Brain Rules

I was reading John Medina's book 'Brain Rules', and I found a very interesting description of development. At about 2 years old, there is an explosion of neural growth (in the brain) and then a process of pruning begins. Just like pruning the branches of a tree.

But that was not the most interesting part. There is a second explosion of brain growth and a second period of pruning. When does this occur you ask? Puberty!

There is a common, antecdotal knowledge that people with Down syndrome decline after puberty. Why?? Is it hormones? Is it pruning?

Wow? Do people w/ DS miss the explosion? and then just get the pruning. Could this be possible?

Dr. Medina also describes how verbal centers in the brain can look different and can be wired differently in different locations. Small, focused areas do better on verbal tests. Wide, spread out areas will perform poorly on verbal tests. I wonder what verbal centers look like in Down syndrome? I can guess.