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Valaczkai Réka
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Main steps of brain development
The human brain is a complex structure which undergoes many changes from its
formation in the embryonic phase till its full development in late adolescence. In this
essay/presentation I would like to introduce the major steps of this process.
It all starts with the formation of the neural tube in the embryo. The ectoderm of the
trilaminar layer starts to fold inwards, forming the neural groove. It closes and hence the
neural tube is created. Some parts of the neural crest remain behind developing into the
sensory dorsal root ganglia in the spinal cord. At one end of the neural tube cells divide more
rapidly and this part becomes the brain later. Neurons cannot divide freely in contrast to glia
cells, therefore proliferation zones are needed along the neural tube where neuroblasts and
glioblasts produce new neurons and glial cells. From these zones cells migrates to their final
place with the help of radial glia cells. After they reached their destination they start forming
connections and synapses with each other and other parts of the body.
In the formation of the brain three ventricles develop first. The prosencephalon
divides into the telencephalon (later it gives the cerebrum and basal ganglia) and the
diencephalon (developing into the thalamus and hypothalamus). The former grows the
quickest enclosing the latter. The majority of the brain develops from this region. The
mesencephalon , also known as midbrain, regulates the body temperature and processes
information from vision and hearing. The rhombencephalon, composed of the
metencephalon (becoming the pons and cerebellum) and the myelencephalon (forming the
medulla oblongata), connects the brain with the spinal cord. From its first, straight form the
brain reaches its curved appearance with three flexures through its development.
This sums up the most intense period , though the brain continues its development
until adolescence forming and creating new connections.