The making of a human brain remains a mostly mysterious process that races from an embryonic neural tube to more than 100 billion interconnected neurons in the brain of a newborn. To achieve this marvel of biological engineering, the developing fetal brain must grow, on average, at a rate of roughly 250,000 nerve cells per minute throughout the course of a pregnancy.
These nerve cells are often generated far from where they will eventually reside and function in the new brain, a migration that, while much investigated in animal models using chemical or biological tracers, has never been studied directly in humans. Until now.
