BRAIN

It looks monotonous, slightly like the shell of a walnut, which fooled anatomists for hundreds of years. Until World War I came along, they had no idea each region of the cortex was highly specialized, with sections for speech, for vision, for memory. World War I was the first major conflict where large numbers of combatants encountered shrapnel, and where medical know-how allowed them to survive their injuries. Some of these injuries penetrated only to the periphery of the brain, destroying tiny regions of cortex while leaving everything else intact. Enough soldiers were hurt that scientists could study in detail the injuries and the truly strange behaviors that resulted. Horribly confirming their findings during World War II, scientists eventually were able to make a complete structure-function map of the brain—and see how it had changed over the eons.