brain development begins a few weeks after conception and is thought to be complete by early adulthood. The basic structure of the brain is laid down primarily during the prenatal period and early childhood, and the formation and refinement of neural networks continues over the long term. The brains’ many functions do not develop at the same time nor do their developmental patterns follow the same time frame. Although basic sensation and perception systems are fully developed by the time children reach kindergarten age, other systems such as those involved in memory, decision making, and emotion continue to develop well into childhood. The foundations of many of these abilities, however, are constructed during the early years.