Stanford researchers find brain may be a composite of two organs

A study published in Nature Neuroscience suggests that the brain may actually be a composite organ formed by the fusion of two independent nervous systems. Researchers from Stanford Medicine found that the forebrain and midbrain derive from an anterior neural ectoderm stem cell, while the hindbrain originates from a separate posterior neural ectoderm stem cell.

Previously, it was believed that the entire nervous system developed from a single common neuroectoderm stem cell. However, this research indicates that these two lineages do not overlap. This suggests that the more primitive parts of the brain, which regulate autonomic functions like breathing, and the more recently evolved parts, which enable higher cognitive functions, emerged from distinct precursor cells during embryonic development and later merged into a single integrated organ.