Answer to Question #118833 in Evolution for Jennifer

Question

What are the observable changes take place in the brain of a 5-week old (human) embryo and a boy who is two years old.

Answer 1

At the five-week developmental stage, the embryo has a brain in the form of five brain vesicles: telencephalon, diencephalon, mesencephalon, metencephalon and myelencephalon. While a two-year-old child has fully formed brain formations, it is natural that there are certain exceptions which are the number of synapses, their deformation, and synaptic plasticity as a whole. That is, a two-year-old child, unlike a five-week embryo, has cerebral hemispheres, hippocampus, fornix, basal ganglia, choroid plexus and many other structures formed. At the same time, the brain has clearly visible gyri and sulci.