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Conception
Pregnancy has begun -
Neurulation
A group of cells in the embryo thicken to form the neural plate. This plate folds to form the neural tube. The cells within this tube (ventricular zone) will become the brain and spinal cord while the cells on the outside will become the other parts of the nervous system. The tube begins as a three-vesicle structure (prosencephalon, mesencephalon, rhombencephalon) and will develop into a five-vesicle structure. These vesicles will develop into the regions of the brain and the spinal cord. -
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Proliferation
Proliferation is the process in which the cells in the ventricular zone proliferate, or multiply at extreme rates. As these cells multiply they create the marginal zone comprised of axons and dendrites. In this stage the cells over multiply and create more neurons than in a mature adult brain. -
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Cell Migration
During cell migration, newly created cells move from in to out (radial migration), from the ventricular zone through the intermediate zone to reach wherever the outer edges of the developing brain are at that time. So the innermost layers develop first then the outer. After 25 weeks all six layers of the cerebral cortex are formed. -
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Myelination
Myelination begins during the fifth month after conception and will continue for some parts of the brain all the way until adulthood. In this process, the axons of neurons are wrapped in fatty cells. This allows for a better conduction of the electrical signal within a neuron. This means the signals are more accurate and transmitted quicker. -
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Synaptogenesis
This is the start of the formation of synapses, the linking of two neuron cells typically between the axons and dendrites. This is not the peak of generation as this often occurs in the first year after birth. The peak changes for each region of the brain. During synaptogenesis, there is an overproduction in order for pruning to occur. -
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Cell Differentiation
Once the neurons migrate to the correct places they begin to either differentiate into a mature neuron or go through apoptosis. If a cell is differentiating into a mature neuron then it will develop axons and dendrites through growth cones on the end of the axons. About half of the neurons won't differentiate into mature neurons and will rather be disposed of. -
Birth
The human baby is born -
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Peak synaptogenesis of visual cortex
This is the peak formation of synapses within the visual cortex of the brain. The period in time in which the peak is found affects the plasticity. -
Start of synapse pruning in the visual cortex
Synapse pruning is essential for the development of the brain. It is what defines intellect. This helps to sharpen the brain's connections and responses. -
First Birthday
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Peak synaptogensis of prefrontal cortex
This is the peak formation of synapses within the prefrontal cortex. -
Second Birthday
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Sources
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3722610/#:~:text=In%20general%2C%20brain%20development%20begins,continues%20over%20the%20long%20term.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2989000/#:~:text=Human%20brain%20development%20is%20a,adolescence%2C%20arguably%20throughout%20the%20lifespan.
https://www.sciencedirect.com/topics/psychology/myelination#:~:text=Myelination%20is%20formation%20of%20the,to%20allow%20for%20improved%20conduction. -
Sources 2
https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/synaptic-pruning#:~:text=Two%20important%20processes%20(synaptic%20pruning,excitatory%20and%20inhibitory%20synaptic%20connections.
https://www.ncbi.nlm.nih.gov/books/NBK28151/#:~:text=In%20humans%2C%20the%20motor%20roots,the%20second%20year%20of%20life. -
Start of synapse pruning in the prefrontal cortex
Synapse pruning is essential for the development of the brain. It is what defines intellect. This helps to sharpen the brain's connections and responses.