Figure 8.

Annualized rate of cortical expansion at different ages. Maps above show different views of the cerebral cortex and the color codes for the estimated rate of expansion (warm colors) or contraction (blue). Note that in some areas of the cortex of 4–6 year olds, the cortical surface is expanding at a rate above 3.5% per year. In older children expansion decelerates and gives way to modest levels of surface area contraction. Measured in the PING sample and described in ²⁵.