In addition to diet, stimulation is a major factor in brain growth.
One thing is fairly obvious--diet again. Brain cell function relies on proteins more than any other body tissue!
But there is another new growth factor introduced here after birth--stimulation.
Referents need to be frequently introduced to the child during this window of opportunity because the growth process of a neuron is linked to excitation. This, like diet, is a facilitator of neural growth. A child, well fed and cared for but without stimulation may experience a significant lack of brain growth.
This was dramatically demonstrated in the case of some Rumanian orphans who were adequately fed and clothed but kept relatively isolated in cribs with minimal touching by the caretakers.
In addition to exhibiting atypical behaviors for children their ages, these children revealed through brain scan seriously diminished neural growth.
NOTES: Brain scan of children deprived of touching versus normal