Running to Their Fates: Neural Crest and Placode Migratory Behavior and Cell Fate Decisions.

Neural crest cells are among the most migratory cells in the vertebrate embryo. They initially arise within the forming neural tube, the precursor to the brain and spinal cord, but then migrate away by undergoing an epithelial-to-mesenchymal transition (EMT). Different neural crest populations exist along the body axis that differ in their flavor of EMT, migratory pathways, and cell types into which they differentiate. In the head region, neural crest cells interact with ectodermal placodal cells, another migratory cell type unique to vertebrates, that form sensory structures of the head. Here, we focus on select neural crest and placodal populations, highlighting how their region-specific migrations may be linked to cell fate choices and discuss how neural crest-placode interactions influence each other's behavior and derivative formation.