Infant Brain at 3 Weeks of Age cross section
Brain growth in the first year of life is very rapid. The brain uses 60% of the total energy consumed by the infant and nearly triples in size from the time of birth. Brain maturation in the infant shows trends of increasing myelination (formation of the myelin sheath around a nerve fiber) from occipital to frontal lobes, and from central to subcortical white matter (medial to lateral) as the subject ages. The child's brain has basically finished growing by age 2, although cognitive development clearly continues beyond that time.