The document discusses brain development from conception through adulthood. It notes that the brain begins developing shortly after conception and continues throughout life. During early childhood, the brain undergoes rapid changes in size and myelination as plasticity allows it to learn and adapt. Neglect or abuse can impair proper frontal lobe development. During adolescence, pruning and myelination increase efficiency as the brain matures into adulthood. Both genetics and the environment influence how genes express themselves in the developing brain.