Brain development and plasticity
Early brain development:
A hectic first few weeks
- Within a week of conception 150 cells (blastocyst) attach to the uterine
wall
- Inner cell forms an embryonic disk comprising of three germ cells
Endoderm – later becomes organ
Mesoderm – later becomes bones and muscles
Ectoderm - later becomes the nervous system and skin
1. During weeks 2 and 3 part of the ectoderm begins to fold and form a
neural tube
Human nervous system forms when the embryo is 2 weeks
2. Neural tube sins under the skin and develops into the hindbrain,
midbrain and forebrain
3. The rest becomes the spinal cord
4. The fluid filled cavity within the neural tube becomes the central
canal and 4 ventricles containing CFS (cerebrospinal fluid).
Maturation of the brain
Growth and development of neurons
- Cells of the neural tube proliferate and migrate outwards
- During migration neurons differentiate to take their final form
- Axons myelinate and synapses are formed
Proliferation – the production of new cells / neurons in the brain occur
early in life.
The cells lining the ventricles divide
, Some cell becomes stem cells then continue to divide
Others remain and become neurons or glia, some migrate to other locations
Migration
Movement of primitive neurons and glia towards the final destination
Chemicals (immunoglobin and chemokines) guide cells to their destination
Differentiation and synaptogenesis
Neurons differentiate and develop an axon and dendrites.
Axons grow before dendrites either while the neuron is migrating towards its
destination or once it has reached target
This differentiates neurons from other cells in the body
Synaptogenesis
Final stage of neural development – formation of synapses between neurons
Neurons are constantly forming new connections and discarding old ones, but
it slows later in the lifetime
Myelination – allow rapid transmission
Glial cells produce myelin – In humans myelin forms first in spinal cord before
forming in brain (forebrain is last)
Why is forebrain last to be myelinated? – related to reduced executive
function in adolescence.
Myelination begins during prenatal period an continues into adulthood.
Cell bodies in periphery make up the grey matter
Myelinated axons form white matter
Early brain development:
A hectic first few weeks
- Within a week of conception 150 cells (blastocyst) attach to the uterine
wall
- Inner cell forms an embryonic disk comprising of three germ cells
Endoderm – later becomes organ
Mesoderm – later becomes bones and muscles
Ectoderm - later becomes the nervous system and skin
1. During weeks 2 and 3 part of the ectoderm begins to fold and form a
neural tube
Human nervous system forms when the embryo is 2 weeks
2. Neural tube sins under the skin and develops into the hindbrain,
midbrain and forebrain
3. The rest becomes the spinal cord
4. The fluid filled cavity within the neural tube becomes the central
canal and 4 ventricles containing CFS (cerebrospinal fluid).
Maturation of the brain
Growth and development of neurons
- Cells of the neural tube proliferate and migrate outwards
- During migration neurons differentiate to take their final form
- Axons myelinate and synapses are formed
Proliferation – the production of new cells / neurons in the brain occur
early in life.
The cells lining the ventricles divide
, Some cell becomes stem cells then continue to divide
Others remain and become neurons or glia, some migrate to other locations
Migration
Movement of primitive neurons and glia towards the final destination
Chemicals (immunoglobin and chemokines) guide cells to their destination
Differentiation and synaptogenesis
Neurons differentiate and develop an axon and dendrites.
Axons grow before dendrites either while the neuron is migrating towards its
destination or once it has reached target
This differentiates neurons from other cells in the body
Synaptogenesis
Final stage of neural development – formation of synapses between neurons
Neurons are constantly forming new connections and discarding old ones, but
it slows later in the lifetime
Myelination – allow rapid transmission
Glial cells produce myelin – In humans myelin forms first in spinal cord before
forming in brain (forebrain is last)
Why is forebrain last to be myelinated? – related to reduced executive
function in adolescence.
Myelination begins during prenatal period an continues into adulthood.
Cell bodies in periphery make up the grey matter
Myelinated axons form white matter
