For example , between the ages 2 and 6 , the brain increases from 70 % of its adult weight to 90 % .
In this phase there is significant synaptic growth and myelination of neural fibers in the brain , especially within the frontal lobes .
Between the ages 2 and 6 , the brain increases from 70 % of brain 's adult weight to 90 % .
In this phase there is significant synaptic growth and myelination of neural fibers in the brain , especially within the frontal lobes .