Published on SDB CoRe: Jan 17 2012
Morphogenic Movements: Neurulation
Morphogenesis: Cell Movements
Ectoderm-derived: Nervous System
Stage of Development: Embryo
Scanning electron microscopy of a transverse section of a 1-day chick embryo undergoing neural fold convergence. Neurulation is the process through which the neural ectoderm or neural plate forms the neural tube (NT). The NT forms the brain and spinal cord of vertebrates. In chick, neural plate bending is initiated at the future midbrain level and progresses both rostrally and caudally along the neural axis simultaneously. As the neural plate bends, its lateral edges rise, forming the elevating neural folds. Neural folds converge and fuse at the midline, forming the NT. This process, called primary neurulation, characterizes the anterior portion of the chick embryo. In the posterior portion of the chick embryo, the NT forms by secondary neurulation. In this process, the neural ectoderm condenses to form a solid rod called the medullary cord that then hollows out to form a tube. Despite their different origins, anterior and posterior portions of the NT fuse to form one continuous tube.
Colas, J.F., Schoenwolf, G.C. Towards a cellular and molecular understanding of neurulation. Developmental Dynamics, 2001, 221:117-145.