Difference Between Neural Crest and Neural Tube

The key difference between neural crest and neural tube is that neural crest is a fold on the neural plate where the neural and epidermal ectoderms meet while the neural tube is the embryonic precursor to the central nervous system of vertebrates.

Neural crest and neural tube are two structures found in developing vertebrate embryos. Both structures are formed from the ectoderm layer. The neural crest is a group of temporary cells present at the dorsalmost regions of the neural plate. The cells of the neural crest are able to migrate and differentiate into different types of cells. The neural tube is the primitive structure from which the central nervous system develops. In vertebrates, the neural tube runs immediately above the notochord and extends beyond its anterior tip.

CONTENTS

1. Overview and Key Difference
2. What is a Neural Crest 
3. What is a Neural Tube
4. Similarities Between Neural Crest and Neural Tube
5. Side by Side Comparison – Neural Crest vs Neural Tube in Tabular Form
6. Summary

What is a Neural Crest?

The neural crest is the bilaterally paired strips of cells originating at the dorsalmost region of the neural tube. It is unique to vertebrates. And, it originates from the ectoderm. Neural crest cells are multipotent cells. These cells are able to migrate to different locations and differentiate into different cell types. Hence, the fate of neural crest cells depends on where they migrate to and settle. Neural crest cells migrate and differentiate into cells of the neural, skin, teeth, head, adrenal glands, gastrointestinal tract, and within the embryo. Moreover, these cells contribute to the peripheral nervous system. Therefore, the key feature of neural crest is the ability to migrate into other embryonic tissues to form specific neural and non-neural cells.

There are four functional domains of the neural crest. They are cranial (cephalic) neural crest, trunk neural crest, vagal and sacral neural crest and cardiac neural crest.

What is a Neural Tube?

The neural tube is the embryonic precursor to the central nervous system. Hence, all vertebrate embryos have a neural tube prior to the development of the CNS. During the primary neurulation, the neural tube develops as a result of the proliferation, invagination of neural plate cells and pinching off from the surface to form a hollow tube. It eventually becomes a closed cylinder that separates from the surface ectoderm. In the beginning, the neural tube consists of a single layer. Later, the neural tube becomes multilayered. In the head region, the neural tube expands to form the brain. In the trunk region, it expands to form the spinal cord. Thus, the entire central nervous system of vertebrates originates from the neural tube.

When the neural tube does not close properly, neural tube defects happen. Neural defects are birth defects. Spina bifida (a spinal cord defect) and anencephaly (a brain defect) are the two most common neural tube defects. The fetal spinal column doesn’t close completely in spina bifida. Most of the brain and skull do not develop in anencephaly.  Generally, neural tube defects take place in the first month of pregnancy. Hence, they are diagnosed before the infant is born. Neural tube defects can be prevented by getting enough folic acid prior to and during pregnancy.

What are the Similarities Between Neural Crest and Neural Tube?

• Neural crest and neural tube are unique to vertebrates.
• They show ectodermal origin.
• Neural crest originates at the margins of the neural tube.
• Neural crest cells delaminate from the neural tube and migrate extensively.

What is the Difference Between Neural Crest and Neural Tube?

The neural crest is the bilaterally paired strips of cells originating at the dorsalmost region of the neural tube while the neural tube is the embryonic precursor to the central nervous system of vertebrates. So, this is the key difference between neural crest and neural tube. Moreover, the neural crest does not contribute to the formation of CNS while the entire central nervous system of vertebrates originates from the neural tube.

The below infographic summarizes the differences between neural crest and neural tube.

Summary – Neural Crest vs Neural Tube

Both neural crest and neural tube are two embryonic structures of vertebrates. The neural crest is a population of multipotent embryonic cells that are pinched off during the formation of the neural tube. Its cells delaminate from the neural tube and migrate into different places and differentiate into different cell types. On the other hand, the neural tube is the precursor to the central nervous system of vertebrates. Thus, this summarizes the difference between neural crest and neural tube.

Reference:

1. “Neural Crest Development.” Embryology, Available here.
2. Gilbert, Scott. “Formation Of The Neural Tube”. Ncbi.Nlm.Nih.Gov, 2020, Available here.

Image Courtesy:

1. “Neural crest” By NikNaks – File:Neural_Crest.png (Public Domain) via Commons Wikimedia

2. “Gray19 with color” By Derivative of Image:Gray19.png by (presumably) User:The cat – Image:Gray19.png (Public Domain) via Commons Wikimedia