Brain vesicles are the bulge-like enlargements of the early development of the

neural tube In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural folds become elevated, ...

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

s, which eventually give rise to the

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

. Vesicle formation begins shortly after the rostral closure of the neural tube, at about embryonic day 9.0 in mice, or the fourth and fifth gestational week in

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

s. In zebrafish and

chicken The chicken (''Gallus gallus domesticus'') is a domesticated subspecies of the red junglefowl (''Gallus gallus''), originally native to Southeast Asia. It was first domesticated around 8,000 years ago and is now one of the most common and w ...

embryos, brain vesicles form by about 24 hours and 48 hours post- conception, respectively. Initially there are three primary brain vesicles: prosencephalon (i.e.

forebrain In the anatomy of the brain of vertebrates, the forebrain or prosencephalon is the rostral (forward-most) portion of the brain. The forebrain controls body temperature, reproductive functions, eating, sleeping, and the display of emotions. Ve ...

), mesencephalon (i.e. midbrain) and rhombencephalon (i.e. hindbrain). These develop into five secondary brain vesicles – the prosencephalon is subdivided into the telencephalon and diencephalon, and the rhombencephalon into the

metencephalon The metencephalon is the embryonic part of the hindbrain that differentiates into the pons and the cerebellum. It contains a portion of the fourth ventricle and the trigeminal nerve (CN V), abducens nerve (CN VI), facial nerve (CN VII), an ...

and myelencephalon. During these early vesicle stages, the walls of the neural tube contain neural stem cells in a region called the neuroepithelium or ventricular zone. These neural stem cells divide rapidly, driving growth of the early brain, but later, these stem cells begin to generate

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

s through the process of neurogenesis.

References

{{Reflist Embryology of nervous system

See also

References