The neural plate is a key developmental structure that serves as the basis for the nervous system. Cranial to the primitive node of the embryonic primitive streak, ectodermal tissue thickens and flattens to become the neural plate. The region anterior to the primitive node can be generally referred to as the neural plate. Cells take on a columnar appearance in the process as they continue to lengthen and narrow. The ends of the neural plate, known as the neural folds, push the ends of the plate up and together, folding into the neural tube, a structure critical to brain and spinal cord development. This process as a whole is termed primary neurulation. Signaling proteins are also important in neural plate development, and aid in differentiating the tissue destined to become the neural plate. Examples of such proteins include bone morphogenetic proteins and cadherins. Expression of these proteins is essential to neural plate folding and subsequent neural tube formation. Involvement in primary neurulation Generally divided into four, the process of primary neurulation involves the neural plate in the first three steps. The formation and folding of the neural plate is the first step in primary neurulation. This is followed by the refinement and growth of neural plate cells. The third step of primary neurulation does not involve the neural plate per se, but rather the edges of the neural plate, which come together, turning the plate into the start of the neural tube. With the neural plate having folded into a tube, the neural folds come together to complete the fusion of the neural tube. This process is illustrated in the figure to the right, where the neural plate is shown in purple. The lime green marks the edges of the neural plate, which become the neural folds, involved in the folding of the plate to create the neural tube. The figure demonstrates the development of the neural plate into the neural tube, which is where the neural crest cells are derived from as well. In primary neurulation, the layer of ectoderm divides into three sets of cells: the neural tube (future brain and spinal cord), epidermis (skin), and neural crest cells (connects epidermis and neural tube and will migrate to make neurons, glia, and skin cell pigmentation). Development During the stage of neural plate formation the embryo consists of three cell layers: the ectoderm that eventually forms the skin and