NNeurulation begins with the formation of a neural plate, a thickening of the ectoderm caused when cuboidal epithelial cells become columnar. Changes in cell shape and cell adhesion cause the edges of the plate fold and rise, meeting in the midline to form a tube. The cells at the tips of the neural folds come to lie between the neural tube and the overlying epidermis. These cells become the neural crest cells. Both epidermis and neural plate are capable of giving rise to neural crest cells.