This video from Harvard University explains how the basic architecture of the brain is constructed through a process beginning early in life and continuing into adulthood. Simpler circuits develop first and more complex brain circuits build on these later. Genes provide the basic blueprint, but experiences influence how, or whether genes are expressed. Together, they shape the quality of brain architecture and establish either a sturdy, or a fragile foundation for all future learning, health, and behaviour. Plasticity, or the ability for the brain to reorganise and adapt, is greatest in the first years of life and decreases with age.