To examine the brain’s functions, researchers have to study a working brain, which means they can’t use cadavers. Invasive studies, in which researchers actually put instruments into the brain, can’t be done in humans, though they can be done occasionally during medically necessary brain surgery. Researchers usually use invasive techniques in animal studies. There are two main types of invasive animal studies:

Because they cannot use such invasive techniques on humans, researchers study human brains in two ways:

Recently, high-tech innovations have made studying human brains easier. Researchers use three types of imaging equipment to study the brain: