A groove on the embryo formed by the unfolding of the outer layer of cells and destined to become the nervous system in humans.
A groove on the back of an embryo formed as the neural plate closes to form the neural tube.
A longitudinal indentation that forms on the dorsal surface of the embryonic ectoderm. It is bordered by the neural folds, which merge dorsally to form the neural tube, a cylinder around the groove. Superiorly, the groove forms the ventricles of the brain; inferiorly, it becomes the central canal of the spinal cord.