the reptilian brain at the base, where functions like breathing and heart rate are controlled, the mammalian brain in the middle, which processes sensory input and includes the limbic system responsible for the formation of memories, and the outermost primate brain, which controls complex functions like movement, decision-making, and goal-setting.
Through desire the child discovers his solitude, and through solitude his desire. He depends upon a reliable but ultimately elusive object that can appease but never finally satisfy him.