September 22, 2026

@michaelokun

Could the human brain begin as two different developmental programs? And what could this mean for Parkinson’s, Alzheimer’s and ALS? Neural ectoderm progenitors are very early cells that ultimately give rise to the brain. Jokhai, Dundes and colleagues describe in a new paper in Nature Neuroscience evidence challenging the traditional idea that the entire brain emerges from one common neural progenitor. Instead, their mouse lineage-tracing and human pluripotent stem cell experiments support two parallel progenitors; an anterior lineage committed to forebrain/midbrain and a posterior lineage committed to hindbrain. They also generated hindbrain motor neurons that have previously been difficult to produce in the laboratory. Key points: - Two distinct neural ectoderm progenitors emerged during very early development, one destined largely for forebrain/midbrain and the other for hindbrain. - These developmental identities appeared remarkably early and were supported by distinct gene regulatory and chromatin programs. - Mapping the hindbrain pathway enabled the investigators to generate specific human hindbrain motor neurons from pluripotent stem cells, opening an important experimental door for studying diseases affecting these neurons. My take: This paper made me rethink something very basic; perhaps we should not always think of the brain as one organ following one developmental roadmap. Why does this matter for neurodegeneration? Parkinson’s, Alzheimer’s and ALS attack different populations of neurons and different brain regions, and understanding how these cells acquired their identities in the first place may help us understand their selective vulnerability later in life. For ALS the connection is particularly intriguing because degeneration of hindbrain motor neurons contributes to swallowing and other bulbar problems. For Parkinson’s and Alzheimer’s, the implications are more indirect, but this developmental roadmap could help us build better disease models and ultimately generate more precisely specified cells for studying degeneration and testing therapies. https://www.nature.com/articles/s41593-026-02433-7