neural plate

Examples of neural plate in the following topics:

• Development of the Peripheral Nervous System

  • In vertebrates, the first sign of the nervous system is the appearance of a thin strip of cells along the center of the back, called the neural plate.
  • The inner portion of the neural plate (along the midline) is destined to become the central nervous system (CNS), the outer portion the peripheral nervous system (PNS).
  • The sequence of stages from neural plate to neural tube and neural crest is known as neurulation .
  • After gastrulation, neural crest cells are specified at the border of the neural plate and the non-neural ectoderm.
  • During neurulation, the borders of the neural plate, also known as the neural folds, converge at the dorsal midline to form the neural tube.

• Neurulation

  • This strip is called the neural plate, and it is the origin of the entire nervous system.
  • The neural plate folds outwards to form the neural groove.
  • The anterior (ventral or front) part of the neural tube is called the basal plate; the posterior (dorsal or rear) part is called the alar plate.
  • In general, it entails the cells of the neural plate forming a cord-like structure that migrates inside the embryo and hollows to form the tube.
  • Transverse sections that show the progression of the neural plate into the neural tube.

• Development of the Central Nervous System

  • The central nervous system (CNS) develops from a longitudinal groove on the neural plate that forms the rudimentary nervous system.
  • During early development of the vertebrate embryo, a longitudinal groove on the neural plate gradually deepens and the ridges on either side of it (the neural folds) become elevated and ultimately meet, transforming the groove into a closed tube, the ectodermal wall of which forms the rudiment of the nervous system.
  • Development of the neural tube in human embryos (Prentiss-Arey).

• Embryonic Development

  • Primary neurulation begins after the neural plate has formed.
  • The edges of the neural plate start to thicken and lift upward, forming the neural folds.
  • The center of the neural plate remains grounded allowing a U-shaped neural groove to form.
  • A secondary signaling center is then established in the roof plate, the dorsal most structure of the neural tube.
  • Shh secreted from the floor plate creates a gradient along the ventral neural tube.

• Development of Vision

  • The eye develops from the neural tube, the epidermis, and the periocular mesenchyme, which receives contributions from both the neural crest and mesoderm lineages.
  • First, an outpocketing of the neural tube occurs, creating optic vesicles.
  • Development of the optic vesicles starts in the three-week embryo from a progressively deepening groove in the neural plate called the optic sulcus.
  • As this expands, the rostral neuropore (the exit of the brain cavity out of the embryo) closes and the optic sulcus and the neural plate becomes the optic vesicle.
  • The eyes make their appearance before the closure of the anterior end of the neural tube.

• Development of Nervous Tissue

  • In vertebrates, the first sign of the nervous system is the appearance of a thin strip of cells along the center of the back, called the neural plate .
  • The inner portion of the neural plate (along the midline) is destined to become the central nervous system (CNS), the outer portion the peripheral nervous system (PNS).
  • At this point the future CNS appears as a cylindrical structure called the neural tube, whereas the future PNS appears as two strips of tissue called the neural crest, running lengthwise above the neural tube.
  • The sequence of stages from neural plate to neural tube and neural crest is known as neurulation.
  • Induction of neural tissues causes formation of neural precursor cells, called neuroblasts.

• Embryonic Development of the Brain

  • This strip is called the neural plate, and is the origin of the entire nervous system.
  • The neural plate folds outwards to form the neural groove.
  • The anterior (front) part of the neural tube is called the basal plate; the posterior (rear) part is called the alar plate.
  • The basal plate becomes the diencephalon.
  • Shown is the dorsal root ganglion (green ellipsoid regions where cells express neurofilament) and the ventricular zone (red region where cells proliferate) as well as the neural tube with roof and floor plate.

• Glossopharyngeal (IX) Nerve

  • The motor division of the glossopharyngeal nerve is derived from the basal plate of the embryonic medulla oblongata, while the sensory division originates from the cranial neural crest.

• Somite Development

  • In the developing vertebrate embryo, somites are masses of mesoderm that can be found distributed along the two sides of the neural tube.
  • The mesoderm found lateral to the neural tube is called the paraxial mesoderm.
  • It is separate from the chordamesoderm underneath the neural tube.
  • As the primitive streak regresses and the neural folds gather preceding the formation of the neural tube, the paraxial mesoderm divides into blocks called somites.
  • The dermatomes contribute to the skin, fat, and connective tissue of the neck and of the trunk, though most of the skin is derived from the lateral plate mesoderm.

• Fourth Week of Development

  • The fourth week of gestation is characterized by the flexion of the superior portion of the neural tube to create the mesencephalon.
  • Late in the fourth week of gestation, the superior part of the neural tube flexes at the level of the future midbrain, the mesencephalon.
  • The optical vesicle (which will eventually become the optic nerve, retina, and iris) forms at the basal plate of the prosencephalon.