Ramachandran helped discover the mirror neuron, a type of brain cell that does not work the same way in autistic people. He also figured out how to help people with phantom pain. A person who is missing part of their body, for example a hand, may feel as if the hand is still there. They may feel hot or cold or as if their hand is closed too tight. This is called a phantom limb. They may feel pain in their hand, even though it is not there. Really, it is the brain's sensory cortex making this pain. Ramachandran figured out how to use mirrors to trick the person's brain into thinking that the limb was there and healthy, so it would stop hurting.