Para su consideración:
EMBRYO
"The cells of the embryo now multiply and begin to take on specific functions. This process is called differentiation. It leads to the various cell types that make up a human being (such as blood cells, kidney cells,
and nerve cells)."
Esto nos dice que las celulas que van a dar origen al cerebro están ahi desde el principio
The Brain During Development
The nervous system develops from embryonic tissue called the ectoderm. The first sign of the developing nervous system is the neural plate that can be seen at about the 16th day of development. Over the next few days, a "trench" is formed in the neural plate - this creates a neural groove.
By the 21st day of development, a neural tube is formed when the edges of the neural groove meet. The rostral (front) part of the neural tubes goes on to develop into the brain and the rest of the neural tube develops into the spinal cord. Neural crest cells become the peripheral nervous system.
At the front end of the neural tube, three major brain areas are formed: the prosencephalon (forebrain), mesencepalon (midbrain) and rhombencephalon (hindbrain). By the 7th week of development, these three areas divide again. This process is called encephalization.
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con dibujito como te gusta Etanol
Esto nos dice que para el dia 21 despues de la gestación el proceso del desarrollo del cerebro ya se inició. y se termina como dije anteriormente en la edad adulta.
AH, y mis fuentes de información son publicaciónes cientificas. No blogsitos ni wikis