A groundbreaking Stanford Medicine study published in Nature Neuroscience reveals that the human brain develops from two distinct progenitor cell populations rather than a single source, effectively acting as a composite of two ancient nervous systems integrated over 550 million years of evolution. By targeting the correct early pathway, scientists successfully cultivated functional hindbrain motor neurons in the laboratory for the first time, offering a vital new model to study devastating neurodegenerative diseases like ALS and SMA.
Two-progenitor brain development discovery
- ▪The two progenitor cell populations exhibit fundamentally different chromatin configurations that package DNA differently, committing them to separate developmental pathways from the start.
- ▪A study led by Stanford Medicine researchers found that the human brain develops from two distinct populations of early progenitor cells rather than a single developmental source.
- ▪During embryonic gastrulation, one progenitor cell population expressing the Otx2 gene forms the forebrain and midbrain, while a separate population expressing the Gbx2 gene forms the hindbrain.
- ▪The Stanford Medicine study, published in Nature Neuroscience on September 18, 2026, was co-first authored by graduate students Carolyn Dundes and Rayyan Jokhai, with associate professor Kyle Loh as senior author.
Ancient dual nervous system evolution
- ▪The dual-system developmental pattern is conserved across approximately 550 million years of evolution and was identified by researchers in chickens, zebrafish, and acorn worms.
- ▪The Stanford Medicine study suggests the human brain is a composite structure formed from two ancient nervous systems that evolved independently and were integrated spatially over evolutionary history.
- ▪Jellyfish, which diverged from the human lineage about 600 to 700 million years ago, possess two separate nervous systems positioned at different ends of their bodies.
Forebrain versus hindbrain functions
- ▪Hindbrain neurons direct muscles in the face, tongue, and throat that are involved in speaking, facial movements, and swallowing.
- ▪The forebrain is responsible for higher-level cognitive functions including language, consciousness, abstract reasoning, and mathematics.
- ▪The hindbrain, located at the base of the skull, controls essential automatic survival processes such as breathing, sleeping, heartbeat regulation, and hunger.
Laboratory neuron cultivation breakthrough
- ▪By recreating the early embryonic developmental stage, the Stanford Medicine researchers successfully guided human pluripotent stem cells to generate functional hindbrain motor neurons in the laboratory.
- ▪Previous laboratory attempts to generate hindbrain neurons likely failed because researchers tried to coax forebrain and midbrain progenitor cells into hindbrain fates, which the study shows is impossible.
- ▪The laboratory-grown hindbrain motor neurons exhibited genuine characteristics including action potential electrical activity and proteins associated with regions controlling facial and swallowing muscles.
Neurological disease research implications
- ▪Dr. Lokesh B of Aster CMI Hospital cautioned that while the Stanford Medicine study is a positive step for neurological research, it will not immediately change clinical diagnosis or treatment in hospitals.
- ▪The ability to cultivate functional hindbrain motor neurons in vitro provides a new model to study neurodegenerative diseases that destroy these cells, such as spinal muscular atrophy and amyotrophic lateral sclerosis.
- ▪The Stanford Medicine research team plans to investigate the developmental origins of the spinal cord and study how spinal muscular atrophy and amyotrophic lateral sclerosis disrupt hindbrain neurons.
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