The fine art of brain development
Perhaps the grandest sculpture of all, the human brain, is shaped by a combination of these basic processes—an early “building up” of the brain’s bulk, followed by a “roughing out” of the major brain regions, and later, a meticulous refinement of the detail that imparts its unique functions.
Sculpting a brain—or indeed, an entire nervous system—takes a lot more than a hammer and chisel, requiring at least one half of the entire human genome. The end product, a grayish-pink, 3-pound gelatinous mass, may be the most complex structure in the known universe— containing at least 100 billion nerve cells (neurons) and one trillion support cells (glia), which can make at least one quadrillion connections between them. The perhaps hundreds of different chemicals (neurotransmitters) that relay information between these neurons further increase the complexity.
It’s no wonder that many questions about how the brain develops—both normally and abnormally—remain unanswered. How is the incredible diversity of brain cells and connections generated from our finite genome? How do the maturing neurons know where to go and which neighbors to “hook up” with? And how do events during development affect the brain’s ability later in life to acquire and store new information through rewiring (plasticity)?
Using a range of animal models from fly to mouse, Vanderbilt researchers across a number of disciplines are probing the many mysteries of brain development and are providing insights into how it may go awry in neurological disease.
“Normal brain development is a staggeringly beautiful and wondrous thing,” says Kendal Broadie, Ph.D., Stevenson Professor of Neurobiology and professor of Biological Sciences and Pharmacology at Vanderbilt University. “It gives rise to this structure that’s beyond our comprehension—a structure that allows you to see, think, run and sing.”
This remarkable structure begins to emerge from a single layer of neural stem cells lining a tube in the early embryo at around the third to fourth week of gestation in humans.