In general terms, describe brain development in middle childhood

What will be an ideal response?

Gray matter
The frontal lobe, which manages executive functions, reaches maximal thickness at ages 11 to 12, and thins out over the next decade.
There are gains in gray matter density in some areas, but the overall pattern involves reduction of gray matter.
These changes are at least partly guided by genes.
White matter
Increases linearly throughout childhood and adolescence.
Primary areas of growth include pathways connecting lower brain centers (basal ganglia and thalamus) to the frontal lobe.
Thought to increase the ability of the frontal cortex to regulate behavior.