggests that evolution took two existing neural systems and pushed them together spatially.
The human brain consists of two ancient nervous systems cleverly packaged together — a more primitive part that regulates our hearts’ beating, our breathing and other functions, and another that makes us distinctly human, capable of poetry, mathematics and wondering about our own origins.
We’ve shown for the first time that the front of the brain arises from a totally different progenitor cell than the back of the brain.
The adult brain has three main regions: the forebrain, midbrain and hindbrain. The forebrain handles higher-level thinking — language, consciousness and abstract reasoning. In contrast, the hindbrain, located at the back of the skull and often called the brain stem, controls essential, automatic functions that keep us alive: breathing, sleeping, and regulating our heartbeat and hunger urges. The hindbrain neurons also control the muscles of the face, tongue and throat, which affect speech and swallowing.
Even 500 million years ago, there were these separate neural systems, which now almost operate as one, which is very cool.
https://med.stanford.edu/news/all-news/2026/09/two-separate-brains.html