Simple Circuits Connect First; More Complex Circuits Build On That Foundation Language Higher Cognitive Function Sensory Pathways (Vision, Hearing) Synapses Formed as a Result of Experiences This conceptual graph shows how different sets of skills develop at different times in the brain, and how more complex skills build on the more basic skills that came before. Circuits build on circuits, and skills beget skills. Note that the prenatal period and first year of life are extended in this graph to show more clearly how much growth occurs in this time frame. Note that the rapid proliferation of neural connections is followed by a drop-off – that’s the natural process of pruning, which helps the brain become more efficient by eliminating connections that are not being used. This is critical when we consider the timing of our public investments—the brain is doing its formative building and even pruning at a very young age, even before public school begins. It’s critical for those circuits that are supposed to be built at each stage to be used well and frequently for them to provide a strong foundation for the more complex circuits that come later. Source: Nelson, C.A. (2000). Change and continuity in neurobehavioral development. Infant Behavior and Development, 22, 415–429. FIRST YEAR -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9 10 11 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Birth (Months) (Years) Source: C.A. Nelson (2000)